United States Environmental Research EPA 600 3-79-102
Environmental Protection Laboratory September 1979
Agency Corvallis OR 97330
Research and Development
Management of
Bottom Sediments
Containing Toxic
Substances
Proceedings of the
Fourth U.S.Japan
Experts' Meeting
October 1978
Tokyo, Japan
^JH
EPA/600/3-79/102
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development U S Environmental
Protection Agency have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface m related fields
The nine series are
1 Environmental Healtn Effects Research
2 Environmental Protection Technology
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7 Interagency Energy-Environment Research and Development
8 Special Reports
9 Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series This series
describes research on the effects of pollution on humans plant and animal spe-
cies, and materials Problems are assessed for their long- and short-term mflu-
ences Investigations include formation transport and pathway studies to deter-
mine the fate of pollutants and their effects This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments
This document is available to the public through the National Technical informa-
tion Service, Springfield, Virginia 22161
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MANAGEMENT OF BOTTOM SEDIMENTS CONTAINING TOXIC SUBSTANCES
Proceedings of the Fourth U.S.-Japan Experts' Meeting
October 1978--Tokyo, Japan
edited by
Spencer A. Peterson and Karen K. Randolph
Corvallis Environmental Research Laboratory
Corvallis, Oregon 97330
CORVALLIS ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
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DISCLAIMER
This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
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FOREWORD
Effective regulatory and enforcement actions by the Environmental Pro-
tection Agency would be virtually impossible without sound scientific data on
pollutants and their impact on environmental stability and human health.
Responsibility for building this data base has been assigned to EPA's Office
of Research and Development and its 15 major field installations, one of which
is the Corvallis Environmental Research Laboratory (CERL).
The primary mission of the Corvallis Laboratory is research on the ef-
fects of environmental pollutants on terrestrial, freshwater, and marine
ecosystems; the behavior, effects and control of pollutants in lakes and
streams; and the development of predictive models on the movements of pollu-
tants in the biosphere. In May 1974 the United States-Japan Ministerial
Agreement provided for the exchange of environmental information on several
areas of mutual concern. This report is the compilation of papers presented
at the Fourth U.S.-Japan Experts' Meeting on the Management of Bottom Sedi-
ments Containing Toxic Substances which was held October 30-November 3, 1978
in Tokyo.
Thomas A. Murphy
Director, CERL
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CONTENTS
JAPANESE PAPERS
Dredging and Treatment of Sediments in the Port of Tagonoura
Toji Inada 1
The Improvement of Water Quality at Lake Kasumigaura
by the Dredging of Polluted Sediments
Mineo Matsubara 11
Lake Suwa Water Pollution Control Projects
Akira Sakakibara and Osamu Hayashi 31
Dredging of Polluted Bottom Sediments in the Ibo River
Sadao Kishimoto 65
Pollution Control in Tokyo Bay
Masai Yako and Keitchi Akimoto 91
Release of Nutrients from Lake Sediments
Ken Murakami and Kiyoshi Hasegawa 127
Test Results from Demonstration Dredging and
Spillwater Treatment at Hiro Harbor
Toshihiko Fukushima and Tathuo Yoshida 143
The Contribution of Sediment to Lake Eutrophication
as Determined by Algal Assay
Ryuichi Sudo and Mitsumasa Okada 161
Toxic Material and Nutrients from Contaminated Sediments
Yoshiharu Nakazono and Yasuji Saotome 181
The Filtering Effect of Containment Walls on Supernatant
from Contaminated Dredge Material
Takeshi Monji 207
Accumulation of Mercury by Fish from Contaminated Sediments
R. Hirota, M. Fujiki, Y. Ikegaki and S. Tajima 225
UNITED STATES PAPERS
Approaches for Mitigating the Kepone Contamination
in the Hopewel1/James River Area of Virginia
K. M. Mackenthun, M. W. Brossman, J. A. Kohler, and C. R. Terrell. . .241
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CONTENTS (cont)
PCB Contamination of the Sheboygan River, Indiana Harbor
and Saginaw River and Bay
Karl E. Bremer 261
Developmental Aspects and Current Policies for Restoration and
Protection of Publicly Owned Freshwater Lakes in the United States
Spencer A. Peterson and Robert J. Johnson 289
Sediments and Sediment Disturbance During Dredging
John F. Sustar 311
Bioaccumulation of Toxic Substances from Contaminated Sediments
by Fish and Benthic Organisms
Robert M. Engler 325
Management of Containment Areas to Promote Dewatering and Solidification
C. C. Calhoun, Jr 355
Impacts of Oil Spill and Clean-up on the European Coast: Amoco Cadiz
William P. Davis 371
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DREDGING AND TREATMENT OF SEDIMENTS IN THE PORT OF TAGONOURA
Toji Inada
Chief, Port and Harbor Section, Civil Engineering Division
Shizuoka Prefectural Government, Japan
INTRODUCTION
The paper industry in the Gakunan district near the Port of Tagonoura has
prospered by using the extensive water and forest resources at the foot of Mt.
Fuji. The industry began manufacturing paper about 90 years ago and has
expanded through mechanization and integration of smaller businesses.
After World War II, many enterprises such as Nissan Motor Company,
Toshiba Electric Company, and Asahi Chemical Industry Company, built large
factories in this district. Now there are 1,300 factories producing paper,
pulp, foods, machines and metal merchandise. The opening of the Port of
Tagonoura in 1961 improved cargo transportation. Construction of the man made
port started in 1958. It accomodates 10,000 ton-class ships.
The industrial output in this district is 950 billion yen, of which 47%
is produced by the paper, pulp and paper-processing industry the largest
such group in Japan. The factories use about 2.0 x 106 m3 of water a day.
Sewage drains into the Port of Tagonoura via the Numa River, the Urui River
and the Gakunan drainage basin. Suspended solids (SS) from the sewage accumu-
late on the bottom of the port.
The sewage sludge is called "hedoro" in Japanese. In 1970, 1.2 x 106
metric tons of Hedoro was discharged into the environment. The sludge spread
and interfered with port functions. It produced toxic H2S gas. The odor
became a public nuisance.
The first management effort, in 1971, was to remove the sludge. The plan
was to use self-propelling barges to dump the sludge in the open sea, 320 km
from the Port of Tagonoura. The barge hulls were reinforced and remodeled to
carry sludge.
Before the plan could be activated it was opposed by fishermen and scien-
tists who had attended the World Oceanography Congress, and therefore the plan
had to be changed. On-land treatment was the only alternative.
On-land treatment creates problems on how to dehydrate the sediments and
avoid secondary public nuisances from unpleasant odors, toxic gases produced
by the dehydration process and contamination of groundwater by infiltration of
polluted water. The dry bed of the Fuji river was selected as a treatment
site since it had extensive area available for mass dehydration.
1
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The bottom sediments were first dredged using a cutterless suction dredge
to minimize sediment agitation. Sediments were loaded on a barge and carried
to the mouth of the Fuji River where they were pumped to a dehydration pond
via pipeline.
With this system the first management effort dehydrated 110,000 tons of
sediment at a cost of 820 million yen. Since the capacity of the dehydration
pond had been determined, the second and third mass management effort used a
bigger suction dredge.
The second and third management efforts were implemented from 1972 to
1974. The sediment was dredged by a 5,000 ps suction dredge and carried
directly to the dehydration pond on the dry bed of the Fuji River through a
pipe 6 km long. Natural dehydration then occurred.
The system was continually improved. Steel-covers were installed on the
upper part of the outside of the cutter so the sediment would not be dispersed
through agitation. Fishing nets were used to cover the dredging area to avoid
contamination of the sea. The pipes for carrying sediments were pressure
tested at 15 kg/cm2 which exceeded the maximum pressure of the dredge pump.
Pressure gauges were installed at each kilometer of pipe and readings were
monitored and telephoned to the dredge tender.
A Ca(OH)2 solution of 1,500 ppm was injected into the pipe during transit
to remove H2S. A FeCl3 solution (39%) of 333 ppm was added to adjust the pH
value. A high molecular cohesion agent of 10 ppm was added to accelerate
dehydration. Finally, an aeration tank was installed at the pipe outlet to
remove any remaining H2S gas.
The sediment's water content was about 98% before dehydration and was
reduced to about 80% after natural drying in the dehydration pond. The dehy-
drated sediments were reclaimed after mixing with gravel and cobblestones from
the dry river bed in a ratio of one to one. This was done with a bulldozer.
A total of 1.3 x 106 m3 of sediment was removed by these three management
efforts. During the same period, effluent standards were established to
control the source of wastewater. These standards were raised four times. As
a result, new accumulations of sludge have decreased, however 5.2 x 105 m3 of
sediment still remained in 1975. If the sediment had been left as it was,
pollution would recur. Therefore, a fourth sediment management effort was
scheduled to be implemented by the Public Nuisance Countermeasure Council.
This paper reports on the fourth management effort in the Port of
Tagonoura.
FOURTH MANGEMENT EFFORT
PROPERTIES OF THE SEDIMENT
The properties of the sediment were: muddy sludge, 20.4% average igni-
tion-loss (ash-free dry weight), 70-80% water content, an infinitesimal quan-
-------
tity of heavy-metal, and an average value of 28.5 ppm of PCBs. The PCB con-
tent had been decreased by the more stringent regulation of water quality and
the prohibition on using PCB-containing copy paper as toilet tissue. The PCB
could not be detected by an elution test. Taking all matters into considera-
tion, the plan was to remove only the sediment containing PCB in excess of 10
ppm or with an ignition loss of more than 15%.
PLANNING
Since on-land management was mandatory, the adjacent right fork of the
dry Fuji River and a timber pond in Port Tagonoura were selected as the land-
fill areas. The timber pond was chosen because the sediment could be used as
fill material in a separate project to remodel the pond into a timber depot.
The right folk of the dry river bed was selected for two reasons. First,
reclamation of the sediment in the left fork of the dry river bed had proven
to be safe and effective. Second, a sporting arena to be constructed on the
reclaimed ground of the left fork had gained consideable public favor.
Engineering methods were studied which could do this project inexpensive-
ly, effectively and safely, and without creating any secondary public nuisance
factors.
A big suction dredge and natural dehydration was considered. But, the
system was discarded for the following reasons. First, the right fork of the
river bed was narrower than the left fork and, consequently, limited the space
for dehydration ponds, thus restricting the working hours of the big suction
dredge and lowering the efficiency of the whole system. Second, the dredge
discharge pipe was vulnerable to flood damage since it would have to be in-
stalled across the river. Third, the system carried a risk of polluting water
supplies near the right fork of the dry riverbed. Fourth, the natural dehy-
dration method could not be used in the timber pond area since the pond con-
tained too much water and noxious odors from the sediment would pollute the
residential zone around the pond.
Next, methods of mechanical dehydration instead of natural dehydration
were examined. These methods had been widely used in the wastewater disposal
plants of the paper factories. But, this method was found unsuitable by
experiments which showed that the equipment would be corroded by seawater and
screens broken by materials such as vinyl, wire, blocks of wood, or any earth
and sand carried downstream from large washouts near Mt. Fuji.
METHOD OF TREATMENT
Because of the above problems, a system using rented machinery requiring
little capital investment was adopted. This method picked up highly-polluted
sediments with a grab dredge and added agents to dehydrate and solidify them.
We started to look for processing agents for this system.
Quicklime was first considered because it has been used successfully to
strengthen weak soils. Quicklime absorbs 32% of its weight in water and
quicklime-enforced sludge is stable over time. Results of these experiments
showed that a 72.5% water content in the sediment decreased linearly to 62.2%
-------
10 minutes after the the addition of 5% quicklime and to 5.9% 10 minutes after
the addition of 10% quicklime, and that the addition of 20% quicklime solidi-
fied the sediment enough to make it suitable for reclamation soil.
Although the problem of controlling lime dust and vapor produced by the
reaction was trivial in the laboratory, the problem could not be ignored for
large scale use involving several tons of quicklime. Different approaches
were considered, including mixing with scrapers in enclosed barge and mixing
under an air curtain created by a power blower installed on the barge. No
completely satisfactory perfect answer was found. In addition to this, there
was another problem. Mixing of the quicklime solution had to take place very
rapidly because of the tendency for quicklime to solidify immediately.
As a result of the number and complexity of these problems, quicklime was
discarded as a hardening agent. When selecting the proper agent, the follow-
ing characteristics were considered:
1. The solidifying agent must strengthen the mixed sediment to more
than 1.0 kg/cm2 of uniaxial compression strength (referred to as DCS) so it
can be worked by a swamp bulldozer during reclamation. Although the ordinary
load for a swamp bulldozer is 0.3 kg/cm2, a standard of 1.0 kg/cm2 was adopted
for safety.
2. It must be easily mixed.
3. It should not produce any dust or fumes during mixing.
4. No harmful substance should be detectable and no secondary public
nuisance factors should be created by it.
5. It must be economical.
More than 1500 combinations of 40 kinds of material were tested, includ-
ing solicic acid soda, volcanic ash, cements, plasters, incineration ash, and
some dehydration agents developed by private companies. A combination of 12%
cement, 5% incineration ash and 4% exhaust-gas-desulfurization-plaster (EGDP)
was selected. The following three ingredients - aluminum in the ash (A1203,
50-58%), calcium in the EGDP (CaS04-2H20) and calcium in the cement - dehy-
drate and promote solidification of the high-water content sediments.
Incineration ash can be produced by nearby paper factories. The EGDP
could be obtained from factories at the port. Both of these are waste and can
be purchased inexpensively. Later research determined that good quality
incineration ash to meet environmental standards could not be produced in
sufficient volume. As a result, fly ash cement [referred to as FA (B-type)]
was used instead of incineration ash and it was necessary to increase its
volume to 13% to make the required DCS (Figure 1).
The UCS of the sediment 48 hours after the addition of 4% EGDP and 13% of
various kinds of cements showed good values of 0.8 kg/cm2 for FA (A-type) and
1.12 kg/cm2 for FA (B-type), which are better than the value of 0.68 kg/cm2
for normal Portland cement. Consequently, it was found that including a
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1.5
1.0
UCS
0.5
kg/cm2
o
-o
72 hours after
48 hours after
o 24 hours after
J_
I
1
1
FA (B type) (%)9 10
EG DP 2.7 3.0
surf ace active agent 0.08 0.08
W/C (water cement ratio) 70 70
W/C of the raw sediment
II 12 13 14
4.0 40 40 4.0
0.08 0.08 0.08 0.08
70 70 70 70
15 16
4.5 4.8
008 008
70 70
Figure 1
1.5
UCS
1.0
0.5
kg/cm2
78.01 78.01 78.01 78.01 78OI 78.01 7801 78.01
(surface active agent cement volume X 008%)
Comparison of uniaxial compression strength
(UCS) for various combinations.
72 hours after
O O 48 hours after
O O 24 hours after
O-..
O
p. A, O
1.0
UCS
0.5
F.A. FA. normal processing
BtVDe AtVD Portland agent by
cement Mitsubishi Co.
Figure 2. Strength by annexations of
various kinds of cements.
kg/cm2
OO 72 hours after-
O-O 48 hours after'
O o 24 hours after"
5
EGDP
10
Figure 3. Strength by the annexa-
tion of EGDP.
1.5
UCS
1.0
0.5
kg/fcm2
I
i
72 hours after.
- 48 hours after
O 24 hours after
1.0
UCS
0.5
60 100
water cement ratio
Figure 4. UCS for W/C
i
hours after
ป48 hours after
O- -O24 hours after
kg/cmx| 0.000.040.06008 o.io
surface active agent
(cement volume x %)
Figure 5. UCS for surface active agent.
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suitable quantity of the fly ash solidifys and strengthens sediment which
contains a large quantity of paper sludge (Figure 2). The most effective
mixing ratio of the EGDP was found at 4% (Figure 3).
To add the agents, the cement and EGDP at a 70% water-cement ratio was
mixed with the surface active agent to promote hydration. The water-cement
ratio was selected by considering the efficiency of machinery, reactivity and
dust prevention (Figure 4). Compared to no additive, the UCS was doubled by
the addition of 0.08% surface active agent to the cement's volume (Figure 5).
These experiments showed the combinations of 13% FA (B-type) and 4% EGDP
to the weight of the sediment, and 0.08% surface active agent to the weight of
the cement was the proper combination for this program.
IMPLEMENTATION
Ideally, the methodology works like this: The sediment dredged by a grab
dredge should be carried by a barge to the quay wall, and it should then be
mixed with the processing agents. Next, the mixed sediment should be hauled
by dump trucks to the reclamation site (Figure 6).
The processing volume per day was planned at about 1,100 m3 based on
considerations of economics and efficiency; namely, the holding capacities of
the temporary depots, the mixing plant and the spillwater-processing appara-
tus as well as the impacts on neighboring activities created by the noise,
traffic tieups caused by dump trucks, etc.
The management project in 1977, where sediment was reclaimed only in the
timber pond, was conducted as described below:
Dredging Work
A 6 m3 bucket dredge enabled the management of 1,100 m3 sediment per
8-hour day in a program cycle of dredging, mixing and temporary detention.
Four closed-bottom box type barges with 500 m3 of loading capacity were used.
This allowed for a 20% volume increase after mixing the processing agents into
350 m3 of dredged sediment.
To prevent pollution of nearby areas caused by turbulence and release of
sludge from the grab, control measures were selected carefully. This problem
is most important in management of secondary public nuisance factors. There-
fore, a silt curtain was laid in the sea surrounding the dredging site (Figure
6).
The curtain was made of soft vinyl-covered canvas which could withstand
the range of tides. Steel had been considered as a curtain material but it
was discarded since the height could not be changed at the ebb tide and it
could not be easily moved.
The 50 kg anchors with chain ballasts were installed at the lower end of
the curtain to enable the curtain to conform to the contour of the uneven sea
floor. Since the curtain is lowered as the sea-bottom is deepened by dredg-
ing, seawater inside the curtain cannot flow to the outside.
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DREDGING
MIXING AND LANDING
\mixing plant
n I stock bin for EGDP
6.0 M a grab dredger
a floating
frame
a suspended curtain
iซ200 pipes
injection
equipment
500 M
50kg Anchor with chain ballast
CONVEYANCE AND RECLAIMING
sediment
fence to prevent pollutions
''"
Figure 6. Treatment program.
The shape of the vertical section of the curtain was a trapezoid: 10 m
for the upper part, 18 m for the middle and 28 m for the lower part. Approxi-
mately 500 m3 of sediment was expected to be dredged from each curtain
shrouded site. Two sets of curtains and frames were constantly employed. The
curtain was moved to the next site after dredging was completed at the initial
site. Each curtain was moved only after adding 3 ppm of coagulation agent to
precipitate the suspended solids inside the curtain.
No abnormal signs were observed at observation points around the curtain
during dredging. The curtain effectively prevented pollution. Emission of
the offensive odor of H2S gas was negligible because the dredging was done
during the cool season. Also, hypochlorous acid soda was sprayed for desul-
furization and deodorization. As a result, no air was polluted.
The average dredging time required to load 350 m3 of sediment onto a
barge was 2h hours. This entailed 90 grabs. The efficiency of the grab was
good because the water content of sediment decreased as dredging depth in-
creased.
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Mixing the Sediments with the Processing Agents
The processing agents were mixed in a plant installed behind the quay
wall. The mixing process was mechanized and controlled at a single station.
In the process, EGDP and water were combined to allow a 70% water-cement
ratio. Then cement and activator were weighed and mixed in by a 1-m3 turbo-
mixer. Next, the mixed agents were injected into the sediment while still in
the barge. The time required from weighing to injection was about one minute.
The mixing could be done almost continuously because every batch was removed
by pump after temporary detention in the storage chambers.
Since the water content varied with every batch of dredged sediment, and
since the water-cement ratio affects the DCS, it is necessary to quickly
determine how much cement to add to the mix. The water-cement ratio was
determined from the water-content value measured either by a Kett moisture-
measuring instrument or by comparison with the water content of sediments
gathered in test dredging.
As a result of testing, it was proven feasible to be within 65% of the
average water-cement ratio since the precise value of the latter measurement
was close to the measured value and also since the water content had been
homogenized by the narrowness of the dredging area and by drainage of exces-
sive water from the barge.
Two clamshells were used to mix the sediment with the solidifying agents
on the barge. The mixing took about 2 hours per barge (350 m3). This time
was determined from data on the strength of the mix relative to the frequency
of mixing, as found by experiments and observations at the job site. The
value of the DCS measured at the job site after 48 hours was 0.3~1.0 kg/cm2.
Soft sediments were strengthened by extending the temporary detention time.
The mixed sediment was temporarily detained for 24 hours in the barge,
and again detained for 24 hours after unloading. The sediment was then car-
ried to the reclamation area. The vicinity was free of pollution because the
emission of noxious odors and H2S gas was minimized by the mixing.
After some accidents occurred where the bottom of the barge was damaged
by an unskilled grab operator, it was necessary to reinforce the bottoms of
the barges.
Reclamation Work
Our policy was to avoid exudation of sediments. The open part of the
timber pond was coffered with steel sheet piles, back-filled with fine sand
and covered with vinyl sheets. All the levees of the pond were covered with
vinyl sheets even though they were considered safe.
It was estimated that pollution of groundwater would not occur because:
The bottom of the pond had a good clay layer; no percolation happened in the
experiments; the sediment to be reclaimed was safe because no harmful substan-
ces had been detected in it; and the sediment would be gradually solidified
with chemical agents. To make doubly sure, several wells were sunk around the
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pond and the quality of the underground water was monitored throughout the
reclamation project.
The sediments were pushed out from a side levee using a swamp bulldozer,
because the sediments should settle in the water of the pond. The water
surface was covered with vinyl sheets to prevent the escape of offensive odors
and H2S gas. Some hypochlorous acid soda was sprayed under the sheets to
neutralize odors and gas.
The draining of the wastewater from the pond after treatment was done
concurrently with progress of the reclamation project. A settling pond 5 m by
125 m was built in the pond. About 2.0 ppm of cohesion agent and 500 ppm of
FeCl3 (to ajust the pH value) were injected into the wastewater at the inlet.
The solid materials in the wastewater coagulated and settled in the main pond
and the water was then drained outside the pond after rapid filtration through
a sand bed.
Water quality of the outflow was constantly monitored by measuring trans-
parency. Acceptable values were determined by the correlation of experimental
values of transparency relative to SS and PCB. No elution of PCB was detected
by later analysis. This demonstrated the efficacy of the methods.
Some sediment from the bottom of the timber pond was brought to the
surface during the reclamation. We treated the sediments by mixing 13% ce-
ment, 4% EGDP and 0.08% activator.
The reclaimed ground was soon available as a timber depot because its
firmness had increased from 3.9~13/0 kg/cm2 after only 2 months. Work was
done from March, 1977 to May, 1977 and from October, 1977 to December, 1977,
thus avoiding the production of gases in summer. In this project 15,000 m3 of
sediment was reclaimed in the timber pond at a cost of 790 million yen, of
which 2,160 yen per 1 m3 of sediment was for the cement and chemical agents.
The cost does not include the expenses of bank protection and finishing the
reclaimed ground.
Supervision Plan
This work was supervised under the provision of "A Tentative Guide to the
Management of Sediments" issued by the Director General of the Environmental
Agency of Japan. Basic observation stations were established at the mouth of
the port to monitor seawater quality. A supplementary observation station was
set up to allow estimates of water quality changes at the main observation
station. This permitted stop/proceed decisions on dredging. Also, stations
for monitoring air pollution were established. The Life Environment Division
and the Agriculture and Fishery Division of Shizuoka Prefectural Government
took the observations at these stations.
The observed items and the standards for action are given below. No
abnormal values were observed.
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Station
Observation Items
Frequency
Standard Values
for Action
Basic
pH, DO, COD
SS, Cl
transparency
PCB, Hg
I/day COD not exceeding
8 ppm
" PCB should not be
detected
" Gross Hg 0.0005
ppm
" transparency 7 cm
or more
Supplementary
Outlet of drainage
transparency
PCB
transparency
4/day
I/day
7 cm or more
0.01 ppm
proportional to
the above value
Underground Water
PCB
H2S
I/day
continuous
should not be
detected
should not con-
tinue for 2
hours or more
at 0.2 ppm at 2
points at the
same time
Air
weather conditions
PCB
continuous
2/month
not exceeding 0.5
ug/cm3
Fishes & Shellfish
PCB
not exceeding 3
ppm
CONCLUSION
The result of this sediment management effort was the test which, if
successful, would permit the treatment of the remaining 370,000 m3 of sedi-
ment. The excellent outcome, which created no secondary public nuisance
factors, was a result of the refinement of techniques to prevent seawater
pollution, H2S gas and offensive odors.
If a large depot for temporary detention can be secured or sediments can
be reclaimed on land, it is anticipated that expenses and quantities of cement
and EGDP can be reduced.
REFERENCE
Ichikawa, Takashi. The Management of Sediments of the Port Tagonoura
10
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THE IMPROVEMENT OF WATER QUALITY AT LAKE KASUMIGAURA
BY THE DREDGING OF POLLUTED SEDIMENTS
Mineo Matsubara
Kasumigaura Work Office, Kanto Regional Construction Bureau
Ministry of Construction, Japan
LOCALE
LAKE KASUMIGAURA
Lake Kasumigaura is the second largest lake in Japan (Figure 1). It is
located northeast of the Tokyo metropolitan area at the southeastern end of
Ibaragi Prefecture. It actually consists of three lakes: Nishiura, Kitaura
and Sotonasakaura. Nishiura Lake drains into Lake Sotonasakaura via the
Kitatone River, and Kitaura Lake drains into Lake Sotonasakaura via the Wani
River. Sotonasakaura Lake is connected with the Tone River via the Hitachi
River at a point 18 km from the Pacific Ocean.
Lake Nishiura covers 171 km2 and Lake Kitaura covers 34 km2. The total
area of Lake Kasumigaura, including Lake Sotonasakura and the rivers is about
220 km2. The average depth of the lakes is 4 m. The deepest spot does not
exceed more than 7 m. It is too shallow to maintain high water quality.
The average water level is approximately Y.P 1 m (the average sea water
level + 16 cm). The lake volume is about 800 million. The lake used to be an
inlet of the sea divided by the Kashima plateau. Then the mouth of the inlet
was closed by sand and soil deposited by the Tone River. The water of the
present lake therefore is a mixture of fresh water and sea water.
DRAINAGE BASIN
The area of the Kasumigaura basin is 2169 square kilometers - about 35%
of Ibaragi Prefecture (Figure 2). The basin consists of the hilly country
between 20 and 30 m above sea level and the rice fields extending along the
coastal region of Lake Kasumigaura, except for parts of Mount Tsukuba (876 m
elev.), Mount Ashio (628 m elev.) and Mount Kaba (709 m elev.) which are
located along the reaches of the Sakura and Koise Rivers which flow to Lake
Nishiura.
The average annual rainfall is 1350 mm. This produces an annual water
input of 1.2 x 109 m3 to Lake Kasumigaura. Dividing this volume by the ap-
proximate capacity of the lake yields an annual replacement rate of 1.5 times.
11
-------
40'
30ฐ
130ฐ
135ฐ
140ฐ
Figure 1. The location of Lake Kasumigaura in Japan.
12
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TSUKUBAStudy
and Education
City
SUOHIURA
Kashima
Kashima
Port
Hatachi
River
luice
kGatex
International
Airport
rYOKAICHJฃ/
Figure 2. Lake Kasumigaura and its drainage basin.
13
-------
More than fifty rivers including the Ono, the Sakura, the Koise, the
Sonobe, and the Tomoe flow into Lake Kasumigaura, while only the Hitachi Tone
River (the Kita Tone River and the Hitachi River are generally known as "the
Hitachi Tone River") flows out of this lake. The Hitachi Tone River has a
complicated hydraulic mechanism because the slope of the river bed is gentle.
The water level is affected by that of the Tone River, which is influenced by
tidal levels.
The basin area includes 47 cities, towns and villages in Ibaragi and
Chiba Prefectures. The population of this area is estimated at 720,000.
Agriculture is the biggest industry in the region. This is one of the most
prominent regions in Japan for hog farming and carp rearing.
Large-scale projects undertaken in this area include the Kashima Coastal
Industrial Zone in the eastern part of Kasumigaura and the Tsukuba Study and
Educational Institution in the western region.
At Kasumigaura, the Kasumigaura Development Project is starting to cope
with the increased demand for water by the metropolis. By 1983, when this
project is completed, water resources of 40 m3/S will be developed by utiliz-
ing the 2.6 x 108 m3 available between the water levels of Y.P 1.30 m and Y.P
0 m.
The lake will become a freshwater lake by temporarily employing the
Hitachi River Sluice Gate to prevent tidal intrusion upriver. This sluice
gate, at the juncture of the Hitachi and the Tone Rivers, was completed in
1963.
Thus, since the lake has been resurrected as a storage reservoir, the
maintenance of good water quality is very important.
CONSERVATION OF WATER QUALITY IN LAKE KASUMIGAURA
WATER QUALITY AT THE PRESENT TIME
The water quality standard for Lake Kasumigaura was established in Novem-
ber, 1972 as "type A-(c), COD 3.0 ppm, provisional standard type B, COD 5.0
ppm" for the lakes and marshes in the area of Kasumigaura, Kitaura (including
the Wani River) and the Hitachi Tone River.
The average figures for 1977 water quality, measured at eight places in
Kasumigaura, are given in Table 1. Observation points are indicated in Figure
3. The COD, which is the typical index for water quality of lakes and
marshes, is between 6.0 ppm and 7.9 ppm. This is considerably greater than
the 3.0 ppm which is the standard for Kasumigaura. (Figure 4)
T-N and T-P, which are indices of eutrophication, are 0.77 ppm to 1.25
ppm and 0.04 ppm to 0.08 ppm, respectively. Both of these figures exceed the
general standards of 0.15 ppm T-N and 0.02 ppm T-P.
Past changes in water quality are not well known because the data are
insufficient. However, a deterioration of the water quality has been conspic-
14
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uous since 1968. Eutrophication of the lake has developed rapidly. In the
summer, as water temperature increases, phytoplankton blooms are common. This
algal bloom causes the surface of the lake to look as if green paint were
floating on it. In the summer of 1973, a Microcystis bloom caused the drink-
ing water to smell unpleasant and also killed many fish.
CONSERVATION MEASURES
The Japanese government and the prefectural authority are improving the
water quality of the Kasumigaura basin. They are trying to restore it to
conditions prevailing in 1965 and to set a standard for research and implemen-
tation of this type of project.
General techniques for conservation of water quality are:
(1) Removal of pollutants at the source by regulating drainage.
(2) Removal of pollutants from the river which feeds the lake by con-
structing a treatment pond.
(3) Removal of pollutants from the lake by dredging polluted sediments.
(4) Dilution of the polluted water with clean water.
The best technique or combination of techniques depends on the particular lake
or marsh.
At Kasumigaura the following operations are planned or underway:
(1) Establishment of sewage and storm drainage.
(2) Disposal of livestock wastewater.
(3) Regulation of industrial drainage.
(4) Dredging of polluted sediments from feeder rivers.
(5) Dredging of polluted sediments from Lake Kasumigaura.
(6) Removal of Microcystis aeruginosa.
(7) Introduction of clean water to dilute the polluted water.
(8) Cleanup of Lake Kasumigaura by the inhabitants of the coastal
cities, towns and villages.
DREDGING POLLUTED SEDIMENTS FROM LAKE KASUMIGAURA
Drainage from residential,-industrial, and agricultural activities is the
source of impurities found in the water of Lake Kasumigaura. The bottom
sediment of the lake itself also releases impurities to the water. Therefore,
dredging has been done since 1975 as a water quality improvement measure and
is included in the overall project for cleaning up the river.
18
-------
To eliminate the sediment as a pollution source to Lake Kasumigaura, 1.2
x 106 m3 of sediment must be dredged. About 3.0 x 105 m3 of the total are to
be dredged by 1981 as part of the project for controlling the water sources of
the Kasumigaura. This project in turn is part of the General Development
Project for Kasumigaura.
A special pneumatic pump cutterless suction dredge, the "Kasumi", was
developed for exclusive use on this project. It is designed to prevent excess
turbidity and secondary pollution. The "Kasumi" and another dredge of the
improved type, the "Koryu", have been dredging offshore from the mouth of the
Sakura River at Tsuchiura City (Figure 5). About 4,000 m3 were dredged in
1975, 18,000 m3 in 1976, and 13,000 m3 in 1977. The depth is between 1.4 and
5.7 m after dredging and the thickness of the cut is 0.5 m on the average.
The water content averages 260% and ranges from 140% to 400%. Water content
was computed according to the formula:
w = Ww
Ws
where: w = water content, dry wt. basis
Ww = weight of water
Ws = weight of solids
The dredged mud was pumped by pipeline to the disposal area two kilometers
distant from the dredge, except in 1975 when the mud was transported by barge.
The disposal area will become a park belonging to Tsuchiura City. When the
mud at the disposal area is dry, is will be covered with soil and the facili-
ties for the park will be constructed.
THE TWO DREDGES
The ''Kasumi", a Sludge Dredge with Pot Type Suction Head and Pneumatic Pump,
6_0 m3/H Negative Pressure Suction and Positive Pressure Discharge.
In 1971 the Sectional Committee for Studying the Development of New Types
of Machinery and Methods of Reclamation began meeting. It was part of the
Engineering Management Conference sponsored by the Bureau of Construction,
Kanto District.
To establish a method for dredging the bottom while minimizing the resus-
pension of sediment, the dredge "Kasumi" was constructed. The following
conditions were used to develop the dredge:
(1) The dredge should operate with a higher percentage of mud content
than a hydraulic dredge.
(2) The turbidity caused by dredging should be curtailed as much as
possible.
(3) The dredging cost should be less than the current costs.
These conditions for development led to the utilization of the "air-lift"
(pneumatic) system developed in Italy. The method employs cylindrical pump
bodies pushed into the bottom sediment. Modification of the pneuma system
19
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employs a vacuum inside the pump body to suck bottom sediment in. Compressed
air is then forced into the pump body to push the mud out (Figure 6). This
dredge was constructed with the same specifications as the 200 ps class of
pump dredge regarding draft, clearance and beam so that the clearance of
bridges and the span of bridge piers will pose no problem when it is being
transported. A plan of the sludge dredge is shown in Figure 7 and the speci-
fications are given in Table 2.
TABLE 2. MAIN SPECIFICATIONS OF SLUDGE DREDGE "KASUMI"
Type: Pot type suction head. Negative Pressure Suction and Positive Pressure
Discharge
Capacity: 60 m3/H
Maximum Discharge Distance: 30 m
Maximum Depth of Dredging: 5 m
Dimensions of the Hull: 60mx5mx0.9m (Length x Beam x Draft)
Weight: 78 Tons
Engine: Water-Cooled Type, 4 Cycles, Diesel Engine.
Output Horsepower: 220 PS
Generator: Waterproof, Self-Cool ing, with Self-Excited Generator.
Output Power: Continuous Duty 180 KVA
Voltage: 440 V
The pontoons which provide flotation also house the generator, vacuum
pump, air compressor and winch. The boom with the mud-sucking equipment is
installed at the front of the dredge. A vacuum pump and air compressor are
both used for dredging. The inside of the suction head is alternately pres-
surized and depressurized. An automatic valve causes the sediment to be
sucked up and sent down the discharge pipe. The swing wires at the front and
the anchor wires at the rear are used to move the suction head and are oper-
ated by a winch on the pontoon. Two suction heads are used to provide contin-
uous cycle dredging. The volume of one cycle is 0.5 m3 and the duration
averages 60 seconds. Thus the dredging volume per hour is estimated at 60 m3.
The ship is designed with a maximum height of less than 2 m to clear overhead
obstructions such as piers and bridges.
The discharge distance is only 30 m. This is because the mud is dis-
charged onto a barge where the surface water drains into the river so that
only the mud is transported to the disposal area.
The sediment near cities and towns is denser because the surface is
covered at high water and uncovered at low water. This dredge was developed
and manufactured to be used under these conditions. Its use in Lake
Kasumigaura area required little alteration. Special features are:
(1) Pot type. Mud suction head with pneumatic pump.
21
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(2) Ability to dredge without causing turbidity.
(3) Disposal of water in the river instead of at the disposal area. ^
The results of the performance test are shown in Table 3.
The "Koryu", a Sludge Dredge with Swing Type Suction Head and Pneumatic Pump
100 m3/H Negative Pressure Suction and Positive Pressure Discharge.
Dredging has been done in the Lake Kasumigaura region since 1975. The
dredge "Kasumi" worked from 1975 to 1977. The volume dredged had been esti-
mated at 1.2 x 106 m3. About 3.0 x 105 m3 of this was to be dredged by 1982,
in accordance with the project plan regulated by the Special Law for Securing
Water Sources. The dredge "Kasumi" had too small a capacity to fulfill this
project and it could not dredge the lake bottom smooth; it left the bottom
wavy. Therefore it was necessary to build another dredge.
When a sludge dredge is constructed today, environmental factors weigh
heavily. A dredge of large capacity would not be favored over one of small
capacity which caused less secondary pollution. The requirements for an
environmentally sound dredge are that it dredge the lake bottom flat, that the
suction head or swing does not generate excess turbidity, that the discharge
has a high mud content and that it be capable of discharging the mud for a
long distance through a pipeline. Two kinds of suction heads lend themselves
to this kind of work. One is the pot type, the other the swing type (Figure
8). The "Kasumi" was a pot type. It was decided to build the new dredge as a
swing type.
This office built the sludge dredge "Koryu" in 1977. It was paid for by
the budget of the Construction Machinery Arrangement Expenses. It was de-
signed as both an experimental and operational machine. , The basic
structure of the dredge "Kasumi", built in 1971, was adopted for use on the
"Koryu". The new dredge was equipped with a swing type pneumatic pump suction
head instead of the pot type.
The dredge was completed in March, 1978, and is shown in Figure 9 with
specifications given in Table 4. Following are the improvements over the
"Kasumi" design:
(1) Mud suction mouth of the swing pneumatic pump type.
(2) Mud collection equipment which does not generate turbidity. It has
a drag suction head with grating.
(3) Sonic thickness monitoring equipment.
(4) Spuds, anchors and wires used to move the dredge.
(5) Long discharge distance.
(6) No overall turbidity.
(7) No disposal of effluents.
24 I
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28
-------
TABLE 4. MAIN SPECIFICATIONS OF SLUDGE DREDGE "KORYU"
Type: Swing Type Suction Head. Negative Pressure Sediment Suction and Posi-
tive Pressure Discharge
Capacity: 100 m3/h (Water Content = 66%)
Maximum Discharging Distance: 2000 m
Maximum Dredging Depth: 7 m
Dimension of Hull: Length 25 m x Breadth 8 m x Depth 2.4 m x Draft 1.3m
Weight: 260 Tons
Engine: Water Cooled, 4 Cycle, Diesel
Output Horsepower: 430 PS x 2
Generator: Waterproof, Self-Cooling, with Self-Exciting Generating Equipment
Output Power: Continuous Duty 350 KVA
Voltage: 440 V
To swing the dredge head an hydraulic winch winds anchor-fixed wire ropes
through a sheave which is installed at the end of the dredging ladder. Spuds
are put into the ground alternately to move the dredge while it is working.
With the "Kasumi," the mud was sent to a dumping barge or discharged by a
booster pump. In the new dredge, the sludge is first stirred in a stock tank
installed in the dredge to change the viscosity. It is then sent to a second-
ary hopper. The dust is removed by a vibrating screen installed in the sec-
ondary hopper. The sediment is stirred again and discharged by pump. The
volume of the flowing sediment can be controlled by a valve on the bypass pipe
between the pump and the secondary hopper. Sonic thickness monitoring equip-
ment is installed to check how much bottom sediment is dredged. Because of
local conditions, the maximum height of the dredge while operating is less
than 3.3 m. This dredge is appropriate for work at Kasumigaura because the
water content of the shallow sediments is high.
The results of a short field performance test are given in Table 5.
Although future actual daily operations will probably yield different results,
it is clear that the designed nominal working capacity of 100 cubic meters per
hour at 66% water content will be met. This also meets the planned annual
dredging volume required by the program. From now on both dredges, "Kasumi"
and "Koryu", will be used to dredge the bottom of Lake Kasumigaura.
SEDIMENT DISPOSAL STUDY
About 1.2 million m3 of bottom sediment must be dredged by 1985. In Lake
Kasumigaura, the sediments total 40-50 million cubic meters, according to rod
surveys conducted at 35 points in the lake. The average thickness of the
sediment is about 20 cm. These sediments had values of 11-27% ignition loss,
indicating the presence of many organic substances. Therefore, it will be
necessary to remove most of these sediments. It will be impossible to dispose
of this large quantity of dredged sediment unless we make use of a special
feature of the district. Although it's located on the fringe of the metropol-
itan area, 80% of the land (2200 km2) is agricultural and the sediment can be
disposed of on the farm lands.
29
-------
TABLE 5. PERFORMANCE CAPACITY, SLUDGE DREDGE "KORYU"
No.
1
2
3
4
5
6
7
8
9
Discharge
Volume (rnVhr)
128
110
107
106
108
102
101
97
101
97 - 128
Water
Content (%)
200 - 300%
Tsuchiura City (population 100,000) and Ishioka City (population 40,000)
are located along the Jooban Line of the Japan National Railway at the north-
western part of the lake. The Kashima Coastal Industrial Zone is located
downstream of the rivers, where the existing rice fields are to be reclaimed
for the city.
Disposal techniques are under study to use the sediments for rice produc-
tion and landfill for the city. Experiments are being conducted to compare
rice growth in two kinds of soil, one comprised of sediment, the other the
usual soil. Also underway are experiments to dry the sediment naturally on
land surrounded by a soil embankment where the dredged mud is deposited to a
thickness of 50-150 cm. The water in the mud separates as the sediment set-
tles and consolidates. The water is drained and then permeates underground.
The mud left behind dries in the sun. Low water content mud is used for this
purpose. Following is the result of a survey from February, 1977 to March,
1978. The accumulated thickness of mud was 150 cm and the initial water
content was 60-75%. The final water content was 54-60%. The complicated
influences of weather, water table, and evaporation from the leaves of planted
vegetation on the process of settling and consolidation will be studied.
Officials plan to investigate ways to shorten the disposal period by using
supplementary solidification chemicals.
REFERENCES (titles are in English, the document is printed in Japanese)
Matsubara, Mineo. Reports from the Working Site. Kasen Review No. 22.
Kinoshita, Ken and Tetsuo Kaai. Development of Sludge Dredger of Pneumatic
Pump Type. Kensetsu No Kikaika July 1978.
30
-------
LAKE SUWA WATER POLLUTION CONTROL PROJECTS
Akira Sakakibara, Director
Qsamu Hayashi, Chief, River Development Section
Civil Engineering Management Office for Lake Suwa and Surrounding Region
Nagano Prefecture Department of Civil Engineering, Japan
INTRODUCTION
More than a decade has passed since water pollution in Lake Suwa first
attracted public attention. During this time, eutrophication of the lake has
continued with no significant improvement in water quality. Algae continue to
bloom from summer to fall every year.
In view of the seriousness of the problem, concerned public and private
interests are intensifying their studies to develop drastic measures to purify
the lake water. This is the tenth year of dredging. Partial use of the
basin-wide sewage system will start next year. This paper outlines their
efforts and other research and projects which are one part of the slow but
steady progress being made to improve the water quality of Lake Suwa.
The water pollution control measures being taken in Japanese rivers and
lakes were outlined last year at the Third U.S.-Japan Experts' Meeting on
"Management of Bottom Sediments Containing Toxic Substances" (1). In Kato's
paper (1) the dredging of bottom sludge at Lake Suwa, considered the most
polluted lake in the country, is used to illustrate lake clean-up efforts in
Japan.
BRIEF DESCRIPTION OF THE LAKE SUWA BASIN
Lake Suwa is located in the center of Nagano Prefecture at what is called
the "roof" of the Japanese Archipelago. There are 31 rivers flowing into it,
but only the Tenryu river flows out. The drainage area is 531 km2, the height
above sea level, 759 m, the planned lake area, 13.3 km2, the circumference,
16.2 km, the maximum depth, 6.8 m, and the average depth, 4.0 m. It is also a
major recreational fishery and water resource.
The four cities of Okaya, Suwa, Shimosuwa and Chino are on the periphery
of the lake. These cities (combined population about 170,000) form an import-
ant industrial area producing optical and precision machinery and food prod-
ucts. In recent years, the modernization of lifestyles and expanding industry
have led to water pollution in the lake. The eutrophication of Lake Suwa
currently has reached its peak, with "Aoko" (Microcystis) growing in profusion
in the summer, rapidly covering the lake like a green carpet. To make matters
worse, Aoko creates an offensive odor as it dies and decomposes. The concom-
31
-------
itant "Susumizu phenomenon" (oxygen depletion) adversely affects the lake's
fishery. These factors contribute to the decreasing use of shoreline facili-
ties by tourists and local residents.
Today, the dredging of the polluted sediments and the construction of the
basin-w.ide Lake Suwa sewage system and related public sewage networks are
being carried out to improve the environment of the four peripheral cities and
prevent future contamination of the lake.
WATER POLLUTION OF LAKE SUWA
The periphery of Lake Suwa has been rapidly developing as an industrial
area and tourist resort. The pollution of the lake is a by-product of the
regional development.
Lake Suwa has long been known as a lake with extensive eutrophication but
recent levels have been extreme. The inadequate sewage system around the lake
is a significant cause of pollution, but the sludge which has accumulated on
the bottom for a long time is also a contributing factor. The dominating
impact of the contamination, from whatever source, is the nuisance growth of
Aoko and clouds of mud in the water.
EXTERNAL FACTORS
The rivers and waterways flowing into Lake Suwa carry wastes from indus-
try, homes, agriculture and hot springs. These loads create a BOD amounting
to 14,000 kg per day (Table 1).
TABLE 1. EXOGENOUS BOD LOADS PER DAY (1972), LAKE SUWA
Classification BOD
Industrial waste 10,634 kg
Domestic sewage 3,395 kg
Livestock excretions 209 kg
Raw sewage 137 kg
Agricultural waste
Total 14,375 kg
The advanced stage of eutrophication in the lake is attributed to nutrients
such as nitrogen and phosphorus, which flow in via the river (Table 2).
INTERNAL FACTORS
Nitrogen and phosphorus input to the lake and, accompanied by high BOD,
cause an abnormally fast growth of plankton and aquatic plants. These organ-
isms in turn provide sources of nitrogen and phosphorus for other organisms,
or die and become bottom sediments. The contamination of the lake is accel-
erated by this cyclic pattern.
32
-------
TABLE 2. SOURCES OF NUTRIENT INPUT, LAKE SUWA
Total
Inflow
N load
3,327.3 (100)
(kg/day) (%)
P load
Human wastes
Septic tanks
Sewage disposal facilities
Industrial wastes
Agricultural fertilizers
Mountains and forests
Fishery (feed)
Livestock wastes
Hot spring wastes
Gas well wastes
Rainwater
420
310
546
363.
754
247.
99.
55.
41.
463.
25.
8
3
8
6
3
9
7
(12.
( 9.
(16.
(10.
(22.
( 7.
( 3.
( 1.
( 1.
(13.
( 0.
6)
3)
4)
9)
7)
4)
0)
7)
2)
9)
9)
116
21
47
53
85
4.
8.
24.
5.
7.
0.
2
5
6
3
5
68
(31.
( 5.
(12.
(14.
(22.
( 1.
( 2.
( 6.
( 1.
( 2.
( o.
1)
6)
6)
2)
8)
1)
3)
6)
4)
0)
2)
372.7 (100)
(kg/day) (%)
Note: The calculation of the above table is based on a run-off coefficient
of 70%. The pollution unit employed is borrowed from the 1970
survey of the Ministry of Construction (Example: Human wastes
N = 3.0 g/man-day, P = 0.83 g/man-day).
QUALITATIVE CHANGE IN WATER QUALITY
Studies of Lake Suwa have been conducted by various investigators since
1910. These provide some data on the historical changes in water quality.
Because of differences in sampling and testing methods they may not be di-
rectly comparable, but they show trends of change to the present state.
Figure 1 shows the location of sampling sites in Lake Suwa. Figure 2 repre-
sents the qualitative change in the lake's water quality based on such past
data. Figure 3 shows the change in COD value in the center of the lake during
the past six years. Figure 4 shows the water quality from April to December,
1977. The extremely high COD and SS values in July through September indicate
the vigorous growth of Aoko (Microcystis). Line "A" shows the COD values of
the lake water when filtered through filter paper (equivalent to JIS Class 5C:
0.45 p pore size). The COD values are almost as low as the environmental
standard of 3 ppm. This demonstrates that the water quality can be drastic-
ally improved by removal of the suspended matter, including Microystis.
Figure 5 shows the 1976 investigation of the influences of Aoko and other
phytoplankton on the water quality at four points in the lake. In the figure,
"upper layer" refers to a position 0.5 m below the surface, and "lower layer"
1.0 m above the bottom. The figure shows that the average COD values of the
water after filtering out the Aoko are very close to the environmental stan-
dard. These data were collected in 1976 by the Suwa Health Center in accord-
(text continues on page 41)
33
-------
SHIMOSUWA
LAKE SUWA
1. Center of Lake Suwa
2. 200 m offshore of the mouth of the Miyagawa river
3. West of Hatsushima Island
4. 200 m offshore of the mouth of Osawa river
5. 200 m offshore of the mouth of the Tsukama river
6. 200 m offshore of the mouth of the Obori river
Figure 1. Sampling sites in Lake Suwa.
34
-------
ppm
10
8
6
4
2
0
o>
O
Q.
Dr.
Tan oka
1910
Transparency (winter)
Transparency (summer)
Industrial
Research
Institute
Dr.
Kobayashi
Nagano Research
Institute for Health
and Pollution
Dr.
Yoshimura
M
2.5
2.0
1.5
1.0
0.5
Q
3
CO
i
O
'20
'30 '40
YEAR
'50
'60
'70
Figure 2. Qualitative change in water quality of Lake Suwa (2)
35
-------
in
o
m
I
CD
O
N-
O
Is-
CD
g
Is-
o
Is-
ro
in g
(uudd )
CM
o CD
O)
-l->
c:
CD
O
QJ
.*:
(O
GO
QJ
(O
(O
Z5
cr
i.
QJ
+->
(O
QJ
CD
C
rd
O)
S-
36
-------
ss
ppm
40--20
30-
20 10
IO--5
COD
ppm
15
o-^-o
Woter quality at center of Lake Suwa
April - December,1977
i i i I i i i i r
-COD
SSyx
Environmental limit level
i i i i i
DO i
ppm
PH
ppm
20--10
I5--9
10--8
5--7
4 5 6 7 8 9 10 I
MONTH
12
Note: @ represents the COD values of filtered lake water
(Number 5C filter paper).
Figure 4.
37
-------
200m offshore of mouth of 1he Miyagawa River
Average COD: 6.3 ppm
Average COD of filtered
water: 3.1 ppm
Upper layer
Lower layer
Environmental standard
Upper layer (filtered)
Lower layer (filtered)
JUN AUG OCT
Center of Lake Suwa
DEC
20
15
fO
COD
ppm
5
0
T
T
Average COD: 7.6ppm
Average COD of filtered
water: 3.0 ppm
Upper layer
Lower layer
Environmental standard
Lower layer (filtered)
Upper layer (filtered)
JUN
AUG
OCT
DEC
Figure 5. Effects of phytoplankton on lake water.
38
-------
200m offshore from the mouth of the Osowa River
30
25
20
15
COD
ppm
10
0
Average COD: 11.2 ppm
Average COD of filtered
water-. 3.5 ppm
I
_L
Upper layer
Lower layer
->.0b.0.Environmental standard
^""^ Upper layerlfiltered)
Lower layer (filtered)
JUN AUG
OCT
DEC
Figure 5.
39
-------
West of Hotsushimo Island
Average COD: 10.9 ppm
Average COD of filtered
water: 3.3 ppm
I
Upper layer
Lower layer
Environmental standard
Upper layer (filtered)
Lower layer (filtered)
JUN AUG
OCT DEC
Figure 5.
40
-------
ance with the lake water measurement plan, 6-12/76. Filtering was done with
0.45 u filter paper.
Figure 6 shows the results of water analysis at the center of the lake in
an undredged area and at the west of Hatsushima Island where dredging has been
carried out. These results show that dredging has little effect in lowering
the DO value. Data in Figure 6 were taken from measurements of local water
for public use (Pollution Section, Nagano Prefecture Department of Living
Environment).
BOTTOM MATERIAL
Lake Suwa was divided into 13 1-km square grids. The bottom material in
each of the 13 grids was analyzed in 1976 and 1977. Figure 7 shows the aver-
age results of the analyses.
Currently, there seems to be no explicit standard for the removal of
organic sludge. However, elsewhere in the country, the following criteria
have been used:
Ignition loss 15% or more
COD 20 mg/g or more
Sulfides 1.0 mg/g or more
The above criteria can be used to conclude that there are about 60 cm of
bottom sediment in Lake Suwa.
QUALITATIVE CHANGES IN ALGAL GROWTH
The most obvious impact of the eutrophication of Lake Suwa is the rampant
growth of algae. The pollution of the lake may be characterized by the propa-
gation of Aoko (Microcystis) during the summer time.
Diatoms (Diatomaceae) which generally grow in less eutrophic lakes were
reported in 1918. By 1948 diatoms had increased in kinds and green algae and
blue-green algae (Cyanophyta) were also found. In the 1960s the growth of
Aoko began to attract attention. In the 1970s, its growth increased in inten-
sity.
WATER POLLUTION CONTROL IN LAKE SUWA
The Lake Suwa Pollution Control Measures Investigation Committee was
established in 1965 to study the lake's pollution and immediately took action
to control and eliminate the pollution. The committee conducted investiga-
tions for two years and reported its conclusions in 1968. To control external
sources of pollution it recommended the construction of the Lake Suwa Basin
sewage treatment system to eliminate the influx of polluted water (Figure 8).
To control the endogeneous sources the Committee suggested dredging the or-
ganic sludge deposited on the bottom.
41
-------
UNIT
567
MONTH (1974)
8 9 10 II 12
2 3 Ave.
ppm
25
20
15
10
5
0
COD
ป i i i i i I I
UNDREDGED AREA
West of Hotsushimo
Island (dredged area)
DREDGED AREA
Center of lake
(undredged area)
ppm
15
10
Center of lake
(upper layer)
West of Hatsushima Island
(upper layer)
- West of H. Is.
(lower layer)
HI>
Center of lake
(lower layer)
H 1 1 1 1 r-
ppm
25
20
15
10
5
0
SS
West of H. Is. /
(dredged area) /
j_ i i i
^ Center x.
of lake (un- \
l dredged area))
i i
j i
Figure 6. Results of water analysis at center of lake in an undredged area.
42
-------
o
DO
0.0
0.3
0.6
0.9
1.2
COD 0
SULFIDE 0
IGN. LOSS 13
T-N 2
I
10
0.5
14
3
---- Hi T-N
A - A IGNITION LOSS
p ------ -Q SULFIDES
COD
I
I
20
1.0
15
4
30
1.5
16
5
mg/g
mg/g
Percent
mg/g
Figure 7. Average results of bottom sediment analysis in 1976 and 1977,
43
-------
-------
LAKE SUWA BASIN SEWAGE SYSTEM CONSTRUCTION PROJECT
A major cause of pollution in Lake Suwa was raw sewage, so construction
of a large-scale sewage and treatment system was a fundamental step.
The construction project began in 1971 and will be completed in 1992.
Tables 3, 4, and 5 provide statistical data on the project.
TABLE 3. LAKE SUWA REGIONAL SEWAGE SYSTEM PLAN
District
Okay a
Suwa
Chi no
Drainage
Area
(ha)
1,508
1,423
715
Shimosuwa 516
Total
Table 3
Sewer
System
Sepa-
rate
System
4,162
(cont. )
Treatment
Plant
(GA ha)
Toyota
Sewage
Treatment
Plant
18.7
Future Total
Population Distance
(Est. 1,000) (km)
1985: 200
1990: 212
Pumping
Station
(GA m2)
Shimo-
suwa
Sewage
Pumping
Station
1,320
Koshu TS
(Trunk Sewer)
Chi no TS
Chuoh TS
Nishiyama TS
25.6
Construction
Period
(FY)
1971 - 1985
Sewage
Volume Treatment
(1 ,000 nrVday) Process
Ordinary
Activated
1985: 334 Sludge
Process
1990: 337
Administrative
Authority Authorization
Authorized by
Prefecture
Dec. 27, 1971
Nagano Authorized by
Prefec- City Planning
ture Law
March 24, 1972
Authorized by
Sewage Law
Feb. 28, 1972
GA = ground area
FY = Fiscal year
(continued)
-------
Table 3 (cont.)
Estimated Sewage Volume (m3/day)
Average
Per
Item Day
Sanitary -,,. ~0-,
r J 76,337
Sewage '
Industrie!
Hot
Spring 17,257
Waste
Ground ?3 ,(-
Water '
rtrVday 337,099
m3/hour 14,000
Tnt ->1
m3/sec 3.9
Maximum
Per
Day
95,425
220,310
21,571
23,395
360,401
15,000
4.2
Maximum
Per
Hour
143,140
330,468
32,357
23,395
528,954
22,000
6.1
Outline of Sewage
System
Item
Koshu
Trunk Chinฐ
Sewer Chuoh
Nishiyama
Sewage Pumping
Station
Sewage Treatement
Plant
Discharge #1
Trunk #2
Pipe
Diameter
(6 m)
0.9 - 2.4
0.7 - 1.2
0.8 - 1.4
0.4 - 1.4
2 Stations
(Toyota &
1 Plant
(Toyota)
1.5 - 4.5
0.8
Distance
(km)
11.6
6.8
6.2
1.4
Shimosuwa)
4.7
4.3
46
-------
The construction progress is shown in the following tables. Partial use
of the system is expected by October, 1979.
TABLE 4. CONSTRUCTION PROGRESS OF LAKE SUWA
BASIN SEWAGE SYSTEM (MILLION YEN)
Item
Total
Construction
1971 - 1978
Remaining
Construction
TABLE 5. CONSTRUCTION PROGRESS OF COMPLEMENTARY
PUBLIC SEWAGE NETWORKS (1973-1978)
Progress
Trunk sewer
Discharge trunk
Toyota sewage
treatment plant
Shimosuwa sewage
pumping station
Subcontracting;
wages, etc.
Total
12,789
4,952
40,251
1,023
2,985
62,000
6,664
448
7,993
713
2,212
18,030
6,125
4,504
32,258
310
773
43,970
52.1
9.0
19.9
69.7
74.1
29.1
City
Okay a
Suwa
Chino
Shimosuwa
Total
Constructed
area (ha)
46.3
108
37
26.8
218.1
Distance
(m)
10,525
19,685
6,634
4,772
41,618
Cost
(million yen)
1,030
1,743
467
466
3,706
Total
area (ha)
1,507.8
1,423.4
714.7
515.6
4,161.5
Progress
(%)
3.1
6.2
5.2
5.2
5.2
EFFLUENT CONTROL OVER INDUSTRY
Since completion of the sewage system is still several years away, local
governments enacted ordinances setting their own environmental standards.
These drainage standards required designated business firms in the basin area
to meet the nation's environmental standard for lakes and marshes. Such
standards are applicable to factories and offices whose average drainage per
day exceeds 30 m3. Local health centers are assigned to conduct on-site
inspections to insure compliance.
47
-------
DREDGING PROJECTS
Lake Suwa is a shallow lake with an average depth less than 4.0 m.
Deposited on the bottom is a thick sediment layer resulting from the inflow of
polluted water into the lake over a long period of time, and organic sludge
from dead and decomposed aquatic plants and plankton. The adverse effects of
these bottom sediments on the water quality is quite evident, particularly
when sedimentary mud churned up by high waves creates water masses with a low
oxygen content. This "Susumizu phenomenon" is doing extensive damage to the
lake fishery. Dredging is therefore another fundamental step, along with the
sewage system, towards regaining a clean lake. Table 6 presents environmental
standards for lakes and marshes.
TABLE 6. ENVIRONMENTAL STANDARDS FOR LAKES AND MARSHES (Natural lakes and
marshes and artificial lakes of at least 10 million m3 capacity)
Standard
Water
AA
A
Quality
City water 1st
grade
Fishery 1st grade
Natural environment
and Classes A, B, C
City water 2nd, 3rd
grades
Fishery 2nd grade
Bathing and Classes
B, C
pH
6. 5 or
above
8.5 or
below
6.5 or
above
8.5 or
below
COD
1 ppm
or
below
3 ppm
or
below
SS
1 ppm
or
below
5 ppm
or
below
DO
7.5 ppm
or
above
7.5 ppm
or
above
Col i form
Count
50
MPN/100
ml or
below
1,000
MPN/100
ml or
Body
Lake Suwa*
Lake
Shirakaba*
Lake
Tateshina*
Fishery 3rd grade
Industrial water
1st grade
Agricultural water
and Class C
6.5 or 5 ppm 15 ppm 5 ppm
above or or or
8.5 or below below above
below
C
Industrial water
2nd grade
Environmental
protection
6.0 or
above
8.5 or
below
8 ppm
or
below
No
sus-
pension
of dust
2 ppm
or
above
entire lake
48
-------
Basic Dredging Concepts
Basic concepts to support the dredging efforts are based on the following
results from the studies made by the Lake Suwa Pollution Control Measures
Investigation Committee:
1) Easily decomposed organic matter is deposited on shallow areas near
shore.
2) Higher aquatic plants do not proliferate at water depths of over 2.5
m.
3) Dissolved oxygen (DO) at a depth of 2.5 m is higher than at lesser
depths and almost equivalent to the DO at greater depths.
Thus, dredging at water depths of less than 2.5 m will be most effective.
Based on this conclusion a plan was drafted to build a new shoreline
while retaining a substantial lake area of 13.3 km2 for flood control (Figure
9). The old lake area was 14.06 km2. The dredged sludge would be dumped in
the area between the new and old shorelines and a greenbelt of streets and
parks would be created by covering it with clean soil.
TENRYU RfVER
KAMAGUCHI FLOODGATE
FLOOD CONTROL
EMBANKMENT
RECLAIMED AREA
(EXAGGERATED)
SHIMOSUWA
FIRST STAGE
DREDGING AREA
RUINS OF
SONE
SUWA
KAMIGAWA
RIVER
Figure 9. Dredging and diking plan for Lake Suwa.
49
-------
Dredging Plan
The dredging at Lake Suwa was initiated in 1969 as one of the "river
environment protection projects" subsidized by the Japanese National Treasury
(50% subsidy). The project is currently about 70 percent completed (Table 7).
TABLE 7. FIRST STAGE OF DREDGING PLAN
Item
Total Plan
1969 - 1977
Completion (%)
Project
cost
(million yen)
2,466
1,466
63.7
Dredged
sludge 1,656,000 1,211,860
(m3)
73.2
The planned dredging area is about 2.5 km2 or about 18 percent of the
planned lake area of 13.3 km2. About 78 percent of the dredged sludge was
used as fill material between the new and old shorelines and 22 percent as top
dressing to cover fields. This activity has been implemented with care to
avoid secondary pollution.
13.5 m
WATER LEVEL 759^45(1.1) ^
'FOOT PROTECTION -'P"-" I
'DREDGED OR FILL MATERIAL
Diagram of dredge and backfill of new shorelines.
Dredged Sludge
The soil at the dredging area, typified by such characteristics as granu-
lar variation, hardness and specific gravity, affects the dredging ability.
The results of soil examinations are shown in Table 8; test sites are identi-
fied in Figure 10.
50
-------
TABLE 8. SOIL SAMPLE CHARACTERISTICS
Sample No.
Item
True specific
gravity
Liquid limit
Plastic limit
Gravel content %
Sand content %
Silt content %
Clay content %
Max. grain size
mm
Uni formity
coefficient Uc
Curvature
coefficient U'c
Soil type
PH
Ignition loss %
Remarks
10
2.517
NP
NP
0
5.2
80.3
14.5
0.84
10
-
silt
7.2
5.1
dark
brown,
offen-
sive
odor
11
2.615
NP
NP
0
27
59.5
13.5
0.84
17
-
Psam-
mitic
silt
5.8
11.5
dark
brown,
offen-
sive
odor
12
2.693
NP
NP
0
15.7
77.5
6.8
0.42
4
-
Psam-
mitic
silt
6.4
9.1
dark
brown
13
2.419
-
-
0
22
24
54
0.42
-
-
clay
-
-
dark
brown,
offen-
sive
odor
14
2.828
NP
NP
0
93
4
3
-
2.9
1.2
sand
-
-
dark
brown
15
2.627
NP
NP
0
12
76
12
-
8.8
1.6
Psam-
mitic
silt
-
-
dark
brown,
offen-
sive
odor
16
2.629
NP
NP
0
15
75
10
-
7.3
1.5
Psam-
mitic
silt
-
-
dark
brown,
offen-
sive
odor
51
-------
TOGAWA RIVER
YOKOKAWA RIVER
16
TENRYU RIVER
10
LAKE SUWA
STOCKS OF
AQUATIC PLANTS
KAMIGAWA RIVER
MIYAGAWA RIVER
soil sample (see Table 8)
o core sample
Figure 10. Test sites.
Dredging Methods
For this project a pump dredge was selected from among the various types
of available dredges. This was done for the following reasons:
1) Lake Suwa is a shallow inland lake.
2) There are many fishing facilities and ferry lines operating within
the lake.
3) Pump dredging can be performed with a high mud content of the
dredged material and without dispersing the sedimentary mud in the
water.
52
-------
Pipeline transportation of dredged material avoids emission of offensive
odors. The pipelines were laid along the lake bottom to avoid obstructing
vessels. Dredging equipment and pipeline specifications are shown in Tables 9
and 10 and Figure 11.
DREDGE
PUMPING METHOD TO SEND MUD THROUGH PIPELINE TO DUMPING AREA
Figure 11. Pipeline system.
TABLE 9. DREDGING EQUIPMENT
Speci fi cations
Main dredge (one)
Auxiliary dredge
(one)
Relay boat (one)
Total weight (tons)
Type
Length (m)
Width (m)
Draft (m)
Main engine
Dredging depth (m)
96
125
65
Portable, on site Portable, on site Portable, on site
fabrication fabrication fabrication
18.0
6.5
1.0
Electric motor
(350 PS)
4.0
19.0
7.0
1.0
Diesel engine
(420 PS)
4.0
15.0
6.0
0.8
Diesel engine
(420 PS)
distance (m)
Pumped water (m3/h)
Total pump head (m)
900
70
45
900
70
45
600
70
45
Note: Mean mud content up to 50%
Sludge transport pressure 5 kg/cm2
53
-------
TABLE 10. PIPELINE SPECIFICATIONS
Pipeline pressure during sludge transportation: 50 kg/cm2.
Flow rate in pipe during sludge transportation: 3.025 m/sec.
Diameter of sludge pipe: 310 mm
Length of sludge pipes in water (synthetic rubber pipes): 12 m/pipe.
Length of sludge pipes on land (cast iron pipes): 6 m/pipe.
Based on dredging results, (Figure 12), it is recommended that a relay
boat be used where the transport distance is over 1,300 m.
Dredged sludge contains polluted water; when it is used as fill it can be
a secondary source of pollution if allowed to return to the lake. To prevent
this, the sludge is induced to settle rapidly at the reclamation area. The
area between the new and old shorelines is divided by dikes into small ponds
(average length: 50 m, width: 30 m, depth: 1.8 m). The sludge is pumped
into these ponds and the water is removed. From the viewpoint of sedimenta-
tion efficiency, the best sludge transportation rate was 0.3 m/min or less.
From the standpoint of an efficient dredging project, this rate was too slow
and could not be tolerated. The relationship between grain size, settling
time and depth is shown in Table 11.
TABLE 11. APPROXIMATE SETTLING TIME (HOURS)
Settling depth
Grain size 1.0m 1.8m
1.0 u
0.7 u
3
4
3.6
4.8
The local prefecture's SS criteria calls for 70 ppm. The national stan-
dard is 150 ppm (Water Pollution Prevention Act). Natural settling without
coagulant agents produced 100 ppm SS discharges. Dredged material discharge
to the settling ponds could not reasonably be reduced 0.3 m/min in order to
meet the return flow SS criterion, therefore it was necessary to use a coagu-
lant. The SS value was reduced to 50 ppm when 150 to 180 ppm of polyaluminum
chloride coagulant was used.
Remaining Problems
About 10 years have passed since the first stage of the Lake Suwa Dredg-
ing Plan began in 1969. The project will be about 80 percent completed by the
end of 1979. Even with the completion of the first stage in a couple of
years, no noticeable improvement of the lake's water quality is expected,
partly because the sewage system around the lake has not been completed.
54
-------
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Every summer the Aoko phytoplankton bloom that symbolizes the pollution
of Lake Suwa turns the entire surface of the lake green. The Susumizu phe-
nomenon, triggered by bottom sludge, still occasionally occurs. There is,
however, a promising aspect to the project which requires further investiga-
tion. Up until 1963, the annual harvest of prawns from the lake averaged 8
tons. By 1968 it was reduced to zero. But since 1970, the second year of
dredging work, the prawn catch has gradually increased to a current level of 3
tons per year.
Even when dredging is completed in all areas of the lake less than 2.5 m
in depth, more than 80 percent of the deposited sludge will remain in the
lake. It may still cause phytoplankton blooms and is therefore an obstacle to
the rehabilitation of the lake.
Construction of the basin-wide sewage system (started in 1971) has been
making steady progress and partial use of the system is expected in October of
1979. Its effect on the lake water will be known in a few years.
Consideration is also being given to expanding dredging to areas deeper
than 2.5 m (over 80% of the total lake area). Before a final decision can be
made it will be necessary to determine what the new sewage system can do. In
addition, a study is currently being conducted on the flux of organic matter
and nutrients in the lake.
What remains is to accurately measure the influence of bottom sludge on
water pollution. A small portion of this work has already been finished and
is reported in the following section.
The biggest problem to be solved in the future is how and where to dis-
pose of newly dredged sludge, since the fill area between the new and old
shorelines has been almost completely filled.
OUTLINE OF BOTTOM MATERIAL ANALYSIS
In 1976 and 1977 a study was made of the bottom sediments of Lake Suwa
(Figure 13). It consisted of sediment analysis, elutriate testing, examina-
tion of mud suspension in the water column, and determination of sediment
thickness. The idea was to determine the effects of the sediments on the
water and the minimum dredging depth required to clean up the lake water.
LIST OF ANALYSES
a. Sediment analysis
Sample: 4 depths per station: 0, -30, -60, -90 cm
Total samples: 52
Analysis: Water content as percent dry weight, simple weight
per volume, ignition loss, total carbon, total nitro-
gen, sulfide, COD.
56
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b. Elutriate test
Sample: 2 depths per station: 0, -60 cm
Total samples: 10
Analysis period: 10 analyses per sample:
Day 1, 3, 6, 10, 15, 20, 30, 45, and 60
Analysis: COD, TOC, total nitrogen, NH4-N, total phoshporus,
P04-P, DO
c. Analysis of mud suspension in the water column
Sample: 2 depths per station (upper and lower water layers)
Total samples: 16
Analysis: SS, water content, specific gravity, total phosphor-
us, total nitrogen, COD, N02-N, N03-N, NH4-N, P04-P.
d. Sludge thickness
Device: Model RS-72 (Rasa Electronic Industries, Ltd.)
Frequency: 400 kHz, 30 kHz
Total distance traversed: 27.0 km
Results of the investigation are detailed in Tables 12 through 15.
TABLE 12. AVERAGE CONTENTS OF BOTTOM SEDIMENTS AT
DIFFERENT DEPTHS IN THE UNDREDGED AREA
Depth
- 0 cm
-30 cm
-60 cm
-90 cm
Water
content
(%)
473
349
282
180
Weight
(g/cm3)
1.14
1.17
1.27
1.37
Ignition
loss
(%)
16.3
16.4
14.7
13.5
TOC
(mg/g)
42.2
40.8
35.5
26.3
T-N
(mg/g)
4.49
4.00
3.41
2.73
Sulfide
(mg/g)
1.10
1.40
0.91
0.53
COD
(mg/g)
30.1
31.1
18.5
15.8
58
-------
TABLE 13. EFFECTS OF BOTTOM SEDIMENTS AT 0 cm AND -60 cm ON WATER
QUALITY AS DETERMINED BY ELUTRIATE ANALYSIS AFTER 60
DAYS WHEN THE SEDIMENTARY MUD IS CONSIDERED MOST STABLE
Sample
0 cm
sample
1
2
3
4
5
Average
COD
(mg/1)
- 1.
- 0.
0.
0.
1.
0.
0
4
2
2
1
0
TOC
(mg/1)
- 2.0
-
-
1.0
1.0
0.0
T-N
(mg/
- 0.
0.
0.
- 0.
- 0.
- 0.
NH4-N
1) (mg/1)
33
30
34
77
37
17
T-P
(mg/1)
0.
0.
0.
0.
0.
0.
10
06
06
01
07
06
P04-P
(mg/1)
0. 14
0.15
0.14
0.13
0.16
0.14
DO
(mg/1)
- 3.
- 2.
- 3.
- 4.
- 3.
- 3.
2
9
1
0
1
3
-60 cm
sample
1
2
3
4
5
Average
0.
0.
0.
1.
1.
0.
9
2
1
3
5
8
-
2.0
-
1.0
1.0
0.8
- 0.
- 1.
- 1.
"1
- 2.
- 1.
85 - 0.05
30
70 - 0.28
14 - 1.26
42 - 2.36
48 - 0.79
0.
0.
0.
0.
0.
0.
07
08
07
10
10
08
0.16
0.16
0.16
0. 16
0. 16
0.16
- 1.
- 1.
- 1.
- 1.
- 1.
- 1.
5
3
0
0
1
2
(-60 cm
(0 cm
s) -
s)
0.
8
0.8
- 1.
31 - 0.79
0.
02
0.02
2.
1
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TABLE 15. EFFECTIVENESS OF DREDGING BASED ON THE RESULTS
OF THE CURRENT INVESTIGATION AND EXISTING DATA
Data
Item
Effective
depth
Effect
Current
Investi-
gation
DO
Sulfide
Ignition
loss
COD
Suspended
Mud
Sludge
Thickness
-60 cm
DO consumption reduced by 2 ppm
-60 to -90 Maximum at -30 cm. Almost same value at
cm bottom surface and -60 cm. Reduced dras-
tically at -60 to -90 cm, the value being
below 1.0 mg/g at any point
-90 cm No drastic reduction seen. 15% or below
at -90 cm at most sites (11 out of 13
stations).
-30 to -60 20 mg/g or below at -60 cm at all points.
cm
-30 cm Returns to bottom material before "Susumizu
phenomenon" occurs.
-20 to -60 Eliminate sludge layer
cm
Existing Methane
data Production
-20 cm
Reduced bottom surface production to 1/10.
RESULTS OF ANALYSIS
1. In the elutriate test, the materials at 0 cm and 60 cm in depth were
sampled at 5 points. About 150 g of evenly mixed mud was put in 1-1 dark
bottles with 700 ml of filtered lake water (5A filter paper). Dark bottles
were also filled with filtered lake water only as controls. Both types of
bottles were sealed and retained for testing. Water analyses of both bottle
types were made on each specified day.
Lake water sampled for the test (on August 3rd and 4th, 1977) contained
little NH4-N. Most of the total nitrogen is considered to exist in an organic
state. This may be due to nitrogen uptake by Aoko (Microcystis) in the upper
layers.
About 80-100% of the phosphorus in the water existed in P04-P.
Microcystis growing rapidly in the summer quickly takes up P04-P as well as
NH4-N. The fact that P04-P existed with little NH4-N and N03-N in the lake
water suggests that N is the limiting factor in the propagation of phytoplank-
61
-------
ton in the upper water layer of the lake, at least at the time of sampling
(Table 16).
TABLE 16. ANALYSIS OF RESULTS OF CONTROL BOTTLES OF
FILTERED LAKE WATER (5A filter paper)
C.O.D.
(mg/1)
3.0
T.O.C.
(mg/1)
8
T - N
(mg/1)
1.99
NH4-N
(mg/1)
0.01 or
above
T - P
(mg/1)
0. 19
P04-P
(mg/1)
0.19
DO
(mg/1)
7.2
2. The methodology used in the mud tests was proposed by Dr. Koyama of
Nagoya University and others. Sampling devices were made and used for one
month. Two of the devices sustained damage from ferryboats. At three of six
stations, a large quantity (15-8 cm) of particles with specific gravity
greater than 1.1 were suspended 1 to 2 m above the bottom. At the other three
points the SS layer was much less (less than 3 cm).
The 1.0 to 2.0 m thick suspended solid layers contained 600 to 1000 ppm
of SS. Once resuspended, this mud suspension does not settle easily. Once in
suspension it can migrate to higher layers or to the surface.
The thickness of bottom sediments contributing to the dense overlying
layers of suspended mud was calculated from the data to be less than 1 cm. In
the lake it would be a few centimeters at most. Since Lake Suwa is very
shallow with an average depth of about 4 m and a maximum depth of 6.8 m,
wind-blown waves can easily reach the bottom and cause mud resuspension.
3. The results of sludge thickness measurements showed that the sludge
in the dredged area was about 10 cm thick. That of the undredged area was 20
to 60 cm.
4. The bottom sediments of Lake Suwa display very small unit weight and
grain size. Consequently, dredging to a depth of -90 cm may not effectively
prevent mud resuspension. But the Susumizu phenomenon caused by suspended mud
did not occur before 1966. The rate of sedimentation in Lake Suwa is 5 to 20
cm over 10 years. Considering that the sediment thickness which causes mud
resuspension is only a few centimeters, we estimate about 30 cm of dredging
will restore the bottom to 1965 conditions, when the Susumizu phenomenon did
not occur.
CONCLUSION
More than a decade has passed since water quality control efforts began
in Lake Suwa, one of the most eutrophic lakes in Japan. During this period,
scientific investigations have been conducted and administrative measures
taken. But pollution continues and algal blooms occur yearly.
62
-------
However, the construction of the Lake Suwa Basin Sewage System has made
steady progress since its beginning in 1971. Partial use of the system will
begin in October, 1979. Progress is also being made in the river improvement
projects around the lake and in dredging of the lake itself. But a method for
total rehabilitation of the lake has not yet been found. Research is now
being done to determine the mechanisms of organic pollution and the methods
appropriate to predict the behavior of pollutants in the lake.
It will take a long time, but all the projects in Lake Suwa are making
progress toward restoring the lake to cleaner, purer water quality.
REFERENCES
(1) Lake Suwa Purification Measures Investigation Committee, "Studies on
Purification of Lake Suwa".
(2) Nagano Research Institute for Health and Pollution, Pollution Section,
Nagano Prefecture Department of Living Environment, "Report on Investiga-
tion of Countermeasures against Eutrophication of Lake Suwa".
(3) The Civil Engineering Management Office for Lake Suwa and Surrounding
Region, "Examination of Lake's Bottom Material as Part of River Environ-
ment Improvement Works".
(4) Nagano Prefecture, "Pollution White Paper".
63
-------
DREDGING OF POLLUTED BOTTOM SEDIMENTS
IN THE IBO RIVER
Sadao Kishimoto
Director of Himeji Work Office
Kinki Regional Construction Bureau
Ministry of Construction, Japan
INTRODUCTION
Located in the western part of Hyogo Prefecture, the Ibo River flows into
the Seto Inland Sea at Himeji City - about 80 kilometers west of the Interna-
tional Port of Kobe. This region is located along the Sanyo Route, histori-
cally an important connection between the western part of mainland Japan and
Kyushu Island, Shikoku Island and the Chugoku Region.
Various industries have developed in the basin, notably brewing, the
production of Japanese noodles, and leather manufacturing. The leather manu-
facturing factories along the Hayashida River, a tributary of the lower main
channel of the Ibo, have created a serious water pollution problem in both
rivers. This has also caused a large volume of bottom sediments containing
polluted substances to accumulate on the river beds. In the dry season,
unavoidable impacts from this pollution are found in the form of foul odors
and other negative influences on irrigation, fishing and the general environ-
ment. The volume of polluted bottom sediments is estimated at 8,000 m3 at the
confluence of the Ibo and its tributary, the Hayashida River. The total
volume, including that in the river estuary, is estimated at several tens of
thousands of cubic meters of sediment.
To deal with this problem, stricter regulation of wastewater discharge,
the construction and improvement of sewage treatment facilities and dredging
of bottom sediment are now being adopted. This paper describes the plan for
dredging the bottom sediments.
THE OUTLINE OF THE BASIN
The Ibo River is shown in Figure 1. Its headwaters begin at Mt.
Fujinashi (1,139 m) in the Chugoku mountain chain. As it flows to the Seto
Inland Sea it is joined by major tributaries - the Hikihara, Kurusu, and
Hayashida Rivers. The area of the Ibo basin is approximately 810 km2, and the
length of the main river channel is 71 km.
65
-------
CATEGORY A
NEW SANYO LINE
SANYO LINE
CONFLUENCE
ESTUARY-'.:'-
Figure 1.
The Ibo River Basin.
-------
The major part of the basin is situated in mountainous terrain - the flat
area is only 170 km2, about 20% of the total area. Hayashida Watershed occu-
pies 97 km2 of the basin.
The geology consists of basaltic andesite and quartz diorite in the
mountains and alluvial strata in the valley. The total forest area of 640 km2
is composed of 190 km2 coniferous forest, 260 km2 deciduous forest and 190 km2
brush.
Annual average rainfall in the basin is about 2100 mm upstream, about
1600 mm in the middle stream and about 1400 mm downstream. The riverbed slope
is 1/2000 to 1/100 in the Ibo River and 1/360 to 1/280 in the Hayashida.
Table 1 shows the 18 year average stream flow at Tatsuno in the main
river. Table 2 shows the monthly mean flow at Tatsuno, Kamigawara (Ibo River)
and Karnae (Hayashida River) for 1975 and 1976. As these tables indicate,
heavy flow is expected in the rainy season, and zero flow in the dry season.
The watershed area of the Hayashida River is affected by the climate of
the Seto Inland Sea. Its discharge per unit drainage area is roughly 70% of
that of the main river.
The Ibo River drainage area contains two cities and eight towns, total
population about 200,000. Downstream the Harima seaside industrial zone is
located, an area of extensive chemical and heavy industries. From Tatsuno
City to Himeji City brewing, noodle and leather industries are dominant.
These industries are major sources of pollution, particularly the leather
industry.
The present water rights in the Ibo River are 0.09 mVsec (0.2%) for city
water use, 5.15 m3/sec (15.9%) for industrial water supply, 16.98 mVsec
(52.4%) for agricultural use and 10.20 mVsec (31.5%) for power. The maximum
volume is 32.41 m3/sec. The water withdrawn below the Hayashida River conflu-
ence is used for agricultural and industrial purposes, thus water quality is a
major concern.
PRESENT CONDITION OF WATER QUALITY AND BOTTOM SEDIMENTS IN THE IBO RIVER
WATER QUALITY OF THE IBO RIVER
In May 1973, the law which set environmental standards was applied to the
Ibo River, and the stream above the Hayashida confluence was classified as
category A and the stream below as category B, (Figure 1, also Table 3 for A
and B).
Since the biological oxygen demand (BOD), suspended sediments (SS) and
dissolved oxygen (DO) values in the middle and upstream Ibo are respectively
1.0-1.5 mg/1, 13-19 mg/1 and 9.9-10.4 mg/1, there are few pollution problems
there. Therefore this discussion will concentrate on the severely polluted
tributary, the Hayashida River and its confluence with the main river.
Three bottom sediment monitoring stations, shown in Figure 2 were estab-
lished: Tatsuno station in the Ibo River, Kamae station in the Hayashida
67
-------
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TO TSUYAMA
TO OKAYAMA
SYNYO LINE
TO OKAYAMA
TATSUNO
NAKAI BRIDGE
1
HOMERE BRIDGE
EIKYU BRIDGE
JO HIMEJI
HONKYU BRIDGE
TO KOBE
KAMIGAWARA
INTAKE WEIR
TO KOBE
MANAGO BRIDGE
KAMAE
9,10, II,I2
KAMIGAHARA
A WATER QUALITY MONITORING STATIONS
BOTTOM SEDIMENT MONITORING STATIONS
Figure 2. Major monitoring stations.
71
-------
TABLE 4. THE CHANGE IN WATER QUALITY WITH TIME AS ANNUAL MEAN
Item
pH
DO
COD
BOD
o
c
3
+>
(O
i
1
O)
ฃ
o
1 1
SS
_
Cl
NH4-N
N02-N
N03-N
NH4-N+
N02-N+
NO *
Item
PH
DO
CD
rd
ro
s_^--
O)
Cฃ.
T3
i
>
COD
BOD
SS
Cl~
NH4-N
N02-N
Unit
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
-N
Unit
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
)
7
9
3
3
10
12
0
0
0
0
9/1
.5
.8
.2
.1
.7
.07
.020
.20
.290
1971
10
0
148
233
172
472
28
0
.3
.9
.0
.048
1972
7.4
10.4
3.0
2.0
7
16.3
0.12
0.038
0.26
0.418
1972
10.5
2.1
81.4
145
99
342
10.8
0.101
1973
7.4
10.8
1.5
1.8
12
8.8
0.15
0.029
0.43
0.609
1973
10.8
1.3
72.1
223
156
434
15.7
0.012
1
7
10
1
1
17
6
0
0
0
0
Year
974
.4
.0
.8
.6
.8
.11
.008
.53
.648
Year
1974
10
1
62
268
142
377
15
0
.2
.8
.4
.0
.057
1975
7.3
10.1
0.9
1.5
12
6.4
0.09
0.008
0.79
0.888
1975
10.4
1.0
65.9
182
252
399
13.9
0.093
1976
7.4
9.9
1.6
1.5
19
5.8
0.06
0.009
0.58
0.649
1976
10.7
0.3
123
231
248
458
16.6
0.028
7.4
10.4
1.4
1.8
7
6.2
0.11
0.012
0.68
0.802
1977
10.6
0
204
236
372
710
23.6
0.013
N03-N mg/1 0.19 0.18 0.18 0.34 0.93 0.01 0.15
NH4-N+
N02-N mg/1 28.238 11.081 15.892 15.397 14.923 16.638 23.763
72
-------
TABLE 4. (continued)
Year
Item
PH
DO
(O
fO
s
(O
en
i
-------
mg/l
12
10
PH
300
200
100
_ SS
200
100
BOD
TATSUNO
KANAE
KAMIGAWARA H
N
l I I l
V
I I
I 1 I
mg/
600
400
200
l r
Cl
12
8
I l
- DO
I I
30
20
10
I T
_ NH4-N+N02+ N02-N+N03-N_
1971 72 73 74 75 76 77 1971 72 73 74 75 76 77
YEAR
Figure 3. The change in water quality over time (annual mean value)
74
-------
The SS value at Tatsuno, low at 7-19 mg/1, shows no tendency to change.
At Kamae, SS levels ranged between 99-172 until 1974. Since then the level
has increased rapidly to 372 mg/1 in 1977. At Kamigawara, SS levels were a
little higher (by 5-10 mg/1) than at Tatsuno, but compared to the other en-
vironmental factors little influence from the Hayashida River is observed.
This may be caused by the effects of settling as the river flows downstream to
the station.
The Cl" value at Tatsuno is 5.8-16.3 mg/1. Its average value over the
past seven years has been 9 mg/1, which is normal river water quality. The
minimum value at Kamae was 342 mg/1 in 1971, but since then has increased to
almost twice that figure (710 mg/1 in 1977). This was caused by wastewater
discharge from the leather industry where salt was being washed from hides.
The Cl is different from other factors since it is not physically and bio-
logically decomposed. The Kamigawara station was directly affected by the
Hayashida River and after 1975, the chloride at Kamigawara increased to about
ten times that of Tatsuno.
Inorganic nitrogen values for NH4-N and N02~N at Tatsuno are relatively
small, but N03-N has increased rapidly from its minimum of 0.2 mg/1 in 1971.
N03-N is the final decomposition product for inorganic nitrogen. The ratio of
NQ3-N to total inorganic nitrogen is largest at Tatsuno. In contrast, inor-
ganic nitrogen at Kamae is 11-28 mg/1, of which NH4-N is more than 90%. The
N03-N at Kamigawara is almost the same as that of Tatsuno, but the NH4-N
increases by 1.5-2.0 mg/1 due to the influence of the Hayashida River. From
these facts, it may be concluded that biodegradation does not reach the nitri-
fication stage during the 1/2 km it takes the river to flow from Kamae to
Kamigawara.
Another investigation of water quality conducted on the Hayashida River
showed that the total phosphorus (0.2-1.7 mg/1) is relatively small compared
with BOD. This may be caused by domestic wastewater. But total chrome is
also relatively high at 1-10 mg/1 of discharged water. Thus, the water pollu-
tion in the Hayashida River is mainly caused by the leather industry.
BOTTOM SEDIMENTS IN THE IBO RIVER
Since there is no specific pollution problem in the middle and upstream
of the Ibo River, the discussion will be confined mainly to the Hayashida
River and the confluence with the main channel where the water is badly pol-
luted by the leather industry.
In this investigation, pH, COD, volatile and fixed material, total nitro-
gen, total phosphorus, sulfide, total chromium, water content and grain size
composition were measured as bottom sediment characteristics. PCB, total
mercury, al kyl-mercury, cadmium, lead, cyanogen (CN)2, arsenic, hexavalent
chromium and organic phosphate were measured in elutriate tests.
The Hayashida River has a steep bed with a slope of about 1/300. The
flow velocity is very high. Consequently, suspended solids or minute sludges
may not settle, but organic sludges generated from polluted wastewater
75
-------
will accumulate at weirs and at the confluence where the velocity is reduced.
The "sludge" component of the bottom sediments has a low specific gravity
of 1.78-1.90. The water content is high at 63.1-90.3%. m = where-
wt
m = water content, wet wt. basis
Ww = weight of water
Wt = total wt. of soil
Clay and silt with a diameter of less than 74 M make up 75-95% of the sludge.
The unit volume weight is small at 1.02 g/cm3.
The sand-gravel component in the bottom sediments is 65-94% gravel
Specific gravity is in the range of 2.64-2.68.
Figure 4 shows the relationship between COD and volatile and fixed matter
in the bottom sediments of the Hayashida River. The volatile and fixed sus-
pended matter in the sludge differs from that in the sand-gravel component.
In the former, it varies from 8.8% to 68.6%, but most fall into the ranqe of
40-70%.
The COD value is also separated into the two components. It is in the
range of 11 mg/g to 290 mg/g dry weight in the sludge but mostly in the range
of 40-300 mg/g. These results show that the bottom sediments of the Hayashida
River are composed of organic sludge with a large amount of volatile and fixed
matter and COD.
Sulfide content is small (about 40 mg/kg, dry weight) upstream of the
Hayashida River. It increases to 417 mg/kg in the lower stream and near the
confluence it is 1,090 mg/kg. This shows that reduction is occurring during
stream flow.
Depending upon the location, the total chromium content is 1,300 mg/kg to
21,000 mg/kg. This is caused by the leather industry wastewater which in-
cludes protein compounds and chromium resulting from the leather tanning
process. High nitrogen content of 605-22,100 mg/kg dry weight and phosphorus
content of 850-2,780 mg/kg also exists.
The results of the elutriate tests showed the leaching rate to be lower
than the limit of quantative analysis for all the tested items, as shown in
Table 5.
THE WATER POLLUTION MECHANISM AND CONTROL MEASURES CRITICAL IN THE IBO RIVER
WATER POLLUTION MECHANISM
As discussed in the previous section, water pollution in the Ibo is
caused by wastewater from industry along the Hayashida River. Bottom sedi-
ments accumulate around weirs and at the confluence of the two rivers where
flow velocity is reduced.
76
-------
mg/g
300
200
100
50
COD
r\s\
20
10
5
1
i i i t i i i
4(5 -
O SLUDGE 76Q <53 -
A SAND GRAVEL 5
8
O
,O l2
1 Q)n
09
SEDIMENT REMOVAL THRESHOLD
OlO
2
0
A
A A
AAA
A
1 1 1 1 1 i 1
5 10 1520 30 50 100
PERCENT
Figure 4. COD and volatile and fixed material in sediments.
77
-------
TABLE 5. ELUTRIATE TEST OF SURFACE SEDIMENT
Monitoring Poi
Item
T - Hg
R - Hg
Cr6+
Pb
Cd
As
Hayashida
River
mg/1
mg/1
mg/1
mg/1
mg/1
mg/1
not
not
not
not
not
not
detected
detected
detected
detected
detected
detected
nt
Confluence of
the Hayashida
and Ibo River
not
not
0.
not
not
not
detected
detected
0005
detected
detected
detected
Limit of
Quantative
Analysis
0.0005
0.0002
0.005
0.01
0.005
0.01
Minimum
Acceptable
Level
0.005
N.D.
0.5
1
0.1
0.5
Org.
Phosphate mg/1
CN
PCB
mg/1
mg/1
not detected not detected 0.005
not detected not detected 0.03
not detected not detected 0.005
1
1
0.003
Ref: The method for performing tests is given in notice
No. 14 of the Environmental Agency.
The poor water quality of the Hayashida affects that of the lower main
Ibo and polluted sludge moved by floods further aggrevates the water quality
of the lower stream. The deterioration in the river water, together with
polluted bottom sediments, has affected agriculture and industry. It causes
eutrophication, DO reduction and some anoxic conditions which result in the
death of aquatic organisms. This pollution mechanism is diagrammed in Figure
5.
A variety of approaches should be followed in cleaning up the river,
including restriction on discharge of industrial wastewater, installation of
sewage treatment facilities and industrial waste, introduction of clean water
to the polluted river and dredging of bottom sediments to enhance the capacity
of the river for self-renewal.
These steps have been or are now being taken. Wastewater discharge
restrictions have been applied to all local industry and installations of
pre-treatment facilities are now occurring.
In Tatsuno City, the construction of public sewage facilities is making
steady progress. In the upper Hayashida, construction of a dam has been
launched to control the stream flow.
78
-------
1
1
WATER QUALITY
DETERIORATION
v
WASTE INFLOW
*
DETERIORATION
OF ENVIRONMENT
BLUDGE
ACCUMULATION
DECREASE OF
AQUATIC
LIFE DEATH
DECLINE
IN
USEABILITY
POLLUTION OF
BOTTOM SEDIMENTS
DETERIORATION
OF WATER
QUALITY
OC.
U
X
cn
RE-POLLUTION
POLLUTION OF
BOTTOM SEDIMENTS
EUTRIPHICATION
BY AQUATIC
MICROORGANISMS
DC
UJ
>
a:
o
CD
CHANGE IN
FISH
SPECIES
ACTIVE
AVOIDANCE OF
FISH
DEATH OF FISH
Figure 5. Water pollution mechanism in the Ibo River.
79
-------
CRITERIA FOR REMOVAL OF ORGANIC SLUDGE
Although organic sludge is detrimental to the environment there are yet
no rules to judge whether river bottom dredging is necessary. However, fixed
dredging criteria have been developed for major ports.
Provisional standards for removal of organic sludge have been set by
Hyogo Prefecture so that dredging can be performed as a eutrophication control
measure. According to these standards, the necessity for removal is based on
three criteria: 1) volatile and fixed suspended matter, 2) COD and 3) sul-
fide. Sulfide can be omitted from the standards for rivers because little
sulfide formation occurs in fresh water.
Levels of 15% volatile and fixed suspended matter and 20 mg/g COD (dry
weight) are set as the standards. If one of these criteria is exceeded the
bottom sediment should be removed.
The sand-gravel component does not need to be removed but almost all the
sludge should be dredged, as shown in Figure 4. As a consequence, the major
area to be dredged is around the confluence where the average depth of accu-
mulated sediments is 0.8 m, the total area is 6,300 m2, and the total volume
is 5,000 m3. Elsewhere in the Hayashida River there are about 3,000 m3 of
accumulated sediments.
DREDGING OF BOTTOM SEDIMENTS
In dredging organic sludge, secondary pollution must be avoided. In the
selection and adoption of a plan for dredging, sludge treatment and disposal,
individual processes must be considered as components of a total process.
Figure 6 shows a total process beginning with the dredging of sludge and
sediment and with final disposal.
This total process is divided into five major steps:
1) Prevention of Dispersion of Pollutants
2) Dredging and Removal
3) Treatment
4) Final Disposal
5) Environmental Monitoring
After various laboratory and field tests were conducted, integrated
examination and analysis resulted in the following proposal for each step:
1) Dispersion Prevention: use of silt protector
2) Dredging and Removal: use of vacuum collector and dump truck moun-
ted receiver tank
80
-------
, i SELECTION OF REMOVAL AND \.
1 l TREATMENT METHOD
DISPERSION PREVENTION
DEWATERING AND
CONCENTRATION
WASTE WATER
WASTEWATER
TREATMENT
WASTE GAS
TREATMENT
SOIL
CONDITIONER
EXHAUST
GAS
RECLAIMING
5 FINAL
DISPOSAL ( DISCHARGE
Figure 6. Sludge removal process,
81
-------
3) Treatment: combination of natural dewatering at dry river bed and
use of chemical solidifiers
4) Final Disposal: landfill disposal by dump truck
5) Environmental Monitoring: monitor water quality of dredge area and
work only in winter to avoid odor problems
PREVENTION OF POLLUTANT DISPERSION
Tests were performed in winter. The "Provisional guidelines for treat-
ment and disposal of bottom sediments containing toxic substances" provided
baselines for judging water quality and bottom sediments before, during and
after the dredging. Basic and supplementary monitoring points were installed
beforehand. At the same time, water pollution inside and outside of the silt
protector was monitored to judge the performance of the silt barrier.
One result was that the turbidity around the suction nozzle of the vacuum
collector was greatly affected by water depth. When the water depth was about
10 cm, average turbidity was as high as 653 degrees, but it was about 179
degrees when the water depth was 20-40 cm. The turbidity before the work was
74-143 degrees. When water depth is shallow, extreme care must be taken. The
turbidity inside and outside of the silt protector was smaller than the tur-
bidity measured before the work at the upper and lower water layer. The silt
protector should be installed in a closed loop so that currents cannot
DREDGING AND REMOVAL
In dredging organic sludge it is important to prevent secondary pollu-
tion. Disturbance of the sludge must therefore be minimized. To reduce the
volume of wastewater after the dredging, the concentration of dredged material
should be kept as high as possible.
Taking these factors into consideration, the dredges which could be used
in the Ibo River would be the following:
1) Pump dredge (with vacuum collector)
2) Grab dredge (with closed grab bucket)
3) Bulldozer (amphibious)
4) Others
In selecting dredges, many factors such as influence on the environment,
ease of use and economy were considered. The vacuum collector mounted on a
truck with a receiver tank carrier for transportation of dredged sediments was
adopted. In conducting tests, a 100 ps vacuum collector with a suction head
having either 0.08 m x 1.0 m rectangular opening or a 0.23 m diameter round
opening was used. The apparent average sludge concentration rate was in
82
-------
the range of 51% for the rectangular type, and 69% for the round type. When
the depth of sludge accumulation is about 20 cm, the rectangular suction
mouthpiece is best suited; for 40-60 cm, the round one is more effective.
Soundings showed condition of the river bottom after dredging was in very good
shape.
TREATMENT
Dredged sludge contains a large volume of water and its fluid nature
causes problems in transportation to the dumping site. After natural de-
watering using a dry river bed, chemicals are used to solidify the sludge for
transporting.
Using sludge samples with water contents of 300% and 600% (dry wt.
basis), solidification tests were conducted using Portland cement and fly ash.
The results are shown in Figures 7 and 8. In spite of the large difference in
water content, there was no significant difference in the strength per unit
area. The more solidifier used and the longer the curing time, the greater
the strength.
The unconfined compression strength of a cylinderically molded soil
sample could not be measured. Although bottom sludge with an extremely high
critical ratio was composed primarily of organics, it was relatively easy to
treat.
In the field test, dredged sludge was put into a storage basin in a dry
river bed, and the stages of the natural dewatering process were observed.
After that, solidification tests were carried out. Table 6 and Figure 9 show
the change of water content in drained sludge with time.
TABLE 6. CHANGE IN WATER CONTENT OF DREDGED SLUDGES.
Elapsed Time Water Content
0
3 days
7 days
14 days
28 days
1,640%
1,090%
500%
370%
260%
As shown in Table 6, the natural dewatering is very effective, particu-
larly in the first week. Although a blind culvert was installed in the sludge
storage basin, most of the water permeated through the silt and a small amount
came through the blind culvert.
The quality of water permeating through the blind culvert was analyzed.
The turbidity was very high, and also the values of BOD and normal hexane
83
-------
(FAST-SETTING PORTLAND CEMENT)
WATER CONTENT
600% 7 DAYS
600% 28 DAYS
A A 300% 7 DAYS
; A 300% 28 DAYS
oiV
10
15
20
25
30
Figure 7.
DOSAGE RATE OF SOLIDIFIER
(PERCENT)
Relationship of solidifier dosage and strength, for curing times
of 7 and 28 days.
84
-------
CM
O
A
(T 4
h-
(f)
2
O
cc
CL
^
O
UJ
2
U.
8
o
FLYASH:
I5P/0 7 DAYS
* 15% 28 DAYS
O 30% 7 DAYS
30% 28 DAYS
50% 7 DAYS
T 50% 28 DAYS
0 5 10 15 20 25
DOSING RATE OF SOLIDIFIER (PERCENT)
SOLIDIFIER: PORTLAND CEMENT
WATER CONTENT: 600 PERCENT
Figure 8. Relationship of dosage rate of solidifier and strength, for
7 and 28 days of curing.
85
-------
ฃ40
Ld
a 30
o
o
CO
u_
o
Q.
LU
Q
20
10
0
SLUDGE STORAGE BASIN
(I)
V
(IV)
-(Ill)
1500
1000
500
f-
LU
CJ
cr
LU
Q_
LU
h-
O
O
(T
UJ
0
0
4 6
DAY
114
28
Figure 9. Change of depth of bottom sediment and water content with
elapsed time.
86
-------
extraction materials, but nine other tests of water quality relating to human
health satisfied the discharge standards.
To obtain better water quality during operations it was necessary to
adopt sand filtration for the blind culvert. Also, when the sludge storage
basin is used more than twice, it has to be dug to a certain depth because of
clogging.
In field tests using fast-setting Portland cement as the solidifier and
fly-ash as an additive, a backhoe was used to mix the material for a period of
10 days. Unconfined compression strength using Portland cement and 20% fly-
ash was as low as 0.1-0.2 kg/cm2 for day 7, and day 28 was 0.4-0.7 kg/cm2. In
the case of 40% fly-ash day 7 was 0.2-0.3 kg/cm2 and day 28 was 1.1 kg/cm2 as
shown in Figure 10. The critical ratio was in the range of 1.5-4.0 in the
latter case. The volume was increased by about 18%, when 40% of the additive
was used.
FINAL DISPOSAL
The strength needed for excavation, dumping and
sludge is 0.3 kg/cm2 for excavation and loading, more
transportation and dumping, 0.8 kg/cm2 for covering, and
ing after reworking the soil.
covering of treated
than 1.0 kg/cm2 for
1.0 kg/cm2 for bank-
Because the solidified sludge was intertwined with animal hairs that
existed in the bottom sediments, the necessary strength for excavation and
loading, transportation and dumping, covering, and banking were respectively
0.1-0.2 kg/cm2, 0.4 kg/cm2 or more, 0.3 kg/cm2 or more, and 0.5 kg/cm2 in
terms of the strength after disturbance.
The most economical conditions that met these figures are as follows:
1) Solidifier
Fast-setting
Portland cement li
2) Additive
fly-ash
20%
3) Curing time
not less than 28 days
4) Water content of treated sludge : not more than
70%
Ref: Above conditions are based on sludge with an initial water content
of 500% and the use of a backhoe for mixing.
Before covering operations began it is necessary to wait for natural
de-watering at the dumping site as well as for the recombination of soil par-
ticles, since the strength does not reach 0.3 kg/cm2 at the time of trans-
portation. From the test data on the critical ratio, solidified sludge cannot
be used for banking materials. It cannot be used as backfill material in
revetment, for the same reason.
87
-------
1.5
CM
w 10
cc l.u
LU
CC
0.
0.5
Q
LU
8
o
FLYASH CURING DAYS (%)
1
0 5 10 15 20 25
DOSAGE RATE OF FAST-SETTING PORTLAND CEMENT
(PERCENT)
Figure 10. Unconfined compression strength and dosage rate of solidifier for
7 and 28 days of curing.
88
-------
Consequently, dumping in dry river beds or transportating them to a
neighboring land reclamation site and covering the surface with better soil
may be the only possible way of final disposal.
ENVIRONMENTAL MONITORING
Downstream of the dredging site are industrial water intakes and a com-
mercial fishery. Careful monitoring is necessary to avoid the generation of
secondary pollution by dredging which would have a negative impact on these
water users. As mentioned earlier, the water quality has been monitored for
several factors such as turbidity, pH, BOD, COD, normal hexane extraction and
DO at basic and supplementary monitoring points installed downstream from the
worksite. Downstream samples are compared with control samples to prevent
water quality deterioration due to dredging.- The installation of the closed
silt protector proved to forestall such problems.
Odor monitoring is also required. During the field tests in winter
neither H2S nor methyl mercaptan were detected at a distance of 5 to 50 cm
from the surface of dredged sludge in the disposal basin. When heated inside
to 30%C, 5 mg/1 H2S was detected. A threshold concentration for human health
is 10-15 mg/1. At this level, H2S will cause eye irritation within 6 hours.
CONCLUSION
The particle size distribution curve for bottom sediments before and
after the test dredging is shown in Figure 11. The bottom sediments prior to
dredging are composed mainly of minute particles; after dredging they consist
more of coarse particles.
The cost for dredging depends on site and volume. A rough estimate is
about 8,700-10,000 yen per cubic meter, of which the solidification treatment
costs 3,700 yen.
In conclusion, after extensive laboratory and field tests, useful knowl-
edge has been obtained which is applicable to actual dredging.
89
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POLLUTION CONTROL IN TOKYO BAY
Masai Yako and Keitchi Akimoto
2nd District Port Construction Bureau
Ministry of Transport, Japan
INTRODUCTION
This report indicates the distribution and properties of the sapropel
which has accumulated in Tokyo Bay, clarifies the effects of this sapropel on
water quality and the biota and investigates the results of dredging designed
to control pollution from this source.
POLLUTION IN TOKYO BAY
BOTTOM DEPOSITS
Sapropel is a soft mud, containing large amounts of organic detritus such
as algae, pollen, spores or animals. Sapropel accumulates under reducing con-
ditions (anaerobic areas) in calm sea areas. The sapropel was found to be
widely distributed from off Haneda to the middle of the bay with a thickness
of 40-50 cm (Figure 1). Samples of sapropel and the underlying mud, 50-80 cm
thick, were collected together without disturbing the layers and the samples
were analyzed.
The conditions of the bottom deposits were classified according to 1)
surface layer, 10 cm down from the top of the sapropel, and 2) substratum, the
clay and silty layer 50-60 cm below the sapropel (Figure 2).
Analyses of the deposits showed that the surface layer had higher values
than the substratum with respect to water content, sulfides, ignition loss and
chemical oxygen demand (COD). There was also a remarkable amount of organic
pollution in the surface layer in the innermost part of the bay. In addition
to these organic pollution indices, the nutrient content (nitrogen and phos-
phorus) was high and matched the areas where the sapropel was thick (Figures
3-8).
WATER QUALITY
In summer there was a thermocline and halocline at depths of 5-10 m.
Water quality differed remarkably above and below this layer. pH was high in
the surface layer and tended to be low in the bottom layer. Dissolved oxygen
(DO) was supersaturated in the surface layer, while the bottom water in the
innermost and middle parts of the bay was poor in oxygen. COD and total
91
-------
Arakawa Nakagawa
Sumidagawa River River River
TOKYO
SHINAGAWA
HANEDA
Tamagawo River
KAWASAKI
Edoqowa River
CHIBA
O) 10 O *
00 O
o o o
o
OKDHAMA
HONMOKU
TOMIOKA
YOKOSUKA
FUTTSUZAKI
ANEGASAKI
BANZUNOHANA
KISARAZU
KANNONZA
0.1-0.3
0 0.3-0.7
Figure 1. Distribution and thickness of sapropel in Tokyo Bay (in meters)
SEA BOTTOM
Figure 2.
Diagram of core
sample.
FLUID MUD
J J_SURFACE (0-IOcm)
SAPROPEL
J_
I
50 (cm under sapropel)
SUBSTRATUM (10 cm)
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organic carbon (TOC) were also high in the surface layer and low in the sub-
stratum. These results indicate that above the thermocline the water is rich
in orgam'cs.
Nutrient concentrations were high in the coastal regions but tended to de-
crease towards the mouth of the bay. There were high values for phosphorus,
in the form of phosphates (P04-P), and nitrogen in the form of ammonia
(NH4-N), in the water directly above the sea bed, corresponding to the zone of
oxygen-poor water (Figures 9-11).
BENTHOS
Sampling was performed twice with a Koken mud sampler. This device
samples an area of 1/15 m2 with a sample size of 5.6 1. The macrobenthos
retained on 1 mm-mesh sieve was identified and counted.
In the summer survey, areas totally devoid of life were observed in the
innermost and middle parts of the bay. Only one or two organisms were found
nearby. The species found included polychaetes and mollusks in the middle and
mouth of the bay and crustaceans at the mouth of the bay. There tended to be
greater diversity toward the mouth of the bay (Figure 11). In the winter
survey, there were no areas devoid of life, but there were many places in the
inner bay where only two or three organisms were found. This was correlated
with the spread of organic pollution.
Figure 12 shows the relationship between the benthos and the values for
COD, sulfides and ignition loss in the mud deposits of Tokyo Bay.
According to these results, polychaetes gradually decreased when the
value of COD fell below 15 mg/g, sulfides fell below 0.5 mg/g and the ignition
loss fell below 10%.
In the case of crustaceans, maximum numbers were seen at a COD of about
13 mg/g, sulfide content of 0.25 mg/g and an ignition loss of about 7.5%.
When these values became higher or lower, the number of crustaceans decreased
as well as percent contribution to the population. This suggests that there
are optimum values for crustacean success.
The total number of benthic organisms, the number of species and the
biotic index (BI) showed optimum values for a COD of 8-10 mg/g, sulfide con-
tent of 0.3-0.5 mg/g and an ignition loss of about 5%.
Figure 13 shows a histogram correlating the number of species in the
benthos with the values of COD, sulfide and ignition loss and mud deposits in
a survey of Tokyo Bay conducted in October, 1972. According to these results,
the number of species reached a maximum at a COD of 5 mg/g, sulfide content of
0.25 mg/g and an ignition loss of about 5%. When these results are compared
with the present surveys, the COD value is seen to be rather low, but the
sulfides and ignition loss values match closely the best conditions from the
standpoint of the benthos.
96
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o 50-111
0
10
20
30
40
0
1 10
a. 20
UJ
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30
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Figure 9. Sampling stations for water quality gradients.
15 29 48 69 90
NUMBER
15 29 48 69 90 15 29 48 69 90 15 29 48 69 90
o 21
WATER TEMP (ฐC)'^
i ' i
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P04-P(ppm) '7*-
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TOC(ppm)
I I I
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Figure 10. Vertical profiles along the longitudinal section delineated in
Figure 9.
-------
3) LOCATION OF NO
LIVINGORGANISMS
Figure 11. Distribution of benthic species composition September 1977.
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80
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L 0
40
h40
- 0
L 0
-6r> On VO n -6-6
5 0 IGN.LOSS(%)
Figure 12. Correlation between zoobenthos and COD, sulfide and ignition loss.
99
-------
60
30
en
IGNITION LOSS(%)
5 20
u 60
Q.
en
15
10
0 30
oc.
UJ
CD
60
30
SULFIDE (mg/g)
COD (mg/g)
40 30 20 10 0
Figure 13. Histogram correlating benthic species with sediment values.
1m
-20cm
WATER SAMPLER
D.Q METER
-ACRYLIC PIPE
WATER (about 20:1)
30cm
Figure 14. Leaching experiment
apparatus.
100
-------
EFFECT OF BOTTOM DEPOSITS ON WATER QUALITY
There are two ways in which bottom deposits affect water quality - by
leaching of organic matter and nutrients from the deposits, and by the con-
sumption of dissolved oxygen from the water.
In Japan there have been few experiments on the amounts of substances
leached into the sea, and there is only a general notion of the way the con-
tents and temperature of organic matter and nutrient salts in the mud, and
dissolved oxygen in the water just above the sea bottom, influence the leach-
ing process.
There are often cases where deposits consume the dissolved oxygen in the
water and the oxygen-poor conditions which produce a cyclic pattern promoting
further deterioration of the deposits, lower water quality, and adverse
effects on the benthos.
In the leaching experiments, samples were taken simultaneously from the
surface layer of the deposit (1-30 cm) and the substratum (50-80 cm under the
sap^opel). The water directly above the bottom was also taken for use in the
experiment. Figure 14 shows the experimental apparatus.
The experiment was performed for five days and the amount leached per
unit area per day (mg/m2/day) was calculated from changes in the concentration
in the water. The average amount leached was the average of these daily
values.
The average values obtained in experiments performed in September, 1976,
and September, 1977, are shown in Table 1. Large differences were observed
between the surface layer and the substratum.
TABLE 1. AVERAGE AMOUNTS LEACHED (mg/m2/day)
COD TOC T-N T-P
Surface layer 285 192 145 27
Substratum 232 125 136 10
OXYGEN CONSUMPTION RATE IN THE DEPOSITS
The samples and j_n situ seawater for this experiment were collected by
the same method as used in the leaching experiment. After they were brought
to the laboratory, they were reaerated in a constant temperature chamber (20 ฑ
2ฐC). The experiment was_ started when the DO concentration in the seawater
increased. The DO and S~ concentrations in this water were measured at in-
terval s.
101
-------
The experiment was performed for five days and the average oxygen con-
sumption was calculated using the same method as in the leaching experiment.
The S ioji was converted to oxygen iji the. ratio of 2 moles of 02 produced to 1
mole of S , based on the equation S04~ ^ S + 202 (gas).
The results gave an average oxygen consumption rate of 2.5g 02/m2/day in
the surface layer and 1.32g 02/m2/day in the substratum. The surface layer
consumed 1.7 times more oxygen than the substratum. These results show that
the sapropel has a deleterious effect on the aquatic environment and that the
environment can be restored by removing the sapropel.
THE RESULTS OF REMOVING THE SAPROPEL
Seawater purification can be broken into two types - biochemical purifi-
cation produced by microorganisms, or physical purification such as seawater
exchange.
The use of microorganisms involves their ingestion of organic matter
present in the water. Part of this matter is converted to substances neces-
sary for the growth of the microorganism and the remainder becomes a respira-
tion byproduct which is oxidized to inorganic material. The bacteria even-
tually die and this material is utilized by other bacteria. There is, there-
fore, a partial change to inorganic material in this process. The organic
matter is decomposed more quickly as the number of times the organic matter
passes through the bacteria increases. When there are protozoa or zooplankton
present to feed upon these bacteria, the number of cycles through organisms
increases and the organic matter is decomposed at a faster rate.
This ingestion of organic matter by microorganisms is part of the process
by which substances circulate in the water. The way to understand the process
of biological control of organic matter is to investigate the circulation of
organic matter in the biota and the cyclic rate. Figure 15 shows the circu-
lation of organic material in Tokyo Bay.
Because this survey was conducted in summer when there is a lot of tur-
bidity, many points remain unclear. Various coefficients of the material
circulation model were determined by site observations and laboratory exper-
iments. The idea was to determine, by means of numerical simulation, what
degree of water purification can be expected by the removal of the sapropel.
BASIC EQUATIONS OF THE EUTROPHICATION MODEL
In the preparation of the eutrophication simulation model, the following
five items had to be quantified to simulate the seawater turbidity mechanism:
1) The quantities of COD and nutrient salts in the water which flows
into the bay
102
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103
-------
2) The quantities of organic matter and nutrient salts which leach from
the bottom mud
3) The rate of decomposition of organic matter
4) The rate of precipitation of organic matter
5) The rate of assimilation and absorption by photosynthesis
These five parameters were quantified by means of field and laboratory experi-
ments.
Four substances were used as indices in the numerical analysis: COD, DO,
limiting organic nutrients (phosphorus) and inorganic nutrients. The circu-
lation process of these substances was expressed by developing eight diffusion
equations, given below. The following points were guidelines for development
of the equations:
1) In the euphotic zone, there are diffusion, flow, production, decom-
position, precipitation and an exchange between the surface layer and sub-
stratum.
2) In the aphotic zone, there are diffusion, flow decomposition, pre-
cipitation, leaching from deposits, DO consumption by the deposits and ex-
changes between the surface layer and substratum.
3) Production involves the assimilation of inorganic nutrient salts by
phytoplankton and their conversion into organic nutrient salts. This results
in an increase in the COD and DO.
4) The inflow load refers only to flux into the euphotic zone.
(A) Diffusion Equations of Nutrients
1) Euphotic zone
- yNo + LNo (1)
8NTh 3NTh 3NTvh 3 3Nr 3 3N
-งr -~^- - 1- +3
jh + pNon+ LNj (2)
104
-------
2) Aphotic zone
3N'oh' aN'oiTh' aN'ov'h'. 3 ,u.u* 3lTo , 8 ,.. ^3NTo .
~9t~ 9^ ay~ a^ (K h ~^~ } ay C ~W~)
+Kz (No - N'o) - pN'oh' + v (No - N'o) + Bo (3)
at a d a a a
+Kz (Nj - N'j) - pN'oh' + Bj (4)
No : Organic nutrient concentration in euphotic zone
NT : Inorganic nutrient concentration in euphotic zone
N'o : Organic nutrient concentration in aphotic zone
N'y : Inorganic nutrient concentration in aphotic zone
K : Horizontal diffusion coefficient in euphotic zone
K' : Horizontal diffusion coefficient in aphotic zone
Kz : Exchange coefficient between surface layer and substratum
a : Rate of photosynthesis
p : Rate of decomposition
Y : Rate of precipitation
p' : Rate of decomposition in aphotic zone
Bo : Amount of organic nutrient salts leached per unit time and area
BT : Amount of inorganic nutrient salts leached per unit time and area
LNo : Amount of organic nutrient salts received from land
LNT : Amount of inorganic nutrient salts supplied from land
h, h' : Thickness of euphotic and aphotic zones
105
-------
u, u': Flow rate in x-axis direction in euphotic and aphotic zones
v, v': Flow rate in y-axis direction in euphotic and aphotic zones
(B) COD Diffusion Equations
(1) Euphotic zone
3Sh _ 3Suh aSvh 3 ,. 3S, 3 ,. 3S, ,.
3F ~ " ~3F "37" +3T~(Kh iV 3y~ (Kh 37; Kz (S
+ aaNjh - K^h -K3S + LS (5)
2) Aphotic zone
SB (6)
S : COD of euphotic zone
S' : COD of aphotic zone
a : Ratio of nutrient salt concentration and COD concentration in
phytoplankton
Kx : Reduction coefficient in euphotic zone
K3 : COD precipitation rate in euphotic zone
K\ : Reduction coefficient in aphotic zone
K'3 : COD precipitation rate in aphotic zone
SD : Amount of COD leached per unit area and time
D
[_- : Amount of COD load received from land
106
-------
(C) DO Diffusion Equations
(1) Euphotic zone
5Ch = Muh . |vh + ^_(Kh
+ K2 (C$ - C)h - K! Sh
(2) Aphotic zone
(Kh _j _ Kz (c . r) + fa
(7)
'inr ac'v'tr. 3 ,,,., ac; a ,Kh-_ac\ , k7 rr _
" ~ " (Kh } " (Kh ~) (
at ax ay
- Ki' s'h - DB (8)
P : DO release rate by photosynthesis
K2 : Reaeration coefficient
C<- : DO saturation rate
Kx : Deoxidation coefficient
DR : Amount of DO consumption per unit area and time
DETERMINING THE COEFFICIENTS
The coefficients used in the calculations were derived as follows:
Production
The production rate was calculated from the nutrient salt intake of the
plankton obtained from an algal potential productivity (AGP) test performed on
surface layer water collected at the site. The average value for the whole
area was used.
Decomposition
The rate of decomposition was calculated from the difference between the
initial concentration and the final concentration, after decomposition in a
dark room, using samples collected at each water level (both surface layer and
substratum). The average for the whole area was used.
107
-------
Precipitation
The sediment sampler was deployed at the site from dawn to sunset. The
precipitates were then collected and the concentration of specific substances
in the precipitates determined. The rate of precipitation was calculated by
comparing water qualities in the same water layer for both the surface layer
and substratum. The average value for the whole area was used.
Leaching
Water just above the sea bottom, and cores of mud were collected at the
site by divers. After the samples were brought back to the laboratory, the
quantity leached was calculated from changes in the concentrations of sub-
stances in the collected water. The value was divided over three blocks for
the substratum.
Oxygen Consumption
Samples were collected in the same way as for the leaching test. After
the samples were returned to the laboratory they were reaerated. The amount
of oxygen consumption was calculated from the changes in the concentrations of
substances in the collected water.
Influx Load
The actual values were used as measured in 1976 in Chiba, Tokyo and
Kanagawa Prefectures.
RESULTS OF DIFFUSION CALCULATIONS
Validation by Hi storical Records
Since the 1976 influx load values were used, a companion 1976 investi-
gation of water quality (Figures 16-18) was used to check the validity of the
model.
The coefficients used in the model were obtained from surveys performed
in September, 1976 and August-September, 1977. These values are given in
Table 2. The experimental values were corrected to those shown in the column
on the right and are considered to more closely resemble current values.
The results from the model equations are shown in Figures 19-21. These
results are outlined below.
COD
In the surface layer, the isopleths of 2 ppm and 3 ppm generally match
current conditions, so the accuracy appears to be good. In the substratum,
the values currently are 2 ppm or less near the center of the bay. The calcu-
lated values match those from the mouth to the middle of the bay. But the
calculated values are 1-2 ppm higher than the current values in the innermost
part of the bay.
108
-------
40ฐ
50ฐ
140ฐ
40ฐ
50ฐ
140ฐ
40ฐ
30<
20ฐ
10ฐ
1.0-3.0
O 3.0-7.3
SURFACE
I
40ฐ
30ฐ
20ฐ
10ฐ
0.7-2.0
O 2.0-3.9
SUBSTRATUM
Figure 16. COD (ppm) average of July, August, September 1976.
40ฐ 50ฐ 140ฐ 40ฐ 50ฐ 140ฐ
40ฐ
30ฐ
20ฐ
10ฐ
O 0.050-0.280 _
40ฐ
30ฐ
20ฐ
10ฐ
0.009-0.050
O 0.050-0.179
SUBSTRATUM
Figure 17. PO.-P (ppm) average of July, August, September 1976.
109
-------
40ฐ
50ฐ
140ฐ
40ฐ
50ฐ
140ฐ
40ฐ
30ฐ
20ฐ
10ฐ
5.0-9.0
O 9.0-10.9
SURFACE
I
40ฐ
30ฐ
20ฐ
10ฐ
0.9-3.0
O 3.0-7.7
SUBSTRATUM
Figure IP. DO (pprc) average of July, August, September 1976.
SURFACE
Figure 19. Model results for COD distribution.
110
-------
P04-P (ppm)
120 TIDAL
SURFACE
Figure 20.
Model results for P04-P distribution.
SURFACE J 120 TIDAL SUBSTRATUM
Figure 21. Model results for DO distribution,
111
-------
TABLE 2. COEFFICIENTS USED AS MODEL PARAMETERS.
Block
or
Coefficient layer
Production
amount Top
(/day)
Decompo-
sition K
<^!> Bฐ"ฐป
Precipi- Top
tation
amount
(m/day)
Bottom
Block
Amount 1
leached Block
(mg/m2/day) 2
Block
3
Block 1
Amount of Block 2
DO Block 3
consumption
(g02/m2/day)Total
area
Initial Total
value (ppm) area
Item
P04-P
COD
0-P
COD
0-P
COD
0-P
COD
0-P
COD
P04-P
COD
P04-P
COD
P04-P
DO
DO
concen-
tration
COD
P04-P
Experi-
mental
val ue
0.409
0.095
0.040
0.078
0.017
0.57
0.93
0.92
1.10
650
65
400
30
0
0
5.5
4.0
0
8.0
ppm
1.0
0.08
Current
Reason for Correction value
(used)
30% reduction; remarkable in- 0.29
crease in COD concentration in
top layer
0.095
0.040
Same 0.078
0.017
30% reduction; large precipi-
tation coefficient and drop in 0.40
concentration of water quality.
40% reduction (further reduction
made from 30% since reproduc- 0.56
tion of surface layer phosphorus
concentration still difficult).
30% reduction; large precipi-
tation coefficient and large 0.67
reduction in concentration of
water quality. 0.77
(Maximum leached value of 650
amounts 1976 and 1977 was 80% 65
of the value statistically.) 400
Same 30
INO UlbLllUULIUII Ul SctptOpel ,-.
Same 5.5
(80% value according to calcu- 4.0
lation method as with the case 0
of the amount leached).
DO concentration corresponding
to 100% DO saturation. Tokyo 8.0
Bay, summer: 7.5-8.5 ppm) ppm
Monthly value for the bay
from results of water quality 1.0
measurements in 1976. 0.08
Remarks
Calculated tide: 120 tidal
dilution coefficient: 1.0
diffusion coefficient: 105 cnr/sec,
112
-------
In the surface layer, the values resemble the current values of 0.02 ppm
near the mouth of the bay. But, the current values from the middle to the
innermost part of the bay are higher.
DO
In the surface layer, the calculated values for the whole area are more
than 8 ppm. Actual measurements show supersaturated areas of 7 ppm or over,
except in the western part of the bay. However, in the substratum, there are
wide-ranging oxygen-poor conditions, especially in the area on the east coast
of the inner bay where the calculated values were 4 ppm or less and their low
values match the actual measurements. The 5 ppm isopleth at the mouth of the
bay closely resembles the current value.
Summary
When the above results are summarized, it is evident that the model's
accuracy was rather poor for COD in the substratum and for P04-P in the sur-
face layer. But in general the calculated values matched the current values
quite well from the mouth to the middle of the bay.
PREDICTION OF EFFECTS OF SAPROPEL REMOVAL
The following two cases were considered to determine the effects of
removal of sapropel:
Case 1: Removal of 75 km2 of sapropel for areas in the bay with particu-
larly high leaching rates and oxygen consumption (Figure 22).
Case 2: Removal of 400 km2 of sapropel from abiotic areas (Figure 22).
Figures 23 to 28 show the predicted changes in water quality for Cases 1 and
2.
In Case 1 the 4 ppm and 5 ppm predicted COD isopleths in the middle of
the bay, when compared with current conditions, would shift inside the bay in
the surface layer, as would the 3 ppm isopleth in the substratum. The predic-
tion is, therefore, that Case 1 removal would purify the water in the inner-
most and middle parts of the bay. The P04-P would not change much in the
surface layer - there would be an improvement of about 0.01 ppm in the inner
bay. There would be few differences for DO in the surface layer, but in the
substratum there would be fewer areas of 4 ppm or less and the oxygen con-
centration would increase near the mouth of the bay.
In Case 2, the COD concentration would decrease by 0.5-1.0 ppm from the
middle to the innermost part of the bay, and there would be a remarkable
improvement in water quality. The P04-P would show small values in the inner-
most part of the bay with large decreases in the substratum. There would be
almost no change in the DO in the surface layer, but in the substratum there
would be an increase in the oxygen concentration of about 1 ppm.
113
-------
0510 km
HIGHLY POLLUTED AREA (CASE I)
ABIOTIC AREA (CASE 2)
DIVISION BY BLOCKS
Figure 22. Critical areas for sapropel removal
114
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116
-------
117
-------
118
-------
119
-------
120
-------
Article 9 of the Basic Law for Environmental Pollution Control (1967)
sets standards intended to develop and maintain water quality in public water
areas with respect to the protection of human health and the environment. The
health standards are uniform for all areas, but those concerning the environ-
ment include different standards for various types of water areas, such as
rivers, lakes and the sea, depending on the purpose for which the water is
used. By categorizing aquatic areas by use, the environmental quality stan-
dards for a critical area are clearly indicated. In Tokyo Bay, the water use
categories for 18 regions are shown in Figure 29.
Table 3 shows the environmental quality standards for COD with respect to
present conditions and the Case 1 and Case 2 predictions. The results indi-
cate that, at present, the standards have been achieved for about 61% of Tokyo
Bay as a whole. Among the various types of areas, the B type showed a par-
ticularly low achievement ratio of about 36%. For the simulated cases where
the sapropel is removed, the improvement is naturally much greater when the
removal area is larger. In Case 2 where 400 km2 of sapropel is to be removed
from the abiotic zones, it is difficult to achieve the required standards in
more than 75% of the B category areas, but the percentage rises to 77% for the
whole bay and such an improvement can be expected to create a fairly good
aquatic environment.
TABLE 3. ENVIRONMENTAL QUALITY STANDARDS AND ACHIEVEMENT RATES (Unit: %).
Item COD
Use Category A B C Whole Bay
Standard values 2 ppm or less 3 ppm or less 8 ppm or less
Current values 78.4 35.7 82.9 61.4
removal (Case 1)
400 km2 of saprcpel
removal (Case 2)
78.4
89.2
38.9
60.3
82.9
87.8
62.7
77.1
IMPLICATIONS OF MODEL RESULTS FOR THE BENTHOS
Figure 30 shows the relationship between the benthos and COD, sulfides,
and ignition loss in bottom deposits. It is the same as Figure 12 but is
marked with the predicted values from the simulation. The removal of sapropel
improved ignition loss to 7%, sulfides to 0.2 mg/g and COD to 13 mg/g. It can
be assumed that the number of organisms and the species diversity will there-
fore increase.
121
-------
TOKYO
KAWASAKI
YOKOHAMA
CHIBA
ICHIHARA
KISARAZU
Bn
YOKOSUKA
Utilization Category
TOKYO BAY 1 Conservation of environment
2
3
4
5
6
7
8
9
10 Fishery, class 2: industrial
water and uses listed in C
11
12
13
14
15
16
17 Fishery, class 1; bathing;
conservation of natural environ-
ment and uses listed B, C
18
Category
C
C
C
C
C
C
C
C
C
B
B
B
B
B
B
B
A
A
Figure 29. Area ranked by environmental standards
122
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123
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Figure 31 shows the relation between the benthos and water quality. At a
DO concentration of 5 ppm, the number of species decreased to five or less and
at about 3 ppm, the organisms numbered five or less. Since an increase in DO
concentration in the substratum is one of the anticipated effects of the
removal of sapropel, there should be a correspondingly better environment for
organisms with improvement of bottom deposits and water quality. This will
have a major effect on the recovery of marine life as outlined by the flow
diagram in Figure 32.
CONCLUSION
Through studies of bottom deposits, water quality and biota in Tokyo Bay,
it has become clear that sapropel, which has accumulated widely in the bay,
has a major deleterious influence on the water quality and biota.
A mathematical eutrophication model was developed to investigate the
effects of the removal of sapropel on water quality. The model was construc-
ted based on data from experiments on leaching of organic detritus and nutri-
ents from the deposits and DO consumption by the deposits. The results indi-
cated that water quality would be greatly improved by the removal of sapropel,
especially in the middle of the bay.
However, many questions still remain unanswered; among them are the
long-term accumulation, decomposition rates and formation of new sapropel
deposits after removal. This research will therefore be continued in the
future.
124
-------
REMOVE ACCUMULATED POLLUTED SLUDGE
REDUCE SIZE OF LOW OXYGEN REGIONS
FACILITATE DECOMPOSITION OF DETRITUS, PREVENT NUTRIENT
RELEASE, STABILIZE TOXIC SUBSTANCES
ฑ
PREVENT RED TIDE BY DECREASE OF SECONDARY POLLUTION
PREVENT LOW DIVERSITY BENTHIC COMMUNITIES
REDUCE WATER POLLUTION BY DECREASE OF COD,
TOC, NX AND Px AND INCREASE OF DO
RE-ESTABLISHMENT
OF A
VIABLE
LIVING
COMMUNITY
INCREASE IN FISHING (MIGRATION OF FISHES...
SAUREL, GRAY MULLET, SPRAT)
INCREASE OF BENTHOS (BIVALVES.. .SHORT NECKED CLAM,
ARK SHELL, FLATFISH, YOUNG
SEA BASS, GIANT CLAM)
INCREASE OF
ZOOPLANKTON
DECREASE OF
PHYTOPLANKTON
(CRUSTACEAN)
(DECREASE OF RED TIDE)
- DECREASE OF ABIOTIC (MULTIPLICATION OF
ZONE SLUDGEWORMS)
Figure 32. Flow chart showing effects of improved bottom deposits in Tokyo
Bay.
125
-------
RELEASE OF NUTRIENTS FROM LAKE SEDIMENTS
Ken Murakami, Chief
Kiyoshi Hasegawa, Research Engineer
Water Quality Section
Public Works Research Institute,
Ministry of Construction, Japan
ABSTRACT
Laboratory experiments were conducted on the release of nutrients from
bottom sediments under various conditions. The relationships between nutrient
release rates and nutrient content of sediments, temperature, redox potential
of overlying water and other factors are discussed, based on the results of
the experiments.
INTRODUCTION
In recent years, eutrophication has become a serious problem in many
major lakes and reservoirs in Japan including Lake Kasumigaura, Lake Suwa and
Lake Biwa. The phytoplankton blooms accompanying eutrophication not only
obstruct direct water utilization, but scenic spots that used to have beau-
tiful crystal clear water have lost their recreational value. The primary
reason for eutrophication is the increase in nutrient loading from the drain-
age basin of each lake. But it is also well known that nutrient exchange
between bottom sediments and overlying water is strongly related to increased
eutrophication. Much research has been conducted on the role played by bottom
sediments as a nutrient storehouse. However, the rates of nutrient transfer
between the two phases have not been fully quantified. This makes it diffi-
cult to accurately estimate the nutrient budget of lakes, particularly for
short time periods.
Laboratory experiments on the release of nutrients from bottom sediments
used both disturbed samples and undisturbed core samples with flocculant
sediments on the surface. The result of the experiments is discussed in this
report.
EXPERIMENTAL METHOD
EXPERIMENTS USING DISTURBED SAMPLES
Both continuous and batch experiments were carried out using the appara-
tus shown in Figure 1. The vessel is 60 cm high and 40 cm inside diameter
with a capacity of 75 liters. Tests were conducted by filling the bottom with
a sediment layer approximately 10 cm high. In the batch apparatus a magnetic
127
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SATCH TYPE
II l|
DISTILLED
WATER
CONTINUOUS TYPE
II II
CONSTANT
FEED PUMP
SEDIMENT!
I \
Figure 1. Apparatus for experiments with disturbed samples.
stirrer was used to examine the effect of the velocity of the overlying water
on the release of nutrients. Distilled water was used as the overlying water
in both batch and continuous systems.
In the batch test, the gas phase was released to the atmosphere in test
runs under aerobic conditions. In test runs requiring anaerobic conditions,
the water was purged by nitrogen gas and, at the same time, the gas phase
(air) was replaced by nitrogen prior to the tests.
The continuous tests were performed to observe the variation in release
rates when the overlying water of the bottom sediments changed from aerobic to
anaerobic, and from anaerobic back to aerobic. To change the test water from
aerobic to anaerobic, distilled water free from dissolved oxygen was supplied
while, simultaneously the water in the vessel was purged with nitrogen.
The bottom sediment samples used in the tests were collected from Lake
Kasumigaura, Lake Teganuma, Lake Toyanogata and the outer moat of the Imperial
palace in Tokyo. Some sediment samples taken from the bottom of the Anakawa
River and the Tsurumi River were also used.
EXPERIMENTS USING UNDISTURBED SAMPLES
Flucculant sediments on the lakebed
release of nutrients by bottom sediments.
are difficult to collect by conventional
taken using core samplers, and the core
apparatus.
surface could be related to the
Since these flocculant sediments
methods, undisturbed samples were
tube itself was used as a test
128
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As shown in Figure 2, the sampler consisted of an acrylic plastic tube
with an inside diameter of 5.2 cm and a length of about 66 cm. A sufficient
number of samples were collected at a single station to provide 5 tubes for
each test run. The samples were returned to the laboratory where the over-
lying water was carefully replaced by lake water filtered through a 0.45(j
membrane filter.
AIR RELEASE HOLE
ACRYL CORE
SAMPLER
Figure 2. Core sampling for experiments requiring undisturbed samples.
In this experiment, since water volume in the core tubes was small, five tubes
of samples were run simultaneously and used as replicates.
For the experiments under aerobic conditions, the overlying water was
continuously aerated by a small amount of air during the test period. For the
experiments under anaerobic conditions, two modifications were made. The
first was to remove dissolved oxygen in the overlying water by using a nitro-
gen gas purge. The second was to add glucose to the water (20 mg/1 at 20ฐC)
after removing the dissolved oxygen. This helped maintain the anaerobic
state.
The bottom sediments used in these tests were collected from Lake Kasumi-
gaura. The sampling stations are shown in Figure 3. An attempt was made to
maintain a consistent thickness of bottom sediments for each sample. But, in
practice, they varied in thickness from 10 cm to 32 cm with an average of
about 20 cm.
129
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10 km
Figure 3. Sampling stations (core samples) in Lake Kasumigaura.
RESULTS AND DISCUSSIONS
PHOSPHORUS RELEASE
(1) The relationship between phosphorus release rate under anaerobic condi-
tions and phosphorus content of the sediments.
The release of phosphorus from bottom sediments increases markedly when
dissolved oxygen in water and the oxidation-reduction potential decreases.
Figure 4 shows an example of results obtained from a continuous-type test
with a disturbed sample. It is clear from the figure that the phosphorus
concentration in the water begins to increase as the concentration of dis-
solved oxygen decreases. However, the release rate after the dissolved oxygen
reaches zero is not constant. Figure 5 shows the time variation of the phos-
phorus release rate as calculated from the data shown in Figure 4. The gen-
eral pattern is that, immediately after reaching an anaerobic condition, the
release rate shows a marked increase and then decreases after about 6 days.
The phosphorus release rate under anaerobic conditions is, therefore, time
dependent. The average release rate during the first one- or two-week period
after the dissolved oxygen declined to zero was compared to the phosphorus
content of sediments, as shown in Figure 6. The release rate was in pro-
portion to the phosphorus content of the sediments, and could be approximated
by the following equation
Y = 10X
(1)
130
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0
04
O>
8
.-02
-Fe
10 15 20
TtME, DAYS
25 30
Figure 4. Variation of quality of overlying water; continuous
type experiment with Lake Teganuma sediments.
131
-------
30 r-
-20 u
Figure 5. Time variation of phosphorus release rate; continuous type
experiment with Lake Teganuma sediments.
100
UJ
<
""
ESO
K
O
O
X
a.
O
J
I
2468
PHOSPHORUS CONTENT OF SEDIMENTS
P-mg/g DRY SO LIDS
10
Figure 6. Relationship between phosphorus release rate under anaerobic
conditions and phosphorus content of sediments; experiments
with disturbed samples at 20ฐC.
132
-------
where, Y is the average release
conditions at 20ฐC and X is the
solids).
rate of phosphorus (mg/m2/day) under anerobic
phosphorus content of the sediments (mg/g dry
The same relationship was obtained by experiments using undisturbed
samples with flocculant sediments. Figure 7 shows the relationship between
the average release rates during the first 11 days after the start of the test
at 20ฐC, and the phosphorus content of the surface sediments. It is inter-
esting that equation (1) is also a good approximation for the flocculant
sediments.
10
8
LU
S
cr
m
Jr
o
CO
i
Q.
I I I
ANAEROBIC (Glucose Addition)
C ANAEROBIC
O AEROBIC
$
O
O
1
0.2 0.4 0.6 0.8
PHOSPHORUS CONTENT OF SEDIMENTS
P-mg/g DRY SOLIDS
1.0
Figure 7. Relationship between phosphorus release rate and phosphorus
content of sediments; experiments with undisturbed samples
at 20ฐC.
The pattern of time variation of phosphorus release under anaerobic
conditions, particularly the fast rate immediately after conditions become
anaerobic, suggests that reduction of ferric phosphate is significantly in-
volved in phosphorus release from the sediments. As shown in Figure 8, there
is a good correlation between phosphorus and iron in the overlying water.
133
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0.20
0.16
E
o. 0.12
of
o
.c
ฐ o:os
0.04
12
0.2 04 0.6 0.8
Fe~, T-Fe, mg/l
1.0
1.2
Figure 8. Relationship between phosphorus and iron in overlying water;
continuous type experiments with Lake Teganuma sediments.
(2) The relationship between the release rate and the level of dissolved
oxygen in overlying water.
As mentioned previously, phosphorus release from bottom sediments is a
function of dissolved oxygen in the overlying water or a function of oxidation-
reduction potential. Even though dissolved oxygen or oxidation-reduction
potential is constant, the phosphorus release rate is time dependent. There-
fore, it is difficult to find a strict relationship between the release rate
and the dissolved oxygen level. A rough relationship was obtained based on a
large number of data from the batch-type test using disturbed samples. Figure
9 is the result of this analysis, showing the relationship between release
rate (at 20ฐC) and phosphorus content of the sediments for varying dissolved
oxygen regimes in the water. The release rate may be expressed similarly to.
equation (1), i.e.
where Y and X
coefficient "a
Y = aX
in equation (2) are the same as in equation (1).
' is roughly within the range shown in Table 1.
(2)
The value of
134
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1:10
9 r
Ka LAKE KASUMIGAURA
To LAKE TOYAN06ATA
Tega: LAKE TEGANUMA
Ara. ARA RIVER
13
1.2 2
O Ka. 24 (o*Do
-------
TABLE 1. EFFECT OF DO LEVEL ON PHOSPHORUS RELEASE RATE
Range of DO Coefficient a
0 mg/L a > 10
0 -v 0.5 mg/L 10 > a > 3
0.5 ^ 1.0 mg/L 3 > a > 2.2
> 1.0 mg/L 2.2 > a
(3) The relationship between the release rate and water temperature
From the fact that the phosphorus content in water increases markedly in
shallow lakes during the summer, it is assumed that water temperature greatly
influences the release rate of phosphorus. Experiments using undisturbed
samples were performed at 10ฐC, 20ฐC and 30ฐC. The results of plotting the
average release rate for the first 11 days of the test against water tempera-
ture are shown in Figure 10. Under anaerobic conditions the release rate
averaged 2.6 times higher at 30ฐC than at 20ฐC. The effect of water tempera-
ture on release rate is expressed in the following equation.
YT = Y20ฐC 6 "
where the coefficient 0 between 20ฐC and 30ฐC is 1.08.
Although fewer data are available for the 10-20ฐC temperature conditions,
they imply 0 = 1.05 for both aerobic and anaerobic conditions between 10ฐC and
20ฐC.
136
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20
UJ
IT
UJ
15
10
o
i
a.
O
C
o
n
o
n
O
O
I
ST. 1 AEROBIC
ST. 1 ANAEROBIC
ST. 1 ANAEROBIC (Glucose Addition)
ST 2 AEROBIC
ST 2 ANAEROBIC
ST. 2 ANAEROBIC (Glucose Addition)
ST. 3 ANAEROBIC
ST. 4 AEROBJC
ST. 4 ANAEROBIC
D
10 20
TEMPERATURE, ฐC
30
Figure 10. Effect of temperature on phosphorus release rate; experiments
with undisturbed samples.
(4) Other factors influencing release rate
Other physical and chemical factors related to the release rate of phos-
phorus are the velocity of the overlying water and the diffusion coefficient
in the sediments. When comparisions were made using the batch-type tests for
release rates, with and without being subjected to water flow, there were no
significant differences observed. This is because the majority of the tests
were conducted under anaerobic conditions and the release of phosphorus was
predominantly caused by the reduction of ferric phosphate rather than physical
diffusion. The release under aerobic conditions and the steady release under
long term continuing anaerobic conditions may be significantly influenced by
the velocity of the water. No detailed studies were made on porosity or
diffusion in the bottom sediments, but there is probably an influence similar
to that of water velocity.
In addition, the release rate when flocculants were present on the sur-
face of the sediment, showed virtually no differences compared to when floccu-
lants were not present, based on data gathered under anaerobic conditions
(Figures 6 and 7). Since few tests were run with flocculant sediments under
aerobic conditions, no comparison of these results could be made with those
obtained under anerobic conditions. Further studies on this subject will be
made.
137
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RELEASE OF NITROGEN
(1) The relationship between the release rate of nitrogen and the nitrogen
content of the bottom sediments, and between the release rates and the
oxidation-reduction potential of the overlying water.
The mechanism of nitrogen release from the
less time-dependent than
bottom
Tun f.
sediments
is considered
that of phosphorus. Two factors are considered to
control the release rate. One is the decomposition of particulate nitrogen to
dissolved nitrogen in the sediments, and the other is the diffusion of dis-
solved nitrogen into the overlying water. Similar to phosphorus, major fac-
tors influencing breakdown of nitrogen will be the total nitrogen content of
the sediments, aerobic-anaerobic condition of the overlying water, and tem-
perature.
From the results of experiments made at 20ฐC water temperature, corres-
ponding values for nitrogen release rate and nitrogen content of the sediments
were found for both aerobic and anaerobic conditions. The results are shown
in Figure 11. Under either aerobic or anaerobic conditions, the nitrogen
100
80
UJ
cr
UJ
Z E
UJ
CD Z
O i
60
40
20
I I I
O UNDISTURBED SAMPLES, Aerobic
O UNDISTURBED SAMPLES, Anaerobic
UNDISTURBED SAMPLES, Anaerobic
(Glucose Addition)
D DISTURBED SAMPLES, Batch Type
Experiment, Aerobic
A DISTURBED SAMPLES, Continuous
Type Experiment, Anaerobic
a -
>
a
o
D
0
1
a
a
a a
n
i
Figure 11.
02468
NITROGEN CONTENT OF SEDIMENTS,
T-N mg/g DRY SOLfDS
Relationship between nitrogen release rate and nitrogen
content of sediments (20ฐC).
138
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release rate is roughly proportional to the nitrogen content of the bottom
sediments. However, under anaerobic conditions the nitrogen release rate was
about 2 to 3 times greater than under aerobic conditions. The only possible
reason for this is that the rate of decomposition of particulate nitrogen
under anaerobic conditions is much higher than under aerobic conditions. This
is an interesting result. The effect of flocculant sediment was not great
since data from both disturbed and undisturbed samples show a similar trend.
(2) The relationship between nitrogen release rate and water temperature.
Similar to phosphorus, when plotting the average nitrogen release rate
for the first 11 days of the water temperature experiments with undisturbed
samples, the relationship shown in Figure 12 was obtained. The effect of
water temperature on the nitrogen release rate was great. The release rates
at 30ฐC under anaerobic conditions were about twice those at 20ฐC. Assuming
the same relationship as equation (3) for the effect of temperature on the
nitrogen release rate, the temperature coefficient 6 was 1.07 between 20ฐC and
30ฐC under anaerobic conditions. Data for 10ฐC to 20ฐC under anaerobic and
aerobic conditions were limited and therefore are less reliable, however, they
were 1.06 and 1.095, respectively.
80
60
20
I ]
O ST. 1 AEROBIC
O ST. 1 ANAEROBIC
ST. 1 ANAEROBIC (Glucose Addition)
D ST. 2 AEROBIC
B ST. 2 ANAEROBIC
ST. 2 ANAEROBIC (Glucose Addition)
1^ ST. 3 ANAEROBIC
O ST. 4 AEROBIC C>
^> ST 4 ANAEROBIC
O
O
_l
D
10 20
TEMPERATURE, ฐC
30
Figure 12. Effect of temperature on nitrogen release rate; experiments
with undisturbed samples.
139
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(3) The qualitative effect of water velocity on nitrogen release rate.
When comparing the nitrogen release rate with the phosphorus release
rate, the nitrogen release was considered a more stable phenomenon, and thus
more affected by diffusion. From the results of bottom tests employing dis-
turbed samples, the qualitative effect of water flow on nitrogen release was
examined. Comparison of the release rates with and without water flow over
the sediment surface is shown in Figure 13. According to Figure 13, although
the data show quite a spread, the nitrogen release under conditions of flov*
was larger than that without flow for about 80% of the data. Since rotation
of the magnetic stirrer imparting velocity to the overlying water was arbi-
trarily controlled, it was impossible to express the effects of velocity
quantitatively.
1:2
1:0.6
O AEROBIC
ANAEROBIC
0.5 10 15
NITROGEN IN OVERLYING WATER
WITHOUT VELOCITY, T-N g/m*
Figure 13. Effect of velocity on nitrogen release.
140
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CONCLUSION
After careful examination of the test results for both phosphorus and
nitrogen release from the bottom sediments of lakes, the following conclusions
can be made:
(1) Phosphorus release
(a) The major factors that control the phosphorus release from sediment
are the phosphorus content of the bottom sediments, the DO in the overlying
water, and the temperature.
(b) Although the phosphorus release rate under anaerobic conditions is
not constant, the average release rate during the first one or two weeks after
the overlying water becomes anaerobic is in proportion to the phosphorus
content, of the bottom sediments. This relationship holds even when flocculant
sediments are present on the surface.
(c) The phosphorus release rate is small under aerobic conditions in the
water. When dissolved oxygen was over 1 mg/1, the rate dropped to about
one-fourth of that under anaerobic conditions, based on results from experi-
ments using disturbed samples.
(d) The phosphorus release rate is greatly influenced by temperature.
Under anaerobic conditions, the release rate at 30ฐC is more than twice that
at 20ฐC.
(2) Nitrogen release
(a) Similar to phosphorus, the nitrogen release rate depends on the
nitrogen content of the bottom sediments, the DO of the overlying water, and
the temperature. It is also affected to a certain extent by the velocity of
the overlying water.
(b) Under both anaerobic and aerobic conditions, the nitrogen release
rate is roughly proportional to the nitrogen content of the bottom sediments.
But, the release rate under anaerobic conditions is two or three times higher
than under aerobic conditions.
(c) The nitrogen release rate, similar to phosphorus, is also greatly
influenced by temperature. The rate at 0ฐC under anaerobic conditions is
about twice that at 20ฐC.
Some of the above conclusions are tentative. More studies are required
to probe the release of nutrients from bottom sediments, especially under
aerobic conditions, and to elucidate the influence of temperature.
ACKNOWLEDGEMENT
The experiments using undisturbed samples were performed by the Lake
Kasumigaura District Office of the Ministry of Construction. Gratitude is
expressed to those conducting the experiments.
141
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TEST RESULTS FROM DEMONSTRATION DREDGING
AND SPILLWATER TREATMENT AT HIRO HARBOR
Toshihiko Fukushima
Construction Bureau, Kure City Office
Tathuo Yoshida
Japan Bottom Sediments Management Association
INTRODUCTION
Hiro Harbor is located in the Hiro section of Kure-shi, a coastal city
near Hiroshima. Formerly a small fishing village, Hiro became a major indus-
trial import and shipping facility after Toyo Pulp Industries Ltd. built a
large kraft paper mill on its waterfront. The wastewater from the mill pol-
luted the area for a long time and, as a result, large quantities of polluted
sediment now cover the harbor floor.
To deal with this pollution problem, the Kure-shi Municipal Office set up
a pollution control committee for Hiro Harbor which has formulated a plan to
clean up the area. This plan requires the dredging of 200,000 cubic meters of
sediment, which will then be used as fill for a land reclamation project.
The implementation of this project, requires the consent of the residents,
particularly the fishermen, because of their concern over the environmental
impact of the operation. The demonstration discussed here was designed to
help obtain this consent and to determine probable environmental effects.
In early June of 1978, about 900 cubic meters of sediment were dredged
for demonstration purposes. Ancillary tests on spillwater treatment, sludge
solidification, and bioassay techniques were conducted. Results are reported
in this paper.
OPERATIONAL METHOD
The dredging operation was performed as shown in Figure 1.* A special
antipollution suction dredge dumped the dredged material into a barge. The
barge was then anchored to the wharf near the experimental water treatment
plant. The material in the barge was allowed to settle naturally over a
two-day period. During this time the mixture separated into clean supernatant
* Figures and tables for this paper are found at the end of the text, begin-
ning on page 147.
143
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water and precipitated sludge. The water was pumped to the water treatment
plant, and the sludge, after solidification, was hauled to a dump pit. It
took only one hour to dredge the sediment, but about 10 days were required to
treat the spillwater because of the small capacity of the test plant.
This public demonstration of sediment management was worthwhile because
it increased the general public's understanding of the plan to clean up Hiro
Harbor.
TURBIDITY
Turbidity generated by dredging is one of the most difficult problems to
deal with. To control turbidity, several unique suction devices have been
developed in Japan. In Hiro Harbor, one of these devices was used. It is
similar to the one shown in Figure 2.
Two sets of augers with opposite pitches are mounted on a common axis
within the suction device. The rotation of the screw forces the sediment to
move to the center where it is picked up and pumped to the surface. When
dredging with such a device, turbidity is kept low because of the smoothness
of the cut and the near-perfect removal of loosened sediment particles. This
is in contrast to conventional cutter-type devices.
Observations of turbidity were made during the Hiro Harbor demonstration.
Measurements of SS concentration and the degree of turbidity were taken at 9
stations in the area, which was a square 100 m on a side beginning at the
dredge site and running 100 m in the direction of diffusion. Samples were
taken at three depths at each station. The results are summarized in Figure
4.
The maximum SS concentration near the dredge was 6 ppm. We estimate the
increased concentration due to dredging as only 1-2 ppm by subtracting the
background level of SS from the measured values. Therefore, it appears there
is virtually no turbidity created by dredging with this equipment under the
existing conditions. Similarly, the maximum degree of turbidity was only
0.6ฐ.
The demonstration dredging statistics are:
swing width 50 m
swing speed 4 m/min
thickness of sediment 1.2m
thickness of cut 0.4 m
amount of dredged sediment 130-180 m3/hr
percent solids 20-40%
dredged water 650 m3/hr
The sediment thickness and pulpy quality resulted in easy dredging.
SEDIMENT PROPERTIES
Four samples were examined to determine the particulate composition of
the sediment.
144
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Locations of sampling
stations
Table 1 shows that the grain size of the sediment at Hiro Harbor is very
smallover 60% of particles are under 6.8 M. This is smaller than results
suggested by laboratory tests last year which gave a D60 of 12 p and a D30 of
2.4 (j.
Physical and chemical properties of the sediments obtained last year are
given in Table 2. The level of toxic substances is negligible except that
comparatively high contents of Pb (20 ppm), Zn (349 ppm) and As (5.81 ppm)
should be watched.
Organic matter content is fairly high as indicated by the high COD con-
tentthe highest we have ever seen (Table 3). This may be due to the pulpy
nature of the sediment. The content of the n-Hexane extractions is also high.
This means that the sediment contains large quantities of organically derived
oils. The ammonia-nitrogen content is unexpectedly small. This may be due to
conversion of sedimented nitrogen components to easily dissipated ammonium.
The high hydrogen sulfide content is responsible for the bad odor of the
dredge water(Figure 5).
The physical properties of the dredge water were analyzed and results are
given in Table 4.
Data in Table 4 and Figure 6 were obtained from laboratory tests of
dredge slurry containing 10, 20, 30 and 40% solids. These data show the
relationship between SS and various chemical and physical variables. Use of
these data with field measured SS concentrations provides an estimate of the
other variables. It is extremely difficult to measure these variables di-
rectly.
WATER TREATMENT
A schematic of the water treatment plant is given in Figure 7. It is a
demonstration plant which was set up to treat the supernatant water from the
spoils barge after the sediment had settled naturally in the barge hold (Fig-
ure 8).
It took 45 hours to obtain a 1.8 m depth of clean supernatant water.
From this, the mean settling velocity can be calculated as follows:
W = 1.8 ^ 45 = 0.04 m/hr = 0.0011 cm/sec (1)
The plant was operated continuously for 8 hours a day. A circulating
high-speed vertical type filter was used. Sodium hypochlorite, a food addi-
tive, was used for chlorination. A commercial product (Kurifloc PA-331) was
145
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used as a polymeric coagulant. Table 5 shows the additives and operating
parameters for the system.
A precipitation test was carried out using a 1000 cc cylinder. Results
with and without a coagulant added are shown in Figure 9. The mean settling
velocity without coagulation was
W = (165 cm - 140 cm) =- 6 hr = 0.042 m/hr = 0.0011 cm/sec, (2)
which agrees with the first value derived from measurements in the barge.
These slow settling rates will cause difficulty in handling the Hiro Harbor
sediments. The SS concentration in the supernatant water was 30-60 ppm by
weight.
Table 6 shows the water quality at each stage of operation. The initial
SS concentration was reduced to 8-12 ppm after coagulation, and to 1-5 ppm
after filtration. From the data presented in the table, it can be seen that
COD., concentration and the total phosphorus concentration were reduced in
proportion to the SS removed. This is illustrated in Figure 10.
Since the guidelines for discharging this kind of water are generally 30
ppm SS and 20 ppm COD., the water remaining after coagulation of the sediment
might have been clean enough to discharge. However the T-N concentration was
too high. Its value did not drop at all until the filtration stage, although
the SS concentration was already reduced. Only in the last stage, when sub-
jected to chlorination with sodium hypochlorite, did it drop adequately (Fig-
ure 11).
The results of the chlorination test are shown in Figure 12. The concen-
tration of NH4-N decreased rapidly as the active concentration of chloride ion
exceeded 150 ppm, reaching a low point near 200-230 ppm of chloride ion. At
the zero level the minimum residual chloride became noticeable.
In the experimental operation, the effect of activated carbon powder on
the reduction of SS and COD,, at each stage was also examined. The results
are summarized in Table 7. it was found that activated carbon powder has no
effect on the efficacy of the other processes.
From the above results, it is concluded that the greatest problem in
supernatant water treatment is the exceedingly high content of NH4-N in the
dredge water. It appears that this concentration derives from bacteria which
convert the organic matter in the sediment into ammonium ion, and the ammonium
ion then dissolves in the interstitial water of the sediment. Since concen-
trated ammonium ion is toxic to fish, it is necessary to reduce it below toxic
levels. For this purpose chlorination is required. Usually the guideline for
water quality when discharging dredge water is concerned with two itemsSS
concentration and COD. But in the case of Hiro Harbor, NH4 must be added to
the guideline.
SOLIDIFICATION OF SLUDGE
The sludge, which settled on the bottom of the barge, was not discharged
in an untreated state. It was solidified at the site and then hauled by truck
146
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to a dump site. The commercial compound "Chemikolime 235" was used as a
solidifier. This was combined with the sludge as follows:
Batch:
C-235
500 kg
Water
400 kg
C/Water
80%
Concentration
0.89 t/m3
Since 85 m3 of solidifier were used to treat 490 m3 of sludge, the mix
percentage was 16.5%. The solidifier was mixed into the sludge with a clam-
shell bucket. The compression strengths of the solidified sludge are plotted
in Figure 13. The deeper layer is stronger than the shallow one. This may be
due to precipitation of the solidifier. Good agreement between the laboratory
test data and on-site tests are shown by Figure 14. The good results may be
attributed to selection of the proper solidifier and thorough mixing with the
clamshell.
CONCLUSIONS
The results of experiments at the dredging site and water treatment at
Hiro Harbor led to the following conclusions. Turbidity from dredge spoils,
which is the most troublesome aspect of dredging, can be negligible if an
anti-pollution dredge with a special suction device is used. The most impor-
tant aspect of water treatment in this area is the exceedingly high ammonium
ion content in the supernatant dredge water. To reduce it to permissible
levels chlorination is the best treatment but, carbon is necessary to absorb
the residual chlorine.
This demonstration was valuable in increasing public awareness of en-
vironmental problems and providing a basis for understanding the plan to clean
up Hiro Harbor.
TABLE 1. GRAIN SIZE OF SEDIMENT
Station 1 Station 2 Station 3 Station 4 Mean
Maximum Size |j
Deo
D3o
2
8.4
3.6
0.84
6.9
4.0
0.42
6.7
3.2
0.84
5.3
2.1
1.03
6.8
3.2
147
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TABLE 2. PHYSICAL AND CHEMICAL PROPERTIES OF THE SEDIMENT
Soil property
Color
Odor
pH
H20
KC1
Water Content Ratio
Water Content
Specific Weight
Liquid Limit
Plastic Limit
Plastic Index
Black and Sticky
Rotten
7.80
7.58
436.8
81.4
2.572
Unit Weight
Grain Max
g/cm3
H
1. 106
105
12
2.4
286.3
130.7
155.6
Nutrients
Ignition Loss
COD
Mn
COD
Cr
Nitrogen
T-N
NH4-N
N02-N
NO,-N
T-P
Ca
Sulfide
n-Hexane Extracts
mg/g
mg/g
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/g
mg/g
37.6
225
448
6,290
7.53
3.22
3.22
1 ,020
2,540
2.28
11.35
Toxic Substances
T-Hg
Alkyl Hg
Pb
Zn
Cr
As
Cd
Cyanogen
Organic P
PCB
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
0.286
< 0.0005
20.0
34.9
5.81
< 1.0
0.001
< 0.0005
148
-------
TABLE 3. DREDGE WATER RETURN FLOW STANDARDS
Property
Value
Reference
COD
n-Hexane Extracts
Hydrogen Sulfide
Total Nitrogen
Total Phosphorus
20 mg/g
3 mg/g
6700 ppm
625 ppm
88 ppm
JIS K0102
JIS K0102
Sewage Analysis
Sewage Analysis
JIS K0102
TABLE 4. PROPERTIES OF DREDGE WATER RETURN FLOWS (SUPERNATANT)
Property
Concentration of Sediment in Dredge Slurry
10%
20%
30%
40%
pH
SS (ppm)
Turbidity (ppm)
Transparency (deg. )
Color (deg)
CODM (ppm)
T-N Cpprn)
T-P (ppm)
Sulfide (ppm)
7.1
17,400
9,250
< 1.0
52.0
2,160
67.2
28.1
112
7.1
29,800
16,700
< 1.0
67.5
4,050
143
43.1
265
7.0
52,600
27,800
< 1.0
86.3
8,500
285
59.8
395
6.9
83,900
46,000
< 1.0
110
15,600
582
85.5
677
149
-------
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TABLE 6. SUPERNATANT WATER QUALITIES AT EACH TREATMENT STAGE
Stage
Property
Chlorinated
Input Water Coagulated Water Filtrated Water Water
pH 7.1-8.0
Color (deg.) 500-800
Turbidity (deg.) 30-60
SS (ppm) 30-60
CODM (ppm) 25-37
T-N fr>pm) 22-25
NH4-N (ppm) 20-25
T-P (ppm) 1.1-1.5
n-Hexane Extracts (ppm)
< 5
Residual C12 (ppm)
Chloramin (ppm)
Isolated C12 (ppm)
Residual Polymer (ppm)
6.8-7.5
50-150
8-12
10-40
9-13
23-24
22-23
0.4-0.5
< 5
0
6.8-7.5
20-70
2-5
1-5
3-6
22-24
22-23
13-0.14
< 5
6.8-8.0
20-40
1-3
< 1-3
< 1-3
< 1-3
< 1-3
< 0.1
< 5
ND
ND
ND
< 0.1
ND = not detectable
151
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152
-------
EXPERIMENTAL WATER TREATMENT
PLANT
DREDGE
BARGE
BARGE r
. ^JDai
a
Figure 1. Schematic diagram of the experimental operation.
SUBLADDER
DIRECTION OF SWING
GAS SUCTION
xVV '-V'1; / \' , ^ ,"
SCREW
Figure 2. Screw-type or auger suction head,
153
-------
0 50m V 100m 2.8
ง
t
1
i
1
i /
\ /
i /
!/
1 / '
/ *
wL-
i '-=' i
3.5 3.1 2.8
5.5 5.0 5.5
BACKGROUNI
5.9 6.1 5.7
i
1
1
1
8
1
1
1
i
1
m
CUTTER HEAD
5.0
Figure 4. Distribution of SS due to dredging (ppm).
300
2.572
400
CODUn mg/g
'Mn
Figure 5. 3-axis plot showing relationship of ignition loss, COD and unit
weight of sediment in Hiro Harbor.
154
-------
ppm
100,000
50,000
10,000
5,000
z
o
Ul
O
Z
o
o
OT
CO
1,000
500
100
t- o
TURBIDITY
Mn
SULFIDE
I III
ppm
1000
500
100
50
0 10 20 30 40 50%
SOLIDS IN DREDGE WATER
10
I
T-P
I III
0 10 20 30 40 50%
SOLIDS IN DREDGE WATER
Figure 6. Relationship between concentration of various pollution
components of dredge water and sediment content.
155
-------
HIGH-SPEED LOW-SPEED
REACTION MIXING TANK
TANK
ADHESfON TANK
.' ' TANK'.'." .' f; TANK'FOR '!
.FORPAC . ' |. POLYMER/
SETTLING- . ' .'SLUDGE-'.SETTLING' .''.' '. 'FILTRATE .'f. '
TANK' TANK ' TANK ' ' TANK ' "
1 .' ' TANK FOR ACTIVATED '.'. ' ' TANK FDR '
' CARBON POWDER . . . ' NEUTRALIZATION
Figure 7. Schematic of water treatment plant.
Figure 8. Natural sedimentation in barge hold.
156
-------
I I I I I I I
WITHOUT COAGULANT
WITH COAGULANT
I I
I I I
02468
HOURS
Figure 9. Precipitation curves of sediment measured by cylinder.
INITIAL COAGULATED FILTRATION CHLORINATION
LIQUID SEDIMENT
Figure 10. Reduction in concentration of SS, COD and T-P in each stage,
157
-------
g
15
LJ
O
ppm
60
40
20
T-N
INITIAL COAGULATED FILTRATION CHLORINATION
LIQUID SEDIMENTATION
Figure 11. SS and T-N concentration at each stage.
.0
150 200 250 300 350 ppm
500
2500 ppm
1000 1500 2000
ADDED AMOUNT OF NoOCI
Figure 12. Relationship between NH4 concentration and amount of NaOCl.
158
-------
Kg/cm2
0.6
0.4
E 0.2
LJ
cr
CO
O.I
0.08
ง5 0.06
co
LJ
a: 0.04
o
o
0.02
0.01
2.0-2.5m
.0-l.8m
0-0.5m
0
8
246
TIME (DAY)
Figure 13. Compression strength of sludge after solidification.
Kg/cm2
x '-ฐ
fe 0.8
| 0.6
o 0.3
co
LJ
o:
a.
8
O.I
-EXPERIMENT ON SITE
16.5% MIXED
LABORATORY TEST
15% MIXED
L 'I I I I I I I I I
0
8
246
TIME (DAY)
Figure 14. Comparison between laboratory and on-site tests.
10
159
-------
THE CONTRIBUTION OF SEDIMENT TO LAKE EUTROPHICATION
AS DETERMINED BY ALGAL ASSAY
Ryuichi Sudo, Chief
Mitsumasa Okada, Researcher
Freshwater Environment Laboratory
The National Institute for Environmental Studies, Japan
ABSTRACT
The contribution of sediment to lake eutrophication was determined by
using the blue-green alga Microcysti s aeruginosa, which is common in eutrophic
lakes and reservoirs in Japan. Chelating agents in Gorham's medium proved
necessary for the growth of M. aerugi nosa and it was determined that the
organics in the sediments, especially fulvic acid, played the same role as the
chelating agents in the growth medium.
A large release of phosphate from sediments taken from Akanoi-wan in Lake
Biwa was observed during both aerobic and anaerobic incubation. The growth of
M. aeruginosa was highly stimulated by this material released from the sedi-
ment. Under aerobic conditions, some materials that had chelating effects
were released from the surface layer (0-9 cm) of sediments at Akanoi-wan.
INTRODUCTION
The bioassay developed to determine nutrients limiting algal growth in
lakes and rivers is called the "Algal Assay Procedure," abbreviated AAP (NERP,
1971). It is used to assess the effect of wastewater discharge on eutrophica-
tion. The recent increase in eutrophication in Japan has caused many re-
searchers and adminstrators in the water pollution control field to become
interested in AAP, and many reports on the application of AAP have begun to
appear (Sudo et al_. , 1975; Okada and Sudo, 1978; JSWG, 1976). In almost all
the previous freshwater studies that used AAP, the authors selected Selenas-
trum capricornutum as the test alga. Because this alga has never been domi-
nant in Japanese lakes there was a controversy over the appropriateness of its
use.
Another standard test alga in AAP is M. aeruginosa. This alga grows in
typical Japanese eutrophic lakes such as Kasumigaura and Suwako. The forma-
tion of dense blooms by this alga causes many problems including noxious
odors, water treatment difficulties, and fishkills. Thus it appears desirable
to use M. aeruginosa as a test alga in AAP not only because it is common in
Japan, but also because the reason behind the massive blooms is unknown and
basic information is needed to predict their growth.
161
-------
The purpose of this study was to assess the effect of lake sediment on
the growth of M. aeruginosa. This was done by using AAP to:
1) study the effects of organics in the sediment on the growth of M.
aeruginosa,
2) study the effects of materials released from the sediments under
both aerobic and anaerobic conditions on the growth of M. aerugin-
osa.
METHODS AND MATERIALS
CULTIVATION OF ALGAE
The alga used in this study was Microcystis aeruginosa. The test strain
was obtained from the National Environmental Research Center, U.S. Environ-
mental Protection Agency, Corvallis, Oregon. Gorham's medium was used for the
stock culture medium (Table 1) (Okado and Sudo, 1978). Stationary test tube
culture was satisfactory for maintaining the stock culture.
TABLE 1. COMPOSITION OF GORHAM'S NO.
11 MEDIUM
Material
NaN03
MgS04 7H20
CaCl4 2H20
K2HP04
Na2C03
Fe Citrate
Citrate
Na2EDTA
Na2Si03 9H20
* Gaffron's trace elements
Disti 1 led water
Amount
496.0 mg
75.0 mg
36.0 mg
1 .4 mg
20.0 mg
6.0 mg
6. 0 mg
1.0 mg
58.0 mg
0.8 ml
999.2 ml
Gaffron's trace elements
H2B04
MnS04 4H20
ZnS04 7H20
(NH4)6Mo7024 4H20
CO(N03)2 4H20
Na2W04 2H20
KBr
KI
Cd(N032) 4H20
NiS04(NH4)2S04 6H20
VOS04 2H20
A12(S04)3K2S04 24H20
1/10 N H2S04
3100
2230
287
88
146
33
119
83
154
198
20
47
1000
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
mg
ml
162
-------
Precultivation of the inoculum was conducted following the same method as
the algal assay. In this case, Gorham's medium was diluted to 1/5 concentra-
tion and provided as a preculture medium. This is because the high nutrient
concentration in full-strength Gorham's medium may produce an inoculum that
contains excess nutrient pools within the cells which would result in a maxi-
mum cell concentration and produce serious errors.
This algal assay medium was also tried as a stock and preculture medium,
but the results were not satisfactory. The water samples were sterilized by
filtration through a Millipore (0.45 u) filter to prevent contamination by
indigenous algae. Erlenmeyer flasks (500 ml) were used for culturing. The
flasks were cleaned carefully and 100 ml quantities of water samples or media
were added. A 7- to 10-day-old culture of M. aeruginosa in the exponential
growth phase was washed twice and inoculated into the medium or water sample
to give an initial concentration of 10,000 cells/ml. The inoculum concentra-
tion was set lower than called for by the AAP to prevent nutrient carry-over
with the inoculum cells.
Cultivation was conducted in a constant temperature room (25 ฑ 1ฐC)
equipped with "cool white" fluorescent lighting providing a constant light
intensity of 500 lux. The flasks were set on a rotary shaker and shaken at
100 osci1lations/min. Algal biomass was monitored using a Coulter Counter
Model ZF equipped with a mean cell volume computer. From the cell counts and
mean cell volume of the test alga, the total cell volume was calculated and
this volume converted to dry weight (mg/1). Biomass measurements were con-
tinued at 2- to 3-day intervals until the biomass of alga reached a maximum.
HUMIC AND FULVIC ACID EXTRACTION FROM LAKE SEDIMENTS
Humic acid and fulvic acid were extracted from the Kasumigaura Lake
sediments sampled with an Ekman dredge. A 100 g (wet weight) sediment sample
was mixed with 300 ml of 0.1N NaOH and shaken 24 hrs (Figure 1). The extract
was separated by filtration and adjusted to pH 3 using 0.1N HC1. After 24
hours the humic acid had precipitated and the fulvic acid still remained in
the supernatant. The precipitated humic acid was washed twice with distilled
water and then dissolved with 0.1N NaOH. The concentration of humic and
fulvic acid were measured using Chemical Oxygen Demand.
STIMULATION OF GROWTH BY HUMIC AND FULVIC ACIDS
Gorham's medium was used as the basic medium to which was added humic and
fulvic acid to assess their effects on algal growth. It is well known that
these acids are natural chelating agents, so the effects of the chelating
agents already contained in Gorham's medium were determined prior to the
experiment.
ALGAL ASSAY ON SEDIMENT EXTRACTIONS
To assess the influence of sediment on algal growth, core samples were
taken from the sediments at Akanoi-wan and Kusatsa Yamada-oki in Lake Biwa.
The samples were frozen at -70ฐC as soon as possible after sampling, and then
freeze-dried. The freeze-dried samples were mixed with lake water from the
sample site which had been passed through a 1.2 |j Millipore filter. The
163
-------
SUP.
SAMPLE
O.I N-NaOH
FILTRATION
FILTRATE
SOLID
1.0 N-HCI, pH = 3
12-24 MRS
CENTRIFUGE
PT.
FULVIC ACID
DISTILLED WATER
CENTRIFUGE
PT. SUP
O.I N-NaOH, pH= 13
HUMIC ACID
Figure 1. The procedure for extraction of humic and fulvic
acid from sediment samples.
164
-------
mixture was 1 g sediment/liter. This was transferred to a 1-liter Erlenmeyer
flask and magnetically stirred and incubated in a constant temperature room
held at 20 ฑ 1ฐC. An aerobic condition was maintained by aeration from the
bottom of the flask with ammonia-free humidified air which had been passed
through saturated boric acid and distilled water. For maintaining an anaer-
obic condition, the dissolved oxygen in the lake water was purged by nitrogen
gas before mixing with the sediment and sealed tightly during incubation.
Dissolved oxygen levels were maintained below 0.5 mg/1.
Ammonium (NH4-N), nitrite plus nitrate (N02 + N03-N) nitrogen and phos-
phate (P04-P) concentration released from the sediment were monitored during
incubation. DO, pH, and redox potential were also measured to determine if
conditions were aerobic or anaerobic.
The algal assay of the sediment was conducted after 2 weeks of incuba-
tion. Any suspended solids in the mixture were separated by centrifuging and
the supernatant was axenically filtered through a sterile 0.45 p Millipore
filter. Disodium ethylenediamine tetra-acetate (Na2EDTA) at 1 mg/1, P04-P at
0.1 mg-P/1 , and N03-N at 2.0 mg-N/1 were added to the medium to estimate the
nutrients limiting algal growth and the effect of FDTA on M. aeruginosa. All
lake water was filtered prior to the algal assays.
RESULTS AND DISCUSSION
EFFECT OF CHELATING AGENTS ON THE GROWN OF M. aeruginosa
The effects of chelating agents in the Gorham's medium on M. aeruginosa
were studied prior to adding humic and fulvic acids (Table 2). Ferric chlor-
ide or ferric citrate was the iron source at concentrations of 0.007, 0.014,
and 0.028 mg-Fe/ml , and Na2EDTA (0.3 mg/1) or citric acid (0.5 mg/1) was the
chelating agent. These amounts were added to the basic medium (Table 1)
without Na2EDTA, citric acid, and ferric citrate. The values shown in Table 2
are maximum cell concentrations (mg/1) for each combination. The highest
concentration was observed with the combination of ferric citrate and Na2EDTA
+ citric acid. In the cases where ferric citrate was not used, M. aeruginosa
grew with only the addition of Na2EDTA and citric acid, but the maximum con-
centration was lower than with ferric citrate. It was concluded, therefore,
that an iron source such as ferric citrate and a chelating agent such as
Na2EDTA were necessary for the growth of M. aerugi nosa.
TABLE 2. EFFECTS OF IRON AND CHELATING AGENTS ON THE GROWTH OF M. aeruginosa
[Values are maximum growth (mg/1)]
cone.
Chelating Agents Cone":
FeCl
Fe citrate (mg/1)
0.007
0.014
0.028
0.007
0.014
0.028
Citri
Citri
d;
C
C
CRT A
> hU 1 A
Acid
Acid
.
0.
+
mg/ I
5 mg/1
Na2EDTA
.
0.
70.
1
1
0
H"7 O
/ . y
0.0 0.0
38. 21.
0.
180
0
0.0
160
0.0
150
165
-------
EFFECTS OF HUMIC AND FULVIC ACIDS ON THE GROWTH OF M. aeruginosa
Humic and fulvic acids are natural chelating agents which may stimulate
the growth of M. aeruginosa. Figure 2 shows the growth curve for M. aerugin-
osa when grown in the basic medium (including chelating agents). The addition
of each acid increased the maximum specific growth rate from 0.25/day to
0.4/day, In the instance where 12.5 mg/1 fulvic acid was added, maximum cell
concentration increased as well. The lag phase was prolonged when humic acid
was added and the maximum cell concentration was not much different from that
grown on the basic medium.
Figure 3 shows the results of a similar experiment except that no chelat-
ing agent was used in the basic medium. In all cases, the specific growth
rate of M. aeruginosa was decreased, and without either humic or fulvic acids
the growth rate of the control was only O.I/day. With the addition of fulvic
acid at 12.5 mg/1, the growth rate doubled to 0.22/day and the maximum cell
concentration at 34 mg/1 was three times that of basic medium (11 mg/1). The
humic acid sample (7.3 mg/1) also showed a higher maximum cell concentration
of 17 mg/1.
These results show that both fulvic and humic acid could stimulate the
growth of M. aeruginosa. Fulvic acid had the most effect. These effects are
not as pronounced as those produced by the chelating agents used in Gorham's
medium.
THE EFFECTS OF WATER-EXTRACTIONS OF SEDIMENT ON THE GROWTH OF M. aeruginosa
Core samples taken at Akanoi-wan were separated into four subsamples by
depth: 0-4 cm, 4-9 cm, 9-14 cm, 14-24 cm. Each sample was incubated under
both aerobic and anaerobic conditions and monitored for the release of nitro-
gen and phosphorus.
The concentration of P04-P released from the 4 different subsample types
during a 55-day incubation period is shown in Figures 4 and 5. Under both
aerobic and anaerobic conditions, the P04-P concentration in the upper layer
was higher than that of the lower layer. The P04-P concentration reached a
maximum of 0.8 mg P/l for the aerobic experiment and 1.7 mg P/l for anaerobic
conditions over 25 days. A pH of 8.0 and redox potential of 410 mV were main-
tained throughout the aerobic experiment. Under anaerobic conditions, a lower
pH of 6.8-7.5 was observed and the redox potential decreased from 400 mV to
100 mV after a day and remained there during the rest of the incubation per-
iod.
The effect of different incubating conditions on P04-P concentration is
shown in Figures 6 and 7. P04-P concentrations under anaerobic conditions
were higher than under aerobic conditions. The P04-P concentration at the
time of sampling at the bottom and top of the water column was 0.14 mg P/l and
0.03 mg P/l respectively, therefore it is likely that the sediments have a
high potential for releasing phosphate under both aerobic and anaerobic condi-
tions.
166
-------
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QJ '^ O> r-
q- cฃ -(-> QJ
q- u_ to .c
UJ > O
OJ
S-
-------
1.0
0.8
ฃ0.6
Q.
i 04
^j-
0
Q.
0.2
n
-
O Bottom - 4 cm
3 4cm- 9cm
C 9cm- 14cm
I4cm-24cm
O
O ^
3
o
<>
Q
w
08 C
0 1) A
Ll A
m i i i i
O
3
Q
9
A 0
Sample : Bottom sediments of Akanoi-Wan
SS IOOOmg/1
Room Temp: 20ฐ C
AEROBIC CONDITIONS
1 1 1 1 1 1 1
0
10
20 30 40
TIME (DAYS)
50 55
Figure 4. Concentration of PO.-P during aerobic incubation of lake sediment from Akanoi-wan.
1.8
1.5
1.2
en
E
0.9
Q_
I
(5
06
0.3
O
r O
O
O
O
Sample: Bottom sediments of Akanoi-Wan
SS ; 1000 mg/1
Room Temp.: 20ฐ C
ANAEROBIC CONDITIONS
O Bottom - 4 cm
I4cm-24cm
0
0
I
10
20 30 40
TIME (DAYS)
j
50 55
Figure 5. Concentration of PO.-P during anaerobic incubation of lake sediment from Akanoi-wan.
168
-------
o
a.
1.8 r-
1.5
1.2
0.9
0.6
0.3
0
O
O
O Anaerobic condition
Aerobic condition
Sample Bottom sediments of Akanoi-Wan
10-4.0 cm)
SS; 1000 mg/l
Room Temp.: 20ฐ C
O
D
I
I
0
10
20 30 40
TIME (DAYS)
50 55
Figure 6. Concentration of PO.-P during aerobic and anaerobic incubation of lake sediment from
Akanoi-wan 0-4 cm layer.
u.b
- 0.4
o>
ฃ
0.
'ซ 0.2
0
Q.
0
r U
^ o
O
O
0
O Anaerobic condition
_ Aerobic condition
V
Sample: Bottom sediments of Akanoi-Wan
(!4-24cm)
A * SS: 1000 mg/l
m Room Temp.: 20 ฐC
n I i i i ii
0 10 20 30 40 50 55
TIME: (DAYS)
Figure 7. Concentration of PO^-P during aerobic and anaerobic incubation of lake sediment from
Akanoi-wan 14-24 cm layer.
169
-------
Figures 8 and 9 show the release of NH4-N and N02 + N03-N from the sedi-
ments at core depths of 0-4 cm and 14-24 cm. Under anaerobic conditions a
high concentration of NH-N was released, but N02 + NO-N was not detected until
after a day of incubation. This means that denitrification occurred in the
incubator which suggests that mainly NH4-N would be released from the sedi-
ments under anaerobic conditions. But N02 and N03-N were found in the aerobic
incubator. NH4-N was detected only at the beginning of the incubation period
and then decreased due to nitrification. Although the forms of nitrogen
released were different under aerobic and anaerobic conditions, the amount
(1.2 mg N/l) of total inorganic nitrogen (NH4 + N02 + N03-N) did not change
except in the aerobic incubation of the 14-24 cm core sample. It is generally
accepted that the nitrogen available for the growth of algae is inorganic
nitrogen, therefore the fact that total available nitrogen was the same under
all conditions differs from the case of phosphate, where the type of ion is
significant.
Another sampling station at Kusatsu Yamada-oki is not as polluted as
Akanoi-wan. Sediment from this station was separated into three subsamples by
depth in the core: 0-2.5 cm, 2.5-7.5 cm, 7.5-12.5 cm. The sediment in this
area was grey and different from the black sediment at Akanoi-wan. The P04-P
concentration released under the two incubation conditions from sediments at
different depths is shown in Figures 10 and 11. As at Akanoi-wan, more P04-P
was released from the upper layer, but the total amount released from the
upper layer was one-half of that at Akanoi-wan. In the 7.5-12.5 cm layer, the
P04-P concentration was lower than 0.1 mg P/l even under anaerobic conditions.
It is possible that this is because suspended solids with high phosphorus
concentrations have been settling for a long time at Akanoi-wan but only
recently at Kusatsu Yamada-oki.
Figures 12 and 13 show the P04-P released from the 0-2.5 cm and 7.5-12.5
cm layers under different incubation conditions. In the 7.5-12.5 cm layer,
anaerobic release was higher than aerobic release. But, there was little
difference between aerobic and anaerobic conditions in the 0-2.5 cm layer.
This result is very different from that at Akanoi-wan. Although the concen-
tration of P04-P released from the Kusatsu Yamada-oki sediment was very low,
the potential for sediment phosphorus released is high due to the low P04-P
concentration in lake water; i.e. the bottom had 0.21 mg P/l and the lake
surface had 0.001 mg P/l as P04-P.
Figures 14 and 15 show the amounts of inorganic nitrogen released from
the 0-2.5 cm and 7.5-12.5 cm sediment layers. Under both aerobic and anaero-
bic conditions, the release of NH4-N was remarkable. As at Akanoi-wan, the
maximum concentration was higher under anaerobic conditions; i.e. 0.76 mg N/l
for the 0-2.5 cm layer and 0.5 mg N/l for the 7.5-12.5 cm layer. In the case
of P04-P, there was a large difference between Akanoi-wan and Kusatsu Yamada-
oki; however, the amount of nitrogen released from Kusatsu Yamada-oki was
roughly half that of Akanoi-wan. The results under aerobic conditions show
that nitrification did not occur in the Kusatsu Yamada-oki sediment and that
the N02 + N03-N concentration was always low. This is noticeably different
than the case at Akanoi-wan. As at Akanoi-wan, the depth of sediment samples
made only a small difference.
170
-------
1* 1.6
2
i \2
CM
0
z
ซ 0.8
o
05
^[>0.4
0
Figure 8.
^j HIIUCIVUIV; luiiumuii u .. ovmyic- ounvm acumicuia ui
Aerobic condition NH<~N Akonoi-Won ( Bottom-4cm)
SS: 1000 mg/l
_ A Anaerobic condition N+02)N Room Temp.: 20ฐ C
A Aerobic condition NOs
A 0
A 2 ฐ
"
AO ฐ
ฃV A Al A Al A 1 1 1
0 10 20 30 40 50 55
TIME (DAYS)
Concentration of NH.-N and NO,, + NCL-N during aerobic and anaerobic incubation of lake
sediments from Akan3i-wan 0-4 cm layer.
1.6
1 2
'*-
| 0.8
05
0
0
O Anaerobic condition
Aerobic condition 4
A Anaerobic condition
A Aerobic condition NOs
0
0
Al
Sample: Bottom sediments of Akanoi-Wan
(14- 24cm)
SS: 1000 mg/l
Room Temp.: 20ฐ C
1
10
1
20 30 40
TIME (DAYS)
0
50 55
Figure 9. Concentration of NH.-N and NOo + NO,-N during aerobic and anaerobic incubation of lake
sediment from AkanoT-wan 14-24 cm layer.
171
-------
0.5
0.4
en
E 0.3
Q_
i 0.2
O
Q.
O.I
0
O Bottom - 2.5cm
7.5cm-12.5 cm
O
O
0
O
10
O
20
O
Sample : Bottom sediments of
Kusatsu Yamada-Oki
SS : 1000 mg /I
Room Temp: 20ฐ C
AEROBIC CONDITIONS
.
TIME
30
(DAYS)
40
O
50 55
Figure 10. Concentration of PO.-P during aerobic incubation of lake sediment from
Kusatsu Yamada-oki.
u.o
- 0.4
E
Q_
Ij-0.2
O
Q.
0
(
Sample : Bottom sediments of Kusatsu Yamado- Oki
SS : 1000 mg/l
Room Temp. : 20ฐ C
- ANAEROBIC CONDITIONS
O Bottom - 2.5 cm
75cm- 12.5cm
O
O
O
D 10 20 30 40
O
I 1
50 55
TIME (DAYS)
Figure 11. Concentration of PO.-P during anaerobic incubation of lake sediment from
Kusatsu Yamada-oki.
172
-------
w.o
- 0.4
en
e
- 0.3
Q_
1 0.2
0
Q_
O.I
0
O Anaerobic condition
_ Aerobic condition
O
2
o
_ Sample: Bottom sediments of
^ * Kusatsu Yamada- Oki
0* O SS: 1000 mg/l
0 Room Temp. : 20ฐ C
ปoO I i i i
0 10 20 30 40
TIME (DAYS)
O
(0-2. 5 cm)
1 )
50 55
Figure 12. Concentration of PO.-P during aerobic and anaerobic incubation of lake sediment
from Kusatsu Yamada-oki 0-2.5 cm layer.
0.10
Q_
. 0.05
o
Q_
Sample : Bottom sediments of Kusatsu Yamada-Oki
(7.5 -12.5cm)
SS : 1000 mg/l
Room Temp.. 20 ฐC
0
o
O
0
I
O Anaerobic condition
Aerobic condition
i
0
10
20
TIME
30
(DAYS)
40
50 55
Figure 13. Concentration of PO.-P during aerobic and anaerobic incubation of lake sediment
from Kusatsu Yamada-oki 2.5-7.5 cm layer.
173
-------
1.0
I
CJ
O
+ 0.5
c?
05
ro
X
0
O Anaerobic condition
Aerobic condition
NH4~N
A Anaerobic condition N02>
N03
A Aerobic condition
O
O
O
o
Sample: Bottom sediments of Kusatsu
Yamada-Oki (Bottom-2.5cm)
SS: 1000 mg/l
Room Temp.: 20ฐ C
O
1
I
0
10
20
TIME
30
(DAYS)
40
50 55
Figure 14. Concentration of NH.-N and NCL + NO,-N
lake sediment from Kusatsu Yamada-Oki
during aerobic and anaerobic incubation of
0-2.5 cm layer.
LUr o
_
^ A
o> A
i
00
ง 0.5 -
+.
ro
O _
Anaerobic condition
Aerobic condition NH4~N
Anaerobic condition NOa .
Aerobic condition N03
O
O
Sample. Bottom sediments of Kusatsu
Yamada-Oki ( 7.5 - 12 .5 cm)
SS: 1000 mg/l
Room Temp. : 20ฐ C
O
05 Q *
- n <* 8
z O
n^
A
k A^\ A Al ^
1 1 \ KL
0
10
20 30 40
TIME (DAYS)
50 55
Figure 15. Concentration of NH.-N and N0? + NO,-N during aerobic and anaerobic incubation of
lake sediment from Kusatsu Yamada-oki 7.5-12.5 cm layer.
174
-------
A 14-day-old sediment-lakewater extract was used for the algal assays.
Because the P04-P concentration was very high, a dilution technique was
adopted to assess the algal growth potential (AGP) of the sample water. AGP
was calculated using the following equation:
AGP (mg/l)= maximum cell concentration (mg/1) x dilution ratio.
The nutrient concentration and AGP of samples from Akanoi-wan are shown
in Table 3 and Figure 16. AGP in lake water increased from 6.9 mg/1 to 15.2
mg/1 by introduction of EDTA. A nutrient pulse test showed higher AGP values
than in the case of the nitrogen pulse test, but it is difficult to conclude
that nitrogen was the limiting nutrient.
TABLE 3. NUTRIENT CONCENTRATIONS IN AKANOI-WAN WATER SAMPLES USED FOR ALGAL
ASSAY
Total P
P04-P
NH4-N
N02+N03-N
Filtered lake water
0.0-0.4 cm
0.0-4.0 cm
4.0-9.0 cm
9.0-14.0 cm
14.0-24.0 cm
14.0-24.0 cm
Oxic
Anoxic
Oxic
Oxic
Oxic
Anoxic
0.029
0.510
2.30
0.496
0.394
0.261
0.738
0.027
0.440
1.83
0.304
0.304
0.190
0.452
0.034
0.08
0.09
0.05
0.08
0.06
0.05
0.025
1.06
0.00
0.89
0.88
0.90
0.00
The AGP was high in the anaerobic water extract from the upper layer (0-4
cm, 4-9 cm). This seems to be caused by the high concentration of nitrogen
and phosphate released from the sediment. However, the AGP of the lower layer
(9-14 cm, 14-24 cm) was very low even though the nutrient concentrations were
high. By adding EDTA, the AGP of the lower layer increased to the level ot
the upper layer without increasing the AGP of the upper layer. It is possible
that materials similar to EDTA released nutrients in the upper layer, but did
not release them from the lower layer or did release some kind of algal growth
inhibiting materials. A nutrient pulse test showed that the amount of phos-
phate released was much greater than expected based on the N/P ratio required
for the growth of M. aeruginosa.
An aerobic sediment extract showed very low AGP in both the upper and
lower layers. This result seems to be caused by a low nitrogen concentration.
The same results were obtained from the nutrient pulse test, i.e. AGP in
nitrogen spiked samples was very high.
The nutrient concentration in water samples from Kusatsu Yamada-oki are
shown in Table 4 and the AGP is shown in Figure 17. The AGP of sediment
extract with a pulse of EDTA added was higher than that without EDTA. The
growth stimulation effect that was observed in the sediment from Akanoi-wan
did not appear. Although the concentration of P04-P was lower than that of
Akanoi-wan, the P04-P released from Kusatsu Yamada-oki caused a high AGP value
where a nitrogen pulse was added.
175
-------
8 =
cr
tu
E
o
^
CM
I
E
o
i
o>
E
o
E
o
6
m
re
3.
i
O
c.
X
OJ
O)
T3
QJ
LO
-o
ro
S-
+J
(O
3
QJ
ro
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O
Q.
O
s-
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O)
S-
en
(l/Buu) nvilN310d HIMOdO "1V9~IV
176
-------
100
CP
E
LJ
X
I-
o
cr
o
50
0
TEST ALGA
S
E
M. oeruginoso
Standard
EDTA(1mg/l) added
N: N03-N(2mg-N/l)added
P: P04-P(0.lmg-P/l)added
SAMPLE: Bottom sediments of
Kusatsu Yamoda-Oki
FILTERED
AEROBIC
ANAEROBIC ANAEROBIC
BOTTOM - 2.5cm
I
7.5-I2.5cm LAYER
Figure 17. Algal growth potential (AGP) of lake water and
sediment extracts from Kusatsu Yanada-oki.
177
-------
TABLE 4. NUTRIENT CONCENTRATIONS IN KUSATSU YAMADO-OKI WATER SAMPLES USED FOR
ALGAL ASSAY
Total P P04-P NH4-N N02+N03-N
Fi
0.
0.
7.
Itered lake water
0-2
0-2
5-1
. 5 cm
. b cm
2.5 cm
Ox ic
Anoxic
Anoxic
0
0
0
0
001
132
199
032
0
0
0
0
000
122
159
018
0.
0.
0.
0.
07
28
12
08
0
0
0
0
01
04
00
01
THE EFFECTS OF SEDIMENTS ON THE GROWTH OF M. aeruginosa
Chelating agents such as EDTA and ferric citrate play an important role
in the growth of M. aeruginosa. The origin of these chelates in natural water
is in the sediment or metabolites from algae, bacteria, and other organisms.
In this research, fulvic acid extracted during the spring from lake sediment
showed a growth stimulation effect; a more remarkable effect was observed when
fulvic acid was extracted from highly polluted sediments in summer. Tnere-
fore, it can be concluded that the sediments play an important role in the
growth of M. aerugi nosa.
Algal assays were conducted on sediments sampled in Lake Biwa to clarify
the differences between sampling stations and sediment depth. Higher AGP
values were observed in the polluted Akanoi-wan sediment extracts compared to
the less polluted Kusatsu Yamada-oki sediment extracts. This difference
resulted not only from the large amount of nutrients released from the sedi-
ment at Akanoi-wan, but also from the release of materials equivalent to
chelates. Since these chelating agents were not released under anaerobic
conditions, the polluted sediment appears to stimulate the growth of M. aeru-
ginosa even under aerobic conditions.
Advanced wastewater treatment and nutrient capture or diversion are
regarded as effective methods for lake reclamation. However, not all of these
techniques result in success because of internal phosphorus loads (Welch,
1977). It is therefore important to prevent the release of nutrients and
organic materials not only to reduce internal nutrient loads, but also to
decrease the concentration of materials which stimulate algal growth, particu-
larly for the troublesome blue-green algae, M. aeruginosa.
REFERENCES
Hughes, E. 0., P. R. Gorham and U. A. Zehnder (1958). "Toxicity of a Unialgal
Culture of Microcystis aerugi nosa." Can. J. Microbiol., 4, pp. 225-236.
Japan Sewage Works Cooperation (1976). "The Development and Applications of
Indexes for the Control of Eutropication" (in Japanese).
National Eutrophication Research Program, U.S. Environmental Protection Agency
(1971). "Algal Assay Procedure Bottle Test."
178
-------
Okada, M. , 0. Yagi and R. Sudo (1978). "The Growth Stimulative Materials for
Microcystis aeruginosa." 43rd Conf. of Japan Society on Limnology, pp.
129.
Okada, M. and R. Sudo (1978). "Some Problems in Algal Assay Procedure" (in
Japanese). Water and Wastes, 12, pp. 765-779.
Sudo, R. , T. Mori, H. Ohtake, M. Okada, and S. Aiba (1975). "Algal Growth
Potential of Secondary Effluents from Municipal Sewage Treatment Plants"
(in Japanese). J. Japan Sewage Works Association, 12, (6), pp. 1-9
(English Translation). In: Research Treatises on Environmental Protec-
tion Technology in Japan, Research Coordination Division, Environmental
Agency, Japan, pp. 1-31. (1977).
Welch, E. B. (1977). "Nutrient Diversion: Resulting Lake Trophic State and
Phosphorus Dynamics." U.S. Environmental Protection Agency, Corvallis,
Oregon, EPA-600/3-77-003.
179
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TOXIC MATERIAL AND NUTRIENTS FROM CONTAMINATED SEDIMENTS
Yoshiharu Nakazono and Yasuji Saotome
Machinery Division
Port and Harbor Research Institute
Ministry of Transport, Japan
ABSTRACT
This paper describes the characteristics of PCB (polychlorinated biphen-
yls), mercury, phosphate-P, and nitrogen from contaminated sediments. It
discusses the adherence of these materials to soil particles, their removal by
coagulants and a sand filter, and their solubility in water.
The smaller the soil particle size, the higher the content of PCB or mer-
cury. Phosphate-P can be removed by the addition of certain coagulants, but
mercury, PCB, and nitrogen cannot be removed by the coagulating agents used in
this work. PCB and mercury are readily removed by suspended solids.
INTRODUCTION
Contaminated bottom sediments, for reasons of pollution control and
environmental preservation, must be removed as soon as possible. Removal is
currently done by using conventional dredging and reclamation systems. These
techniques require great care to avoid secondary pollution such as dredging-
caused turbidity or wastewater discharged from a reclamation site. Various
dredges and reclamation methods have been designed to deal with these prob-
lems. Sediments removed and sent to reclamation sites must be enclosed by
bulkheads, and wastewater discharged to the sea must meet standards set by the
Cabinet Order for Implementation of the Marine Pollution Prevention Law.
These are shown in Table 1. The removal standards for sediments containing
mercury and PCB are established by the government. In accordance with these
criteria, sediments containing more than 25 ppm mercury in rivers and marshes
are subject to removal, and the ocean criteria are determined by the mean
range, solubility ratio of mercury from the sediments, and the safety factor
relative to any fisheries in the area. Any bottom sediments with more than 10
ppm of PCB should be removed.
Red tides will result from eutrophication caused by the discharge of
wastewater from industrial plants or by the dumping of domestic wastewater,
which provides nutrients such as nitrogen and phosphate-P.
181
-------
TABLE 1. EFFLUENT STANDARDS (June 21, 1971)
Toxic Substances
Permissible Limits (mg/1)
Cadmium and its compounds
Cyanide compounds
Organic phosphorus compounds
(parathion, methyl parathion,
methyl demeton and EPN only)
Lead and its compounds
Chromium (VI) compounds
Arsenic and its compounds
Total mercury
Alkyl mercury compounds
PCB
0.1
1
1
1
0.5
0.5
0.005
Not detectable1
0.003
1 "Not detectable" means that the substance is below the level detectable by
the standard method designated by the Director General of the Environmental
Agency.
STUDY METHODS AND PROCEDURES
SEDIMENT SAMPLING
The contaminated sediments used in this study were sampled at Tagonoura
Port for PCB and nitrogen, at Nagoya Port and Tokyo Bay for mercury, and at
the mouth of the Tama River for phosphate-P. PCB at Tagonoura Port originated
in the wastewater from paper mills which used to produce paper containing PCB.
Straw chips and coarse rubble were removed from the samples according to the
standard method. Samples were collected with Koken and Kumada-type samplers.
The former is a grab sampler and the latter is a dredge sampler. The samples
were packed in polyethylene bags. Their identification and conditions are
shown in Table 2.
In this study the following tests were performed:
1) Sedimentation Test
2) Filtration Test
3) Solubility Test
Concentrations were determined for PCB, total mercury, phosphate-P and
total nitrogen according to standard methods. It is not necessary to be
concerned about detection limits in soil samples because of the high concen-
182
-------
TABLE 2. SAMPLES AND SAMPLING CONDITIONS
Sample Date Conditions of Sediments
PCB-1 Nov. 1976 black, hydrogen sulfide smell
PCB-2
PCB-3 " " " " "
Hg-1 Nov. 1977
Hg-2
P-l Oct. 1976
P-2 " black, sandy
P~3 " black, clayey
N Nov. 1977 black, hydrogen sulfide smell
Depth Remarks
(m)
9.0
12.0
15.0
2.1
2.0 mixture
3.0
4.9
25.0
6.5
trations, but in water the detection limits are as follows for the instruments
and the sample volumes used:
1) PCB -- 0.0005 mg/1
2) Total Mercury -- 0.0001 mg/1
3) Phosphate-P -- 0.003 mg/1
4) Total Nitrogen -- 0.5 mg/1
In performing these tests, both natural Tokyo Bay and seawater and arti-
ficial seawater made from "Aquamarine" were employed. The natural seawater
was used for the PCB and phosphate-P analyses, and the artificial seawater for
the total mercury and total nitrogen analyses.
SAMPLE PROPERTIES
Samples were analyzed for true specific gravity, grain size distribution,
ignition loss, and the content per weight of dried sediment for the items of
interest. The results shown in Table 3 and Figure 1 demonstrate that every
sample consists primarily of particles below 74 urn and that the true specific
gravity is comparatively low because of the high ignition loss. All the
samples were prepared by centrifuging at 3,000 rpm for 20 minutes according to
the standard method, and testing the resultant precipitate.
The preliminary removal standard for sea bottom sediments containing
mercury is calculated using the following equation:
183
-------
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184
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185
-------
TABLE 3.
SAMPLE PROPERTIES
Sample
PCB-1
PCB-2
PCB-3
Hg-1
Hg-2
P-l
P-2
P-3
Content
(ppm)
PCB 52.9
10.9
6.2
T-Hg1 43.3
11.3
P04-P 1.363
1.238
0.986
Ignition Loss True
21.8
23.8
19.. 1
22.0
13.4
9.3
4.6
8.3
Specific Gravity
2.432
2.413
2.490
2.289
2.438
2.594
2.659
2.648
T-N
6640
26.7
2.234
^-Hg, P04-P, and T-N mean total mercury, phosphate-P and total nitrogen,
respectively.
where:
C = 0.18 - ^ 1
J b
H = the mean range
J = the solubility rate, and
S = the safety factor.
For example, at Nagoya Port H, J, and S are 1.53 m, 0.0077, and 50, respec-
tively, so C =3.5 ppm. Consequently, sediments at locations Hg-1 and Hg-2
should be removed.
It is interesting to understand how the material is contained in the
bottom sediments. An attempt was made to obtain the relationships between the
contents per weight of dried sediment and particle size. Samples, except for
PCB, were wet-sieved into several groups to prevent variation in the contents.
The results are shown in Figures 2-4. The curve at Station Hg-1 has a peak of
Hg concentration in the 105 urn to 250 (jm range. In general, the contents of
both PCB and mercury increase with decreasing particle size, but for nitrogen
the content appears to increase with increasing particle size. It is usually
considered that the amount adsorbed per weight of solid increases with the
solid's specific surface area, which usually depends on decreasing particle
volume. The high ignition loss led us to attempt to relate ignition losses to
particle sizes. The relationship between ignition loss and nitrogen content
is shown in Figure 5. Figure 6 shows ignition loss vs mercury content. The
total nitrogen concentration varies linearly with ignition loss, but there is
no correlation with mercury.
Sand used for the filtration test meets the standards set by the Japan
Waterworks Association. The sand contains very little dust, clay or flat or
weak grains. Table 4 shows the properties of the sand and Figure 7 shows the
186
-------
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grain size accumulation curve. The coefficient of permeability of the sand
layer as used for filtration is based on the constant-head permeation method.
This value may differ from the permeability under use conditions.
TABLE 4. PROPERTIES OF FILTRATION SAND
Ignition Effective True Specific Porosity Coefficient of
Loss (%) Grain Size (mm) Gravity (%) Permeability (cm/s)
0.545
0.405
2.610
41.6
0.154
PRINCIPAL ANALYSES
SEDIMENTATION ANALYSIS
Samples were sieved to below 420 urn under wet conditions. Suspensions
were made oy mixing the samples with 50 liters of either Tokyo Bay seawater or
artificial seawater, as mentioned previously. The suspensions, at a pre-
determined concentration, were stirred at 40-60 rpm for 10 minutes in a settl-
ing cylinder 291 mm in diameter and 900 mm in height. Settling time was
measured from the moment stirring stopped. The central part of the water
column was sampled at fixed time intervals.
Increased settling rates caused by coagulants were examined under the
conditions shown in Table 5. Time-dependent variations in SS vs material
concentrations are given in Figures 8-11.
TABLE 5. SPECIFICATIONS FOR SEDIMENTATION ANALYSIS
Sample
PCB-1 \
PCB-2/
SS
(ppm)
3,000
6,000
Coagulant and Its
Addition Concentrati
no additives
aluminum sulfate 1
ferrous sulfate 1
on
00
00
Sampling
Time (min)
0, 5, 10, 15
30, 60, 120,
300, 600
unslaked lime 1 ,000
Hg-i\
Hg-2/
N
50
400
3,000
50
400
400
400
cation polymer
anion polymer
no additives
no additives
no additives
PAC 100
cation polymer 1
1
1
0, 5, 10, 15
30, 60, 300
600, 1440
same as
above
Particle
Size
sieved
below
420 pm
same as
above
same as
above
191
-------
15
10
en
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O
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A
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4
0
0
30
TIME (min)
60
Figure 8. Variation of PCB concentration with time (see Table 8 for symbol
identification).
192
-------
1.5
- 15
1.0
o
CO
CO
CO
CO
0.5
0
i ซNi 11 " i r~~i rj i i i T i i r
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SSo ORDINATE
* 50 SS/SSo
* 400 SS/SSo
3 3000 SS/SSo J
50 T-Hg x ID'4
400 T-HgxIO"3-
o 3000 T-Hg xlO"2-
10 100
TIME (min)
1000
Figure 9. Variation of T-Hg concentration and SS with time
(Hg-1).
en
0L 0
SSo ORDINATE
50 SS/SSo
400 SS/SSo
D 3000 SS/SSo
50 T-Hg x IO"4
400 T-HgxIO"4
3000 T-Hgx IO'3
10 100
TIME (min)
1000
Figure 10. Variation of T-Hg concentration and SS with
time (Hg-2).
193
-------
o
in
\
(/)
0
III. I II
SSo ORDINATE
A 50 SS/SSo
A 400 SS/SSo
o 400 SS/SSo Inorg.
400 SS/SSo Org.
50 T-N
400 T-N
o 400 T-N Inorg.
T-N Org.
L 0
100
TIME (min)
1000
Figure 11. Variation of T-N concentration and SS with
time (N).
194
-------
Effluent standards require reclamation if the concentration is greater than
0.003 mg/1 for PCB and 0.005 mg/1 for total mercury. As in Figures 8-11 the
relationships between SS vs material concentration are plotted in Figures
12-16, but the solid lines in these figures are based on the assumption that
the material is part of the suspended solids, that is, the lines represent
(SS) x (material concentration). In Figure 12 the measured values of PCB
concentration deviate from the line, but Murakami's (1921) measurements show
good agreement with the line. PCB has extraordinarily high chemical stability
and is flammable only at very high temperatures. Generally speaking, PCB is
not soluble in water, but the forced stirring makes it possible for PCB to di-
ssolve to concentrations of 0.3 to 5 ppm. Also, studies have shown that if
surface active agents coexist with the PCB, then its solubility increases.
For example, 10 ppm of "Tween 80" in water is responsible for producing 10-20
ppm solutions of KC-200, KC-300, and KC-400 PCB (Isono and Fujiwara). Surface
active agents are thought to be mixed in natural water in large quantities.
Considering this possibilitythat the water of Tokyo Bay contains surface
active agents the PCB contained in soil particles may dissolve in sea water
from both the stirring and surface active agents and then adhere to particu-
lates as they settle, consequently, reducing the water column concentrations.
To test the above assumption the following experiment was conducted. A
mixture of artificial seawater, surface active agent, and PCB was allowed to
settle and a sample of the upper water layer was taken after a two-hour settl-
ing period. The test conditions were:
SUBSTANCE QUANTITY
PCB (KC-400) 3 grams
Surface active agent [Dodecyle-benzol sulfonate (DBS)]. . . 0, 0.03, 0.1, 0.3,
1.0, 10 mg/1
Seawater 3 liters
The results of this experiment indicate that the surface active agent has
no apparent effect on the solubility of PCB in water (Table 6).
TABLE 6. PCB SOLUBILITY AS A FUNCTION OF SURFACE ACTIVE AGENT CONCENTRATION
DBS Content (mg/1) 0 0.03 0.1 0.3 1.0 10.0
PCB solubility (mg/1) 0.0153 0.0155 0.0159 0.0158 0.0143 0.0155
The solid line in Figure 13 indicates good correlation between T~Hg
concentration and SS when the latter exceeds 50 mg/1. It shows further,
however, that the correlation decreases sharply when SS concentrations are
less than 50 mg/1. For the Hg-2 sample (Figure 14), which is a mixture of two
bottom sediments at Tokyo Bay and Nagoya Port, the solid line corresponds well
with actual measurements. For P-l, P-2, and P-3 (Figure 15), there exists no
195
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relationship between SS and phosphate concentration, but it is deduced from
the figure that coagulation agents such as aluminum sulfate, ferrous sulfate,
and unslaked lime have the same effects as removal of soil particles. It is
found that polymers have no effect. Phosphate-P dissolves in water from soil
particles in the form of ions and exists in the suspension regardless of soil
particles, but the inorganic coagulants and the ions unite and settle as solid
particles. With regard to N the relationship between total nitrogen and SS is
net strong, in addition none of the coagulants appear to remove nitrogen.
From the above results, it is clear that it is possible to monitor water
quality by means of SS instead of direct measurements for total mercury or
PCB, i.e., water quality may meet effluent standards by keeping SS less than
100 mg/1 for Hg-1 and less than 300 mg/1 for Hg-2.
Sedimentation of soil particles can be generally classified into three
types: (1) discrete settling which occurs when SS is very low; (2) flocculant
settling, and (3) zone settling. Consider a standard settling model based on
the assumption that individual particles behave according to Stokes1 Law.
This model fits the type 2 settling classification. The following discussion
shows how the settling curve takes the shape of that of the Hg-1 sample.
Assuming that the grain size accumulation curve takes the shape of a
logarithmic normal distribution, and denoting the particle diameter by x, the
curve can be described by the equation
F(x) =
exp[ -
(1)
V27TO -o
where F(x) denotes percent by weight of soil particles below x, ฃ = Inx,
m = In VX84 X36> a = In Vx84/xie- For the Hg-2 sample, from Figure 1,
m = 2.965 and a = 0.999.
According to Stokes' law, the settling velocity of particles having
diameter x is represented by the equation
- p)z
_ _ _
18u
Let p(x)dx represent the percent weight of soil particles having velocity v in
the suspension whose initial SS is equal to SS0. Let SS at a distance z from
the surface be SS, and elapsed time after stirring be t, the equation
SS/SSo =
p(x) dx
(3)
is obtained. Since dF(x) = p(x)dx, v = z/t, it becomes
ln
SS/SS0 =
exp
_ }
m}
] d|
(4)
199
-------
where a = Vl^M/g (p ~ Pf)- The curve obtained from equation (4) is plotted
in Figure 10. This ideal settling curve is influenced by convection due to a
temperature differential between the upper and lower part of the water column
and the diameter of the container. It is obvious from Figure 10 that sedimen-
tation is better when SS0 is high. Where SS0 was 3,000 mg/1 , SS was reduced
to 1/10 of SS0 in 30 minutes. By comparison the 50 and 400 mg/1 initial
suspensions show a slower sedimentation time than that of the theoretical
model.
Increasing the sedimentation rate by using coagulants was investigated
using a suspension of 400 mg/1 of SS made from sample N and artificial sea-
water. PAC and cation polymer were added separately to the suspension in the
amounts shown in Table 5. Figure 11 shows the test results. Sedimentation is
enhanced by addition of an inorganic coagulant agent and even more by the
organic coagulants.
The above results show that PCB and mercury bond strongly with soil
particles. Therefore, to remove PCB or mercury from seawater, it is suffic-
ient to remove the suspended solids. Some coagulants are effective in remov-
ing phosphate-P from the suspension, but they are not useful for removing
nitrogen.
FILTRATION TEST
For this test samples were passed through a sand filter. The apparatus
was a vertical cylinder 3.2 m high with a 0.291 m diameter. The filter column
was packed with sand having grain size characteristics as shown in Figure 7.
The tests were run by pouring the suspensions into the cylinder and, with
the valve left open at the bottom, periodically sampling the filtered water
and analyzing it for mercury, PCB, and SS. During the experiment the water
was maintained at a constant level by continually adding more of the suspen-
sion being tested. For example, Hg-1 measurements were made of the filtration
ratio (which is defined by the flow rate of the filtered water) and the level
of total mercury in the sand layer at the end of the test.
It is obvious that the majority of SS can be removed by filtration,
therefore PCB and mercury should not penetrate the sand layer. But note that
sediments deposited on the sand layer also act as a filter. These sediments
were several millimeters thick.
Figure 17 shows variations in filtration rate with time. The filtration
rate decreases sharply after several hours. The influences of water pressure
over the sand surface on the filtration rate is also illustrated. A pressure
difference of 1 m of depth slightly increases the filtration rate. Figure 17
also compares the filtration characteristics of the suspensions prepared from
sea bottom sediments sieved blow 420 urn and 74 urn. The filtration rate of the
suspension below 74 pm is greater than that of the suspension below 420 pm.
Total mercury in filtered water is shown in Figure 18. The test condi-
tions under which the results in Figure 18 were obtained were the only ones
that yielded detectable quantities of total mercury. In this test, concentra-
200
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tion decreased sharply with time. Even after only one hour the concentration
of total mercury showed only 0.0012 mg/1, which easily meets the effluent
standard of 0.005 mg/1.
The total mercury concentration at different depths in the sand layer was
measured and the results are presented in Figures 19 and 20. In Figure 19 the
mercury does not reach the bottom of the sand layer; in Figure 20 larger
amounts of soil particles are found at the lowest part of the layer. But even
in this case, total mercury is not detected in the filtered water. This leads
to the conclusion that in the early filtration process almost all the voids of
the sand layer are clogged by soil particles.
The significant conclusion from the above results is that, except for the
early stages of reclamation work, a bulkhead built of earth and sand instead
of expensive watertight structures may prevent PCB or mercury from re-entering
the environment, i.e., filtration through a sand layer of proper grain size is
an effective method for removing PCB and mercury.
SOLUBILIZATION TEST
The test was carried out according to the Methods for Investigating
Bottom Sediments authorized by the Environmental Agency, except that artific-
ial seawater and natural seawater were employed in preparing the mixtures of
bottom sediments and water. The mixture was continuously stirred for four
hours, and after being allowed to settle a bit, it was passed through filter
paper. The filtered water was analyzed for contents. Conditions for the test
are shown in Table 7.
TABLE 7. TEST CONDITIONS AND RESULTS
Sample Mixing Ratio (g/ml) Concentration After Filtering (mg/1)
PCB-1
Hg-1
50/100
25/100
3/100
0.3/100
3/100
1.5/100
0.3/100
0.03/100
0.0006
ND
NO
ND
ND
ND
ND
ND
Mixing ratio is the ratio of soil dry weights (g) to the volume of the mixture
(ml).
ND means "not detectable," i.e., 0.0005 mg/1 or less for PCB, and 0.0001 mg/1
for total mercury.
The Methods for Investigating Bottom Sediments defines the solubilization
ratio as:
202
-------
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203
-------
Sol utilization ratio =
where Wx is the amount of toxic matter (pg) contained in the bottom sediment
sample, and W2 is the amount of toxic matter (p.g) which is contained in a
volume of filtered water equivalent to the mixture prepared in the test.
According to this definition, the solubil ization ratio is calculated to
be less than 7.7 x 10-3 for Hg-1 and 5.57 x 10-5 for PCB-1. The preliminary
criteria for sea bottom sediments were calculated using these values.
CONCLUSIONS
The main conclusions to be drawn from this study are:
1) The finer the particles of the bottom sediments, the higher the concen-
tration of PCB and total mercury. They adhere strongly to soil particles
and it is therefore important to remove fine suspended solids to improve
wastewater quality at reclamation sites.
2) Because a sand layer can prevent suspended solids from penetrating, a
bulkhead filter built with earth and sand is capable of removing PCB and
mercury.
3) Phosphate-P is removed by addition of aluminum sulfate, ferrous sulfate,
and unslaked lime. Except for the nitrogen in soil particles, nitrogen
will not be removed by any coagulation agent.
4) Total mercury concentration in the sand layer is extremely high but
decreases abruptly with depth, leading to the conclusion that almost all
suspended solids remain in a thin layer in the upper part of the sand
layer. The filtration rate decreases sharply with time.
5) A surface active agent did not dissolve PCB in water under the test
conditions employed here. During the test PCB was observed to fall in
spherical particles after stirring stopped.
NOTES
1. In the sedimentation test, the direction of filtration was in the verti-
cal direction, i.e., the sand layer was horizontal, allowing suspended
solids to fall on the surface. This test method is not capable of exam-
ining the permeation of suspensions through bulkheads built up with earth
and sand. But for secondary treatment of wastewater that does not meet
the effluent standards, filtering contaminated suspensions through a sand
layer is an effective method of improving water quality.
2. Regarding the solubility of PCB in water: the surface active agent has
no effect, but it is possible that the deviation between the solid line
and the measurements in Figure 12 may be due to oil, because PCB is
soluble in oil. We intend to clarify this point.
204
-------
TABLE 8. SYMBOLS (APPLICABLE TO FIGURE 8, FIGURE 12, FIGURE 15)
coagulation
no
addition
aluminum
sulfate
ferrous
sulfate
am on
polymer
cation
polymer
unslaked
1 ime
o
a
6,000
3.
REFERENCES (all in Japanese)
Muramaki, K. and Takeishi, K. "On the Behavior of Heavy Metals, PCB, and
so on in Management of Hedoro," Proceedings of Port and Harbor Tech-
niques, Bureau of Ports and Harbors, Ministry of Transport, No. 78, 1977.
Isono, N. and Fujiwara, K. "Pollution caused by PCB I," Journal of
Science, Iwanami Publications, Inc., Vol. 42, No. 5.
"Collections of Hydraulic Formulas," edited by The Japan Society of Civil
Engineers.
205
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THE FILTERING EFFECT OF CONTAINMENT WALLS ON
SUPERNATANT FROM CONTAMINATED DREDGE MATERIAL
Takeshi Monji
Port and Harbor Research Institute
Ministry of Transport, Japan
ABSTRACT
In designing revetments for disposal sites, care must be taken to prevent
pollution of the nearby environment from permeation of contaminated substances
through the containment wall. This paper describes the results of the follow-
ing experiments:
1) Heavy metal adsorption on clay
2) Filtration effects of sand backfill
3) Testing of steel piling seals for permeability
These experiments produced useful data to help design containment walls
for land reclaimed with dredged material.
INTRODUCTION
The large cities of Japan, such as Tokyo, Osaka, and Nagoya are located
in the coastal area. The rapid economic development of the 1960s caused en-
vironmental pollution to become an important problem along the coast, espec-
ially on the bottoms of some harbors, rivers, lakes and marshes. Contaminated
substances with undesirable effects on the surrounding environment accumulated
in these areas. Sources of these sediments are usually from waste discharges
from manufacturing plants, mines, urban sewage, or agricultural effluents.
To cope with this pollution, the government imposed legal restrictions on
effluent discharges and began to dredge the polluted sediments. This policy
resulted in gradual improvment of the environment, but large quantities of
sediment and urban waste are a continuing problem. One of the most difficult
tasks is to find disposal sites for this sediment and waste. In Japan there
is no space for land disposal. Therefore, sediment and waste has usually been
managed as reclaimed land in a port area. After a period of time, these
reclaimed lands have been used effectively for port facilities, urban redevel-
opment, distribution stations, and other uses. However, it is becoming more
difficult to find appropriate disposal sites. Construction of revetments for
dredged material has become more complex because of the technical problems
associated with building on thick deposits of soft soils and in deep water.
The most important consideration in constructing a containment wall for this
207
-------
purpose is to prevent secondary pollution due to permeation of contaminated
substances through the wall. To construct an absolutely waterproof revetment
is not impossible, but it is expensive and unnecessary. The author and his
colleagues have begun studies to determine a safe, economical structure for
revetments. This paper is an interim report of these studies, particularly on
the filtering effects of these porous containment walls.
CONTAINMENT WALL CHARACTERISTICS
TECHNICAL CONSTRUCTION PROBLEMS
Containment walls for land reclamation have different characteristics
than conventional wharves and revetments. First, conditions at the construc-
tion site are difficult because of soft ground and deep water. Second, design
variables such as quality of material for reclamation, the height of the
structure, and the residual water level are more severe. Third, and most
important, is to prevent contaminated substances from permeating the wall.
Though we can cope with the first two problems using conventional techniques,
the third problem has unknown factors such as sand filtration effects and
permeation rates of contaminated substances.
In Japan two types of containment walls have usually been constructed
the gravity type (caisson, cellular, stone masonry, etc.) and the sheet pile
type (double wall, steel pile, etc.). Figure 1 shows typical Japanese revet-
ments for reclaimed land. Methods of protection against permeation of contam-
inated substances are discussed for both types.
TECHNIQUES TO PREVENT PERMEATION OF CONTAMINATED SUBSTANCES
Techniques to prevent permeation of contaminated substances through
revetments are shown in Figure 2. They may be classified into 5 groups:
1) Protection Sheet. Many kinds are commercially available and are
effective for prevention of pollution. However, more study of
durability and sheet arrangement is necessary to make practical use
of this technique.
2) Backfill. This is often used as a protection method but a precise
determination of the relationship of thickness and grain size dis-
tribution to permeation of pollutants still remains unsolved because
the sand filter mechanism is not yet fully understood.
3) Sheet Pile. Piles are usually driven into the impermeable layers.
4) Grout. Sheet pile joints are sometimes sealed with asphalt, ure-
thane, or mortar.
5) Direct Mixing. Direct mixing of asphalt or cement mortar with the
disposed material. This causes soil stabilization.
In constructing revetments it is impractical to make them perfectly
watertight. To prevent as much pollution as possible is the objective. Thus,
208
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209
-------
the purpose of the experiments described in this paper is to determine the
filtering effect of sand backfill and fill on the permeation of contaminated
substances and, finally, to determine the proper design criteria for revet-
ments.
METHOD
KIND OF WASTE
TOTAL
PROTECTION SHEET
8
SHEET PILE
GROUTING JOINTS
(Gravity type)
A -Waste from manufacture including
toxic substances
B- General waste
C - Others
WIDENING OF BACKFILL
3321
WIDENING OF BACKFILL
PROTECTION SHEET
(1975)
GROUTING JOINTS
SHEET PILE TYPE
Mfrl
FILL (Celluler
bulkhead)
15
Figure 2. Techniques to prevent permeation of contaminated substances.
SAND BACKFILL AS A FILTER FOR HEAVY METALS
Clay mainly consists of silica, alumina and water. Some kinds of clay
include magnesium, iron, alkaline-metal and alkaline-earth-metal. Clay grains
are negatively-charged from ion exchange in the crystals of clay and from
imperfections on the surface of clay particles. Though the electric charge
depends on a combination of factors, heavy metal is generally adsorbed to
clay. This is why bottom sediments in the coastal areas and rivers in Japan
include some heavy metals which are deleterious to health.
In dredging these contaminated sediments and disposing of them as re-
claimed land, the most important considerations are elution of toxic sub-
stances by dredging, disposal of the supernatant water of dredged sediment and
the permeation of contaminated substances through the containment area revet-
ment.
If clay is put into a solution containing heavy metal and agitated, the
heavy metal is adsorbed to the clay. So when contaminated sediments are
disposed of as reclaimed land, heavy metals in
the suspended soils and these suspended soils
backfill sand in the revetment.
the water will be
will be filtered
adsorbed to
out by the
210
-------
By knowing the rate of adsorption of heavy metal to clay and the filter-
ing capacity of sand backfill for suspended soil, the concentration of heavy
metal in the effluent from contaminated substances can be controlled at a
level which will satisfy the requirements.
These considerations allow revetments to be designed safely and economic-
ally by determining the kind and thickness of backfill sand. The filtering
effect depends on both adsorption of heavy metal to clay minerals and the
filtering out of suspended soils. The amount of heavy metal adsorbed to the
clay varies with the kind of clay, type of heavy metal, concentration of
seawater, and the pH of the suspension. The filtering effect of sand changes
with the particle size of the sand, particle size of the clay, water pressure,
density of sand and other factors.
CHARACTERISTICS OF MARINE CLAY AND BACKFILL SAND IN JAPANESE PORTS
Coastal Japan is covered with soft alluvial clays which come from rivers
and in some cases derive from volcanic ash. Clay minerals are the result of
chemical weathering of rock and consist mainly of kaolinite, montmorillonite
and illite.
Clay particles are negatively charged. Cations such as heavy metal ions
are thereby adsorbed to the surface of the clay particles. The higher the
electric charge or the smaller the radius of the cations, the stronger the
adsorptive adherence. The present experiments do not investigate in detail
the chemical reaction of clays. At this time general information is more
useful in designing containment walls.
Soil samples, including sea bottom clay or sand used for backfill were
collected from the various locations shown in Figure 3. Using these samples,
several series of experiments were made on heavy metal adsorption to clay and
on the filtering effect of backfill sand. The physical and chemical charac-
teristics of the clay and sand are given in Figures 4 and 5 and Table 1. With
few exceptions all the clays used have similar physical properties.
The sands have a similar pattern of grain size distribution, somewhere
between the Takahagi sand and the Toyoura sand used in the author's labora-
tory. Backfill sand samples were made by mixing these two sands for the
experiments.
EXPERIMENTS ON CLAY ADSORPTION
FACTORS CONTROLLING THE ADSORPTION OF HEAVY METAL
The purpose of this experiment was to determine the rate of heavy metal
adsorption on to clay. Lead, cadmium and mercury were the heavy metals used
in this experiment and Kawasaki clay was used for the suspension. The main
factors considered in the experiments were the concentration of the heavy
metals and suspensions in solution. Additional factors investigated were
agitation time, mesh size of filter, position of the agitating apparatus and
pH.
211
-------
-AOMORI
I 3
FUSHIKITOYAMA
KOBE
NAGOYA
Figure 3. Main ports in Japan (clay and backfill sand from these ports were
used in the experiment).
The heavy metal solution was prepared by dissolving bichloride of mer-
cury, cadmium nitrate and lead nitrate in fresh water and ion-exchanged water.
Five liters of undiluted solution, including clay, were agitated in a cylinder
by rotary action for 30 minutes. After filtering, the concentration of heavy
metal, turbidity, pH and other factors were measured.
Results of this experiment are:
, Co - C nnr,
A = p x 100
o
A: Adsorption percentage
Co: Concentration of solution with heavy metal
C: Concentration of solution after being adsorbed onto clay
(1) Adsorption of mercury to clay increases in proportion to the loga-
rithm of turbidity, i.e. 70% for 100 ppm of turbidity and more than
80% for 500 ppm of turbidity. Lead and cadmium show the same ad-
sorptive tendency as mercury (see Figure 6).
212
-------
TABLE 1. CHARACTERISTICS OF CLAYS IN JAPAN
Clay Type
Characteristics
Spec!!ic (Gs)
gravity
;;sd <ซป
"ป?t1c w %
?idซc1ty<*ป --
Gravel %
Sand %
Silt %
Clay %
Classification
Total -mercury ppm
Cadmium ppm
Lead ppm
Sulfide mg/g
pH
O.R.P. 100 mV
Aomori
2.56
70.4
46.7
23.7
0.5
14.0
55.2
30.3
F
0.36
0.75
56.1
1.90
7.9
-3.10
Kawasaki
2.69
75.6
37.8
37.8
0
4.7
38.3
57.0
f
0.33
0.23
39.4
0.28
8.4
-1.40
Nagoya
2.68
64.5
30.9
33.6
5.1
17.1
34.3
43.5
F
0.23
0.32
41.2
0.22
7.9
1.60
Fushiki
Toyama
2.66
63.8
32.9
30.9
0.2
19.5
51.9
28.4
F
0.48
0.64
35.9
2.30
8.0
-3.40
Kobe
2.70
100.4
39.2
61.2
0.1
1.1
36.3
62.5
F
0.17
0.24
40.2
0.21
7.8
0.60
Moji
2.70
76.5
29.6
46.9
0.3
10.2
30.5
59.0
F
0.05
0.10
19.9
0.06
7.7
1.40
(2) Adsorption of heavy metal to clay is low in acid solutions (pH >_ 6)
and high in alkaline solution (pH < 7). This tendency is more
noticeable for cadmium and lead (see Figure 7).
(3) Adsorption of each metal when all three metals are mixed together is
the same as that for individual metals.
(4) Changing agitation time (0.5-60 minutes) has no influence on adsorp-
tion.
213
-------
I I I I II III
0 Aamori
A FushikiToyama
a Kawasaki
Nagoya
Kobe
Moji
0.001
0.01 O.I
GRAIN SIZE (mm)
Figure 4. Grain size distribution of clay.
100
80
LJ
C_>
tr
LJ
a.
60
40
20
0
Akito
- Nigota
-o Fushiki Toyama
o- o Fukui
A Aomori
A A Kawasaki
Shimonoseki 1
a --- a " 2
D- -a n 3 _
0.005 O.I I.O
GRAIN SIZE (mm)
Figure 5a. Grain size distribution of backfill sand.
-------
100
80
o
cc
40
20
TTTTJ
i r
A Toyoura
o Takahagi
0
0.05 O.I
1 1 LIJl
1 1 1
Figure 5b.
(mm) 1.0 5.0
Grain size distribution of sand used for the experiment.
100
ui
80
ui
o
cr
ui
a.
60
Q.
QL
a
40
0
III!
o Pb- Low O.I ppm
Pb- High 1.0
ACd- Low 0.01 "
ACd- High 0.10 "
a Hg- Low 0.005 "
Hg- High 0.050 "
i I I i
50 100 500 1000
TURBIDITY (ppm)
I
I
3000
Figure 6.
Adsorption of heavy metal onto clay. Note: Adsorption percentage
A is defined as
_ Co - C
x 100
A: Adsorption percentage
Co: Concentration of solution with heavy metal
C: Concentration of solution after being adsorbed onto clay
-------
100
UJ
80
UJ
o
E 60
CL
-z.
O
t
o:
o
CO
Q
< 20
0
O Lead (Pb)-1.0 ppm
A Cadmium (Cd)-O.IO ppm.
D Mercury (Hg)~0.05 ppm
(Suspension-. 500 ppm)
0 2 4 6 8 10
pH
Figure 7. Relationship between pH and adsorption.
12
(ppm)
Pb Cd Hg
1.0
0.8
0.6
04
0.2
rO.IO
^0.08
-0.06
hO.04
-0.02
rO.05
-0.04
-0.03
-002
-0.01
0
i i i I I ii| i ill rj ill
ฐ(Pb)SS
Pb
A(Cd)SS
A Cd
a (Hg} SS
Hg
1000
(ppm)
SS
5000
4000
3000
2000
1000
0
I 10 100
TIME (min)
Figure 8. Change of heavy metal concentration and SS in sedimentation test.
216
-------
EXPERIMENTS ON ADSORPTION AND SEDIMENTATION OF HEAVY METAL IN SEAWATER
The purpose of this experiment was to investigate heavy metal adsorption
onto clay, and sedimentation of heavy metal in seawater. The authors used
Kawasaki clay in suspension plus mercury, cadmium, and lead as heavy metals.
The seawater was from Yokosuka in Tokyo Bay. The heavy metal solution was
prepared by the same method as described above. The experimental apparatus
was an acrylic cylinder (d = 190 mm, h = TOO cm). The prepared solution was
poured into the cylinder to 90 cm in depth and allowed to settle after 1
minute of agitation. The solution was sampled by siphon at 45 cm of depth and
analyzed. The results of this experiment are
(1) Clay particles flocculate in seawater and are deposited more rapidly
than in freshwater.
(2) The concentration of mercury and lead in the solution decreases in
relationship to the sedimentation of clay particles (SS), but the
concentration of cadmium in the solution is unaffected by the sedi-
mentation of clay particles (see Figure 8).
This may be because substances in seawater which are less easily ionized
than cadmium are adsorbed onto the clay.
EXPERIMENTS ON ADSORPTION OF HEAVY METALS TO SANDS
The purpose of this experiment was to investigate heavy metal adsorption
onto clay which is mixed with sand. Factors such as clay fractions, grain size
of sand and immersion time were considered. Takahagi sand, Toyoura sand, and
Kawasaki clay sieved through a 0.074 mm mesh and seawater were used. The
solution, including heavy metal but excluding clay particles, was prepared by
the method described above. Samples contained in acrylic cylinders (d = 290
mm, h = 100 mm) were made by mixing small amounts of clay with sand in differ-
ent ratios ranging from 0.001% to 5%. The solution, including different kinds
of heavy metal, was poured into each container. The samples were left in the
container for from 30 minutes to 3 hours and the filtrate was analyzed to find
the adsorption of heavy metal to clay. Results of these experiments are
(1) Adsorption of mercury increases in proportion to the clay fraction
regardless of immersion time and the percentage of adsorption was
the same as that in the suspension.
(2) Adsorption of cadmium is 30%-50% regardless of both immersion time
and clay fraction because of effects due to seawater.
(3) Adsorption of lead is about 80% regardless of both immersion time
and clay fraction.
EFFECTS OF CLAY TYPES ON ADSORPTION OF HEAVY METALS
In this experiment, the difference in adsorption by types of clays was
investigated. Six kinds of clay, shown in Table 1, and coral sand from Okin-
awa were used. For the purpose of a precise comparison, all clays were sieved
through 0.074 mm mesh and artificial seawater was used. The experimental
217
-------
method is the same as described for the sand experiments. Results of this
experiment are shown in Table 2 and may be described as follows:
(1) Generally, adsorption of heavy metal increases in proportion to
turbidity. But the influence of a pH change on adsorption of heavy
metal is not clear.
(2) The percentage of mercury adsorbed is higher than that of lead and
that of cadmium.
(3) Heavy metal is more easily adsorbed on coral sand than on clay.
TABLE 2. ADSORPTION OF HEAVY METAL TO DIFFERENT KINDS OF CLAY IN JAPAN
Clay Type
Aomiri
Kawasaki
Nagoya
Fushiki-
Toyama
Kobe
Moji
Okinawa
(coral sand)
%
pH
%
pH
%
PH
%
pH
%
PH
%
pH
%
pH
Metal
cc
oo
(ppm) 20
-
4.3
-
4.1
0
4.2
-
4.3
-
4.0
-
4.0
-
6.5
Lead
200
-
4.8
6
4.9
-
4.4
-
4.6
3
5.0
-
4.4
88
9.3
2000
91
5.6
99
6.6
84
6.0
46
5.8
99
7.2
97
6.7
99
9.5
Cadmi urn
20 200
0
5.2 5.6
6
5.5 6.2
1
5.1 5.4
1 4
5.1 5.5
0 11
5.3 6.4
2 0
5.3 6.1
7 12
9.0 9.6
2000
11
5.5
62
6.9
32
5.3
5
6.2
83
6.3
40
7.0
74
9.7
20
36
5.4
36
5.5
2
5.4
10
5.1
9
5.3
32
5.3
94
8. 1
Mercury
200
70
5.1
93
6.3
90
5.8
95
5.7
93
6.4
92
6.1
89
9.6
2000
98
5.8
90
6.8
97
6.5
85
6.3
98
6.4
92
7.1
70
9.7
EXPERIMENTS ON SAND FILTRATION
FILTERING EFFECT ON BACKFILL SAND
The absorption experiments show that heavy metal is adsorbed to clay and
that the percentage of adsorption depends on the kind of clay, kind of water,
pH of the solution, turbidity and other factors. If the clay particles,
including heavy metal and other contaminated substances, remain in the back-
218
-------
fill sand while water permeates through the sand, secondary pollution in the
vicinity can be minimized.
The purpose of this experiment was to investigate the filtering capacity
of sands used for backfilling. The experimental apparatus consists of two
cylinders as shown in Figure 9. Kawasaki clay, Takahagi sand, and Toyoura
sand were used for the filter media. Factors such as concentration of the
suspension, water pressure, thickness of sand, kind of sand and kind of water
were tested. The results of this experiment are
(1) The filtering effect of the sand changed with time until the sand
finally became impermeable due to clogging by clay (Figure 10).
(2) In the Toyoura sand, which has a small grain size, the filtering
effect is nearly total.
(3) The clay particles flocculate in seawater and thus the filtering
effect of sand becomes more pronounced than in freshwater.
(4) The most important factor seems to be the grain size of sands, that
is, if the grain size is smaller, the filtering effect is more
significant.
(5) Any noticeable difference in filtering effects due to factors such
as water pressure, thickness of sand layer and concentration of the
suspension was not found.
EFFECTS OF GRAIN SIZE OF SANDS ON FILTRATION
The purpose of this experiment was to investigate the effect of sand
grain size on the efficiency of filtering solutions with heavy metals. In
preparing test samples, careful attention was paid to adjusting the grain size
of sands and clays. Kawasaki clay, Takahagi sand and Toyoura sand were care-
fully sieved. A cylinder (d = 10 cm, h = 70 cm) was kept at 500 ppm and the
water head was kept at 60 cm. The filtration time was 1 hour. In considering
the relative influence of grain size of sands to that of clays, the clay-sand
ratio, R (d/D10) is defined as the ratio of the maximum grain size of clay, d
= 0.074 mm, to the effective grain size of sand, D10. The experiment was
carried out by changing this ratio, R. Figure 11 shows the results of these
experiments and from this it is apparent that the filtering effect does depend
on the clay-sand ratio, R, and is about 100% effective when R >_ 0.2.
PERMEABILITY TESTING OF SEALS FOR PILING JOINTS
In Japan, several kinds of seals have been used to make the joints be-
tween sheet piles watertight. These seals are classified into four types:
mortar, asphalt, urethane and cellulose. Since information on the permeabil-
ity of conventional mortar seals is available, the permeability tests were
performed on the other three types of seals. Urethane and cellulose work as
sealing materials by swelling. Asphalt simply fills the joints.
219
-------
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221
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The apparatus and results are shown in Figures 12 and 13. From Figure 13
it is clear that the coefficient of permeability, K, is on the order of 10-3 N
10-4 cm/sec and increases in proportion to the water pressure. For practical
use of these results, further investigations on the durability of seals with
hot water and other substances are necessary.
CONCLUSIONS
Several series of experiments were conducted to investigate the filtering
effect of containment walls for landfills with dredged materials. From the
experimental results, it was concluded that:
1) Adsorption of heavy metals (such as mercury, cadmium, and lead) to
clay increases in proportion to turbidity.
2) Adsorption of heavy metal to clay is greater in alkaline solutions
than in acid solutions and this tendency is more notable for cadmium
and lead.
3) Cadmium is not adsorbed on clay in seawater.
4) Clay particles produce floes in seawater and are deposited more
rapidly than in freshwater.
5) Heavy metal is adsorbed on clay in sands in the same way as in
suspension.
6) Clay samples taken in the main ports of Japan had similar physical
and chemical properties; hence they showed a similar tendency toward
adsorption of heavy metals.
7) The filtering effect of sand depends on the clay-sand ratio, R,
defined as the ratio of the maximum grain size of clays, d = 0.074
mm to the effective grain size of sands, D10 and is nearly 100% for
R > 0.2.
8) It is expected that backfill sand has a filtering effect which
prevents the permeation of contaminated substances.
9) Seals used for making watertight joints between sheet piles are
useful in preventing permeation. When seals are used the coeffic-
ient of permeability, K, is on the order of 10-3 N 10-4 cm/sec.
Although useful data were obtained on prevention of permeation of contam-
inated substances, it is necessary to continue the research because many
problems remain unsolved regarding long-term permeation, the permeation veloc-
ity of contaminated substances and the influence of tides and earthquakes.
222
-------
o
o>
(A
\
O
CD
LL)
o:
LU
CL
LL
O
I-
LJ
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LL.
LL.
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1.0x10"
1.0x10
I.OxlO"3
I.OxIcf
I.OxlO"
I I
ASPHALT
A _
I
I
012345
WATER PRESSURE P (kg/cm2)
Figure 13.
Relation between coefficient of permeability K and water
pressure.
223
-------
ACCUMULATION OF MERCURY BY FISH
FROM CONTAMINATED SEDIMENTS
R. Hirota,1 M. Fujiki,2 Y. Ikegaki3 and S. Tajima2
ABSTRACT
The relationship between body length and mercury concentration in fish is
not known for fish that inhabit areas of the sea bottom sediments containing
mercury. Fish captured from Minimata Bay where there is a great deal of
mercury pollution and uncontaminated fish grown in pens in Minamata Bay were
studied to determine if there was a correlation between accumulation of mer-
cury in fish flesh and rearing time in Minamata Bay.
The correlation coefficients (r) between the concentration of accumulated
mercury and body length were 0.676 for common seabass, 0.65 for marbled rock-
fish, 0.63 for jack mackerel, 0.61 for black sea bream, and 0.35 for rockfish.
These are considered statistically significant. Correlation coefficients of
0.3 for red sea bream, 0.096 for the common nibbler, and -0.06 for mullet were
not statistically significant.
Fish were separated into four groups and reared in pens at two stations
in Minamata Bay. The tendency for mercury accumulation in the fish from the
different experimental groups was different for each species.
From the results it appears that selected species and ages of fish should
be used when a mercury monitoring program is implemented in Minamata Bay.
INTRODUCTION
More than seven years have passed since a chemical factory, using mercury
as a catalyst, stopped discharging its effluent into Minamata Bay. However,
the bottom sediment of the bay still contains mercury. It is estimated that
over 25 ppm of mercurymore than 1.5 million m3 contaminates the bay's sedi-
ments. The highest concentration of mercury has been reported at 262 ppm.
It is known that the mercury accumulated in fish gradually increases in
proportion to body weight as the fish grows older. However, no investigation
of the exact relationship between the concentration in the fish and the body
1 Aitsu Marine Biological Station, Kumamoto University, Kumamoto, Japan.
2 Institute of Community Medicine, the University of Tsukuba, Ibaraki, Japan.
3 Assistant Chief, Environmental Department, Kumamoto Prefectural Government,
Japan.
225
-------
weight had been done for fish living in the sea where the bottom sediment
contained mercury, such as in Minamata Bay.
Since 1973 the government of Kumamoto Prefecture has investigated the
concentration of mercury in fish captured from Minamata Bay, and it has also,
since 1975, been investigating the relationship between the mercury concentra-
tion in red sea bream, common nibbler and marbled rockfish and rearing time
for fish reared in the pens at Minamata Bay.
This paper reports on the results obtained from statistical analysis of
the data derived from these investigations.
MATERIALS AND METHODS
INVESTIGATION A
Fish captured from Minamata Bay were used for the investigation. The
body length and concentration of mercury in the muscle of fish were measured.
Flameless atomic absorption spectronhotometric techniques we^e used to analyze
the total mercury in the fish muscle.
Rockfish, red sea bream, common nibbler, mullet, common seabass, marbled
rockfish, jack mackerel and black sea bream were selected as test species from
the many kinds of fishmostly because these were captured in sufficient
numbers for statistical analysis. Correlation coefficients (r-values) between
the concentration of the accumulated mercury and body length were determined
for the above eight species of fish.
INVESTIGATION B
Red sea bream grown from eggs in a fish farm at Oyano Marine Station in
Kumamoto Prefecture and marbled rockfish and common nibbler captured in the
field were used in the investigation. The fish were separated into four
groups and were reared in pens at the two stations in Minamata Bay shown in
Figure 1. The rearing period was as follows: Group A: red sea bream and
marbled rockfish were reared from July 1975 to December 1975. Group B:
common nibbler were reared from December 1976 to May 1977. Group C: red sea
bream and common nibbler were reared from June 1977 to November 1977. Group
D: red sea bream and common nibbler were reared from November 1977 to May
1978.
Ten fish from each group were taken from the pen every 10 days during the
rearing period and the concentration of total mercury in the muscle tissue was
measured using a flameless atomic absorption spectrophotometer. Using these
data, the relationship between rearing time and accumulated mercury was stu-
died.
RESULTS
The results of Investigation A are in Table 1. The concentration of
accumulated mercury in common seabass and marbled rockfish showed 0.41 ppm
226
-------
KOIJI ISLAND
t.;MIDORIURA
&TSUKINOURA
$y.:. ;--. ;
'.-YUDOO'- ' '
Figure 1. Rearing pen sites in Minamata Bay.
(wet weight) and 0.85 ppm (wet weight), respectively. These values were
higher than the Japanese government's provisional criteria for mercury in fish
of 0.4 ppm (wet weight).
The statistically significant correlation coefficients between accumu-
lated mercury and body length were 0.676 for common seabass (p ซ 0.001), 0.65
for marbled rockfish (p ซ 0.001), 0.63 for jack mackerel (p ซ 0.001, 0.61
for black sea bream (p ซ 0.001) and 0.35 for rockfish (p < 0.001). Correla-
tion coefficients (r-values) of 0.3 for red sea bream (p < 0.1), 0.096 for
common nibbler (p < 0.3) and -0.06 for mullet (p < 0.6) were not statistically
significant.
For the eight species of the fish, scatter diagrams for the concentration
of accumulated mercury vs body length are given in Figures 2 to 9*
The results of Investigation B are shown in Figures 10 to 13. For group
A, the concentration of mercury in red sea bream increased gradually, although
that of marbled rockfish did not increase during the rearing period. For
group B, the concentration of mercury in the common nibbler increased a lit-
tle. For group C, the concentration of mercury in red sea bream and common
nibbler did not increase. And for group D, the concentration of mercury in
red sea bream and common nibbler increased gradually.
DISCUSSION
It is important to monitor water quality so no further pollution of the
marine environment is caused by the dredging which will clean up pollution in
Minamata Bay. If mercury elutes from the bottom sediment to the marine water,
^Figures 2 through 13 are found at the end of the text, beginning on page 230.
227
-------
TABLE
CORRELATION OF ACCUMULATED MERCURY AND BODY LENGTH IN FISH
Rockfish Red sea bream Common nibbler
Mullet
121
27
129
85
Body length
(cm)
Total mercury
(ppm)
Regression line
X
Sx
y
sy
r
t
d.f.
P
15.615
2.51
0.2255
0.0850
0.35
4.093
119
<0.001
y=0.012x
+ 0.04
12.9
4.51
0.231
0.135
0.3
1.778
25
<0.1
y=0.0009x
+ 0.23
18.767
3.760
0.1256
0.043
0.097
1.100
127
<0.3
y=0.0011x
+ 0.105
32.66
5.200
0.045
0.032
-0.06
0.529
83
<0.6
y=-0:-00004x
+ 0.045
Common seabass Marbled rockfish Jack mackerel Black sea bream
114
133
133
97
Body x
length Sx
(cm)
Total y
mercury Sy
(cm)
r
t
d.f.
P
Regression
1 ine
36.803
11.034
0.4125
0.3561
0.676
9.712
112
ซ0.001
y=0.0217x
- 0.387
14.747
2.29
0.8488
0.3179
0.65
9.842
131
ซ0.001
y=0.091x
- 0.5
21.604
6.309
0.1379
0.0938
0.63
9.236
131
ซ0.001
y=0.0093x
- 0.06
21.89
5.228
0.384
0.4308
0.610
7.497
95
ซ0.001
y=0.0495x
- 0.70
228
-------
or if the concentration of mercury in marine food products is increasing, the
dredging must be slowed or stopped unt.il the cause of the pollution is deter-
mined. To support the monitoring plan, the baseline condition of fish in
Minamata Bay must be established before dredging begins.
The results presented in this paper show that the concentration of mer-
cury in common seabass, marbled rockfish and some of the black sea bream was
higher than the Japanese government's provisional criteria for mercury in
fish. This suggests that Minamata Bay is still polluted by mercury when
compared to other areas.
Correlations between the concentration of accumulated mercury and body
length were statistically significant for common seabass, marbled rockfish,
jack mackerel, black sea bream and rockfish. The concentration of mercury in
the above five species of fish increases in proportion to the age of the fish.
The presumed ages of common seabass, marbled rockfish and jack mackerel were 1
to 7 years old and black sea bream was 1 to 5 years old for those fish used in
the investigation. The correlation coefficients between body length and
concentration of accumulated mercury in red sea bream, common nibbler and
mullet were not statistically significant. This may be because the presumed
age of red sea bream was 1 year old. Another reason for the lack of correla-
tion between the concentration of accumulated mercury and body length is that
rates of mercury uptake in common nibbler and mullet are low and rates of
excretion from these fish are high.
The studies of accumulation vs rearing time showed no relationship be-
tween the experimental groupings of fish. The accumulation of mercury in fish
may be lower than the statistical deviation of the level of concentration of
mercury among fish because the rearing period was only 6 months. There was a
slight accumulation exhibited by the marbled rockfish and common nibbler.
CONCLUSION
This investigation suggested that certain species and ages of fish should
be identified as bio-monitors to signal any increased pollution in Minamata
Bay. Jack mackerel and black sea bream would be good species for a monitoring
effort because these have the highest correlation between body length and the
concentration of accumulated mercury in muscle tissue. Also, the present
concentration of mercury in muscle tissue of these fish is below the govern-
ment criterion of 0.4 ppm.
229
-------
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231
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236
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APPROACHES FOR MITIGATING THE KEPONE CONTAMINATION
IN THE HOPEWELl/JAMFS RIVER AREA OF VIRGINIA
K. M. Mackenthun, M. W. Brossman,
J. A. Kohler, C.R. Terrell
Criteria and Standards Division
Office of Water and Waste Management
U.S. Environmental Protection Agency
Washington, D.C. 20460
ABSTRACT
The Kepone Mitigation Feasibility Project discussed at the third U.S./
Japan meeting on management of bottom sediments containing toxic substances
has been completed. The four-volume project report was forwarded to the
Governors of Virginia and Maryland, together with a recommendation of forma-
tion of a task force to consider and implement the report's recommendations.
This paper summarizes the nature of the contamination found in the
Hopewel1/James River area and describes the mitigation approaches evaluated
and the mitigation actions recommended.
Extensive sampling efforts revealed the highly persistent Kepone contami-
nation remains on the land in Hopewell, in sewage lines and streams and in the
James River. Accordingly, mitigation methods had to focus on the problems of
land, water and sediment contamination. Conventional (dredging), non-conven-
tional, and degradation/biological approaches to mitigation were investigated.
The investigation of conventional mitigation/removal approaches included
an analysis of world-wide dredging techniques, with an evaluation of the most
promising dredging techniques for removal of contaminated sediments from
specific sites, engineering studies to contain, stabilize or remove contami-
nated sediments at points of inflow into the James River and evaluation of the
engineering requirements for removal of Kepone-contaminated sediments from the
James River, assessment of dredge spoil sites, fixation of the dredge spoil
and treatment of the elutriate.
A wide range of non-conventional mitigation approaches was evaluated for
dredge spoil fixation, elutriate treatment, in situ stabilization, and isola-
tion. Approaches ranged from silicate, organic- and sulfur-based fixation
agents through use of retrievable and non-retrievable sorbents which would
take up Kepone from the contaminated sediments and water.
Natural degradation and biological mitigation approaches were examined
concurrently with engineering approaches. However, none of these approaches
shows high promise for Kepone mitigation at this time.
241
-------
As a result of these investigations, a number of immediate mitigation
actions were recommended in addition to further development of promising
mitigation techniques. Among the recommendations was the adaptation of
Japanese dredging and sediment fixation technology. In addition, the investi-
gative techniques and findings were recommended for solution of other similar
waterway contamination problems in the United States.
INTRODUCTION
At the third U.S./Japan meeting on management of bottom sediments con-
taining toxic substances a paper was presented, "Mitigation Feasibility for
the Kepone-Contaminated James River, Virginia" (1). That paper described the
origin of the Hopewel I/Virginia Kepone contamination, the study approach to
assess the problem, preliminary findings on the nature and extent of the
contamination and the specific conventional (dredging) and unconventional
approaches under investigation to mitigate the problem. The study is now
completed and the four-volume project report has been provided to the
Governors of Viginia and Maryland.
This paper is devoted primarily to characterizing the nature of the
contamination found, techniques evaluated for mitigation of the contamination
problem and the specific recommended mitigation actions. Additional details
may be found in the Kepone Mitigation Project Report (2).
NATURE OF THE CONTAMINATION
Kepone, a highly chlorinated hydrocarbon pesticide, was discharged into
the environment around Hopewell, Virginia from 1966 to 1975 from two manufac-
turing operations. The Allied Chemical Corporation's Semi-Works Plant pro-
duced Kepone intermittently from 1966 to 1974. Life Science Products Company
began Kepone production under contract to Allied Chemical in 1974 and con-
tinued production until closure of the plant in September 1975. Fish and
sediment samples indicate Kepone contamination existed in the James River as
early as 1967. Figure 1 shows the principal landmarks around the Hopewell
area which will be cited in the discussion of the contamination and remedial
actions.
Ear.ly warnings of Life Science Products careless manufacturing and dispo-
sal practices were apparent with the malfunctioning of the digesters of the
Hopewell sewage treatment plant and the deleterious health effects on the
production workers. Subsequently, the finding of high levels of Kepone con-
tamination in James River fish brought about a ban on fishing for a wide range
of species. The releases from the Life Science Products plant into the envi-
ronment were associated with atmospheric emissions, wastewater discharges and
bulk disposal of off-specification batches. The atmospheric emissions from
the plant settled on the surface soils. Wastewater discharges entering the
sewage system passed through the Hopewell sewage treatment plant into Bailey
Creek, passing into Bailey Bay and the James River. Disposal of off-specifi-
cation batches and manufacturing residues of Kepone occurred at a minimum of
two sites-the Hopewell landfill and the disposal trench at the former Pebbled
Ammonium Nitrate Plant. Following closure of Life Science Products, residues
from the dismantled plant and site cleanup were buried at the landfill.
242
-------
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Drummed residues from Kepone production were stored at te Hopewel1 sewage
treatment plant and at Portsmouth, Virginia. Kepone-contaminated sludge from
the Hopewel1 sewage treatment plant was stored in a lagoon constructed at the
sewage treatment plant site.
Almost three-years following the closure of the Life Science Products
plant, the disposal of the drummed Kepone production residues and the Kepone-
contaminated sludge is unresolved. Several sites in the City of Hopewell
contain Kepone; small inflows of Kepone continue into the James River, and the
levels of contamination remain sufficiently high in the 110 km of the river
from Hopewell to the mouth to cause continued closure of the James River to
recreational and commercial fishing for many species of fish and shellfish.
Table 1 summarizes the estimates of Kepone residuals in the Hopewel1/James
River area.
TABLE 1. ESTIMATE OF KEPONE RESIDUALS
Residing In
Estimated Quantity of Kepone
Ib
Sewer System
Surface Soil (1 inch)
Kepone Sludge Lagoon
Bailey Bay Sediments*
James River Sediments*
Drums at Hopewell
Drums at Portsmouth
Landfill!
Pebbled Ammonium Nitrate
Plant Site
Rounded total*
23
45 - 450
100
540 - 2,000
9,000 - 17,000
9,400
13,000
1,400
100
33,700 - 43,600
50
100 - 1,000
220
1,200 - 4,300
20,000 - 38,000
20,700
28,800
3,100
220
73,500 - 95,500
* Low value reflects estimate extrapolated from mean concentrations, high
value reflects estimates based on mean plus one standard deviation.
t Includes identified deposits only.
CONVENTIONAL MITIGATION/REMOVAL APPROACHES
The project investigation of conventional mitigation/removal approaches
included: (1) site surveys, analysis of world-wide dredging techniques, and
assessment of the most promising dredging techniques for removal of contami-
nated sediments from specific sites; (2) engineering studies to contain,
stabilize or remove Kepone-contaminated sediments at points of inflow into the
James River, together with an assessment of their effectiveness and potential
environmental impacts; and (3) evaluation of the engineering requirements for
244
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removal of Kepone-contaminated sediments from the James River, assessment of
dredge spoil sites, fixation of the dredge spoil, and treatment of the elu-
triate.
The majority of these efforts were carried out by the Norfolk District
Corps of Engineers for the Kepone Project Office and are described in detail
in Appendix B of EPA's Kepone Mitigation Feasibility Report (2).
DREDGING TECHNOLOGY ASSESSMENT
The evaluation of world-wide dredging technology involved a survey of
mechanical, hydraulic and pneumatic dredges. The most common dredges in the
United States are the mechanical and hydraulic type. Table 2 summarizes the
characteristics of the major types of mechanical and hydraulic dredges in use
in the United States.
Often considerable turbidity is generated in the use of these dredges.
Accordingly, when dredging contaminated sediments, such dredges pose a serious
threat through secondary pollution. To control this problem, various types of
silt curtains and turbidity barriers have been devised with varying degrees of
success. Conventional hydraulic dredges pose additional problems in handling
contaminated sediments since they collect only 10 to 30 percent solids.
Disposal of dredge spoil can induce secondary pollution from runoff or leach-
ing from the dredge spoil site, or impose high costs in treatment of the
elutriate at the dredge spoil site prior to return of the liquid to the re-
ceiving water.
Dredging technology in Europe is generally similar to the capabilities in
the United States. However, special purpose dredges have been devised. Of
these, a pneumatic dredge, the Pneuma dredge developed in Italy, has special
advantages in handling contaminated sediments. The advantages of the Pneuma
include minimum wear, continuous flow, limited secondary pollution and high
solids removal60 to 80 percent solids by volume. The Pneuma dredge, how-
ever, is only practical for removal of sediments at considerable depth as the
hydrostatic pressure of water is required to move the sediments into a chamber
from which the material is expelled through a pipe to a containment site by
compressed air.
Japanese dredging technology for handling of contaminated sediments is
considerably advanced over that in the United States. Table 3 summarizes the
characteristics of the major types of dredges developed in Japan. Analysis of
the characteristics of these dredges and a site survey of operations in Japan
indicated that the Oozer dredge does not require hydrostatic pressure to force
the sediment into its chambers*. The Oozer dredge utilizes a vacuum to draw
the sediment into its chambers, subsequently discharging the dredge spoil
Comprehensive side-by-side comparisons of potentially promising dredges
operating under James River conditions do not exist. However, testing of
the Oozer dredge in the James River would at a minimum provide on-site
operating parameters for evaluating competing systems.
245
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TABLE 2. MECHANICAL DREDGES IN THE UNITED STATES
Type of
dredge
Method of operation
Dragline
Dipper
Grab
Endless
Chain
(bucket
ladder)
Contains scoop that is lowered into
water and slices material to be
removed as scoop is drawn toward
dredge.
)
Contains shovel that is lowered into
water and slices material to be )
removed as shovel is drawn away )
from dredge. )
Scoop, shovel, or
clamshell is
lifted by crane
and dredged
material is depo-
sited either on a
barge or on the
bank.
Contains grab or clamshell bucket. )
Material is removed by forcing )
opposing bucket edges into it. )
Bucket is then closed. )
Includes endless chain of buckets. Material removed by
forcing single cutting edge of successive buckets into
material. Material deposited in barge or other
conveyance.
HYDRAULIC DREDGES IN THE UNITED STATES
Cutterhead
Plain Suction
Dustpan
Hopper
Sidecaster
Rotary blades cut into bottom material. Centrifugal pump
removes material with dilution water and transports it in
a pipeline to disposal area.
Operates same as cutterhead but without rotary cutter.
Material removed with water jets and picked up with dilution
water by a wide but shallow suction inlet, pumped through
discharge line, and returned into water adjacent to channel
Dredge equipped with suction pipe, draghead, and hoppers or
bins that store hydraulically dredged material. There is
no pipeline. Disposal is either at sea or pumped into a
disposal site at the pier.
Material picked up with dilution water and pumped back
directly into adjacent waterway, a distance from the
channel.
246
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TABLE 3. DREDGES DEVELOPED IN JAPAN
Type of
dredge
Method of operation
Clean Up Looks like a conventional hydraulic cutterhead except for
clean-up head installed on ladder. Head is equipped with
a movable wing or shield to overlie bottom sediment, a
movable shutter plate, an auger, a device for collecting
gas, and sonar devices to indicate elevation of material
before and after dredging.
Anti-turbidity Overflow system on hopper dredges is designed to have turbid
water (slurry hopper dredges mixture) that is discharged
overboard quickly submerged. Discharged slurry settles
rapidly to the bottom instead of remaining suspended in
the water column.
Oozer Comparable to Pneuma pump in utilizing water pressure to
raise material to be dredged. In addition suction is in-
creased by creating a vacuum in the tank. After material
has filled tank, compressed air forces sludge to be dis-
charged. Transports sludge in high density and without
causing significant turbidity. Well suited for removal
of viscous sediments.
Watertight Closed type. Especially designed for dredging without giving
Grab Bucket rise to secondary pollution when used for dredging settled
sludge.
under air pressure directly by pipeline to a dredge spoil site or barge. This
dredge is capable of removing dredge spoil with high solids content, operates
at minimal draft, effectively controls secondary pollution, and has shown
minimal operational difficulties under a range of sediment conditions.
ENGINEERING STUDIES TO CONTAIN CONTAMINATED INPUTS INTO THE JAMES RIVER
Engineering approaches for preventing continuing inflows of Kepone con-
tamination into the James River were investigated. Eighteen engineering
alternatives were proposed and evaluated. These alternatives considered the
feasibility and utility of checking Kepone contamination from Bailey Creek and
Gravelly Run which discharge into Bailey Bay, as well as removal and contain-
ment of contamination from Bailey Bay which discharges into the James River.
The alternatives were limited to structural solutions such as dredging;
various types of levee, dam and wall construction; channel improvement or
modification; covering or sealing; and other combinations of structural solu-
tions. The analysis included an investigation and evaluation of the engineer-
247
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ing feasibility, implications, and cost for removing the Kepone-contaminated
sediments from Bailey Bay and Bailey Creek areas. Based on related project
efforts, it was concluded that implementation of most of these alternatives
was viable only if complete cleanup of the James River were contemplated.
However, two of the alternatives offered potential utility and benefits as
dredge spoil sites in Bailey Bay for currently contemplated maintenance dredg-
ing.
ENGINEERING STUDIES FOR REMOVAL OF KEPONE FROM THE JAMES RIVER
Both complete removal of Kepone-contaminated sediments from the James
River and partial removal of contaminated sediments from "hot spots" were
evaluated. Figure 2 illustrates key physical features of the area.
Complete Removal
Complete removal of contaminated sediments would involve approximately
110 kilometers (69 miles) of river from Hopewell to the mouth. These sedi-
ments are generally characterized as silty clay, less than 64 microns.
The parameters and conditions considered in the analysis of full-scale
removal of sediments from the James were as follows: excavation would be
limited to the James River from Hopewell to the James River Bridge (no dredg-
ing was considered in tributaries of the James); excavation depth would be
limited to 38 centimeters; disposal be limited to adjacent sites; sand for
disposal area construction would be within an economical pumping distance of
each site; the Oozer dredge would be available; approximately 25 percent
excess material would be removed due to over-dredging; and the Oozer pipeline
has a capability to pump material 1,524 meters (5,000 ft).
Thirteen disposal areas were proposed for confinement of Kepone contami-
nated spoil. Preference was given to sites contiguous to the shore and care
was taken to select locations that would have minimal impact on adjacent
drainage patterns. Some filling of interior low areas was anticipated.
Design levels, based on 100-year flood level, dictated an elevation of 3
meters (10 ft) above sea level datum. Areas not utilized to capacity would
provide dredge spoil sites for future maintenance dredging.
The results of this analysis are shown in Table 4. Removal of 133 bil-
lion cubic meters (169 billion allowing a 25 percent excess) of material and
disposal would cost approximately $1 billion.
If elutriate treatment and spoil fixation costs are considered, the total
cost of the project would range from $1 to $7.2 billion, depending on the
treatment chosen. Elutriate treatment costs for ultra-violet/ozone were
calculated considering a portable UV/oxone unit and a treatment rate of $.067
1,000 liters ($0.23/1,000 gallons), excluding logistics or capital costs or
possible water clarification costs. A summary of a complete treatment costs
estimate for treating the James River sediments with intra-basin disposal is
presented in Table 5.
248
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NORTH
CAROLINA
TOPPAHANNOCK
LOCATION MAP
40 0 40 MILES
CHESAPEAKE
RICHMOND
HOPEWELL
PRINCE GEORGE
CO .
v AHAMPTON
PORTSMOUTHYf. '-TV VIRGINIA
''..; Sf VN- BEACH ' -
CHESAPEAKE-. . ;
NORTH CAROLINA
NORFOLK DISTRICT CORPS. OFENOINEERS- SEPT. 1977
SCALE IN MILES
Figure 2.
249
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TABLE 4. SUMMARY FOR CONVENTIONAL REMOVAL OF KEPONE CONTAMINATED SEDIMENTS IN THE JAMES RIVER
Disposal
Areas
1
2
3
4
5
6
7
8
9
10
11
12
13
TOTALS
Acres
444
560
248
411
276
767
736
907
533
872
1572
1635
725
9766
Elevation of
Slurry mse
10.4
10.3
7.1
8.9
8.4
6.7
5.4
7.4
9.3
7.5
10.4
9.2
8.4
ROUNDED
Dredged Qual ity
15" depth
7,440,000
8,610,000
2,790,000
6,740,000
5,050,000
10,440,000
12,830,000
18,440,000
11 ,300,000
14,260,000
37,780,000
28,460,000
12,780,000
176,920,000
(177,000,000)
in Cubic Yards
25%
Excess Included
9,300,000
10,762,500
3,487,500
8,425,000
6,312,500
13,050,000
16,037,500
23,050,000
14,125,000
17,825,000
47,225,000
35,575,000
15,975,000
221 ,150,000
(211 ,000,000)
ROUNDED
Dredging Costs
at $4. 30/cu yd
for 15" depth
$31 ,992,000
37,023,000
11 ,997,000
28,982,000
21 ,715,000
44,892,000
55,169,000
79,292,000
48,590,000
61 ,318,000
162,454,000
122,378,000
54,954,000
$760,756,000
$761 ,976,000*
(762,000,000)
Disposal Site
Preparation Cost
$3,550,000
4,480,000
7,610,000
11 ,990,000
11,050,000
9,200,000
15,110,000
15,340,000
13,950,000
11 ,620,000
17,380,000
20,200,000
10,840,000
$153,120,000
$220,490,000*
(220,500,000)
Total Cost for Dredging and Disposal Including Contingencies
Engineering and Design Studies and Administrative Costs
Total Project Costs
$902.5 x 106
$1 billion
Total Dredging Cost
$762 x 106
Rounded
Total Disposal Cost
$220 5 x 106
(Total removal and disposal costs amount to $5.55/cubic yard.)
*Total cost includes contingencies, engineering and design studies and administrative costs.
250
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Battelle Pacific Northwest Laboratories, in separate efforts, determined
costs and some environmental consequences for other i_n situ mitigation propo-
sals. These results are also included in Table 5.
MITIGATION THROUGH CLEANUP OF ELEVATED AREAS OF CONTAMINATION
Certain areas of the James River contain more Kepone than others as a
result of the discharge patterns and hydro!ogic influences. For example,
Bailey Bay sediments contain up to 10 ug/g (ppm) of Kepone as a result of
proximity to the discharge source at Hopewell. Concentrations of the order of
1 |jg/g (ppm) of Kepone are contained in the sediments of the turbidity maximum
zone as a result of estuarine hydrologic influences. The Battelle model was
utilized to evaluate the effectiveness of partial clean-up.
Ten selected zones of high Kepone sediment contamination were designated.
The local effects of cleanup were assessed as well as the effect near the
mouth of the James River discharging into Chesapeake Bay. Results were com-
pared with the no-cleanup case for total, dissolved and suspended particulate
Kepone (attached to sediments). The model results indicated essentially no
improvement locally or near the mouth of the James River through cleanup of
Bailey Bay. Only two cases of cleanup involving 32 to 56 kilometers (20 to 35
miles) of river reach in the turbidity maximum zone showed significant local-
ized improvement. None of the cleanup options has any appreciable effect on
the contamination near the mouth of the James River. In addition, none of the
partial cleanup options reduced the levels of contamination sufficiently to
eliminate the hazard of bioaccumulation of Kepone by fish to the action lev-
els. It was therefore concluded that "hot spot" or partial cleanup operations
could not be recommended. However, partial cleanup of "hot spots" would
potentially reduce the time for closure of the river due to contamination.
Accordingly it was recommended that the dredge spoil from maintenance dredging
of the river be removed to safe land containment sites.
NONCONVENTIONAL MITIGATION APPROACHES
In addressing nonconventional mitigation methods, the project team fo-
cused on evaluating alternatives to dredging, as well as treatment and/or
fixation processes complementary to dredging for application to Kepone contam-
inated sediments in the James River System. Four types of alternative ap-
proaches were studied: dredge spoil fixation, elutriate treatment, J_n situ
stabilization, and isolation.
DREDGE SPOIL FIXATION
Dredge spoil fixation is necessary to prevent leachate of contaminated
materials from the dredged spoil site. Fixation processes investigated were
classified according to base ingredients. These included: silicates, organ-
ics, sulfur, gypsum, and asphalt. Twenty-one samples were tested and the
sampling included eight different companies. A silicate-based, organic-based
and sulfur-based fixation agent showed the most promise for the Kepone appli-
cation.
252
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Silicate-Based Agent
In general, most silicate-based agents rely on high pH conditions to set
the stabilized material. Kepone is solubilized under these conditions and if
the fixation additive does not isolate the Kepone, it will occur in leachate
at equivalent or higher levels than is found with natural sediments. The
Japanese firm Takenaka utilizes a silicate-based agent. However, they im-
proved their additive agents over the first series of tests which indicated no
better fixation capabilities than natural sediments. Results of the latest
fixation efforts on Bailey Bay sediment samples showed leachate Kepone concen-
trations of only 0.08 ug/1 (ppb) in fixed sediments which originally showed a
leachate of .57 ug/1 (ppb) of Kepone. Takenaka officials believe that they
can reach a level of 0.01 ug/1 (ppb) to 0.03 ug/1 (ppb).
The Takenaka technology offers the advantage over other fixation pro-
cesses in that fixation can be performed in-place. Most processes necessitate
removal, treatment and then replacement of the fixed material, thus adding
considerably to the costs of the process. In addition, the Takenaka technol-
ogy has had widespread operational use in Japan under a range of conditions.
Large scale projects have been ongoing for several years in contaminated
harbors and rivers in Japan, and involve fixation of contaminated industrial
sludge, contaminated dredge spoil, and i_n situ fixation operations on contami-
nated bottom sediments at depths up to 40 meters. To date, the fixation
processes have been used effectively on sludge contaminated by mercury, cop-
per, zinc, cadmium, lead, chromium, and PCBs. Laboratory tests have shown the
processes to be effective on arsenic as well.
Organic-Based Agent
Por Rok Epoxy Sealant, an organic base fixation agent, is a synthetic
epoxy material which is mixed with a coarse aggregate material and is used as
a grout or surface sealant. It reduced Kepone leachate concentrations an
order of magnitude lower than those of standard sediments. This stabilization
agent showed promise as a means of reducing Kepone releases from spoils.
However, application costs are high - $442/m3 ($12.50/ft3) and the material is
limited in availability.
Sulfur-Based Agent
Molten sulfur used as a fixation agent offered an order of magnitude
reduction of leachate concentrations in laboratory tests. However, the prac-
ticality of molten sulfur for a large scale application to Kepone contaminants
is unknown. Furthermore, it is recognized that there could be severe eviron-
mental impacts associated with this dredged spoil fixation process because
elemental sulfur, while stable in water, readily changes to soluble and poten-
tially toxic forms when mixed with reducing as well as oxidizing sediments.
Molecular compounds of concern include carbon disulfide, hydrogen sulfide and
sulfur dioxide. These compounds should be handled carefully. Accordingly,
the molten sulfur technique will require additional investigation and evalua-
tion.
253
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ELUTRIATE TREATMENT
The elutriate associated with contaminated dredged spoil material must be
treated prior to return of the elutriate to the receiving waters. This treat-
ment is especially critical with Kepone-contaminated elutriate since Kepone in
low concentrations can be bioaccumulated rapidly.
Elutriate/slurry treatment methods investigated consisted of: photochem-
ical degradation; amine photosensitization; chlorine dioxide, ozone and UV/
ozone treatment in combination radiation with gamma rays and electron beams;
catalytic reduction; and carbon adsorption.
Based on the study investigations, the UV/ozone and the temporary filtra-
tion/carbon adsorption scheme were deemed best suited for elutriate treatment.
Ultra-Violet/Ozone Treatment
Research on combined ozonation and ultra-violet irradiation by Westgate
Research Corporation exhibited better than 80 percent Kepone removal from the
effluent of Hopewell's primary treatment plant when samples were subjected to
exposure periods of one hour.
Cost projections for large treatment plants, developed by Westgate Re-
search for other applications indicate a capital cost of $33,022 to $37,000
per MLD ($125,000 to $140,000 per MGD) capacity and operation and maintenance
costs, including amortization, of $.03 per 1,000 liters ($0.11 per 1,000 gal-
lons) treated.
In continued research to determine whether ultraviolet irradiation pro-
cesses are limited to clear samples receiving direct irradation, Westgate
treated sediment slurry samples taken from a contaminated creek bed. There
was a significant loss of Kepone, 63.8 percent, in the sediment during the
first 30 minutes of reaction time. It is believed that Kepone is being des-
troyed in the water phase, and that the partition coefficient permits continu-
ous release of Kepone from the sediment to the water. This could explain the
relatively constant values obtained in the supernatant analyses. The sedi-
ment, about 20 percent by volume, was held in suspension in the "Ultrox"
reactor by the ozone spargings (Westgate, 1978). This ability to handle high
solid content slurries also holds promise for the direct treatment of dredged
slurries or sediments, if the sediments are put in slurries of 20 to 50 per-
cent solids. However, further evaluation of the process is required to deter-
mine the extent of Kepone degradation and assess the potential toxicity of the
by-products. It appears that degradation occurs by the removal of chlorine
from the Kepone molecule forming monohydroKepone.
From these very preliminary but encouraging results, it is estimated that
an optimum large-scale portable treatment system could treat 20 to 50 percent
solids slurry for 13 to 26 cents per cubic meter (10 to 20 cents per cubic
yard), not including equipment amortization. However, further testing is
needed to adequately define operating parameters and associated costs.
254
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No major environmental impacts are anticipated with the application of
the UV/ozone treatment process other than those associated with construction
of the facilities and the increased demand for power. However, as indicated,
by-products and/or deleterious residues have not been studied.
Filtration/Carbon Adsorption
During the decontamination efforts in early 1976, the EPA mobile spill
treatment unit was brought to Hopewell to help decontaminate washwaters and
liquid wastes. Carbon adsorption proved effective in removing Kepone from
solution. Accordingly, the Kepone project team contacted companies experi-
enced in large scale applications of carbon adsorption treatment.
The Calgon Corporation has developed a filtration/carbon adsorption
wastewater treatment system which shows promise in treating dredge slurry
water containing Kepone. In their conceptual design, the dredged slurry would
be pumped from the dredge to an impoundment basin where the solids would
settle from the water. From the impoundment basin the water would flow to a
gravity slow sand filter, constructed in a lined earthen basin. From the sand
filter the water would flow by gravity to an adsorption basin and be directed
through a bed containing a layer of gravel and a layer of Filtrasorb activated
carbon. From the filter bed, operated in a flooded condition to prevent
channeling, the treated water would overflow to a spillway and be returned to
the river. At the conclusion of the dredging, the entire sand filtration and
carbon beds could be encapsulated and backfilled to prevent future leachate
contamination. Calgon estimates the capital costs for a 50 MLD unit at $.81
million (50 MGD unit at $3.06 million). More extensive analysis of the site
and operational requirements will be required to develop operating costs.
Comparison of the Ultra-Violet Light/Ozone and Filtration/Carbon Adsorption
Both the UV/ozone treatment system, proposed by Westgate Research Corpor-
ation, and the temporary filtration/carbon adsorption wastewater treatment
system proposed by Calgon Corporation were recommended for further evaluation
for elutriate treatment. The UV/ozone option seems to destroy Kepone, but the
degradation products and their relative toxicity still need to be determined.
The use of the temporary filtration/carbon adsorption option may still pose
disposal problems if future leachate contamination is to be prevented.
IN SITU STABILIZATION AND ISOLATION
If} situ stabilization processes as a category are the newest of the ap-
proaches to removal/mitigation of in-place toxic materials. As such, most are
less developed than other approaches. Several of the more promising new
options were selected for testing in the Battelle laboratory. Since biologi-
cal approaches currently evaluated appear to offer little with respect to the
removal of Kepone from the James River system, work focused on two types of j_n
situ approaches: use of sorbents and use of polymer films. In addition to
these approaches, the Japanese Takenaka fixation process previously described
can be used in j_n situ mitigation of contaminants. (The Japanese fixation
process is a proven large scale operational in-place fixation technology.
This fixation process generally costs $13 to $20 a cubic meter, and eliminates
255
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removal costs). However, indications are that the top few centimeters at the
sediment/water interface may be difficult to fix. Consequently, such an
application for Kepone, with the present state of knowledge, is far less
desirable than removal of the contaminated sediments and fixation in carefully
contained dredge spoil sites. Also any in-place fixation technique may have
major impacts on benthic communities.
Natural sorbents (such as activated carbon) and synthetic sorbents (such
as the macroreticular resins) have been shown to be effective in concentrating
organics similar to Kepone. In application, sorbents act much as natural
sediments do in maintaining levels of Kepone much higher than those in adja-
cent waters. Sorbents having lower partition values (concentration in water/
concentration in substrate) than those exhibited in natural sediments will
reduce the levels of dissolved Kepone in the water if introduced to the sys-
tem. A three-phase equilibrium is established with the highest concentrations
of Kepone on the new material, a lower concentration on the sediment, and the
lowest concentration in the water.
Based on Battelle's initial screening results sorbents ES863, XAD-4,
XAQ-2, and Filtrasorb 300 were selected for further study. The three proprie-
tary products are macroreticular synthetic sorbents produced commercially.
Filtrasorb 300 is a commercial activated carbon. In addition to these, a
specialty carbon product formed around iron particles became available in time
for subsequent evaluation. Allied Chemical also performed laboratory tests
utilizing anthracite coal.
Following Allied Chemical Company's promising initial results with coal,
batch adsorption tests were initiated in the Battelle laboratory on a variety
of coals. Results indicate that coals tested had less affinity for Kepone
than Bailey Bay sediments. Consequently, these coals did not offer any miti-
gation utility for Bailey Bay sediments. However, Bailey Bay sediments are
high in organic content and testing on more representative James River sedi-
ments should be undertaken before final determinations are made on the appli-
cabi1ity of coal.
Although sorbents applied to sediments j_n situ are capable of reducing
the availability of a material to the water column, they do not destroy or
remove the contaminant. Removal can be achieved, however, if media are made
to be retrievable. Laboratory work at Battelle indicates that this is possi-
ble through the inclusion of magnetite or iron particles in the sorbent matrix
which will render the media particles susceptible to magnetic fields. How-
ever, the practical application is unevaluated. The magnetic sorbents would
have to be mixed into the river sediments and then recovered. Strong magnetic
fields may be required and dispersion of contaminants avoided. Costs for
using synthetic sorbents are prohibitively expensive on wide scale application
unless they can be made retrievable. Even then, costs of using synthetic
sorbents is estimated to be $31/m3, (0.90/ft3) sediment compared to $l.l/m3
($0.032/ft3) sediment for coal and $18/m3 ($0.52/ft3) sediment for activated
carbon.
It was noted previously that activated carbon had been successfully
applied to remove Kepone from solution. The same is true for any of the
256
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sorbents found to be effective for i_n situ evaluations such as XAO-2 and
ES863. Consequently, sorbents, if developed for operational application,
should be considered as candidates for both elutriate and j_n situ application.
In j_n situ use, activated carbon might be considered for application directly
to the river without retrieval. This would be done in the same manner as an
application of coal, but activated carbon offers a high degree of adsorption.
However, availability of the resultant contaminated carbon to the biota has
not been evaluated.
Of the J_n situ approaches considered, all show some degree of effective-
ness. The potential of using coal is still not resolved. Based on laboratory
comparisons, activated carbon is more appropriate than coal as an i_n situ
additive. Any J_n situ use of activated carbon or coal, if it proves to be
operationally effective, would be limited in application to areas contaminated
to less than 1 pl/g (ppm). In areas where Kepone concentrations were greater
than or equal to 1 ug/g (ppm), retrievable media or fixation techniques should
be given further consideration. The latter exception is made to reflect the
fact that at high Kepone concentrations in sediments, the potential reduction
in Kepone availability with coal or activated carbon would still allow unac-
ceptable levels of Kepone in the water. For these areas, retrievable media
and fixation, if effective, would be costly.
Environmental impacts associated with j_n situ treatment are not well
understood. However, j_n situ treatments potentially pose many physical,
biological and chemical impacts on the river and its biota. Accordingly, no
j_n situ treatment approaches are recommended at this time for the James River.
NATURAL DEGRADATION AND BIOLOGICAL MITIGATION APPROACHES
As part of the Kepone Mitigation Feasibility Project, natural degradation
and biological approaches seemed viable avenues for amelioration or elimina-
tion of the Kepone contamination problem. They were examined concurrently
with engineering approaches. These methods, if they proved successful, could
offer the possiblity of in-place mitigation without elaborate or expensive
engineering programs or structures. Our investigation of potential biological
mitigation methods included: (1) degradation or destruction of Kepone by
microorganisms; and (2) biological uptake and concentration of Kepone by an
animal or plant with subsequent harvest and destruction. Natural biodegrada-
tion of Kepone was the most hopeful route because many substances are capable
of some degredation by natural means.
DEGRADATION
A search of the literature indicated only indirect and circumstantial
evidence that Kepone could degrade, either photochemically or biologically.
Laboratory efforts were aimed at degradation studies under a variety of condi-
tions, including aerobic and anaerobic situations. The EPA Gulf Breeze Envi-
ronmental Research Laboratory and Battelle Pacific Northwest Laboratories
performed experiments to determine if Kepone degradation would occur under
laboratory conditions.
257
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Studies by Garnas et al_. (3) and Bourquin et al_. (4) of Gulf Breeze
employed static water/sediment systems to assess both biological and non-
biological degradation of Kepone. James River sediments with and without
Kepone were used and the fate of Kepone monitored with radio-labelled Carbon
14 material and with total budget chemical analyses. The investigators em-
ployed a variety of experimental conditions including oxygen concentration,
nutrient additions, Kepone levels, sediment sources, sunlight, temperature,
and salinity.
Gulf Breeze experiments indicated that Kepone does not degrade either
biologically or chemically in the laboratory situations, which simulated
natural states as closely as possible. These results indicate that currently
evaluated degradation processes will not reduce the levels of Kepone now found
in the water and sediment of the James River.
The Battelle Laboratories found results similar to those of Gulf Breeze.
While some evidence exists that certain bacteria can survive in the presence
of Kepone-contaminated sediments, degradation of Kepone has not been demon-
strated or confirmed. The half-life of Kepone in the environment has not been
determined, but laboratory evidence suggests it may be on the order of dec-
ades.
Fungi offered a potential for Kepone degradation, and Atlantic Research
Corporation believes they have a series of fungi which will degrade Kepone.
One isolate showed 41 percent disappearance of Kepone in 22 to 31 days.
However, these experiments have been performed only in the laboratory, and no
seal ing-up has been attempted. The fungi may have difficulty competing and
surviving under natural conditions, thus their usefulness is restricted to
controlled environments, such as containment lagoons. Such an approach would
not be feasible for the amounts of Kepone-contaminated sediments in the James
River which need treatment.
BIOLOGICAL UPTAKE AND HARVESTING
Studies with other chlorinated hydrocarbons have shown that they can be
bioconcentrated by plants and that uptake increases with water solubility.
However, studies to date with Kepone indicate that plant uptake is not an
effective mechanism for mitigating Kepone in the environment.
Algae were found to bioaccumulate Kepone to as much as 800 times the
ambient levels of Kepone (5). This approach was examined for the possibility
that Kepone-contaminated algae could be harvested and destroyed by incinera-
tion to eliminate the Kepone. Problems, similar to those of fungi, became
apparent. Furthermore, the algae bioconcentrated Kepone from the water in-
stead of the sediments where the bulk of the Kepone is located.
In a similar fashion, Kepone attached to rooted aquatic plants such as
water hyacinths, could be isolated, harvested and destroyed. Although the
water hyacinths may accumulate Kepone on their leaf surfaces, the plants are
free-floating and would not be in contact with the large percentage of Kepone
which resides in the James River sediments, giving this method limited value
for mitigation purposes.
258
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Although Kepone is intimately bound to sediments of the James River, it
can desorb from those sediments, or organisms can extract it from the sedi-
ments to become incorporated into living systems. It can be passed between
organisms readily as one animal uses another as food. Kepone is also avail-
able to animals from the water. Although animals can bioconcentrate Kepone,
they were never viewed to have utility for Kepone uptake with subsequent
harvesting to destroy the Kepone. As with plant harvesting the logistics are
impractical. Ultimately any mitigation method proposed to ameliorate the
effect of Kepone must address the bioconcentration of Kepone by James River
organisms, which traditionally have been used as a food resource.
SUMMARY OF RECOMMENDED MITIGATION APPROACHES
The project findings which lead to the recommended mitigation approaches
are too extensive to detail here. These are covered in the Kepone Mitigation
Project Report (2). However, some of the key findings will be summarized here
as they relate to specific recommended mitigation approaches. A special task
force consisting of representatives from EPA and the States of Virginia and
Maryland has already been established to consider and implement the recommen-
dations.
CHESAPEAKE BAY MITIGATION APPROACHES
Modeling and monitoring studies indicated that Chesapeake Bay is not
currently threatened by the contamination of the James River. However, severe
storms and like events could alter the situation. Accordingly, continued
systematic monitoring of Kepone levels in water sediment and biota was recom-
mended. In addition, development of a long range strategy including use of
submerged silt dams to implement emergency mitigation measures was recom-
mended.
JAMES RIVER MITIGATION APPROACHES
Based on the enormous costs of total James River amelioration efforts,
the lack of knowledge on ecological impacts of widespread mitigation efforts,
the unavailability of economic impact determinations, and supportive evidence
that most of the Kepone will remain in the zone of turbidity maximum, no
full-scale cleanup action was recommended for the James River at this time.
However, since navigational dredging is required in the James River, these
dredging operations afford a continuing opportunity to initiate removal of the
contaminated sediments. Accordingly, it was recommended that the Oozer dredge
be considered for such dredging and the dredge spoil be disposed of in ade-
quately protected dredge spoil sites developed along the James River.
Among the key issues deterring progress in physical removal of the con-
taminated sediments from the James River were uncertainties regarding the
effectiveness and costs associated with treatment of elutriate and dredge
spoil. However, promising technologies were found whose further development
was recommended. Two of the technologies were recommended for developmental
fundingthe Takenaka fixation technology developed for Kepone-contaminated
sediments and the UV/ozone treatment of Westgate Research.
259
-------
HOPEWELL AREA MITIGATION APPROACHES
Contamination of the land around the Hopewell area is extensive. Some
limited land areas within the city limits, accessible to the population, have
levels ranging to 1,530 ugg (ppm). Accordingly, it was recommended that the
health threat be assessedthe most expeditious action being removal of the
contaminated soil and disposal.
A marsh area contiguous with a creek discharging into Bailey Bay and
thence the James River was found to contain an estimated 1,363 kg (3,000 Ib)
of Kepone. Containment or physical removal of the contaminated material was
recommended.
A lagoon containing Kepone-contaminated sludge obtained from the early
cleanup operations around Hopewell has suspected leakage into a nearby creek.
It was recommended that the material be removed from the lagoon or covered and
containment be initiated.
CLOSURE
United States' experience in handling in-place toxic pollutant problems
of the extent exhibited by the Kepone contamination in the Hopewel1/James
River area is limited. However, adaptation of Japanese technology in dredging
and sediment fixation holds promise for substantial assistance in solving such
problems. In addition, it is hoped that the investigative techniques and
findings of the Kepone Mitigation Feasibility Project will not only provide a
basis for moving forward with the solution of the Kepone contamination prob-
lem, but will provide an approach to solution of other serious waterway con-
tamination problems in the United States.
REFERENCES
1. Mackenthun, K.M. , M.W. Brossman, J.A. Kohler, and C.R. Terrell, 1977.
Mitigation Feasibility for the Kepone-Contaminated James River, Virginia.
Presented at the Third Annual U.S./Japan Meeting on Management of Bottom
Sediments, Easton, Maryland, September 1977.
2. Brossman, M.W., K.M. Mackenthun, J.A. Kohler, and C.R. Terrell, 1978.
Mitigation Feasibility for the Kepone-Contaminated Hopewell/James River
Areas. EPA Report, Washington, D.C., June 9, 1978.
3. Garnas, R.L., A.W. Bourquin and P.H. Pritchard, 1978. The Fate of 14-C
Kepone in Estuarine Microcosms. Presented at 175th National Meeting of
the American Chemical Society, Anaheim, California, March 1978.
4. Bourquin, A.W., P.H. Pritchard and W.R. Mahaffey, 1977. Effects of
Kepone on Estuarine Microorganisms. Developments in Industrial Micro-
biology, Vol. 19 (in press).
5. Walsh, G.E., K. Ainsworth and A.J. Wilson, Jr., 1977. Toxicity and
Uptake of Kepone in Marine Unicellular Algae. Chesapeake Science 18(2):
222-223.
260
-------
PCB CONTAMINATION OF THE SHEBOYGAN RIVER, INDIANA HARBOR
AND SAGINAW RIVER AND BAY
Karl E. Bremer
U.S. Environmental Protection Agency
Chicago, Illinois 60604
ABSTRACT
Current PCB contamination in three harbor areas of the Great Lakes has
resulted in problems related to maintenance dredging, disposal, or fish con-
tamination. The Sheboygan River shows high PCB residues in fish and bottom
sediments as a result of improper PCB disposal. Indiana Harbor, one of the
most highly contaminated harbors in the Great Lakes is experiencing delays in
maintenance dredging of approximately 750,000 cubic yards of bottom sediment.
High concentrations of mercury, lead, zinc, manganese, arsenic, and PCBs have
been detected throughout the harbor and ship canal. A new dike disposal area
has been completed in Saginaw Bay. Possible use of this confined disposal
site will be made for PCB-contaminated sediments from the Saginaw River.
INTRODUCTION
There are approximately 180 harbor areas in the Great Lakes Basin which
are served by commercial shipping. To maintain a minimum depth of 8.2 meters
(27 feet) in these harbors, continued maintenance dredging occurs at various
harbor areas along the extensive shoreline of the Great Lakes.
The United States and Canada continue to maintain these ports with a
joint determination to restore and enhance water quality. In the Agreement on
Great Lakes Water Quality of April 15, 1972, the Governments of the United
States and Canada directed that specific attention be given to assessing the
potential for deleterious environmental aspects from dredging activities
within the Great Lakes basin. In addition, two Acts have been passed within
the last three years to specifically deal with toxic substances problems in
both countries. In Canada, the Environmental Contaminants Act, and in the
United States, the Toxic Substances Control Act have been implemented. These
Acts will definitely impact dredging activities on the Great Lakes during the
next few years.
As part of the U.S. role in maintaining Great Lakes water quality, toxic
contaminant problems were evaluated in three waterways of particular impor-
tance: the Sheboygan River, Indiana Harbor, and Saginaw River and Bay.
251
-------
SHEBOYGAN RIVER
The Sheboygan River and its tributaries, the Mullet River, Onion River,
Weedens Creek, and Greendale Creek flow east to the western side of Lake
Michigan in the State of Wisconsin. The River enters Lake Michigan through a
450-foot-wide outer basin of Sheboygan Harbor.
During 1975, 1976 and 1977, the Wisconsin Department of Natural Resources
(the State pollution control agency in Wisconsin) analyzed Lake Michigan and
Sheboygan Harbor fish for PCB contamination (1). Average PCB concentrations
in Sheboygan Harbor fish were similar to PCB levels found in Lake Michigan
fish along the coast (Table 1). Average PCB concentrations in Sheboygan
Harbor sediments in 1977, as analyzed by the U.S. Environmental Protection
Agency (Table 2) were also low when compared with other Lake Michigan harbors
(2).
In March 1978, the Wisconsin Department of Natural Resources analyzed
fish from the Sheboygan River at a location three miles upstream from Sheboy-
gan Harbor. Test results for whole fish ranged from 26 to 750 ug/g (Table 3).
To confirm these analyses, additional samples were obtained March 31, 1978.
These results ranged from 8.3 to 241.5 ug/g. PCB concentrations in all fish
exceeded the U.S. Food and Drug Administration's temporary tolerance level of
5 ug/g.
In April 1978, the Wisconsin Department of Natural Resources and Depart-
ment of Health and Social Services advised the residents of Wisconsin not to
eat fish from the Sheboygan, Mullet and Onion Rivers. During the same period
of time, an investigation was conducted to test fish, river sediments, muni-
cipal and industrial effluents, and river water in the Sheboygan River drain-
age basin.
Fish were collected for PCB analysis at 11 locations in the Sheboygan
River drainage basin (Figure 1). PCB concentrations in fish taken from the
Sheboygan River lakeward from Sheboygan Falls Dam to Lake Michigan ranged from
0.9 to 970.0 ug/g (Table 4). The mean concentration for these samples was
155.0 ug/g. Thirty-eight fish samples upstream of Sheboygan Falls Dam on the
Sheboygan, Mullet and Onion Rivers contained PCB concentrations below the U.S.
Food and Drug Administration's temporary tolerance level of 5 ug/g.
Bottom sediments were analyzed at 13 locations in the Sheboygan River
drainage basin. Concentrations in sediments ranged from 0.1 to 190 ug/g PCB
(Table 5). The highest PCB concentrations were detected in sediments immedi-
ately downstream from the Tecumseh Products Diecasting Plant in Sheboygan
Falls. PCB concentrations showed a decline at locations further downstream
from the diecasting facility.
The Wisconsin Department of Natural Resources analyzed PCBs in municipal
and industrial effluents collected from facilities in the drainage basin
(Table 6). In addition, PCBs were analyzed in river water and in hydraulic
fluid taken from three aluminum die-casting plants. Significant PCB point
sources to the Sheboygan River were not detected by monitoring these municipal
and industrial discharges.
262
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TABLE 2. BULK SEDIMENT CHEMISTRY PCB AND PESTICIDES ANALYSIS
(All values are mg/kg dry weight)
HARBOR: Sheboygan small boat harbor, Wisconsin
SAMPLED: September 16, 1977
Sample Site
Compound
Hexachlorobenzene
beta Benzenehexachloride
Li ndane
Tref Ian
Aldrin
Isodrin
Heptachlor Epoxide
gamma Chlordane
o,p -DDE
p,p'-DDE
o,p -ODD
o,p -DDT
p,p'-DDD
p,p'-DDT
Methoxychl or
Mi rex
2,4-D, Isopropyl Ester
Endosulfan I
Dieldri n
Endrin
Endosulfan II
DCPA
Tetradifon
Aroclor 1016 (1242)
Aroclor 1248
Aroclor 1254
Aroclor 1260
Total PCB
SHB77-1
*
*
*
*
<0.02
<0.02
*
<0.02
*
<0.02
*
<0.03
<0.02
<0.04
*
*
*
*
*
*
*
*
*
0.149
*
0.167
*
0.316
SHB77-2
*
*
*
*
<0.02
<0.02
*
<0.02
*
<0.02
*
<0.03
<0.02
<0.04
*
*
*
A
*
*
*
*
*
0.047
*
0.044
*
0.091
SHB77-3
*
*
*
*
<0.02
<0.02
*
<0.02
*
<0.02
*
<0.03
<0.02
<0.04
*
A
*
*
A
*
A
*
*
0.028
*
0.027
*
0.055
SHB77-3
Repl icate
*
*
*
*
<0.02
<0.02
*
<0.02
*
<0.02
*
<0.03
<0.02
<0.04
)*C
>ปc
>*;
*
*
X
*
*
*
0.040
*
0.055
*
0.095
SHB77-4
*
*
*
A
<0.02
<0.02
*
<0.02
*
<0.02
*
<0.03
<0.02
<0.04
*
A
*
A
A
*
*
*
*
0.070
*
0.035
*
0. 105
^Concentration less than 0.01 mg/kg.
264
-------
TABLE 3. PCB CONCENTRATIONS OF WHOLE FISH OBTAINED FROM THE SHEBOYGAN RIVER
THREE MILES UPSTREAM FROM SHEBOYGAN HARBOR
Sampl i
ing Date
September
September
September
March 31 ,
March 31 ,
March 31 ,
March 31 ,
March
March
March
March
March
March
31,
31,
31,
31,
31,
31,
9, 1977
9, 1977
9, 1977
1978
1978
1978
1978
1978
1978
1978
1978
1978
1978
Species &
Length
5 Carp (12-23 inches)
5 Northern Pike (18-25 inches)
5 White Sucker (10-14.5 inches)
17 Black Bullheads (3.5-9 inches)
12 Black Bullheads (4-9 inches)
1 Rock Bass (8 inches)
2 Common Shiners (4 inches)
1
2
3
4
5
4
Coho
Salmon
Walleye (
Carp
Carp
(10-
17
18
(23-24
Suckers (
Northern
PCB Concentration
(jg/g (ppm)*
750
55
26
41.
34.
10.
49.
(23 inches) 8.
i
.5
i
nches)
inches)
nches)
12-21 inches)
Pi
ke
(21-27 inches)
241.
180.
158.
30.
62.
8
3
0
8
3
5
0
4
0
.6
*ppm - parts per million
265
-------
I SJ._ANN_A
-4-HWYA
ONION OOSTB
RIVER
COAST GUARD
STATION
KI WAN IS PARK
ioHLEpDAlISHEBOYGAN
FALLS\DAM
WEEDEN'S X LAKE MICHIGAN
CREEK
FROM U.S.6.S. I:500,OOOBASI
Figure 1. Sheboygan River drainage basin (PCB investigation area)
266
-------
Sampl ing
Date
Kiwani s
5/16/78
5/16/78
5/16/78
5/16/78
5/16/78
5/16/78
5/16/78
Greendal
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
Species and
Average Length
Park Samples
1 Carp (27 in. )*
1 Carp (23 in.)*
"1 Carp (22 in.)*
"! Carp (25 in. )
1 Carp (23.5 in. )
1 Carp (24.5 in.)
4 Suckers (14 in.
e & Weeden's Creek Sampl
1 Northern Pike
(15.0 in. )**
8 Minnows (6.0 in
17 Minnows (4.5 in
1 Coho Salmon
(14.5 in.)**
6 Creek Chubs (6
18 Mi nnows (5.0 in
Sampling PCB Concentration
Location M9/9 (ppm)***
Kiwanis Park-Sheboygan
Kiwani s Park-Sheboygan
Kiwanis Park-Sheboygan
Kiwanis Park-Sheboygan
* Kiwanis Park-Sheboygan
* Kiwanis Park-Sheboygan
)** Kiwanis Park-Sheboygan
es
Greendale Creek
. )** Greendale Creek
. )** Greendale Creek
Weeden's Creek
in.)** Weeden's Creek
. )** Weeden's Creek
15.3
17.0
12.1
2.0
333.0
970.0
23.9
169
5.9
14.0
0.9
150.0
61.0
Kohler Dam Samples
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
4/26/78
1 Carp (25 ;n. )*
1 Carp (25 MI. )*
1 Carp (?2 in. )*
1 Carp (25 in. )*
3 Carp (22-25 in.
1 Carp (27 in.)*
5 Carp (18.5-20 i
3 Carp (21.5-22 i
5 Suckers (12.5-1
5 Suckers (9-10. 5
5 Suckers (10.5-1
5 Suckers (10-11
5 Rock Bass
(4.5-7.5 in.
12 Common Shiners
(5 in. )**
Above Kohler DanrKohler
Above Kohler DanrKohler
Above Kohler DanrKohler
Above Kohler Dam-Kohler
)** Above Kohler Dam-Kohler
Above Kohler Dam-Kohler
n. )** Above Kohler Dam-Kohler
n. )** Above Kohler Dam-Kohler
3 in.)* Above Kohler Dam-Kohler
in.)** Above Kohler Dam-Kohler
1 in.)**Above Kohler Dam-Kohler
in.)* Above Kohler Dam-Kohler
Above Kohler Dam-Kohler
\**
Above Kohler Dam-Kohler
240.0
180.0
150.0
250.0
350.0
250.0
460.0
320.0
88.0
130.0
39.0
40.0
190.0
100.0
(continued)
*Indicates bone
**Inaicates who
***
ess fi11et sample
e fish sample
ppm - parts per million
267
-------
TABhE 4. (Continued)
Sampl ing
Date
Species and
Average Length
Sampling PCB Concentration
Location ug/g (ppm)***
Sheboygan Lagoon Samples (above Sheboygan Falls)
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
4/27/78
Johnsonvi 1 le
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
Mullet River
5/4/78
5/4/78
5/4/78
5/4/78
5/4/78
5/4/78
Onion River
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
4/28/78
38 Bluegill (3.5 in.)**
10 Redhorse (8.0 in.)**
2 Crappies (6.5 in.)**
6 Rock Bass (8.0 in.)**
4 Northern Pike
(16.0 in.)*
7 Redhorse (15.0 in. )*
1 Carp (25.5 in.)*
1 Carp (23.5 in.)*
4 Carp (17.0 in.)*
5 Carp (17.0 in.)**
5 Carp (16.0 in.)**
8 Carp (15.0 in.)**
8 Carp (14.0 in.)**
Dam Samples
4 Carp (20 in.)**
4 Carp (17 in.)**
1 Carp (21.5 in. )*
1 Carp (23.5 in.)*
14 Suckers (10.0 in.)**
9 Rock Bass
3 Crappies (6 in. )**
] Large Mouth Bass
(9.5 in.)**
14 Stonecats (5.0 in. )**
60 Minnows (3.0 in.)**
Samples
5 Carp (13.0 in. )**
5 Carp (12.5 in. )**
1 Sucker (10.5 in. )**
10 Suckers (7.5 in.)**
14 Bullheads (6.5 in.)**
9 Creek Chubs (5 in. )**
Samples
5 Rock Bass (6.5 in. )**
3 Carp (13.0 in.)**
5 Carp (15.0 in.)**
1 Northern Pike
(20.5 in.)*
5 Carp (13.0 in.)**
5 Carp (18.0 in.)**
3 Carp (24.0 in )**
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Sheboygan Lagoon
Above Johsonville Dam
Above Johnsonvi lie Dam
Above Johnsonvi lie Dam
Above Johnsonville Dam
Above Johnsonvi lie Dam
Above Johnsonvi lie Dam
Above Johnsonville Dam
Above Johnsonville Dam
Above Johnsonville Dam
Above Johnsonville Dam
Mullet River Samples
Mul let River Samples
Mullet River Samples
Mullet River Samples
Mullet River Samples
Mullet River Samples
At Highway V
At Highway A
At Highway A
Below Waldo
Below Waldo
Below Waldo
Below Waldo
5.0
.5
2.0
2.0
1.0
1.0
1.0
1.0
3.0
4.0
2.0
2.0
.8
.8
.4
.6
.2
.5
.7
.4
.4
.4
.2
.2
.2
1.0
3.0
.2
.2
.4
.2
.2
.2
.2
.2
* Indicates
**Indicates
***
boneless fillet sample
whole fish sample
ppm - parts per million
268
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High PCB concentrations were found in soil samples collected on the
Tecumseh property in Sheboygan Falls (Table 7). Granular oil absorbent mater-
ial deposited on the property contained up to 120,000 ug/g (ppm) PCB (12%).
This PBC-contaminated waste desposited on the dike bordering the Sheboygan
River is a significant source of PCBs to the lower Sheboygan River. During
periods of high water the Sheboygan River flows along the dike and is in
direct contact with highly contaminated fill materials. During rains PCBs in
the dike are subject to washing into the stream. PCBs at other locations on
the plant property are likely to soak into the ground and reach the river
through groundwater discharge. The area is subject to periodic flooding which
occurred as recently as May, 1978.
Following the discovery of highly contaminated PCB waste deposits at the
Tecumseh Products site, the Department of Natural Resources issued an order on
May 12, 1978 banning further disposal of solid waste on Tecumseh property. On
June 21, 1978 the Department issued a second order requiring the excavation,
collection and proper storage of all materials likely to contain PCBs from the
dike on the Sheboygan River behind the Tecumseh Plant. PCB-containing mater-
ials include oil-absorbent material, scrap pressure hose, and oil-soaked
debris.
On June 21, 1978 the Department together with the Department of Health
and Social Services lifted the warning against fish consumption in the follow-
ing sections of the river basin: the Sheboygan River from the Sheboygan Marsh
to the Sheboygan Falls Dam, the Mullet River from Plymouth to the junction
with the Sheboygan River at Sheboygan Falls and the Onion River from Waldo to
Gibbsvi1le.
The PCB warning is currently in effect on the Onion River from Gibbsville
to Sheboygan Falls, on the Sheboygan River from the Sheboygan Falls Dam to the
Coast Guard Station at Lake Michigan and on two tributaries of the Sheboygan,
Weeden's Creek and Greendale Creek. The Onion River, Weeden's Creek and
Greendale Creek were included because they are accessible to migrating main
channel fish.
At this time Tecumseh Products Company is proceeding with disposal oper-
ations. Contaminated wastes from the dike are being placed in sealed drums
and stored according to State and Federal regulations until a suitable dis-
posal site becomes available.
INDIANA HARBOR
Indiana Harbor is located at the southern end of Lake Michigan in the
State of Indiana near the Indiana - Illinois border. The harbor consists of a
breakwater in Lake Michigan 1120 feet long, an entrance channel, an anchorage
and maneuver basin, and a ship canal joining the harbor with the Lake George
Branch and the Calumet River Branch of the Grand Calumet River (Figure 2).
During 1977 the Chicago District of the U.S. Army Corps of Engineers
proposed continued maintenance dredging of Indiana Harbor and respective
navigation channels over a five- to six-year period. It was proposed that
273
-------
TABLE 7. TECUMSEH PRODUCTS SOIL SAMPLES*
Location
S- 18
S-19
S-20
S-21
S-22
S-23
S-24
S-25
S-26
S-27
Sample
Description
8' from east fence, dark oily
spot on ground. Pic. 1
5' from south fence, granular
oil absorbent material, alum.
bits. Pic. 2
10' from bldg. , sandy soil
oil dump area oily soil
Pic. 3
10' from bldg., sandy gravelly
soil, oil dump area oily
sample. Pic. 4
3' from bldg., between oil
sep. & bldg., black tarry
soil sample, oil dump area.
Pic. 5
3' from south fence, low area
below rubble pile, topsoil
sample. Pic. 6
Granular oil absorbent
material, alum, bits, outside
of south fence on dike. Pic. 7
Granular oil absorbent
material, alum, bits, 2'
outside of south fence. Pic. 8
Granular oil absorbent
material & alum, bits on
river side of dike. Pic. 9
Granular oil absorbent
material & alum bits, hydraulic
hose on river side of dike. Pic
Sample
Depth
topsoil -
surface to
2" deep
6" deep
surface to
3" deep
surface to
3" deep
surface to
3" deep
topsoil -
surface to
4" deep
4-8" deep
4-8" deep
4-8" deep
4-8" deep
10
Col lection
Date
Col lector
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
5-11-78
Sheffy
PCB
M9/9
(ppm)
390.0
120,000.0
2,300.0
660.0
880.0
1 ,500.0
120,000.0
78,500.0
54,000.0
43,800.0
^Laboratory analysis for these samples was performed by soaking .5-20 grams of
sample in acetone for 1-8 hours. The extract was then injected directly into
the gas chromatograph. This procedure is a more rapid procedure for detecting
high levels of PCB than the standard column elution method.
274
-------
750,000 cubic yards of maintenance dredging from the Harbor will be placed in
the Inland Steel disposal area during the next six years (3). Proposed
dredging will be accomplished using a clamshell. The excavated materials will
be placed in barges and towed to a rehandling area located outside of the
inland disposal facility. The excavated materials will be mechanically re-
moved from the barges using a clamshell on top of the containment wall and
placed in a barge located within the disposal facility. The dredged materials
will then be bottom-dumped in the northeast portion of the disposal facility
as designated by the Steel Company. A temporary opening will be made in the
existing slag dike to provide an access for the towboat and barge(s) which
will operate within the disposal facility. The opening will be closed immedi-
ately after the equipment has entered the disposal area. The dike will be
reopened to permit the equipment to leave the disposal area once dredging
operations have been completed. This process will be repeated for subsequent
dredging operations.
In 1977 at the request of the Corps of Engineers, the U.S. Environmental
Protection Agency evaluated sediment samples in the areas proposed for main-
tenance dredging of Indiana Harbor.
Sediment samples were collected by the Surveillance and Research Staff of
the Great Lakes National Program Office, U.S. Environmental Protection Agency
at 13 locations (Figure 2). Analyses were performed by the Central Regional
Laboratory of the USEPA, Region V. Macroinvertebrate identification and
enumeration was performed by Hiedelberg College, Tiffin, Ohio (4).
Sediments obtained from the upstream limits of the harbor (Stations 1 and
2) to the easterly breakwater (Station 10) were black or dark brown silt
containing visible oil and petroleum odor (Table 8). Sediments lakeward of
Station 10 were characterized as brown or grey sand and gravel. Macroinver-
tebrates were identified at these locations during field sampling. Sieve
analysis data confirmed sediments which were predominantly silt and clay size
at most locations (Table 9).
Bulk sediment analysis was performed on all samples (Table 10). Stations
1 through 11 demonstrated severe contaminant levels with respect to all para-
meters. The lakeward locations (Stations 12 and 13) showed measurable reduc-
tions in mercury, lead, zinc, manganese, and arsenic when compared with mea-
surements taken at other stations.
The elutriate tests show releases of iron, manganese, and aluminum from
virtually all samples (Table 11). All samples except those obtained from
Stations 12 and 13 showed release of TKN, ammonia, cyanide, and phenols.
Arsenic was released from samples at locations 3, 5 (replicate), and 11.
Mercury was released from samples at Stations 1 through 5, 8, 12 and 13. In
general, samples from locations 1 through 3 exhibited the most release and
samples from locations 12 and 13 showed the least release.
Macroinvertebrates were identified at all stations (Table 12). Stations
2, 3, and 4 showed virtual absence of macroinvertebrate taxa. High numbers of
the tolerant Oligochaete, Tubifex, were observed at Station 8. Highest diver-
275
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TABLE 12. MACROINVERTEBRATE DATA AT INDIANA HARBOR
HARBOR: Indiana Harbor, Indiana
SAMPLED: August 30, 1977
Number of Organisms for Each Taxa by Station
Taxa
10
r
12
13
Diptera
Chironomus 9
Micropsectra 1
Microtendipes 1
Dicrotendipes 2
Kiefferulus 2
Procladius 3
Brillia 1
Chaoborus
Chryptochironomus
Trichocladius
01 igochaeta
Tubifex 77
Limnodrilus 44
Peloscolex 3
Branchiura sowerbyi
Unidentifiable immature
210
281
23
45
59
20
76
95
43
24
1,400
290
650
10
150
27
5
9
43
4
20
30
176
25
51
35
375
25
31
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Glossiphonia
Macrobdella
Haemopis
Helobdella
Amphiopoda
Gammarus
Pelecyopoda
Pisidium
Sphaerium
Muscueium
17
41
17
35
85
15
Gastropoda
Lymnaea
Physa
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Helisoma
21
16
2
2
48
Total # of organisms
Total # of taxa
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10
11
5
560
5
114
5
260
7
2576
9
99
7
135
6
306
9
402
4
171
15
282
-------
sity of organisms was measured at Station 13. High diversity and higher
numbers of Pelecepods and Gastropods may be attributed to suitable fine sand
substrate and lower bottom sediment contaminant levels at this location.
The bulk sediment chemistry, PCB (polychlorinated biphenyls), and pesti-
cides results show all compounds except PCBs were below the laboratory's
detection limits (Table 13). The detection limits for some compounds were
higher than usual due to high interferences present in the samples. Low PCB
concentrations were detected at Stations 12 and 13. Elevated levels of PCBs
were found at Station 1, and Stations 6 through 11. High concentrations of
PCBs ranging from 17.9 mg/kg to 25.7 mg/kg were detected at Stations 2 through
5.
CONCLUSION AND RECOMMENDATIONS
In April 1978, the Region V office of the U.S. Environmental Protection
Agency issued the following position on maintenance dredging of Indiana Harbor
(3):
Analysis of Indiana Harbor indicated that bulk sediment concentrations of
toxic constituents such as polychlorinated biphenyls (PCBs), polynuclear
aromatic hydrocarbons (PAHs), mercury, lead, arsenic, cadmium, and chromium
and nutrient concentrations are all high. Elutriate testing shows large
releases of total Kjeldahl nitrogen (TKN), ammonia, iron, manganese, nitrate
and nitrite, phenols, zinc, and aluminum from virtually all samples. Some
releases of cyanide, arsenic, chromium, copper, mercury, and nickel are also
indicated.
There are three municipal drinking water intakes within three miles of
the Indiana Harbor mouth. PCB levels in Lake Michigan are already at problem
levels, and Lake Michigan is experiencing eutrophication problems, particu-
larly in the southern end. Utmost care will have to be taken to ensure
against adverse environmental health effects from release of toxic and carci-
nogenic substances due to dredging and subsequent disposal of sediments from
Indiana Harbor. Consequently, the following contingencies must be incorpor-
ated into proposed plans for dredging and disposal of bottom sediments for
USEPA approval of the proposed action.
DREDGING AND DISPOSAL REQUIREMENTS
1. The dredging must not result in any increase over background water
concentrations (on whole-water, unfiltered sample basis) as measured
between the inner U.S. lights (when dredging upstream of that point)
for mercury, lead, arsenic, cadmium, chromium, cyanide, PCB, PAH,
TKN, ammonia, nitrate and nitrite, total phosphorus, BOD (bio-
chemical oxygen demand), phenols, copper, zinc, aluminum, chloride,
and oil and grease. When dredging downstream of the inner U.S.
lights, these same limitations should be applied as measured between
the ends of the outer breakwaters.
2. Dinn'nrj dredging, no visible debris or nil slick should extend beyond
the ends of the outer breakwaters at any time.
283
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3. The dredging should not result in any increase over background water
concentrations for whole-water, unfiltered samples taken in the raw
water of the three drinking water intakes for the parameters cited
in item 1 above.
4. The U.S. Army Corps of Engineers (COE) should consult with appro-
priate sources to arrive at a proposed dredging method which will
meet the dredging requirements. It should be substantiated, through
modeling and a test situation, that the proposed dredging method
will meet the dredging requirements.
5. In order to determine whether the proposed method of dredging is
likely to meet the dredging requirements, the dredging contractor
should test dredge at typical levels of production in the area
upstream of the inner U.S. lights. Dredging should then be suspend-
ed until sampling results are reported and reviewed.
6. Disposal operations must include chemical fixation of sediments. An
investigation will have to be conducted to determine the most effec-
tive stabilizing agent and optimum dosage for the type of sediments
involved and the environmental conditions that will be encountered.
7. Disposal operations must include construction of another containment
facility within the existing inland facility. The inner facility
would have to be designed to be impermeable, with a weir and what-
ever controls for treatment may be necessary for effluent dis-
charges. The inner facility should be large enough to retain sedi-
ments without discharge until applicable water quality standards can
be met. Water quality should be monitored in the area between the
two dikes, as well as outside of the existing (outer) facility,
during disposal operations. An initial disposal testing period must
be established to determine the effectiveness of the inner-dike
system.
8. Depending on the type of disposal method selected, a water quality
monitoring plan will have to be developed for the disposal area.
The U.S. Army Corps of Engineers and the U.S. Environmental Protection
Agency are currently reviewing these recommendations as well as other options
for maintenance dredging of Indiana Harbor. An alternative disposal site is
also under consideration.
SAGINAW RIVER AND BAY
During 1977, an overview of PCB contamination in the State of Michigan of
Saginaw River and Bay was presented at the Third U.S./Japan Experts' Meeting
on Management of Bottom Sediments Containing Toxic Substances (6).
The presence of PCBs in the Saginaw River and Bay resulted in contami-
nation of fish populations. The Michigan Department of Agriculture detected
PCB levels in channel catfish in excess of the U.S. Food and Drug Administra-
tion tolerance 'eve! of 5 mg/kg. As a result, a ban was issued for commercial
285
-------
catfishing in trie inner Saginaw Bay area. The continued detection of PCBs in
Saginaw Bay fish indicated that PCBs previously released to sediments continue
to be detected in resident fish populations.
In view of existing PCB problems in Saginaw River and Bay, the U.S.
Environmental Protection Agency was unable to concur with proposed maintenance
dredging and disposal in 1976 until a complete sediment analyses program for
PCBs was undertaken.
The U.S. Environmental Protection Agency (Chicago Office) and the U.S.
Army Corps of Engineers (Detroit District) conducted an intensive survey of
Saginaw River and Bay in October, 1976. PCBs were sampled at 35 locations in
Saginaw River and at 11 locations in Saginaw Bay. PCB concentrations in
bottom sediments ranged from <0.1 to 22.9 mg/kg for all locations. Samples
taken in the downstream vicinity of the City of Saginaw Wastewater Treatment
ranged from 5.5 to 22.9 mg/kg PCB. PCB concentrations near the Bay City Waste
Water Treatment Plant ranged from 3.5 to 11.8 mg/kg. Sediment samples ob-
tained in Saginaw Bay had considerably lower PCB concentrations ranging from
1.3 to 4.2 mg/kg.
During 1978, the U.S. Environmental Protection Agency requested that the
Michigan Department of Natural Resources review the two PCB-affected areas,
downstream of the Saginaw Wastewater Treatment Plant and in the vicinity of
the Bay City Wastewater Treatment Plant. The Department of Natural Resources
indicated that a metal casting plant in the Saginaw area and an automotive
motor facility in Bay City were possible sources. Both facilities had hydrau-
lic systems that were previously contaminated with PCBs. PCB hydraulic
fluids were initially flushed at both plants in 1971 and were replaced with
PCB-free hydraulic fluids. Samples from the two facilities and the wastewater
treatment plants are currently being analyzed.
During 1978, maintenance dredging was conducted at the Saginaw River
channel by the Detroit District Corps of Engineers. Dredging was accomplished
by the Hopper Dredge HAINS from areas of low level PCB contamination (<10
mg/kg). Dredged materials were disposed of in the Middle Grounds Disposal
Site in Bay City, Michigan. It has been proposed that subsequent dredging of
more highly contaminated areas will use the recently completed Saginaw Bay
Dike Disposal Facility.
REFERENCES
1. Kleinert, S. J. , T. B. Sheffy, J. Addis, J. Bode, P. Shultz, J. J.
Delfino, and L. Lueschow. Final Report on the Investigation of PCB's in
the Sheboygan River System. Department of Natural Resources, Madison,
Wisconsin. 1978. 51 pages.
2. U.S. Environmental Protection Agency, Region V, Chicago, Illinois.
Sheboygan Small Boat Harbor, Wisconsin, Report on the Degree of Pollution
of Bottom Sediments. 1977. 9 pages.
286
-------
3.
4.
5.
6.
U.S. Army Corps
Impact Statement
Harbor, Indiana.
of Engineers,
on Operation
1977. 40 pages.
Chicago District. Final Environmental
and Maintenance Activities at Indiana
U.S. Environmental Protection Agency, Region V, Chicago, Illinois.
Indiana Harbor, Indiana, Report on the Degree of Pollution of Bottom
Sediments. 1977. 17 pages.
Alexander, G. R. Letter to Howard N. Nicholas, U.S. Army Corps of Engi-
neers, Chicago District Office. April 19, 1978.
Bremer, K. E. An Overview of Bottom Sediment Problems in Saginaw River
and Bay, Marinette-Menominee Harbor, and Waukegan Harbor. Presented at
the Third U.S. Japan Experts' Meeting on Management of Bottom Sediments
Containing Toxic Substances, Easton, Maryland, 1977. 17 pages.
287
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DEVELOPMENTAL ASPECTS AND CURRENT POLICIES FOR RESTORATION
AND PROTECTION OF PUBLICLY OWNED FRESHWATER
LAKES IN THE UNITED STATES
by
Spencer A. Peterson
Corvallis Environmental Research Laboratory
U.S. Environmental Protection Agency
Corvallis, OR 97330
and
Robert J. Johnson
Criteria and Standards Division
U.S. Environmental Protection Agency
Washington, D.C. 20460
ABSTRACT
Some historical aspects of the impact of pollution on lake water quality
in the United States are discussed. The results of two nationwide lake water
quality surveys are addressed and the development of the United States Govern-
ment's involvement in water pollution control is traced from 1912. Although
restoration of degraded lakes and protection of higher quality lakes was
authorized by the Federal Water Pollution Control Act Amendments of 1972, the
"Clean Lakes Program" received relatively low priority for almost seven years.
Other, more geographically pervasive pollution control programs were deter-
mined more important. In fiscal year 1979, as a result of strong public
demand, the Environmental Protection Agency sought funds and positions to
support the program. Thus, the formulation of National Lake Restoration
policy in the United States has been gradual. A regulation is proposed by the
EPA, Office of Water Planning and Standards to facilitate more uniform and
equitable administration of the Clean Lakes Program.
INTRODUCTION
The United States has more than 100 thousand lakes ranging in size from a
few hectares to Lake Superior at 8.41 x 106 hectares. The State of Minnesota
is known as "the land of 10,000 lakes" which is really a misnomer since the
state actually has somewhat in excess of 13,000 lakes. In the past, the large
number of lakes in the United States has produced a certain amount of apathy
among their users. The attitude has been that lakes were there to be used,
and Americans have used them with little regard for their sometimes delicate
ecosystems. Lakes have served as drinking water supplies and for fishing,
289
-------
swimming, boating and various other recreational uses. Unfortunately they
have also served as convenient recipients of municipal and industrial waste-
water.
Historically, the latter uses primarily impacted urban lakes; however,
the problem of water quality degradation of both urban and rural lakes became
more pronounced in the United States after 1945 when phosphate-based deter-
gents were introduced. Within a few years the phosphorus content of domestic
wastewater doubled and the adverse effect on urban lakes became more severe.
About the same time, Americans began to enjoy new freedoms through improved
working conditions and reduced working hours. A 40-hour work week became
commonplace as did the private ownership of automobiles. Largely due to these
two factors, coupled with the introduction of phosphate detergents and larger,
more concentrated populations, the problem which had been generally contained
to urban lakes began to impinge on an increasing number of the Nation's small
rural lakes. By 1972, 92.8% of the vacations and 60.9% of the overnight
recreation trips in the United States involved round trips of 400 miles or
more (USDA, 1973). Reduced working hours meant increased leisure time.
Privately owned cars brought greater mobility and higher living standards
permitted second home ownership for many. Lake fronts were among the most
popular locations for these second homes. By the mid 1950's cabins and homes
completely ringed the shorelines of many previously remote and pristine lakes.
Too frequently, the wilderness weekend retreat was simply an extension of
everyday urban and surburban living. The weekend recreationist washed his
car, clothes, dishes, etc. with high phosphate detergents, flushed his modern
toilet and otherwise overloaded inadequate septic wastewater treatment facili-
ties, thus promoting the flow of enriched groundwater to local lakes (Ellis
and Childs, 1973; Dudley and Stephenson, 1973). Lakeside lawn fertilization
and gardening also produced adverse effects. The situation worsened as life-
styles continued to change and increasing numbers of people made lakefront
homes their primary residences. Recreational experiences became a way of life
in the United States.
Recreation was not the only cause of small-lake water quality problems.
Intensified agricultural practices contributed nutrients, pesticides, herbi-
cides, and silt to the Nation's freshwater streams and lakes. The overabun-
dance of plant nutrients, however, is 'the most evident of these problems,
since the nutrients support massive growths of algae and rooted aquatic plants
which hamper the recreational uses of lakes.
EXTENT AND NATURE OF THE PROBLEM
The fact that a declining water quality condition in lakes was associated
with increased use of phosphorus-based detergents and intensified farming
practices was not coincidental. There is abundant literature to demonstrate
highly significant correlations between algal concentrations in lakes and the
phosphorus content of phosphorus-limited water. An excellent coverage of the
subject is presented in a paper by Nicholls and Dillon (1978).
In 1971 Ketelle and Uttormark (1971) surveyed problem lakes of the United
States. Their primary objective was to identify those lakes that had deterio-
rated so much that rehabilitation would be required if satisfactory water
290
-------
quality was to be re-established. Forty of the 48 contiguous States responded
to questionnaires distributed by the University of Wisconsin. Through this
process, approximately 400 problem lakes were identified. That number cannot
be considered indicative of the problem since some States failed to reply (no
lake problems) while others submitted extensive lists (49 problem lakes in
Florida). Another problem with the survey was that it left individual respon-
dents with the responsibility for determining which lakes had deteriorated to
the extent that restoration would be required.
The survey conducted by Ketelle and Uttormark did point out a number of
significant factors. Of the 40 States that responded, 35 indicated they had
some lakes with severe water quality problems (Table 1). This indicates the
problem was widespread. Although 10 different problem types were listed by
various States, the two most frequently cited were nuisance algal blooms and
nuisance rooted aquatic plants. The most frequent problem source was munici-
pal effluent (a point source), cited nearly 2 to 1 over the next most common
individual problem source. When taken collectively, however, the non-point
source problems were cited more frequently than the point source problems.
Another water quality survey was initiated in early 1972 by the Environ-
mental Protection Agency. This survey stemmed largely from the then active
controversy over the removal of phosphates from detergents due to their al-
leged adverse impact on freshwater lakes and reservoirs. The objectives of
the National Eutrophication Survey (NES) were to:
(1) Identify those lakes and reservoirs in the contiguous United States
that received nutrients from discharges of municipal waste treatment
faci1ities.
(2) Determine the effect of those point source nutrient inputs on the
nutrient levels and primary productivity of the water bodies, and
(3) On the basis of the survey information, to advise the Construction
Grants Program (building of wastewater treatment facilities) on the
cost effective allocation of Federal funds for the construction of
tertiary waste treatment facilities for phosphorus removal.
Under these guidelines the NES sampled 401 lakes east of the Mississippi
River and not surprisingly found that 78% of them were eutrophic according to
the 6 parameter trophic classification system (total phosphorus, chlorophyll
a, Secchi depth, dissolved orthophosphorus, inorganic nitrogen and hypolim-
netic oxygen saturation percentage) used by NES (USEPA, 1974). West of the
Mississippi River the objectives of the survey were broadened to assess non-
point source (NPS) contributions of nutrients to the lakes and to assist in
establishing water quality criteria for nutrients (All urn, Glessner and
Gakstatter, 1977). After sampling 374 lakes in the western United States, the
National Eutrophication Survey determined that 72% were eutrophic.
Lakes contribute substantially to the economy of states which promote
water-oriented recreation. Although accurate cost figures are not readily
available it is evident that eutrophication and water pollution impairs the
water-oriented economy of these areas due to lower property values, cost of
291
-------
restoring or managing the lakes, and their generally reduced usability.
Bartsch (1972) indicated in 1972 that the loss amounted to several million
dollars per year. This figure no doubt has increased substantially since that
time.
LEGISLATION AND CONTROL PROGRAMS
LEGISLATION
The U.S. Federal Government's involvement in the water pollution control
field dates back to 1912 and has its roots in the U.S. Public Health Service.
There was limited activity in this area, however, until 1948 when the Water
Pollution Control Act of 1948 required the Public Health Service to provide
technical information to States. Even then pollution control measures were
not of high priority at the Federal level. A series of Congressional Acts up
through 1956 established public support for Federal responsibility in this
area, but the Acts were generally ineffective. According to Reitze (1972),
"The new Acts were designed to be unenforceable (industry doesn't want con-
trol, the public does. Compromise^ Pollution control laws for the public,
unenforceability for industry.)". The Water Pollution Control Act Amendments
of 1961 (P.L. 87-88, 1961) were significant with regard to the Federal Govern-
ment's involvement in water pollution control since the Amendments authorized
the establishment, equipping, and maintaining of field laboratories at 7
locations in the United States. One of those laboratories was located at
Corvallis, Oregon.
Finally in 1965, the Water Quality Act (P.L. 89-234, 1965) provided the
enabling legislative framework to remove the responsibility for water pollu-
tion control activities from the Public Health Service and to establish the
Federal Water Pollution Control Administration (FWPCA). Reitze (1972) has
pointed out that the Federal Water Pollution Control Administration's chief
concern became the dispensing of large amounts of Federal dollars to construct
sewage treatment plants. Approximately 90% of their budget went for this
purpose; only 10% supported the administration, enforcement programs, research
and development, planning, training and technical assistance activities. In
spite of the limited research efforts of the Federal Water Pollution Control
Administration and largely due to the efforts of Dr. A. F. Bartsch, the Na-
tional Eutrophication Research Program was established in 1968 at what is now
the Corvallis Environmental Research Laboratory (CERL). This laboratory
eventually became the focal point for freshwater ecological effects research
within the Environmental Protection Agency. Information developed by the
Corvallis Research Laboratory and its contractors played a key role in shaping
the future of freshwater lake pollution control in the United States.
In 1969 the public's concern for environmental conditions culminated in a
demand for action by the U.S. Congress. Several pieces of new legislation and
modifications of older legislation began to appear. The Water Quality Im-
provement Act of 1970 (P.L. 91-224, 1970) allowed conversion of the Federal
Water Pollution Control Administration to the Federal Water Quality Adminis-
tration (FWQA), which, in 1971, became part of the newly created Environmental
Protection Agency (EPA). About that same time the National Eutrophication
Research Program at CERL was upgraded to the National Eutrophication and Lake
292
-------
Restoration Program. The first lake restoration research project to be funded
by EPA under this program was located at Shagawa Lake, Minnesota (Malueg et
al_. 1973) where a full-scale advanced wastewater treatment system was built.
It was designed to remove phosphorus from domestic wastewater down to a level
of 0.05 mg/1. In 1972 Congress passed the most far-reaching piece of legisla-
tion to date concerning water pollution control measures, the Federal Water
Pollution Control Act Amendments of 1972 (PL 92-500, 1972). The most signifi-
cant aspect of this law with regard to lakes was Section 314 which states
that:
A. Each State shall prepare or establish, and submit to the
Administrator (of the U.S. Environmental Protection Agen-
cy) for his approval
1. An identification and classification according to
eutrophic condition of all publicly owned freshwater
lakes in such State;
2. Procedures, processes, and methods (including land
use requirements), to control sources of pollution of
such lakes; and
3. Methods and procedures, in conjunction with appropri-
ate Federal agencies, to restore the quality of such
lakes.
B. The Administrator shall provide financial assistance to
States in order to carry out methods and procedures ap-
proved by him under this section.
The law further specified that the amount granted to any State for any
fiscal year to conduct approved methods and procedures under this section
would not exceed 70% of the total project cost. The Act authorized $50 mil-
lion for the fiscal year ending June 30, 1973, $100 million for 1974 and $150
million for 1975 for grants to States to conduct work to comply with the
various provisions of the law.
A number of other sections of the 1972 amendments to the Act would even-
tually impinge on lake water quality. One of the most important was Section
208 which required the development of areawide waste treatment management
plans. It specified that States would identify areas which, as a result of
urban and industrial concentrations or some other factor, had substantial
water quality problems. It directed the States to then develop an organiza-
tion which would put into operation a continuing areawide waste treatment
management planning process. This program would be comprehensive in coverage
of pollutant types and sources, but it identified specifically that agricul-
tural and si 1 vicultural related non-point sources of pollution be identified
and that, to the extent feasible, methods be set forth to control the problem.
The approach of dealing with these and other non-point sources of pollution
coincides with the most frequently cited problem sources shown in Table 1.
Therefore, the Section 208 program will eventually have a significant impact
on a number of freshwater lakes, particularly those in urban settings. While
293
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TABLE 1. PROBLEM LAKES OF THE UNITED STATES SHOWING FREQUENCY OF PROBLEM TYPES
AND SOURCES OF POLLUTANTS (Modified from Ketelle and Uttormark, 1971)*
Lake Location
(State)
Arkansas
Cal ifornia
Colorado
Connecticut
Delaware
Florida
Georgia
11 1 inois
Indiana
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Missouri
Nebraska
New Hampshire
New Jersey
New York
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
South Dakota
Vermont
Vi rginia
Washington
Wisconsin
Totals
Total Surface
Area Impacted
(ha)
1,214
167,552
4,431
1 ,801
1 ,158
251,519
2,108
2,590
2,551
274,082
11,111
32
2,229
7,596
21,659
392
1,096
1,813
2,562
76,295
645
10,013
28,634
41 ,621
10,220
18,430
120,823
1 ,358
10,747
87,872
1,164,154
Number of Lakes
Impacted
1
4
4
8
41
49
2
1
29
11
21
1
23
24
29
1
3
2
26
10
2
11
4
3
14
10
3
4
19
34
394
Frequency of Occurrence
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Those states not reporting the number of surface acres impacted or the nature and source of the problems were
omitted from the original table by Ketelle and Uttormark.
294
-------
the Areawide Waste Treatment Management Program will be important in protect-
ing, and to some degree restoring, lakes by limiting the input of pollutants,
the Section 314 Clean Lakes Program will be primarily responsible for restor-
ing degraded lake systems to an acceptable level and protecting others from
degradation.
CONTROL PROGRAMS
Section 314 of PL 92-500 is known as the "Clean Lakes Section" and the
EPA program associated with it has come to be known as the "Clean Lakes Pro-
gram". Basically, it is a Federal/grantee cost sharing program designed to
improve the water quality and general usability of the Nation's freshwater
lakes. The program, historically, has received a relatively low priority
ranking among what the Environmental Protection Agency has considered more
critical programs. Among these are the Construction Grants Program to build
waste treatment plants, the Areawide Waste Treatment Management Program, the
development of effluent guidelines to control industrial discharges, and more
recently the Toxic Substances Control Program.
EPA entered the lake restoration field in FY 1975 when Congress indepen-
dently appropriated $4 million for expenditure on the Clean Lakes Program.
EPA's Office of Water Planning and Standards was charged with dispensing these
funds for public use.
POLICIES FOR RESTORATION AND PROTECTION OF FRESHWATER LAKES
EARLY POLICY AND LEGISLATIVE AMENDMENT
Policies for implementing the Clean Lakes Program have evolved gradually.
One of the first policy decisions concerned the Federal/grantee cost sharing
fractions. Although authorized by Section 314 of the law to Federally fund
lake restoration projects up to 70%, the Environmental Protection Agency made
an early decision to limit such funding to 50% of the total project cost.
Another early problem was the fact that EPA did not have a funding mech-
anism to disperse funds appropriated under the authority of Section 314. The
Agency did have, however, an established regulation to support research and
demonstration grants. Therefore a policy was established to fund lake restor-
ation projects through that mechanism. This decision eventually caused a good
deal of confusion and will be addressed later in this paper, however, it was a
most reasonable decision at the time considering the state-of-the-art of lake
restoration. Lake restoration technologies were predictable gualitatively,
but not quantitatively; that is, the direction of water quality change caused
by applying a certain technology was known, but not the degree of change.
Another significant decision by the Agency was to make a portion
($400,000) of the initial $4 million lake restoration appropriation available
to the Office of Research and Development to assess the overall effectiveness
of various lake restoration techniques being used in the Clean Lakes Program.
Responsibility for this aspect of the program was transferred to the Corvallis
Environmental Research Laboratory where scientists developed an experimental
295
-------
design to accomplish tne objectives of the evaluation program. Tne design was
approved by the Office of Water Planning and Standards and implemented in
conjunction with the lake restoration program. Descriptions of the experimen-
tal design and approaches to the evaluation program have been reported in a
number of papers (Porcella and Peterson, 1977; Porcella, Peterson and
Glessner, 1977; Peterson, 1978; Porcella, Peterson and Larsen, 1978; and Honey
and Hogg, 1978).
The early policy for reviewing grant applications is illustrated in
Figure 1. According to this procedure, the applications had to be consistent
with State and Federal areawide water quality planning programs. All applica-
tions were reviewed by the Office of Water Planning and Standards (OWPS) staff
members, at least two university consultants, and by a staff member of the
Corvallis Environmental Research Laboratory (representing the Office of Re-
search and Development). The review panel, consisting of members from each of
these groups as well as EPA's Regional Office Lake Restoration Coordinators,
met when deemed necessary by the Office of Water Planning and Standards. The
merits and demerits of each proposal \*ere discussed and the committee made a
decision to either fund, reject or request additional information on a given
proposal. In late 1975 a number of projects were funded using this review
process and the initial $4 million appropriated for the program.
In 1976, the Office of Water Planning and Standards received another $15
million from Congress to meet the growing demand for lake restoration dollars.
Again, part of these funds ($1,500,000) were provided to the Office of Re-
search and Development for evaluation projects. In 1977, Congress reaffirmed
its commitment to the Clean Lakes Program by amending Section 314 of Public
Law 92-500. The Clean Water Act of 1977 (P.L. 95-217, 1977) extended the time
frame of the program through Fiscal Year 1980 and authorized $50 million for
it in 1977 and an additional $60 million per Fiscal Year for 1978, 1979 and
1980. The amendments under Section 304(j) also required the Administrator of
EPA to issue biennially updated "procedures and processes as may be appropri-
ate to restore and enhance the quality of the Nation's publicly owned fresh-
water lakes" (PL 95-217, 1977). In 1977, Congress appropriated another $15
million for program operation. The Agency now had a $34 million program.
In 1978 the Congress looked at the needs of the Clean Lakes Program and
trimmed its funding level to $2.3 million. A major reason for this reduction
in funding was that the program had not obligated several million dollars of
the previous year's budget. What the Congress did not realize was that all
the funds had been committed. As of April 24, 1978, 65 lake restoration
projects in 21 states had been funded (Table 2). During August 1978, the
first National Conference on Lake Restoration was sponsored by EPA and hosted
by the State of Minnesota. The conference attracted over 450 participants
from 39 states and Canada. Increasingly it has become apparent that "Clean
Lakes" is a broadly based, grassroots supported program that has high poten-
tial for dramatic pollution control and water quality improvement of lakes and
their tributaries.
During the FY-79 budgeting process the Agency made its first formal
request for funds and positions to support the program. EPA asked for and
received $15 million and 15 positions. Of greater significance however was
296
-------
STATE AND/OR LOCAL APPLICATION PREPARATION
I
STATE GOVERNMENT CLEARING HOUSE
EPA GRANTS ADMINISTRATION
I
EPA OFFICE OF WATER PLANNING AND STANDARDS
REVIEW PROCESS
OFFICE OF RESEARCH
AND DEVELOPMENT
UNIVERSITY
CONSULTANTS
I
OFFICE OF WATER
PLANNING AND STDS.
REVIEW PANEL
1
RETURNED FOR
ADDITIONAL INFO.
i
REJECTED ON
SECOND ROUND
i
FUNDED ON
SECOND ROUND
REJECTED
MONITORING OF RESTORATION
GRANT BY EPA REGIONAL OFFICE
Figure 1. Clean Lakes application procedures.
297
-------
TABLE 2. CLEAN LAKE PROJECT SITES, FEDERAL FUNDING LEVELS, AND DATES OF THE INITIAL AWARDS
State
California
n
n
n
Florida
n
11 1 inois
Indiana
Iowa
ii
Maine
Maryland
Massachusetts
n
n
n
Michigan
ii
Minnesota
n
n
n
n
n
Missouri
M
n
New York
n
n
M
II
II
II
II
North Carolina
Oklahoma
Oregon
Lake
Stafford*
Temescal*
Lafayette
Ellis*
Jackson
Apopka
Frank Holton*
Skinner
Lenox*
Oelwein*
Blue*
Little Pond
Annabessacook
Lock Raven
Morses Pond*
Charles River
Cochituate
Ellis Brett Pond*
Lower Mystic
Nutting*
Lansing*
Reeds
Long*
Phalen
Albert Lea*
Clear
Chain of Lakes
Hyland
Penn*
Vandal ia*
Finger
Rothwell*
Ronkonkoma
Delaware Park*
Tivol i
Hampton Manor*
Collins Park*
Steinmetz*
Buckingham*
Washington Park*
59th Street Pond*
Mystic*
Pauls Valley
Commonwealth*
Grantee/Location
Novato
Oakland
n
Marysvi 1 le
Tal lahassee
n
E. St. Louis
Ft. Wayne
Lenox
Oelwein
Onawa
Damariscotta
Winthrop
Baltimore
Wei lesley
Boston
Natick
Brockton
Boston
Billerica
Mason
E. Grand Rapids
Arden Hills
Minneapol is-St. Paul
Albert Lea
Waseca
Minneapol is
Maple Run
Bloomington
Vandal i a
Col umbia
Moberly
Islip
Buffalo
Albany
E. Greenbush
Scotia
Schenectady
Albany
n
New York City
Lake Lure
Pauls Valley
Beaverton
Amount
$ 290,250
244,486
49,250
1 ,375,000
302,834
215,734
927,000
403,496
100,000
59,490
372,500
11,710
278,020
110,000
308,740
296,700
125,000
106,500
320,000
166,211
1,255,957
903,452
1,296,715
575,683
302,800
269,075
179,000
161,198
87,900
350,000
50,000
45,000
334,048
141 ,500
121,500
50,000
79,355
36,680
23,250
II
325,020
21,080
300,000
53,200
Date of First Award
04/08/77
03/31/77
03/21/77
05/20/77
08/31/76
01/06/76
03/16/77
09/17/76
03/08/77
03/11/77
11/10/77
02/19/76
08/01/77
04/07/77
08/23/76
09/16/76
08/26/76
01/05/77
11/21/77
05/12/77
04/13/76
06/29/77
12/18/76
01/18/77
01/08/76
09/27/76
02/13/76
08/10/76
03/21/77
02/06/78
02/16/78
02/16/78
09/29/76
02/17/76
04/11/77
04/09/76
01/08/76
12/30/76
04/09/76
H
05/12/77
09/30/77
08/16/77
12/21/76
(continued)
298
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TABLE 2 (continued)
State
Lake
Grantee/Location
Amount
Date of First Award
South Dakota
ii
11
"
Texas
Vermont
Virginia
Washington
H
M
II
II
II
II
Wisconsin
ii
H
11
N
n
H
Kampeska
Swann
Oakwood
Cochrane
McQueeney*
Bomoseen
Ri vanna
Liberty*
Long*
Moses
Spada/Chaplain
Medical
Vancouver*
Sacajawea*
Little Muskego*
Half Moon
Lilly*
Mirror/Shadow
Noquebay
Henry*
White Clay
Watertown
Viborg
Brookings
"
Sequin
Castleton
Charlottesvi 1 le
Spokane
Port Orchard
Moses
Everett
Medical Lake
Vancouver
Longview
Wheatland
Eau Claire
Wheatland
Waupaca
Marinette
Blair
Madison
$ 67,000
39,500
26,500
9,906
120,000
74,640
39,728
577,975
355,970
124,675
99,000
128,217
25,000
1 ,717,562
995,000
371 ,500
273,000
215,000
245,000
220,000
107,200
08/25/76
12/07/76
08/10/76
01/08/76
11/15/77
06/15/77
03/23/77
02/07/77
01/08/76
08/31/76
01/08/76
12/21/76
08/23/76
01/06/78
08/10/76
01/18/76
01/08/76
1)
08/23/76
12/21/76
01/08/76
Notes projects which include dredging or sediment treatment.
299
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the decision to seek permission from the Office of Management and Budget to
develop a regulation to establish policies and procedures for grant assistance
to the States in conjunction with Section 314 of the Clean Water Act. Permis-
sion was given and regulations concerning grants for the restoration and
protection of lakes in the United States are now being developed.
INITIAL PROGRAM GUIDANCE
At the outset of the Clean Lakes Program in 1975, there was no assurance
of its viability. It was a relatively small (first year funding was $4 mil-
lion) program with what appeared to be limited and somewhat regionalized
support. Therefore, instead of adopting new regulations and gearing up for a
new program, it was decided to operate within the existing framework of EPA
grant regulations. As indicated previously, the research and demonstration
section of the Act, Section 104 (h), was selected as the funding vehicle. It
followed from this that the Clean Lakes granting practices would have to
comply with the research and demonstration grant regulations. This operating
procedure was adopted, and general guidelines were formulated for the prepara-
tion of lake restoration grant applications (USEPA, 1976).
The 1976 Guidance Document specified that EPA was most interested in
funding lake restoration projects which:
1. Employed methods to restore lake water quality by eliminating or
otherwise restricting the input of non-point source waste influents
to the lake or that part of its drainage basin where a contributing
pollutional effect on the lake water quality could be demonstrated
and;
2. Used in-lake techniques to remove or inactivate undesirable pollut-
ants, including nutrients, after steps were taken in the watershed
to reduce their rapid re-accumulation.
The following statement from the Guidance Document provides further
evidence that the Clean Lakes Program would stress watershed, non-point source
pollutant control technologies over in-lake treatment techniques. "Reducing
or eliminating the sources of waste loading may be the only restorative mea-
sure that is needed to achieve the desired level of improvement of certain
lakes" (USEPA, 1976). The statement has a strong basis if one considers the
percentage of various pollutants estimated to be derived from non-point sour-
ces (Table 3). It also is clear that the program is directed toward the
problem sources most frequently identified in Table 1 by Ketelle and Uttormark
in 1971.
The Guidance Document further states that Clean Lakes funds provided
under Section 314 wil 1 not be used to control point source waste where the
issuance of permits (according to Section 402 of the Act) or the construction
of wastewater treatment facilities (according to Section 201 of the Act) will
alleviate the causes of pollution. The following types of projects are listed
as examples of those eligible for funding:
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TABLE 3. ESTIMATED PERCENTAGE OF TOTAL POLLUTANT DISCHARGES WHICH
ARE DERIVED FROM NON-POINT SOURCES (from Freeman, 1978)
Non-Point Sources as
Pollutant Percentages of Total Discharge
Suspended Solids 92
Fecal Coliform 98
Total Nitrates 79
Total Phosphates 53
BOD 37
o Lake drawdown and lake bed consolidation;
o Use of flocculants to precipitate nutrients;
o Dredging or covering of sediments;
o Dilution and displacement of pollutants with good quality water;
o Purchase or long-term leasing of land easements to establish buffer
zones for the control of runoff and its effects;
o Diversion of nutrients and sediments from lakes;
o Improving agricultural and other land use practices to keep soil and
nutrients in the watershed.
Projects considered to be ineligible for funding under the program are
described in a later section of this paper under Federal Funding Restrictions
For Phase 1 and Phase 2 grants.
CURRENT LAKE RESTORATION PROGRAM POLICY
There is little doubt that the intent and policies of the program were
designed to control and reduce non-point source pollutants. The program was
tailored to complement the Section 208 Areawide Waste Management Planning
Program. In this respect, by late 1977, several States began making requests
for Federal assistance to develop technically sound lake restoration propo-
sals. However, the initial EPA program guidelines specifically prohibited
Federal funds from being used for that purpose. The funds were for use in
actual lake restoration implementations only. There was a good deal of confu-
sion over the 50% Federal/50% grantee cost-sharing policy established by EPA
301
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for the Clean Lakes Program and the customary 95% Federal/5% grantee cost-
sharing policy for research and demonstration grants administered under the
same section of the law [104(h)]. Another point of difficulty arose from the
fact that Section 314 of the Act stated that grants under this program would
be made only to the States. No other organizations or governmental levels
were mentioned. However, Section 104 permits grants to go to State agencies,
local governmental units, or any group elected by and representing the general
public in areas of control or regulatory authority over a publicly owned
freshwater lake. Inconsistencies between the Section 314 mandate and the
Section 104 funding vehicle were making the increasingly complex Clean Lakes
Program difficult to manage. While the program had been initiated as a demon-
stration program, there was considerable pressure from States and EPA Regional
offices to convert it to an operational program. All of these considerations
led to the conclusion that a new governing regulation would be necessary to
establish uniform policies and procedures for administering the Clean Lakes --
Lake Restoration Program. The new regulatory/policy language is currently
being formulated with the following goals in mind:
1. To present a uniform set of requirements to define eligible grant
applicants and specify the types of projects that would qualify for
assistance under the program;
2. To provide grant applicants with explicit information requirements
to be included in all applications;
3. To assist States in complying with the requirement to prioritize
their lakes for restorative action;
4. To define the administrative procedures used by EPA to receive and
review proposals and prepare funding recommendations; and
5. To define Federal funding for lake restorative and pre-restorative
activities.
The following five sections of this paper and Appendix A draw heavily
from the draft regulation document prepared by the Criteria and Standards
Division of the Environmental Protection Agency. It should be understood that
this information is currently in draft form and subject to change. A proposed
regulation will be made available for a 60-day public comment period. After
that time the final regulation will be developed and promulgated.
Eligibility
Freshwater lake under the draft regulation refers to any inland pond,
reservoir, impoundment, or other similar body of water that exhibits no marine
water intrusion as a result of oceanic or tidal activities. The water body
must have public recreational value and, therefore, public access. Reservoirs
used solely for drinking water supplies are prohibited from receiving funds
under this program. In accordance with Section 314 of the Act, the new regu-
lation would allow grants to be made only to States. However, it would be
permissible for the States to enter into interagency agreements with sub-state
entities (county, township, municipality, city, watershed district, etc.) to
302
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perform various tasks included in the scope of work of specific grants. In
other words, suD-state entities could act as sub-contractors to the States.
All such sub-state interagency agreements would be reviewed by the EPA Re-
gional Administrator and subject to his approval if the sum of the agreement
exceeded $100,000.
The types of projects eligible for funding will remain essentially the
same under the new regulation as they had been under the initial program
guidance document. One significant exception will be mentioned under the
following section on types of grant assistance and information requirements
and under the section defining funding for restorative and pre-restorative
activitiy.
Types of Grant Assistance and
Information Requirements for Application
Perhaps the single most significant deviation from the initial program
operating procedure in the new Clean Lakes policies is the one which deals
with pre-implementation diagnostic-feasibility studies. Support for pre-
implementation studies was specifically prohibited in the initial program
guidance document. It has become clear that many States reguire financial and
technical assistance in these endeavors. The new regulation authorizes pre-
implementation studies to identify and evaluate lake characteristics and to
develop a restoration or water guality protection plan as a part of the Clean
Lakes Program. This type of support is called a Phase 1 matching grant. The
Federal government will provide up to $100,000 on a 70% Federal/30% grantee
cost-sharing basis for Phase 1 grants. Requirements for the diagnostic-feasi-
bility studies are included in this paper as Appendix A.
Actual implementation of pollution control measures or in-lake restora-
tion methods and procedures are to be supported by Phase 2 matching grants.
These grants are the equivalent of those formally issued under the initial
guidance document. The Federal/state cost-sharing percentages for Phase 2
grants are proposed to remain at the 50% Federal/50% grantee level. The
Agency has adopted the position that this funding formula will provide suffi-
cient local commitment to assure optimization of project implementation and a
concern for proper maintenance of the project after it is completed. Phase 2
grant proposals must contain all of the information specified in Appendix A to
receive funding consideration. This represents a significant tightening of
the requirements for funding an implementation project.
State Prioritization of Lakes
Section 314 of the Water Pollution Control Act Amendments requires States
to identify and classify their lakes according to eutrophic conditions. The
draft regulation specifies that a State must accomplish this by January 1,
1982, or become ineligible to receive Federal funds under the Clean Lakes
Program. Phase 1 grant funds may be used by States in order to comply with
this requirement. The method of classification and prioritization is left to
the discretion of individual states.
303
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Application, Review and Evaluation
Annual appropriations for the Clean Lakes Program have never exceeded $15
million. The Office of Water Planning and Standards has taken the position
that there is no equitable way to distribute such a small amount of money
among the States and still maintain a technically and administratively sound
program. Therefore, the policy will be to continue to review grant applica-
tions as they are received and to fund them, project by project based on
technical merit.
Phase 1 and Phase 2 grant applications will be considered separately, but
both will be evaluated according to the procedures outlined in Figure 1 and in
terms of:
o Technical feasibility and the estimated improvement in lake water
quality as determined through information compiled by the grant
applicant;
o The anticipated positive changes in the overall lake ecosystem with
regard to sediment, nutrient, and pollutant loading and the subse-
quent effects on lake biomass as a result of project implementation;
o The degree, nature and sufficiency of unencumbered public access to
the lake;
o The size of the population surrounding the lake which would realize
recreational benefits as a result of the project;
o Other relatively clean public owned freshwater lakes which may serve
the same population adequately;
o Whether the restoration project would disproportionaly benefit
private land owners adjacent to the lake as compared to those some-
what removed from the shoreline;
o The reasonableness of proposal costs in consideration of the various
proposed tasks, likelihood of project success and the projected
benefits;
o The prospect of dealing satisfactorily with adverse environmental
impacts resulting from the proposed course of action;
o The level of state priority for a particular grant application; and
o The recommendation of the review panel members, including those of
technical experts from the university community.
Within 90 days of the receipt of an application it will be either funded,
rejected or returned to the applicant for additional information or due to
lack of funds. In the latter two cases, applications may be resubmitted when
the issues identified during review have been resolved or when additional
funds become available.
304
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Federal Funding Restrictions for
Phase 1 and Phase 2 Grants
Each State may apply for up to $100,000 in Phase 1 pre-implementation,
Federal grant funds (on a 70% Federal/30% grantee cost sharing basis) to
assist them in developing complete, technically sound programs for implement-
ing lake restorative procedures. An application may address more than one
lake. These funds will come from the annual Clean Lakes appropriation and may
amount to as much as 20% of that appropriation, but will in no event exceed $5
million per year. Each grant will be approved for a period not to exceed 2
years.
Further restrictions require that the Regional Administrator will deter-
mine that pollution control measures in the lake watershed have been taken in
accordance with Section 201 (Wastewater Treatment Plant Construction Program),
approved 208 planning (Areawide Waste Treatment Planning Program), and Section
402 (Pollutant Discharge Permitting Program). These activities must be com-
pleted or progressing according to the time schedule of an approved plan, or
discharge permit schedule, by the time a lake restoration (Phase 2) project is
completed. Unlike the Phase 1 grants, Phase 2 grants have no upper level
funding limits. As per the initial 1976 guidelines, Clean Lakes funds may not
be used to support projects to control point source discharges (Section 402)
or for planning and construction of wastewater treatment facilities (Section
201) where those programs will resolve the pollution problems. Certain other
types of projects are similarly prohibited. These include projects using
chiefly palliative methods which treat symptoms of pollution rather than
attempt to eliminate the source of the problem, e.g. harvest of aquatic vege-
tation, herbicide treatment, and maintenance of lake aeration devices. Clean
Lakes funds may not be used for desalination procedures or for the purchase or
long-term leasing of land to provide unencumbered public access to a lake.
The Environmental Protection Agency presently is proposing revised Water
Quality Management Regulations to conform to the recently developed extended
management strategy for Water Quality Management, FY-1979-83. These regula-
tions set forth an increased emphasis on State/EPA Agreements. The initial
results of Clean Lakes Projects clearly show that this program can be the
basis for effectively implementing pollution control practices that improve
dramatically the water quality of both tributary streams and lakes. State and
local communities have shown a great deal of interest in these results and
appear impressed with the potential of this program to assist them with water
quality improvement. Thus, the gradual development of lake restoration policy
has served as an asset. It is anticipated that the newly formulated policies
and procedures of the Clean Lakes Program will facilitate its implementation.
SUMMARY
This paper provides a statement on the type and extent of water quality
problems associated with freshwater lakes in the United States.
It traces the historical course of the Federal government's involvement
in water pollution control activities.
305
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It explains the role of EPA's Office of Water Planning and Standards in
administering the Clean Lakes Program and the role of the Office of
Research and Development in evaluating the effectiveness of various lake
restoration techniques.
It describes the initial policies of the program and the evolution to
their current state.
ACKNOWLEDGEMENTS
We wish to thank Bruce Tichenor, Kenneth Malueg and Karen Randolph of
EPA's Corvallis Environmental Research Laboratory for their reviews and sug-
gestions for improving this paper. A similar thanks is extended to Donald
Porcella, Associate Director of the Utah State Water Research Laboratory at
Logan, Utah and to Kenneth MacKenthun, Director of the Criteria and Standards
Division in EPA's Office of Water Planning and Standards, Washington, D.C.
REFERENCES
Allum, M.O., R. E. Glessner and J.H. Gakstatter. 1977. An Evaluation of the
National Eutrophication Survey Data. Working Paper No. 900. USEPA,
Corvallis Environmental Research Laboratory, Corvallis, OR 97330.
Bartsch, A.F. 1972. Role of Phosphorus in Eutrophication. EPA-R3-72-001.
USEPA, Corvallis Environmental Research Laboratory, Corvallis, OR 97330.
Dudley, J.G. and D.A. Stephenson. 1973. Nutrient Enrichment of Ground Water
From Septic Disposal Systems. Upper Great Lakes Regional Commission
Report, Inland Lake Demonstration Project, University of Wisconsin,
Madison, Wis.
Ellis B. and K.E. Childs. 1973. Nutrient Movement From Septic Tanks and Lawn
Fertilization. Tech. Bull. No. 73-5. Michigan DNR, Lansing, Michigan
48926.
Freeman, A.M., III. 1978. Air and Water Pollution Policy. In: Current
Issues of U.S. Environmental Policy. P.R. Portney !Ed.l Resources for
the Future, Johns Hopkins University Press, Baltimore, Md. 207 pp.
Gakstatter, J.H., M.O. Allum and J.M. Omernik. 1976. Lake Eutrophication:
Results From the National Eutrophication Survey. In: Water Quality
Criteria Research of the U.S. Environmental Protection Agency: Proceed-
ings of an EPA-Sponsored Symposium. EPA-600/3-76-079. USEPA, Corvallis
Environmental Research Laboratory, Corvallis, OR 97330.
Honey, W.D. and T.C. Hogg. 1978. A Research Strategy for Social Assessment
of Lake Restoration Programs. EPA-600/5-78-004. USEPA, Corvallis Envi-
ronmental Research Laboratory, Corvallis, OR 97330.
Ketelle, M.J. and P.O. Uttormark. 1971. Problem Lakes in the United States.
Tech. Rep. 16010 EHR 12/71, Water Resources Center, Hydraulics and Sani-
tary Laboratory, University of Wisconsin, Madison, WI 53706.
306
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Malueg, K.W., et al. 1973. The Shagawa Lake Project. R3-73-026. USEPA,
Pacific Northwest Environmental Research Laboratory, Corvallis, OR
97330.
Nicholls, K.H. and P.J. Dillon. 1978. An Evaluation of Phosphorus-chloro-
phyll-phytoplankton Relationships in Lakes. Int. Rev. Ges. Hydrobiol.
(in press).
Peterson, S.A. 1979. EPA's Lake Restoration Evaluation Program. In "Lake
Restoration" Proceedings of a National Conference, Aug. 22-24, 1978. EPA
440/5-79-001. USEPA, Office of Water Planning and Standrds, Washington,
D.C. 20460.
Porcella, D.B. and S.A. Peterson. 1977. Evaluation of Lake Restoration
Methods: Project Selection. USEPA, Corvallis Environmental Research
Laboratory Report No. 034. Corvallis, Oregon 97330.
Porcella, D.B., S.A. Peterson and R. Glessner. 1977. Evaluation of Restora-
tion Techniques Under the U.S. Environmental Protection Agency's Clean
Lakes Program. Presented at the annual fall meeting of the American
Geophysical Union at San Francisco, California, December, 1977.
Porcella, D.B., S.A. Peterson and D.P. Larsen. 1978. Methods for Evaluating
the Effects of Restoring Lakes. Manuscript.
Public Law 87-88. 1961. Federal Water Pollution Control Act as Amended,
1961.
Public Law 89-234. 1965. Water Quality Act of 1965.
Public Law 91-224. 1970. Water Quality Improvement Act of 1970.
Public Law 92-500. 1972. Federal Water Pollution Control Act as Amended,
1972.
Public Law 95-217. 1977. The Clean Water Act of 1977.
Reitze, A.W., Jr. 1972. Environmental Law, Second Edition. North American
International Publishers, 1609 Connecticut Ave. N.W., Washington, D.C.
U.S. Department of Agriculture. 1973. Outdoor Recreation: A Legacy for
America, Appendix "A", An Economic Analysis. Printed by United States
Depart, of Interior, Bureau of Outdoor Recreation, Washington, D.C.
U.S. Environmental Protection Agency. 1974. An Approach To a Relative Tro-
phic Index System for Classifying Lakes and Reservoirs. National Eutro-
phication Survey Working Paper NO. 24. Corvallis Environmental Research
Laboratory, Corvallis, OR 97330.
U.S. Environmental Protection Agency. 1976. Guidance for the Preparation of
Lake Restoration Grant Applications. Criteria and Standards Division,
Office of Water Planning and Standards. Washington, D.C. 20460. 13 pp.
307
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APPENDIX A
GUIDANCE FOR DIAGNOSTIC FEASIBILITY STUDIES
Proposals for Phase 1 Clean Lakes grants must include the following
information in their scope of work for all Clean Lakes applications.
Diagnostic Study Requirements
1. An identification of the waters to be restored or studied, including
their name, state in which located, location within the state, area,
maximum depth, average depth, detention time, the general relation-
ship with associated upstream and downstream waters.
2. A geological description of the drainage basin including soil types
and soil loss to stream courses that are tributary to the lake.
3. A description of the public access to the lake.
4. A summary of historical lake uses including recreational lake uses
through the present time and how these may have changed through the
years because of water quality degredation. A statement must be
made regarding the water use of this lake compared to other lakes
within a 50 mile radius.
5. An itemized inventory of known point source domestic or industrial
pollutional discharges affecting or which have affected lake water
quality over the past 5 years and the abatement actions that have
been taken, are in progress, or are contemplated within a specified
time period.
6. A description of the land use in the lake watershed with an indica-
tion of what percentage of the watershed each encumbers.
7. A discussion of non-point pollution loading derived from each iden-
tified land use category.
8. A discussion and analysis of current (within one year from the date
of application) baseline limnological data. Such data must include
the present trophic condition of the water body as well as its
surface area, maximum depth, average depth, hydraulic residence
time, area of the watershed draining to the lake, and the physical,
chemical, and biological impact of important tributaries. Batho-
metric maps should be provided and where dredging is part of the
restoration plan, representative bottom sediment core samples and
analyses for nutrient content, heavy metals and persistent organic
chemicals must be provided. An assessment of nitrogen and phos-
phorus inflows and outflows associated with the lake and a hydraulic
budget including groundwater flow must be included. Vertical tem-
perature and dissolved oxygen data are essential and it must be
determined if the hypolimnion becomes anaerobic and if so, for how
long and over what extent of the bottom. The extent of algal blooms
308
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and the predominent algal genera must be discussed. The portion of
the shore line and bottom that is impacted by vascular plants (sub-
merged, floating, or emersed higher aquatic vegetation) must be
estimated and that estimation must include an identification of the
predominant genera. There must be an identification and discussion
of major biological resources in the lake, such as fish populations
and how they might be expected to change.
Feasibility Study Requirements
1. An identification and discussion of the alternatives for pollution
control or lake restorative action considered; and an identification
and justification of a selected alternative when considering all
alternatives including a discussion of expected water quality im-
provement, technical feasibility, and estimated costs that are
attached to each alternative.
2. A discussion of the particular public benefits expected to result
from implementation of the project, including new public water uses
that may be associated with the enhanced water quality.
3. A proposed monitoring or investigative program with schedule for
evaluation. Based on the information supplied by the applicant and
the technical evaluation of the proposal, a detailed monitoring
program to evaluate project effectiveness during and up to one year
following the completion of project implementation will be estab-
lished for each approved project and will be specified in any grant
agreements supporting implementation or restorative procedures. An
additional guidance for monitoring methods and procedures will be
provided at the time of grant award.
4. A proposed milestone work schedule for project completion with a
proposed budget and payment schedule relating to progress mile-
stones.
5. A detailed description of how matching funds will be obtained to
support the non-federal funding requirements for the proposed pro-
ject.
6. A description of pertinent relationships of the proposed project to
local, state and federal pollution control programs such as the
Section 201 Construction Grants Program, the Section 208 Areawide
Wastewater Management Program, the Soil Conservation Service Pro-
grams as described by PL 83-566, the Department of Housing and Urban
Develooment Programs, and any other local, state, and federal pro-
grams which may bear a relationship to the proposed project.
Environmental Evaluation
An environmental evaluation to consider all potential adverse impacts of
the project must be included with the application. The purpose of this docu-
ment is to identify and thus minimize the effects of any adverse impacts which
may be associated with the project.
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SEDIMENTS AND SEDIMENT
DISTURBANCE DURING DREDGING
John F. Sustar
U.S. Army Engineer District, San Francisco
San Francisco, California 90105
INTRODUCTION
During the past ten years numerous studies have been conducted in the
field to quantify the disturbance during dredging operations. The results
have generated wide ranges of data. The conclusions, however, do state that
improving the dredging efficiency will decrease impacts or possible impacts of
dredging operations. Despite extensive studies in San Francisco Bay, signifi-
cant chemical and physical stresses on the biological communities have not
been identified. The conclusion on improving dredging efficiency, however, is
still valid in terms of not only minimizing the disturbance to the biological
system, but also minimizing the investment in maintaining channels. Minimiz-
ing disturbance is also important where known isolated contamination is being
removed.
Studies of sediment disturbance during dredging have been continuously
modified not only to locate the disturbance but to develop handles on ident-
ifying the parameters that control the disturbance. Figure 1 shows schematic
diagrams of the three most common dredging methods in San Francisco Baythe
trailing suction hopper dredge, the hydraulic cutterhead dredge and the clam-
shell dredge. The figure also shows the generally recognized areas of dis-
turbance.
Yagi et al_. (1976) looked at both the hydraulic cutterhead dredge and the
grab bucket (clamshell) dredge. For the hydraulic cutterhead, they concluded
that: "The accumulative ratio of short-absorbed soil, however, decreases with
the increase of the number of cutter swings. On the other hand, the turbidity
has the general trend to increase in opposition to the above mentioned trend."
Their work dealt primarily with the swing speed and the sediment thickness.
Shape of bottom was also concluded to be an important parameter. The sediment
type was only mentioned in terms of the gradient of the vertical turbidity
distribution. With the grab bucket, turbidity was found to be largely de-
pendent on the type of sediment. The closed bucket, which reduces the inter-
action of localized eddies with the sediment interface in the bucket, did
decrease the loading of the water column.
Huston (1S76) concluded that: "Techniques for reducing dredge-induced
turbidity consist principally of good dredging procedures and the proper use
of existing dredging equipment. Some of the items discussed included disturb-
311
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-------
ances by the vessels themselves including the tenders, the inefficiency of
cleanup operations and the effectiveness or skills of the personnel. His work
did not discuss the relationship of the equipment and the type of sediment in
disturbing both the bottom and the water column, although proper use of equip-
ment does imply the selection of the type of equipment for a given project.
With the spectrum of dredging operations and available equipment, this selec-
tion process is not necessarily controlled by the optimization of the opera-
tion efficiency.
The work by Weschler et al_. (1977) does employ a settling jar to evaluate
sediment characteristics for use in a numerical model. The mention, however,
does not explain what actually occurs in the system.
Studies by Johnson et al_. (1975) showed the large scale heterogeneous
loading characteristics of both the hopper dredge and the clamshell with dump
scow. With the operation (elevation changes) of the dragheads on the hopper
dredge, major differences were observed.
Sustar et al_. (1976) identified initial dispersion patterns related to
the type of sediment and the dredging equipment. The major portion of their
studies with the dredging operation concentrated on locating the plume and
describing the plume vertically and horizontally by percent transmission and
suspended solids loading. Although patterns were discernible, variation of
data was very large. Studies were equipment oriented and project oriented.
The type of sediment being dredged has generally been ignored in terms of
interpreting the disturbances that occur in the dredging area. Based on
previous studies in San Francisco Bay on the release pattern during open water
disposal, dredging operations in the Bay were evaluated in terms of the type
of sediment and the efficiency of the operation. An interpretation of the
bottom and water column disturbance using actual dredging operations and
sediment testing is given.
DREDGING EFFICIENCY
If the basic premise (increased efficiency decreases disturbance) were
reversed, a greater disturbance during the dredging should reduce the effic-
iency of the operation. To test this, three dredging periods in Mare Island
using the trailing suction hopper dredge HARDING were evaluated. Figure 2
shows the location of Mare Island Strait.
The shoaling in Mare Island Strait is silty-clay. The October-November
1975 dredging period represented a shoal formed over a several month period
with sediments recirculating in the northern portion of the Bay. The second
period was February-March 1976. The shoaling generally represents new sedi-
ments entering the system with outflows from the Sacramento-San Joaquin Delta.
The third period was July-August 1978. Following an extended drought,
flood flow brought new sediments from the Delta. The delayed dredging from
the usual February-March cycle probably developed with progressive movement of
sediments through the Delta and Carquinez Strait with each storm following the
drought. The total dredging cycles for each of the periods were 606, 430 and
313
-------
SONOMA
PETALUMA
, RIVER
SAN PABLO BAY
BAY
CARQUI EZ
STRAIT \
PITTSBURG . ;S
SAN JOAQUINRI.
.';_" AlARTINE
CENTRAL C.-:. ' ' -
SCALE IN KILOMETERS
GOLDENGATE
ปV. OAK LAND
SAN FRANCISCQ;
;.:r&" SAN LEANDRO
-. SOUTH'. '.(
SAN FRANCISCO^
SOUTH BAY
V.- > FREMONT
REDWOOD CITY . J ป.
WLO ALTO.^*]^f>J;^:;. . '.fl.; .'
INDICATES SUBSYSTEM
BOUNDARIES
Figure 2. Mare Island Strait.
314
-------
396, respectively. Shoaling patterns in Mare Island Strait are very definite
with buildups concentrating in three to four areas.
From the vessel's records, the cubic yards per pumping minute was ob-
tained for each cycle using the load meter and the pumping time. The data
were averaged in ten cycle groups to reduce the variability between successive
cycles. The variability between cycles results from the heterogeneous nature
of the bottom and variations in dredging location with movement of vessels and
day/night time dredging. The average efficiency and plus and minus one stand-
ard deviation are shown in Figures 3 through 5.
All three periods show a decrease in loading efficiency with time. The
first and second periods show definite cycles of decreasing efficiency indi-
cating a work pattern of removing one shoal at a time. The type of equipment
(trailing drags) working the shoal of silty-clay causes both trenching of the
shoal and disturbance with mixing of water in the shoal. After a number of
passes through a shoal, the dragheads will cross previous trenches resulting
in the intermittent variation of suction at the intake, increased water in the
slurry and subsequent reduction in the density of the pumped sediment. The
decreased loading efficiency of each of the discernible cycles (low ten cycle
average divided by preceding high ten cycle average) is as follows:
Oct-Nov 75 Feb-Mar 76 Jul-Aug 78
1st cycle 72% 42% 55%
2nd cycle 59% 57%
3rd cycle 62%
The decrease is based on an "average optimum" condition with the initial
dredging of an undisturbed area.
Although patterns of decreasing efficiency of pumping are evident, the
analysis also shows some increases in efficiency. As the shoals form with
time, different densities occur in the bottom. Assuming optimal operation of
the vessel including the control of the dragheads and the speed of the vessel
relative to the bottom, pumping efficiency is dependent on the density of the
sediment. As the bottom sediments are disturbed, increasing the water con-
tent, an initial increase in pumping efficiency will occur until an optimum
pumping density is reached. As the disturbance continues, the density con-
tinues to decrease, decreasing the pumping efficiency.
SEDIMENT RELATIONSHIPS
Three types of sediments were collected in San Francisco Bay to examine
qualitatively the comparative degree of disturbance with resulting bottom
configuration (trenching) and suspended particulate. The classification of
the sediments is as follows:
315
-------
MARE ISLAND DREDGING - HARDING
OCT- NOV 1975 YD3/ MIN VS TIME
AVERAGE 18 CYCLES
HIGH 117 LOW 68
MARE ISLAND DREDGING-HARDING
OCT-NOV 1975 YD3/MIN VS TIME
TWO STANDARD DEVIATIONS 18 CYCLES
MAXIMUM 32 MINIMUM 5
Figure 3.
316
-------
MARE ISLAND DREDGING- HARDING
FEB - MAR 1976 YD3/ MIN VS TIME
AVERAGE 18 CYCLES
HIGH 92 LOW 39
i|
MARE ISLAND DREDGING-HARDING
FEB- MAR 1976 YD3/MIN VS TIME
TWO STANDARD DEVIATIONS 18 CYCLES
MAXIMUM 22 MINIMUM 5
Figure 4.
317
-------
MARE ISLAND DREDGING - HARDING
JUL-AUG 1978 YD3/ MIN VS TIME
AVERAGE 18 CYCLES
HIGH 113 LOW 59
l|
MARE ISLAND DREDGING - HARDING
JUL-AUG 1978 YD3/ MIN VS TIME
TWO STANDARD DEVIATIONS 18 CYCLES
MAXIMUM 26 MINIMUM 6
Figure 5.
318
-------
Classification
1. Silty Sand (SM)
2. Sand (SP)
3. Clay (CH)
Liquid
Limit
31
99
Plastic
Limit
26
38
5
61
The gradation curves are shown in Figure 6.
100
CO
01
UJ
50
bJ
CJ
o:
LJ
CL
11Vf VTVT
111 i i I I I
10
Figure 6.
I O.I 0.01
GRAIN SIZE IN MILLIMETERS
0.001
The sediments were placed in clear 30 cm x 16 cm containers with nine
centimeters of salt water over the sediments. A standard disturbance was made
in each container using a nine millimeter diameter rod. The rod was pulled
along the same line in groups of five pulls. Uniform speed and pressure were
maintained.
The clay, sample 3, produced the best defined trench with vertical side
walls. The width of the trench (15 cm) was not significantly changed with
increased disturbances along the same line. The silty sand, sample 1, also
developed a trench. Vertical walls were present, but were not as well defined
as with the clay. The width of the trench (25 cm) increased with increasing
disturbance. The sand, sample 2, developed a V-shaped trench, 30 cm at the
top.
319
-------
Sand produced very little turbidity when comparing the suspended particu-
late to a photo density scale (visual observation). The silty sand almost
immediately produced turbidity with very little increase in turbidity with
additional disturbance. The clay produced successive increase in turbidity
with each additional disturbance. The maximum turbidity with the clay was
greater than with the silty sand.
The differences in the trenches can be explained by the type of sediment
irrespective of the type of disturbance. Following a disturbance the sand
comes to an angle of repose, resulting in a V-shaped trench. The silty sand
maintains some vertical wall because it is a low cohesive sediment. The
increased width of the trench results from the susceptibility of the sediment
to erode with successive disturbances. As the cohesive properties of the
sediment increase, the direct action by the disturbing instrument is required
to move the sediment. The narrow width of the clay trench is an example.
Within San Francisco Bay, the type of sediment does influence the pumping
efficiency when comparing Mare Island Strait (clay), Richmond Harbor (silt)
and the San Francisco Bay (fine sand). Mare Island Strait sediment is conduc-
ive to the most efficient pumping. The San Francisco Bar sediment results in
the least pumping efficiency. Pumping efficiency is defined by cubic yards of
load per pumping minute.
In Mare Island Strait, the sediments are less susceptible to mixing with
water; that is, more energy or disturbance is required to decrease the dens-
ity. It should be noted that efforts are made to control the dredging lines
(i.e., reduce the crossing of trenches). Dredging cycles have been conducted
in Mare Island Strait with a hopper dredge in which no overflow was required
to attain an economic load. This means that the sediments were near optimum
pumping density and excellent control of dredging lines was maintained.
The silts in Richmond Harbor are easily disturbed, resulting in a sedi-
ment density below the optimum pumping density. The sands on the San Fran-
cisco Bar are independent of the disturbance. The pumping efficiency is
controlled by the efficiency of the pumps rather than the disturbance of the
sediment. The speed of the dredge over the bottom largely influences the
loading characterization.
The same dredging operations in San Francisco Bay illustrate the levels
of suspended particulates during dredging. Greater turbidity (reduced light
transmission) results from clays because of the increased number of particles
in suspension per unit weight as compared with silts. The level of clay
loading (weight suspended solids) is dependent on the duration of disturbance
(addition and mixing of water to decrease the cohesive properties) and the
flocculation rate. The flocculation rate is dependent on the concentration of
suspended solids, salinity of the system and collision of particles (disturb-
ance in the operation, i.e., overflow, and in the water column, i.e., passage
of the vessel). With Mare Island Strait sediments, the non-dispersed grain
size is about 20 micron. Without additional disturbance, the clays within the
hydraulic regime will react as silts. Although the level of suspended solids
in the water column between clays and silts may be similar, percent transmis-
sion will be dramatically different. Figure 7 represents a logarithmic re-
gression analysis of seven sets of data. The data present i_n situ percent
320
-------
transmission readings, using a ten centimeter light pattern, compared with
suspended solids analysis of samples pumped from adjacent to the transmissom-
eter. The analysis does fit the above description. The clays of Mare Island
Strait generate the highest turbidity (decreased light transmission) as com-
pared to the coarser silts in other areas such as Richmond Harbor and Alameda
Naval Air Station. Within the three regression curves of Mare Island Strait,
the lowest of the curves is at a time of lower salinity with freshwater flows
coming from the Sacramento-San Joaquin Delta. The lower salinity of both the
sediment and the water decreases the rate of flocculation and increases the
time of sediments in suspension. Dredging with stratified water conditions in
Mare Island Strait introduced saline water from the lower water column into
the freshwater in the upper water column. The results were a decrease in
turbidity in the upper water column due to flocculation.
50 100 150 200
SUSPENDED SOLIDS IN MILLIGRAMS PER LITER
250
Line
A.
B.
C.
D.
E.
F.
G.
Location
Date
(f)x
Mare Island Strait
Mare Island Strait
Mare Island Strait
Alameda NAS
Alameda NAS
Richmond Harbor
Petaluma Channel
Sep-Oct 74
Mar
Oct
Dec
Jan
Nov
Sep
75
75
74
75
74
77
104
24
30
38
99
83
268
55
7
46
120.
117.
135.
114.
.91-9.
.87-1.
.33-8.
59-15.
09-20.
17-21.
66-18.
22
41
30
58
66
22
68
1 nx
Inx
1 nx
1 nx
1 nx
1 nx
Inx
0.
0.
0.
0.
0.
0.
0.
56
46
54
,26
.42
.35
75
(1) f(x) = ฐ,
(2) Samples
(3) Samples
'< transmission 10 cm light path.
greater than 500 mg/1 suspended solids excluded.
0% transmission entered at 0.01%.
Figure 7.
321
-------
The turbidity associated with sand is limited to the percent silts and
clays in the sediment and the type and size of equipment. The type and size
of equipment relates to the disturbances and the absorption ratio. The ab-
sorption ratio is the ratio of sediment removed divided by sediment disturbed.
The hopper dredge, working with sand, does introduce grading of sediments
during dredging. Fines are separated through the overflow. The reduced fines
level in the hopper does result in lower turbidity during disposal. This also
is reflected in the contaminant levels. Contaminants in the disposed sedi-
ments are less than the in situ project sediments. A large clamshell dredge
will maintain a greater percentage of fines for transport. The turbidity
during disposal, however, will be greater than from a hopper dredge because
the fines are still present. The turbidity from a hydraulic cutterhead will
depend on the ratio of absorbed sediments, which in turn relates to the suc-
tion's pickup capacity, swing speed, working face and type of sediment. The
four elements are interdependent.
CONCLUSIONS
The type of sediment being dredged is a major parameter in evaluating
both the disturbance generated by the operation and the efficiency of the
operation. The disturbance and the efficiency are related. With silts and
clays a less efficient operation means that more energy is being expended in
adding and mixing water with the sediment. As the disturbance increases, the
efficiency continues to decrease.
Many studies have been conducted during the past several years to define
the disturbance during dredging. The great variation of results within and
between studies probably could be correlated if the type of sediment, the
shape and condition of the shoal, the type of equipment, the method of opera-
tion and relative time of sampling were entered into the analysis. The liquid
limit and water content (presented as multiples of the liquid limit) of the
sediments at any particular time and location of the operation are proposed as
a common basis for evaluating levels of suspended solids in the water column.
Continuous "optimum" efficiency of a dredging operation can not be ex-
pected. Other constraints override the optimum conditions, such as the avail-
ability of a particular type and size of dredge, requirements to minimize
interruptions of commerce, localized channel requirements and safety. Some of
the factors can be controlled or developed to increase or maintain the effic-
iency of the operation. Training operating personnel to become familiar with
the equipment in various types of sediments and shoal configurations is prob-
ably the most effective. Use of instrumentation for horizontal and vertical
control will also increase efficiency. With hydraulic systems such as the
hopper dredge and the cutterhead dredges, recently developed instrumentation
should be utilized to indicate immediate pumping response to both increases
and decreases in pumping densities. Clogging of pumps or breakage of sediment
suction will be reduced and a more "optimum" density will be maintained. The
design of the dredging operation should minimize feather shoals and cleanup
requirements. This may mean an evaluation of neat line payment schedules in
favor of some combination of neat line and pumpage quantities.
322
-------
ACKNOWLEDGEMENT
The material in this paper is based on the author's observations during
studies by the San Francisco District of the U.S. Army Corps of Engineers of
dredged sediment disposal in San Francisco Bay. Publication of this paper has
been approved by the Corps of Engineers. Any views, interpretations or con-
clusions developed, however, are those of the writer.
Critical comments by Mr. William Dickson of the District's Operations
Division is appreciated. Special thanks is extended to my two oldest child-
ren, Peter and Mary, who have reached the age of a scientific appreciation to
play with mud. Their assistance in mixing the mud, making observations and
measurements and cleaning up afterwards was a great help.
REFERENCES
1. Huston, J. W., W. C. Huston, Techniques for Reducing Turbidity Associated
with Present Dredging Procedures and Operations, Contract Report D-76-4,
U.S. Army Engineers Waterways Experiment Station, Vicksburg, Mississippi,
May 1976.
2. Huston, J. , Techniques for Reducing Turbidity with Present Dredging
Procedures and Operations, Proceeding World, WODCON VII, San Francisco,
July 1976.
3. Johnson, E. , et al. , JBF Scientific Corporation published as (U.S. Army
Engineer District) Dredge Disposal Study, San Francisco Bay and Estuary,
Appendix M, Dredging Technology, San Francisco, September 1975.
4. Sustar,' J. F., T. H. Wakeman and R. M. Ecker, "Sediment-Water Interaction
During Dredging Operation," Proceedings of ASCE Specialty Conference on
Dredging and Its Environmental Effects, Mobile, AL, p. 736-767, January
26-28, 1976.
5. Sustar, J. F. , G. Perry, T. H. Wakeman, "Sediment Dispersion from a
Submerged Pipeline," Proceeding Coastal Zone 78, San Francisco, 14-16
March 1978.
6. U.S. Army Engineer District, Dredge Disposal Study, San Francisco Bay and
Estuary, Main Report, San Francisco, CA, April 1976.
7. U.S. Army Engineer District, Dredge Disposal Study, San Francisco Bay and
Estuary, Appendix A, Main Ship Channel, San Francisco, CA, September
1975.
8. U.S. Army Engineer District, Dredge Disposal Study, San Francisco Bay and
Estuary, Appendix C, Water Column, San Francisco, April 1976.
9. Wakeman, T. H. , J. F. Sustar and W. J. Dickson. 1975. Impacts of Three
Dredge Types Compared in San Francisco District. World Dredging and
Marine Construction 11:9-14.
323
-------
10. Weschler, B. A., D. R. Cogley, A Laboratory Study of the Turbidity Gener-
ation Potential of Sediments to be Dredged, Technical Report D-77-14,
U.S. Army Engineers Waterways Experiment Station, Vicksburg, Mississippi,
November 1977.
II. Yagi, T. , T. Koina, S. Miyazaki, Turbidity Caused by Bay Dredging, Pro-
ceeding World Dredging Conference, WODCON VII, San Francisco, July 1976.
324
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BIOACCUMULATION OF TOXIC SUBSTANCES FROM CONTAMINATED
SEDIMENTS BY FISH AND BENTHIC ORGANISMS
Robert M. Engler
Environmental Laboratory
Dredged Material Research Program
U.S. Army Engineer Waterways Experiment Station
Vicksburg, Mississippi 39180
BACKGROUND
The River and Harbor Act of 1970 (Public Law 91-611, Section 123) author-
ized the Corps of Engineers to initiate and conduct a comprehensive nationwide
study of dredging and dredged material disposal operations. Of particular
interest were environmental impacts, productive uses of dredged material, and
new and/or improved dredging and disposal practices.
The U.S. Army Engineer Waterways Experiment Station (WES) was assigned
responsibility for the research program; the program was designated as the
Dredged Material Research Program (DMRP).
The planning and implementation of the DMRP were the responsibility of an
interdisciplinary team established at WES as part of the Environmental Labora-
tory (EL). The thrust of the program involved four major research projects
(1):
a) Environmental Impacts and Criteria Development Project (EICDP).
b) Habitat Development Project.
c) Disposal Operations Project.
d) Productive Uses Project.
This review report is primarily concerned with the findings from Task ID,
the Effects of Dredging and Disposal on Aquatic Organisms, and from Task 1A,
the Aquatic Disposal Field Investigations (ADFI), of the DMRP and observations
from two of the five open-water disposal sites. Findings from related work
will be referenced in this review as appropriate.
The overall objective of the EICDP was to provide definitive information
on the environmental impact of dredging and disposal operations and, where
undesirable impacts were observed, to suggest means of eliminating or reducing
such impacts. As such, this also included studies on water and sediment
quality and the rate and extent of the recolonization of disposal sites by
325
-------
bottom organisms, impacts such as bioaccumulation of toxic substances on
bottom animals, and responses of swimming and free-floating organisms to
disposal.
Task ID (2) included six research efforts that dealt with the direct and
indirect effects of dredging and disposal on aquatic organisms. The aspects
of dredging and disposal investigated for potential environmental effects were
the physical disruption of the bottom environment, the generation of suspended
sediments, and the contaminant load of the sediments being disturbed and
redistributed.
The research reviewed is in the forefront of applied environmental sci-
ence and is a beginning in defining the occurrence of environmental perturba-
tions due to dredging and disposal. Most of the studies reviewed describe
worst-case experimental conditions. Although somewhat limited in scope,
experimental laboratory results showing lack of effects under these conditions
support the conclusion of the field studies that indirect (long-term and
sublethal) effects of dredging and disposal will be minimal.
Potential environmental effects of dredging and disposal are not yet
completely understood due to the many variables involved. Dredging and dispo-
sal operations are carried out in many geographic locations with a wide range
of aquatic environments. Waters may have different salinity regimes and
different levels of natural turbidity. Disturbed areas may have different
contaminant burdens in the water and sediments. Major variables are the
presence of organisms and the species diversity that characterize the differ-
ent dredging and disposal sites. Even different methods of dredging and
disposal may affect the environmental impact of a given project.
The basic approach involved the selection of field sites on the basis of
representativeness of different geographic regions (environments) and disposal
operations. Appropriate strategies were then developed for the collection and
analysis of biological, chemical, and physical samples. Samples were then
taken during controlled disposal operations and compared to samples obtained
under baseline conditions and from reference sites.
FIELD STUDY RESEARCH SITES
Lake Erie (Ashtabula, Ohio)
Seasonal aspects of spring and summer hopper dredge disposal of contami-
nated and uncontaminated sediments from Ashtabula Harbor were investigated at
this site. In addition, the long-term impacts at a historic disposal site
were evaluated. This was the only site located entirely in freshwater.
Duwamish Waterway (Puget Sound, Washington)
This site was chosen for investigations of the disposal of contaminated
sediments in an estuary. Fine-grained sediments contaminated with polychlori-
nated biphenyls (PCBs), metals and petroleum hydrocarbons were mechanically
dredged from the waterway, barged to an Elliott Bay (Puget Sound) site, and
disposed of in 60 m of water.
326
-------
RtStARCH RATIONALE
In general, a multidiscipl inary team approach was used at each site to
investigate the effects of dredged material disposal (3). The primary vari-
ables studied were physical, chemical, and biological parameters as follows:
Physical: Currents, waves, tides, meteorology, bottom profiles, sediment
movement, sedimentology, geochemistry, and mineralogy.
Chemical: Water quality, sediment quality, toxicant release/removal, and
nutrient release/removal.
Biological: Fish, shellfish, benthic macroinvertebrates, phytoplankton,
zooplankton, contaminant bioaccmulation, and recolonization.
Not all variables were investigated at each site, however, this review deals
only with the contaminant uptake potential for select toxic substances by
aquatic organisms.
Three other task areas within the EICDP (1) were closely related to this
work. These were: Movements of Dredged Material (Task IB), Effects of Dredg-
ing and Disposal on Water Quality (Task 1C), and Effects of Dredging and
Disposal on Aquatic Organisms (Task ID). The research for these tasks was,
for the most part, carried out in the laboratory under controlled conditions.
As such, the results are useful for understanding known impacts and for pre-
dicting others that may occur. They cannot, however, be directly applied to
field conditions without verification but can be considered as "worst case"
evaluations. As such, they are useful in defining boundary conditions ex-
pected with aquatic discharge.
Results obtained in the field studies may be site-specific. Dredging and
disposal will almost always cause some degree of environmental disruption.
Disposal, for example, will usually cause the burial of organisms.
The apparent absence of an impact does not definitively demonstrate that
one did not occur. Rather, it may reflect a deficiency in experimental de-
sign, inappropriate methods, or analytical error. This is a particular prob-
lem in the case of chronic or long-term impacts because these may not become
evident for months or years after the causal event.
LABORATORY INVESTIGATIONS
Dredging and disposal are carried out in different locations throughout
the United States and in the territorial sea. Very often disposal is carried
out in an environment different from the dredging site. Dredging and disposal
occur in waters ranging from fresh to estuarine and high salinity waters.
Some of these waters are highly turbid, whereas others normally are quite
clear. Different dredging areas may have different contaminant burdens in
waters and sediments. Another major variable is the organisms present and the
species diversity in different dredging and disposal areas. Some benthic
substrates may host hundreds of species within areas of a few square meters
327
-------
while other substrates may host very few species. 1 he presence of many dif-
ferent species at a given location has been classically interpreted as the
sign of a healthy ecosystem. This is not always true, and it is important to
also take into account the number of major different types of organisms. For
example, in the Oakland Inner Harbor of San Francisco Bay, there is great
animal diversity, but most of the different species are sludge worms, with a
number of other species which are diminuitive, opportunistic, and adapted to
pollutant stress. Conversely, potentially damaged species may bp of commer-
cial value, i.e., the east coast oyster beds. Local pollutant additions
unrelated to dredging may exceed potential dredging and disposal effects or
may act synergistically with dredging and disposal to produce deleterious or
beneficial environmental effects. Even different methods of dredging and
disposal may affect the environmental impact of any given project.
Previous literature on dredging and disposal has been fragmentary and
site or resource specific. Reviews of literature reveal that too few basic
data form a broad scale conceptual framework for the possible environmental
impacts.
CHFMICAL IMPACTS
The potential availability and uptake of sediment-associated heavy metals
by deposit-feeding benthic animals was the subject of DMRP Work Unit 1D06 (4).
This laboratory study attempted to determine the biological availability of
selected heavy metals associated with sediments and the potential for their
uptake from dredged material into the tissues of representative bottom-dwell-
ing species.
Sediment chemistry in relation to organisms impact was further studied in
Work Unit 1D11 (5). This study carried out laboratory experiments on the
transfer of oil and grease residues from oil-contaminated sediments into the
tissues of some representative benthic species.
There has been concern that contaminants from municipal, industrial, and
other sources which become entrapped in aquatic sediments may become biologi-
cally active when disturbed by dredging or disposal activities. Major mater-
ials in question have been numerous heavy metals, persistent pesticides such
as DDT and its derivatives, PCBs and petroleum hydrocarbons. Dredging and
disposal do not introduce new contaminants to the aquatic environment, but at
worst simply redistribute the sediments which are the natural depository of
contaminants introduced from other sources.
Toxic Substance Uptake
In Work Unit 1D06 (4), metal availability and accumulation studies were
conducted using the clam Rangia cuneata, the grass shrimps Palaemonetes pugio
and P. kadiakensis, and the worms Neanthes arenaceodentata and Tubifex sp.
Test sediments, as shown in Table 1, were taken from Texas City and Corpus
Christi, Texas, ship channels (15 and 30 ฐ/0o salinity, respectively) and the
Ashtabula River in Ohio (freshwater). Metals routinely measured were iron,
manganese, copper, cadmium, nickel, lead, zinc, chromium, and mercury.
328
-------
TABLE 1. "I01AL CONCENTRATION OF METALS IN SEDIMENTS
Element
Cu
Cr
Cd
Fe
Ni
Mn
Pb
Zn
Hg
V
Total Concentration,
Texas
City
Channel
48
188
2.4
14,500
48
570
41
161
0.6
136
mg/kg of Dry Weight
Corpus
Christi
Channel
120
82
21
12,000
17
257
316
4,055
18
Ashtabula
River
37
175
4.8
25,000
52
356
42
315
1.1
222
Elutriate Test Results
Metal
Cu
Zn
Mn
Fe
Pb
Cr
Cd
Ni
Hg
Texas
Site water
((jg/1 )
20
44
32
44
1
7
<1
85
0.05
City
El utriate
(M9/D
9
28
5800
52
1
6
<1
75
0.10
Corpus
Site water
(ug/n
9
325
22
10
2
<5
<]
11
<0.05
Christi
Elutriate
(ug/1)
3
1700
890
20
6
<5
<1
9
0.55
Ashtabul
Site water El
(ug/1)
8
85
3
15
1
<5
<]
21
0.11
a
utriate
(ug/i)
6
50
550
650
1.5
<5
<1
20
2.85
For most metals studied (Table 2) uptake by organisms was not evident.
However, when uptake was shown to occur, the levels often varied from one
sample period to another and were quantitatively marginal, usually being less
than one order of magnitude greater than levels in the control organisms even
after 1 month of exposure. It is invalid to compare metals levels in organ-
isms to total sediment chemical concentrations since only a variable and small
amount of the sediment-associated metal is biologically available. This is
discussed in detail in the synthesis report on DMRP Task IE (6). In addition
to not knowing the amount of metal available for biological uptake, animals in
undisturbed environments may naturally have high and fluctuating metal levels.
Therefore, comparisons should be made between control and experimental organ-
isms at the same point in time in order to evaluate bioaccumulation.
329
-------
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Of a total of 168 animal-sediment-sal irn'ty combinations evaluated in
tests carried out by Neff, Foster, and Slowey (4), only 22 percent showed sig-
nificant accumulation due to sediment exposure. The largest uptake was of
iron, a metal generally known for its low degree of toxicity in biological
systems. Significant accumulations of lead were seen in a number of short-
term exposures, although these could not be duplicated in long-term exposures.
Relatively high uptake of lead occurred only in the polychaete Neanthes and
was interpreted to be potentially ecologically significant for this species.
Their literature search showed that heavy metals in solution vary over several
orders of magnitude in availability to benthic invertebrates. Although ac-
cumulation of heavy metals by organisms from the water has been documented,
the literature shows no such clear evidence for accumulation of metals from
the sediments.
Neff, Foster and Slowey (4) also investigated the depuration of heavy
metals after the organisms were removed from the test sediments. In those 37
cases where there was uptake after 8 days exposure, depuration during 2 or 8
days in clean water was seen in 7 instances, with the other 30 cases showing
no decrease in metal concentration in the tissues.
In a field investigation of the San Francisco Bay system, Anderlini e_t
al_. (7) looked at 9 heavy metals (silver, arsenic, cadmium, copper, mercury,
nickel, lead, selenium, and zinc) and 5 invertebrates (Ampelisca mi 1leri,
Hacoma balthica, Neanthes succinea, Mytilus edulis, and Ischadi urn demissum).
Metals concentration in sediments and organisms fluctuated within and outside
the dredged zone during the period of the study. Changes in the mean metal
concentrations in sediments and all invertebrates during the study period were
relatively small, considerably less than one order of magnitude. Mean metal
concentrations in sediments and benthic invertebrates changed by less than a
factor of 2, and changes in metal levels in M. edul i s were no greater than a
factor of 3. These changes could not be directly attributed to dredging
activities. Metal concentrations were similar in M. edulis which were trans-
planted from clean water to stations within and outside the dredged zone.
Mussels transplanted to contaminated Bay stations appeared to accumulate cop-
per, nickel, and zinc over controls kept in clean water coastal stations but
to a lesser extent than native mussels. Desorption of metal species by mus-
sels 27 days after being transferred from Bay or ocean stations occurred in
the following order of decreasing depuration: zinc > mercury > copper > lead
> nickel > cadmium > arsenic. Selenium was not depurated from mussel tissue
in 27 days.
The accumulation potential of a metal may be affected by several factors
such as duration of exposure, salinity, water hardness, exposure concentra-
tion, temperature, and the particular organism under study. The relative
importance of these factors varies from metal to metal. Data of Neff, Foster,
and Slowey (4) on salinity effects are inconclusive, but there was a trend
toward increased uptake at lower salinities. Anderlini et a_]_. ' s (7) 9-day
laboratory study exposed M. balthica to the chloride salts of various metals
in the water column. These data support field observations in which M.
balthica showed the highest metal concentrations following dredging periods
where heavy rains had resulted in a marked decrease in salinity.
331
-------
The Neff, hoster, and Slowey (4) study indicated that the chemical form
of metals had important effects on their bioavailabi1ity. Elevated concentra-
tions of heavy metals in tissues of benthic invertebrates were not always
indicative of high levels of metals in the ambient medium or associated sedi-
ments. Although a few instances of uptake were seen to be of possible ecolog-
ical significance, diversity of results among species, different metals, types
of exposure, and salinity regimes strongly argued that bulk analysis of sedi-
ments for metal content could not, be used as a reliable index of metal avail-
ability and potential ecological impact of dredged material.
Neff, Foster, and Slowey (4) performed sequential and nonsequential chem-
ical extractions on the sediments to evaluate the potential mobility of metals
in different chemical forms. They also determined the total metal concentra-
tion in the sediment. For some species a correlation did exist and for others
a correlation did not exist between any chemical or physical form studied and
bioaccumulation of the metal. These authors state: "At present, it does not
appear that a simple extraction scheme can be developed that might indicate
availability of sediment sorbed metals by benthic organisms. Additional data,
based upon a large number of different sediment types, may indicate, however,
forms most likely to be accumulated by benthic organisms."
For some metals there appears to be good correlation between metal con-
centration in the sediment and in the associated infaunal and epifaunal macro-
biota (4). For other metals no such correlation exists. These correlations
often vary with sediment type. The correlation, when it occurs, may be due to
direct or indirect transfer of metals from sediment to biota or it may repre-
sent the presence of a common source of metals to both the sediment and biota.
Anderlini et aJL (7) concluded that if changes in metals in the water occurred
as a result of dredging activities, the changes were either less than small
natural fluctuations or were of short duration.
Both Neff, Foster, and Slowey (4) (short-term laboratory studies and lit-
erature review) and Anderlini e_t al. (7) (longer term field work and back-up
laboratory experiments) have found the same heavy metal phenomenon. The
accumulation and release of certain heavy metals seems to vary with the metal,
with the species, between sampling times, between sampling sites (dredged and
not dredged), and within controls. These variable results have not been di-
rectly correlated with dredging operations or sediment loading.
A recent field study supporting the laboratory results of Neff, Foster,
and Slowey (4) has been carried out by Simms and Presley (8). These authors
concluded that mollusks, crustaceans, and bony fishes from dredged areas of
San Antonio Bay were lower in almost every heavy metal than were organisms
from other areas where dredging was minimal. Mollusks were observed to con-
centrate metals more than any other organisms studied, but the levels observed
were much lower than those thought to be lethal or toxic. Except for a few
large fish, metal concentrations did not correlate significantly with size or
growth stage. Vigorous shell dredging in the Bay for 50 years apparently did
not cause increases of heavy metals in the tissues of local biota.
Studies in DMRP Work Unit 1D09 (9) used harbor sediments chosen for
physical similarity to bentonite, in order to assay for impacts due to chemi-
332
-------
cal properties of the sediments in suspension. Measurements were carried out
using sediments from relatively uncontaminated reaches of San Francisco Bay
and compared with measurements on more highly contaminated Bay sediments.
Organism responses did not differ greatly between pure mineral suspensions
(10) and uncontaminated natural sediments. In many cases, lethal effects were
more marked with the contaminated sediments. Sediment characteristics are
presented in Table 3. The most sensitive species tested, striped bass, Morone
saxati 1 is, survived only a few hours at levels of 0.5 g/1 of contaminated
sediments, a condition probably representing a worst-case of turbidity genera-
tion associated with a dredging operation. Such conditions are very unlikely
to occur in the field, where motile organisms may escape turbidity maxima, and
where water currents disperse sediments as they settle out of the water col-
umn.
Chemical analyses of several species for heavy metals, pesticides, and
polychlorinated biphenyls (PCBs) as presented in Tables 4-7, indicated uptake
of several contaminants, but none were accumulated to levels which appeared to
be sufficient to influence the survival of the exposed organisms (9). Diffi-
culties in interpreting such chemical data argued for developing assays which
evaluate total toxicity of a sediment regardless of specific toxicants.
Oil and Grease Uptake
This term is used collectively in describing all components of sediments
of natural and contaminant origin which are primarily fat soluble. The lit-
erature review contained in DMRP Work Unit 1D11 (11) demonstrated a broad
variety of possible oil and grease components in sediment, the recovery of
which was dependent on the type of solvent and methodology used to extract
these residues. Trace contaminants, such as the PCBs and chlorinated hydro-
carbons (DDT and derivatives), often occur in the oil and grease. Large
amounts of contaminant oil and grease find their way into the sediments of the
Nation's waterways either by spillage or as chronic inputs in municipal and
industrial effluents, particularly near urban areas with major waste outfalls.
The literature suggested long-term retention of oil and grease residues in
sediments with minor biodegradation occurring. Where oily residues of known
toxicity became associated with sediments, these sediments retained toxic
properties over periods of years affecting local biota. Spilled oils are
known to readily become adsorbed to naturally occurring suspended particu-
lates, and oily residues in municipal and industrial effluents are commonly
found adsorbed to particles. These particulates are deposited in benthic
sediments and are subject to resuspension during disposal.
Using the elutriate test DiSalvo e_t aj. (11) showed some release into the
water of soluble hydrocarbon residues from sediments known to contain 2000 to
6000 ppm total hydrocarbons. Hydrocarbon concentrations in the elutriate (100
to 400 ppb) were from 11 to 400 times higher than background, yet were well
below acceptable effluent discharge, standards. The amount of oil released
during the elutriate test is less than 0.01 percent of the sediment-associated
hydrocarbons under worst-case conditions.
A test scheme was employed in which estuarine crabs (Hemigrapsus
oregonensij), mussels (Mytilus edulis), a"d snails (Acanthina spirata), and
333
-------
TABLE 3. CHEMICAL CHARACTERIZATION OF CONTAMINATED SEDIMENT
USED IN THE ESTUARINE AND MARINE TESTS
Parameter
% water
pH
Eh
Total
Sulfides
Total
Phosphates
Ortho-P
TKN
HNj-N
As
Cd
Cu
Fe
Mn
Hg
Ni
Se
Zn
Total
PCBs
Total DDT
Total
mg/kg
48.3
7.8
-414
6148
878
--
0.15%
--
128
2.3
158
3.62%
333
1.47
104
1.49
381
1.30
0.750
Sediment Fraction
Exchangeable Interstitial Elutriate
mg/kg Water - mg/1 mg/1
__
__
__
--
--
2.3 1.4
--
88.8 -- (3.49)
0.50 0.12 0.14
1.09 0.16 (0.14)
1.6 0.10 0.06
2.5 0.18
114 5.1 0.49
0.55 0.15 (0.16)
62.4 6.4 9.6
0.62 0.48 0.46
4.0 0.12 0.04
__
334
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TABLE 4. CONTAMINANT CONCENTkAl1UNS IN I HE TISSUE OF THE MUSSEL
Mytilus edulis IN THE CHEMICAL UPTAKE STUDY IN THE
CONTAMINATED
SEDIMENT PHASE OF THE ESTUARINE TEST
SS
g/i
At col
0
0
0
0
0
3.6
12.1
15.9
Exposure
days
lection
3
10
15
21
P
P
P
P
Metals (pg/g wet)
0
0
0
0
0
0
0
0
0
As
.oy
.15
.15
.28
.6
.06
.16
.10
.08
Cd
0.96
0.09
0.32
0.26
0.44
0.28
2.15
1.16
1.07
Cu
2.05
5.98
1.74
1.16
1.14
0.85
5.22
2.43
2.83
Fe
71
176
131
100
95
49
154
55
58
Pb
U. 19
0.15
0.19
0.23
0.18
0.15
1.68
0.34
0.18
Mn
2.71
7.74
3.29
1.16
3.09
3.49
2.99
2.92
1.95
Hg
0.15
0.12
0.05
0.02
0.06
0.02
*
*
0.11
Ni
0.68
1.24
0.94
1.74
2.60
3.15
2.72
1.46
1.17
Zn
38.4
45.6
25.0
20.2
39.1
27.5
100.0
55.9
50.0
P = Animals were exposed to indicated suspended solids concentration for 21
days then placed in clear water 5 days to purge the sediment from the
digestive tract and body surfaces before analyses.
* = Insufficient sample for analysis.
TABLE 5. WHOLE BODY CONCENTRATIONS OF SELECTED METALS IN CHEMICAL UPTAKE
STUDY WITH CONTAMINATED SEDIMENT IN THE MARINE TEST
Species
Mytilus
edul i s
Mytilus
cal ifornianus
Crangon
nigromaculata
Cancer
magister
Suspended
Solids
Exposure
Control
Purged
Control
Purged
Control
Purged
Control
Purged
As
0.12
0.20
0.17
0. 12
0.03
0.08
0.03
0.03
Cd
0.34
0.10
0.51
0.45
0.06
0.23
0. 10
0.13
Cu
2.48
7.66
3.52
9.23
4.95
9.08
16.8
13.3
Metals
Fe
154.0
215.0
162.0
88.8
38.8
25.6
55.9
51.4
(Mg/g
Pb
2.14
3.89
0.97
2.28
0.55
0.27
0.31
0.38
wet)
Mn
2.53
2.48
1.62
0.95
0.87
8.20
1.00
8.06
Hg
0.63
0.02
0.21
0.03
0.13
0.14
*
*
Ni
0.
0.
0.
0.
0.
0.
0.
0.
04
05
08
004
01
52
19
37
Zn
25.7
33.6
22.7
25.0
7.2
22.7
13.3
16.8
* -
= Insufficient sample for analysis.
335
-------
TABLE 6. CONTAMINANT CONCENTRATIONS IN THE TISSUE OF THE MUSSEL
Mytilus edulis IN THE CHEMICAL UPTAKE STUDY IN THE
CONTAMINATED SEDIMENT PHASE OF THE ESTUARINE TEST
ss
g/i
Exposure
days DDE
Chlorinated Hydrocarbons (ug/g wet)
Total Aroclor
DDD DDT DDT 1241 1254 1260
Total
PCBs
At collection 0.68 0.32
0 3 1.18 0.38
0 10 0.52 0.84
0 15 0.50 0.46
0 21 0.18 0.85
1.00
1.56
1.36
0.96
1.03
0.02
0.02
0.02
0.02
0.04
0.05
0.06
0.03
0.06
0.02
0.01
0.01
0.01
0.02
0.01
0.08
0.09
0.06
0.10
0.07
0
3.6
12.1
15.9
P
P
P
P
0.55
0.75
0.49
0.47
0.40
0.83
1.10
0.68
0.95
1.58
1.59
1.15
0.06
0.07
0.05
0.05
0.02
0.07
0.03
0.02
0.01
0.02
0.02
0.01
0.09
0.16
0.10
0.08
P = Animals were exposed to indicated suspended solids concentration for 21
days then placed in clear water 5 days to purge the sediment from the
digestive tract and body surfaces before analyses.
- = See note Table 7.
TABLE 7. WHOLE BODY CONCENTRATIONS OF SELECTED CHLORINATED
HYDROCARBONS IN CHEMICAL UPTAKE STUDY WITH CON-
TAMINATED SEDIMENT IN THE MARINE TEST
Species
Mytilus edulis
Mytilus
cal ifornianus
Crangon
nigromaculata
Cancer magister
Suspended
Solids
Exposure
Control
Purged
Control
Purged
Control
Purged
Control
Purged
Chlorinated Hydrocarbons
DDE DDD DDT
1.71 - 0.69
2.02
1.66
2.57
1 . 54
1.39
0.14
0.14
(M9/9)
DDT
2.40
2.02
1.66
2.57
1.54
1.39
0. 14
0.14
- = Below detection limits; DDD < 0.006 ng/g; DDT < 0.008 ng/g. Also below
detection limits were aldrin, dieldrin, heptachlor <0.004 ng/g; chlordane
< 0.008 ng/g; endrin, PCBs < 0.1 ng/g.
336
-------
the freshwater clam, Corbicula sp. , were exposed to contaminated sediments in
order to determine magnitudes of uptake of hydrocarbons which were included in
sedimentary oil and grease burdens. Sediment characteristics are shown in
Table 8.
There was no overt mortality of test organisms that was directly attrib-
utable to exposure to contaminated sediments. Experimental evidence as pre-
sented in Table 9 suggested slight uptake of hydrocarbons by saltwater test
organisms incubated in the presence of Duwamish River sediments which con-
tained almost 500 ppm total hydrocarbons (11). Freshwater clams exposed for
30 days to Duwamish River sediments showed no well-defined uptake of hydrocar-
bons (11). As presented in Table 10, mussels and crabs exposed for 4 days to
New York Harbor sediments containing 2000 ppm total hydrocarbons showed aver-
age uptakes above background of about 50 to 70 ppm (2.5 and 3.5 percent,
respectively, of the sedimentary hydrocarbon concentration).
These results (11) indicated that selected estuarine and freshwater
organisms can be exposed to dredged material that is contained with thousands
of parts per million oil and grease and experience minor mortality for periods
up to 30 days. Uptake of hydrocarbons from the heavily contaminated sediments
appears minor when compared to the hydrocarbon content of the test sediments
and when compared to results describing exposure of uncontaminated organisms
under field conditions where total hydrocarbon uptake ranged to several hun-
dred parts per million (12).
In Work Unit 1D07 (13), attempts were made to trace pathways of uptake of
sediment-associated DDT into the tissues of estuarine deposit-feeding benthic
infauna. The data obtained suggested the possibility of uptake of DDT under
model laboratory conditions which may or may not be operative under field
conditions. Fulk, Gruber, and Wullschleger (14) have reviewed the literature
on pesticides and PCBs in sediments. Algae, suspended solids, bottom sedi-
ments, and water contain various chlorinated hydrocarbons. The studies con-
ducted on the adsorption and desorption of chlorinated hydrocarbons on solids
have generally indicated that the materials are much more readily sorbed than
desorbed. These workers analyzed the sediments from five locations for al~
drin, dieldrin, endrin, lindane, 2,4-D esters, DDT analogs, toxaphene, and
PCBs. PCBs, dieldrin, and the DDT analogs were the most prevalent. The
desorption of the latter materials was studied. No release of DDT residues
was observed. Some dieldrin release was observed in the parts per trillion
range. On the basis of these laboratory studies, it appears that release of
these water-insoluble pesticides will not occur to an appreciable extent
during disposal. In another study, Anderlini et a!. (15) monitored release
from sediments and uptake by organisms of PCBs and compounds of the DDT group
during a disposal operation in San Francisco Bay. Some uptake of p,p'-DDE was
observed but the levels of the other chlorinated hydrocarbons remained con-
stant in Myti1 us edulis.
337
-------
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338
-------
TABLE 9
HYDROCARBON ANALYSES BY TLC OF CRABS (Hemigrapsus
oregonensis) EXPOSED TO DUWAMISH RIVER DREDGED MATERIAL
Tank Seri
SED
SED, Ref
SCR
SCR, Ref
STR
STR, Ref
Hydrocarbon
es* Time Days Alkanes
0 14
17 22
17 8
17 21
17 19
17 25
17 10
Content ug/g dry ti
Arenes
2
7
3
14
10
6
5
ssue (ppm)
Total
16
29
n
35
29
30
15
HYDROCARBON ANALYSES BY TLC OF MUSSELS (Mytilus
edulis) EXPOSED TO DUWAMISH RIVER DREDGED MATERIAL
Hydrocarbon
Tank Series* Time days Alkanes
SED
SED, Ref
SCR
SCR, Ref
STR
STR, Ref
0 143
30 35
30 48
30 84
30 35
30 110
30 63
HYDROCARBON ANALYSES BY TLC OF SNAILS
Content pg/g dry ti
Arenes
35
58
47
54
<6.5
52
15
(Acanthi na spirata)
ssue (ppm)
Total
178
93
95
138
<41.7
162
78
EXPOSED TO DUWAMISH RIVER DREDGED MATERIAL
Hydrocarbon
Tank Series* Time days Alkanes
SED
SED, Ref
SCR
SCR, Ref
STR
STR, Ref
0 <6
30 14
30 4
30 CO
30 6
30 28
30 CO
Content ug/g dry ti
Arenes
<4
7
4
NTAMINATE
2
37
NTAMINATE
ssue (ppm)
Total
<9
21
8
D
8
65
D
* = SED -
SCR -
STR -
Ref -
Organisms in sediment.
Organisms on screen 5 cm above sediment
Organisms on screen 30 cm above stirred
Reference sediment.
.
sediment.
339
-------
TABLE 10
HYDROCARBON ANALYSES BY TLC OF CRABS (Hemigrapsus oregonensis) AND
MUSSELS (Mytilus
edulis)
EXPOSED TO PERTH AMBOY (NJ)
DREDGED
MATERIAL
Tank Series*
Crabs
STR #1
STR #2
Mussels
STR #1
STR #2
Time days
0
0
4
4
4
4
0
4
4
4
4
HYDROCARBON ANALYSES BY
MUSSELS (Mytilus edulis
Tank Series*
Crabs
SED
SCR
STR
Mussel s
SED
SCR
STR
Time days
0
1
1
1
0
27
27
27
Hydrocarbon Content
ug/g dry
Alkanes Arenes
19
21
47
59
66
85
17
22
28
18
20
TLC OF CRABS (Hemigrapsus
) EXPOSED TO BAY RIDGE (NY)
Hydrocarbon Content
6
7
21
34
42
35
46
65
76
86
143
tissue (ppm)
Total
25
28
68
93
108
120
63
87
104
104
163
oregonensis) AND
DREDGED
Mg/g dry
Alkanes Arenes
62
58
24
70
25
72
23
108
11
22
5.2
22
22
121
32
180
MATERIAL
tissue (ppm)
Total
73
80
30
92
46
193
55
288
* = SED - Organisms in sediment.
SCR - Organisms on screen 5 cm above sediment.
STR - Organisms on screen 30 cm above stirred sediment.
340
-------
FIELD INVESTIGATIONS
FRESHWATER SITE
The Ashtabula, Ohio, ADFI site is located in Lake Erie (16) just north of
the entrance to Ashtabula Harbor (Figure 1). The movement of surface water in
the lake is counterclockwise although reversals do occur with northeast winds.
A compensating current is found in the deeper waters of the lake during ther-
mal stratification (June-October). Because of the configuration of the lake,
any contaminants which are released along the south shore tend to move east-
ward along the shore. Oxygen depletion occurs in the deeper water during the
summer.
Sediment in the disposal area primarily originates from material trans-
ported by the longshore current and, to a lesser extent, from the Ashtabula
River which enters Lake Erie through Ashtabula Harbor. The sediment consists
of about equal parts of sand and silt, with a small amount (<10 percent) of
clay. There is apparently little variation in grain size with depth.
Although there have been severe water quality problems in the lake,
striking improvements have been noted in recent years. At the Ashtabula ADFI
site, water quality variables tended to be quite uniform throughout the water
column except during stratification. The expected differences resulting from
stratification were observed; during periods of upwelling, deeper (hypolim-
netic) water was often found quite near the surface.
A variety of invertebrates and fish inhabit the area. The former in-
cludes mollusks, worms, insect larvae, and crustaceans. These form a food
supply for the 40-odd species of fish which were observed. Yellow perch were
the most abundant species, with alewife, gizzard shad, and white sucker being
quite common. Moderate to abundant populations of both zooplankton and phyto-
plankton occur throughout the lake.
The Ashtabula area is heavily industrialized and is a major port facil-
ity. There are a number of industrial and agricultural sources of contami-
nants in the immediate vicinity and there are two fossil-fuel generating
stations east of Ashtabula. These discharge almost 2300 x 106 I/day of cool-
ing and waste water into Lake Erie.
The Ashtabula ADFI spanned 3 years (1975-1977). The study consisted of
four phases: a pilot survey (1975), predisposal sampling (1975), disposal
operations (1975-1976), and postdisposal sampling (1975-1976). Samples for
various parameters were obtained from a disposal area and an adjacent refer-
ence area.
The physical variables measured included currents, temperature, light
transmission, meteorology, waves, bathymetry and sub-bottom profiles, grain
size, sedimentology, and hydrology.
Both pumped samples and grab samples were obtained for analyses of con-
ductivity, pH, turbidity, dissolved oxygen, nutrients, alkalinity, metals,
organic carbon, silicates, and sulfate in the water column. Bulk sediment and
341
-------
LAKE ERIE
DISPOSAL
AREA
REFERENCE
AREA
(ALTERNATE)
Figure 1. Locations of disposal and reference areas,
Ashtabula River disposal site, Ohio.
342
-------
sediment interstitial water were analyzed for nutrients, metals and organic
carbon; bulk sediments were further examined for pH, Eh, percent water, and
cation exchange capacity. In addition, in-place sediment oxygen demand mea-
surements were carried out.
Phytoplankton and zooplankton samples were evaluated in terms of species
present and abundance; primary productivity was estimated by pigment analysis
and carbon-14 uptake. Elutriate from dredged samples was added to phytoplank-
ton samples to determine if inhibitory or stimulatory effects were present.
Bottom grabs were obtained for investigation of macro- and meiobenthic organ-
isms. As with plankton, these samples were evaluated to determine the numbers
and kinds of organisms present.
A variety of fishery studies were carried out. These included sampling
with gill nets and otter trawls, tows for fish larvae, age determination, and
examination of stomach contents. Both fish and invertebrates were analyzed
for heavy metals.
Findings
Spring and summer disposal by hopper dredge resulted in the formation of
mounds of dredged material in the disposal area. These mounds (16) were 30 to
50 cm high, and, rather than a single mound being present, there were numerous
small mounds. Disposal also created a small (< 2ฐC) transient increase of
temperature in the water column; during thermal stratification, disposal did
not alter the thermal structure. There was little change in grain size after
disposal and those few changes observed had disappeared within 3 months.
Erosion of the mounds occurred as a result of fall and winter storms, and
there was a new transport of material to the northwest and southeast.
Almost all of the chemical variables measured in the water column were
affected by disposal (16). Effects were not great, however, and an essen-
tially complete return to ambient predisposal conditions was noted within a
few minutes to several weeks. The overall impact of disposal is not clear as
some constituents increased, presumably through release, while others de-
creased. The latter phenomenon probably resulted from sorption into settling
dredged material.
There were changes in interstitial water (of sediment) chemistry after
disposal (16). A return of predisposal conditions took from 30 to 90 days.
It should be kept in mind that the sediments were eroding and being compacted
and/or reworked after disposal. This process in itself could bring about
various changes in interstitial water chemistry.
The greatest chemical effect of disposal appears to have been observed in
the sediment. Following disposal, nutrients increased in the sediment, but
metals (except mercury) decreased. This effect is not surprising as it re-
flects the relative concentrations of nutrients in lake sediments and harbor
sediments.
Overall interpretation of the results of sediment chemistry are difficult
because of the behavior of dredged material when released and of the natural
343
-------
lake sediments. Rather than there being an overlay of dredged material upon
natural lake bottom, the physical impact of the dredged material striking the
bottom resulted in bottom currents. These currents pushed lake bottom to the
periphery of the study area and on top of previously deposited dredged mater-
ial. Hence, alternating series of dredged material and natural bottom result-
ed, with subsequent compaction and reworking serving to further obscure dif-
ferences between the two sediment types.
Disposal operations at Ashtabula had essentially no measurable impact
upon planktonic organisms (16). Benthic organisms were impacted in several
ways. There was no change in the number of species present in the disposal
area following disposal, but there were a number of changes in species compo-
sition, with new species transported from the harbor replacing those which had
been eliminated. In addition, there was a large increase in the number of
organisms in the disposal area. Many of the changes did appear to be initi-
ally confined to the immediate area of disposal. As erosion spread the
dredged material over a larger area, faunal changes in the expanded area were
observed. Of interest was the finding that gross animal groups (such as the
family level of identification) were not sufficient to determine impacts;
rather, an examination at the species level was required.
Adults and young of pelagic fish did not appear to be impacted by dispo-
sal. However, bottom-dwelling fish showed a negative response to disposal and
migrated from the area. Within an hour after disposal these fish had migrated
back into the disposal area. Overall, the effects of disposal upon fish were
of small magnitude and only persisted for a short period of time.
Heavy metals in fish and invertebrates, as presented in Tables 11 and 12,
showed little change as a result of disposal. The relative concentration of
metals in fish were the same as those observed in the sediment, whereas a
decrease was noted in some of the invertebrates. Hence, bioaccumulation did
not occur.
ESTUARINE SITE
The Duwamish River enters Elliott Bay, a part of Puget Sound (Figure 2).
The entire river is tidal with horizontal and vertical variations in salinity.
These depend upon tidal stage and river discharge. Low (<3-mg/l) dissolved
oxygen concentrations occur near the bottom of the river. Although quite
important as a waterway, the Duwamish is also a major migration route for
salmon and trout.
Elliott Bay is a rather typical estuarine system with a surface layer of
low salinity water being present over a deeper layer of more saline water.
During the summer, density stratification is present but in the winter colder
freshwater from the waterway entrains and mixes with warmer saline water.
Hence, there is usually no stratification in the winter. Because it is an
estuary, water column chemical constituents tend to be rather variable. The
waterway has created an underwater delta along the south side of the bay. The
deltaic sediments consist mainly of silty sand mixed with wood and other
organic debris. The dominant demersal fish in the bay during the winter are
assorted soles, and the dominant benthic invertebrate is the pink shrimp.
Worms and various mollusks are also important components of the bottom fauna.
344
-------
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345
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REFERENCE
SITE B
EXPERIMENTAL
DISPOSAL SITE
4
REFERENCE
SITE A
MOUTH OF DUWAMISH
D
44
.V DUWAMISH
RIVER '
DUWAMISH.-.
RIVER
STATIONS
Figure 2. Locations of Duwamish Waterway disposal and reference sites,
Puget Sound, Washington.
346
-------
Dredging has ordinarily been done in the waterway with an hydraulic pipe-
line dredge and upland disposal has been used. However, the increasing cost
of upland disposal required a shift to the use of mechanical dredging and
open-water disposal with barges. In 1974, there was a spill of almost 1000 1
of PCBs at Slip 1, in the maintenance dredging area of the river. The highly
contaminated sediments were hydraulically dredged and placed in an impervious
containment area (17) while the remaining, less contaminated material was
removed by a clamshell dredge, placed in barges, and transported to the exper-
imental disposal site. The dredging and disposal of the highly contaminated
sediments were carefully monitored by the Environmental Protection Agency
(EPA). The EPA found that there was a minimal release of metals, nutrients,
and hydrocarbons (17).
The ADFI was divided into four phases: a pilot survey and predisposal,
disposal monitoring, and postdisposal studies. During the pilot survey, an
experimental disposal site was chosen for disposal, and two reference sites
(to the east and west) were selected to provide comparative data (Figure 2).
The studies were initiated in 1975 and completed in 1976.
Physical investigations conducted for the various phases included grain
size analyses and measurements of currents, waves, light transmission, fall
velocity of dredged material, and the vertical distribution of dredged mater-
ial in the water column following disposal. In addition, sub-bottom profiles
and the overall bathymetry of the area were obtained to estimate the volume of
material disposed of at the site.
Chemical studies were carried out on the water column and the sediments.
Variables measured in the water column included temperature, turbidity, sus-
pended solids, dissolved oxygen, pH, salinity, nutrients, PCBs, and heavy
metals. Several approaches were employed in the measurement of sediment
variables. These were bulk analysis, interstitial water, and elutriate tests.
In all cases, PCBs and heavy metals were evaluated. Nutrients were analyzed
only in interstitial water and during the elutriate testing. Bulk analyses
included percent water, volatile solids, organic carbon, sulfides, Eh, pH, and
oi1 and grease.
Bottom grabs were taken to characterize the types, abundance, and biomass
of benthic organisms. Dermersal organisms were collected by trawling and were
analyzed in terms of species composition, number/unit of effort, length, and
weight for dominant finfish. Diet studies for finfish were also undertaken.
The concentrations of PCBs and heavy metals in the tissue of fish and shrimp
were determined to evaluate uptake and/or bioaccumulation of these substances.
In addition, organisms were suspended in cages over the disposal mounds to
examine toxicty and uptake of contaminants.
Findings
The dredged material was an oily, black, fine organic silt with a plastic
texture. It was found to leave the disposal barge in clumps or as a well-
defined mass and fall to the bottom with velocities of up to 180 cm/sec. Upon
impact with the bottom, a dense surge of material flared outward at about 36
cm/sec and could be detected more than 200 m from the point of impact. Sus-
347
-------
pended solids returned to ambient conditions within 10 min, but a slight
reduction in light transmittance persisted for several hours (18).
The disposal of 114,000 m3 resulted in numerous mounds 2 to 3 m in height
with a maximum radius of approximately 200 m. Subsequent chemical analyses
for PCBs at 6 and 9 months after disposal indicated that the mound was gradu-
ally spreading (18). This movement was probably brought about by currents
gradually redistributing the dredged material. The spreading was not of
sufficient magnitude to move the contaminated sediments beyond the boundaries
of the disposal site.
The majority of chemical changes in the water column during disposal were
relatively minor (18). There were increases in dissolved manganese, ammonia,
phosphorous, and total PCBs. These changes occurred with increases in sus-
pended particulate matter, and, when particulate matter decreased, so did the
concentrations of contaminants. The increase in particulate matter and asso-
ciated chemical variables was of extremely short duration, usually less than
30 minutes. It is of interest that, prior to disposal, the concentrations of
PCBs in the water column exceeded EPA criteria and these concentrations in-
creased after disposal. It is possible that PCBs were entering Elliott Bay
from the Duwamish Waterway and had approached equilibrium saturation values
prior to disposal.
As would be expected, the chemical changes observed in the sediment are a
reflection of the nature of the dredged material (18). Metals, nutrients,
PCBs, and oil and grease were present in the disposal area sediment in greater
concentrations after disposal than before disposal.
A number of biological variables were investigated during the Duwamish
ADFI and a few showed major changes as a result of disposal. The number of
species, density, biomass, and diversity of benthic invertebrates at the
disposal site were depressed after disposal (when compared to predisposal
values) (18). These effects were most apparent for the central stations of
the disposal site and least noticeable for the corner stations. Some de-
creases in the above parameters were also noted at the two reference stations.
Nine months after disposal the number of species present at the disposal site
was comparable to the numbers present at the two reference sites although the
biomass values continued to be depressed for the central and side stations of
the disposal site. There was evidence that animals at the edges of the disp-
osal site were stimulated by the dredged material.
As presented in Tables 13 and 14, there was essentially no uptake of
metals or PCBs by fish or most invertebrates analyzed during and after the
disposal operations. Pre- and post-disposal specimens were collected from the
disposal site and locations outside Elliott Bay (18). In addition, caged
animals were held at the disposal site for up to 3 weeks. Mussels held in
cages at the disposal site accumulated PCBs to levels above background but the
increase was not statistically significant. It should be pointed out, how-
ever, that some of the animals collected from Elliott Bay prior to disposal
contained substantial amounts of PCBs so a slight uptake may not have been
statistically significant.
348
-------
TABLE 13
MERCURY AND CHROMIUM CONCENTRATIONS IN SEA CUCUMBERS
Exposure
(weeks)
0
1
2
3
Exposure
(days)
0
3
3
7
Exposure
(weeks)
0
2
5
14
27
39
Sample
XIXIXI XI
MERCURY
Sample
XIXIXI XI
MERCURY AND
Sample
X
X
X
X
X
1
Mercury, ppm
Disposal West
Site Reference
Predisposal
0.01 0.01
Postdisposal
0.01 0.01
0.01 0.01
0.01 0.01
AND CHROMIUM CONCENTRATIONS
Mercury, ppm
Disposal West
Site Reference
Predisposal
0.06 0.06
During Disposal
0.06
0.06
0.07
CHROMIUM CONCENTRATIONS IN
Mercury, ppm
Disposal West
Site Reference
Predisposal
0.08 0.06
Postdisposal
0.06 0.06
0.07
0.05 0.06
0.04 0.05
0.04 0.05
Chromium
Disposal
Site
0.32
0.26
0.26
0.26
IN SPOT SHRIMP
Chromium
Disposal
Site
0.64
0.62
0.61
ALASKA PINK SHRIMP
Chromium
Disposal
Site
0.83
0.68
0.63
0.55
0.50
0.62
, ppm
West
Reference
0.32
0.24
0.24
0.24
, ppm
West
Reference
0.64
0.57
, ppm
West
Reference
0.63
0.62
0.67
0.58
0.70
349
-------
TABLE 14
PCBs IN MUSSELS (Mytilus edulis) EXPOSED AFTER DISPOSAL
West Reference Site:
Disposal Site:
Exposure (weeks)
0
1
2
3
1
2
3
Mean ppm
0. 122
0.103
0.131
0.100
0.108
0.200
0.206
PCBs IN SPOT SHRIMP (Pandalus platyceros) EXPOSED DURING DISPOSAL OPERATIONS
Exposure (days) Mean ppm
West Reference Site:
Disposal Site:
0
7
3
3
0. 174
0.190
0.208
0.185
PCBs IN ENGLISH SOLE (Parophyrys vetulus)
Sampling period Mean ppm
West Reference Site: Before Disposal: 2.28
After Disposal:
2 weeks 0.65
1 month 0.87
3 months *
6 months *
9 months 5.90**
Disposal Site: Before Disposal: 2.58
After Disposal:
2 weeks 0.74
1 month *
3 months *
6 months *
* = No samples.
** = One samp le only.
350
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Demersal fish and shellfish (shrimp) seemed to ignore disposal. (here
were fewer present during disposal at the disposal site than at the east
reference site but about the same number as at the west reference site. After
disposal the number of fish decreased at the disposal site and at both refer-
ence sites; this decrease suggests a seasonal change in these organisms rather
than an impact of disposal (18). The number of shrimp captured at the dispo-
sal site after disposal increased compared to those obtained prior to dispo-
sal. Shrimp at the reference sites either remained at the same level (east
reference site) or increased erratically from month to month (west reference
site). Overall, more shrimp were found at the disposal site after disposal
than at either reference site, indicating that the shrimp were attracted to
the disposal site.
SUMMARY
LABORATORY INVESTIGATIONS
Research results show that in general dredged material in the United
States is not as toxic to aquatic organisms as originally conceived, based on
bulk sediment analysis. Nevertheless, some sediments are toxic and disposal
of these sediments may cause environmental harm.
DMRP Work Unit 1D06 (4) evaluated the possibility of obtaining a chemical
extraction method for sediments which would reflect the availability of heavy
metals to organisms. Studies to date have not produced such a technique, and
there is no chemical method for environmental impact evaluation of dredged
material prior to its disposal. DMRP Work Unit 1D11 (11) showed that although
oil and grease levels could be high in sediments, a large part of what is rou-
tinely reported as oil and grease may be harmless elemental sulfur, and a
large part of the hydrocarbon burden of sediments is not released from sedi-
mentary particles nor is it available for gross uptake into the aquatic organ-
isms tested.
Bioaccumulation by itself is difficult to interpret in terms of toxicity.
Accumulation of a known toxicant in a human food source is of obvious impor-
tance. Components can be transferred through aquatic food chains with biomag-
nification. Accumulation may stress the organism and make it more susceptible
to disease or predation. Necessary energy may have to be diverted into detox-
ification mechanisms. Lowered fecundity and abnormal larval development will
ultimately have effects on species abundance and population dynamics within
localized systems. These kinds of sublethal effects can culminate in an unex-
plainable population decline over an extended period of time.
FIELD INVESTIGATIONS
Freshwater site
There were but few important impacts as a result of dredged material dis-
posal at the Ashtabula disposal site. Some chemical changes were observed,
but these were of small magnitude and transient in nature. There were changes
in the benthic community which persisted throughout the study; these primarily
351
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consisted of species replacement and an increase in the abundance of some
organisms. Because these benthic organisms are of importance as food for
fish, these changes would be of concern were it not that the feeding activi-
ties of fish in the area did not seem to be altered.
Estuarine Site
Disposal of material contaminated with PCBs in Elliott Bay during the
Duwamish Waterway ADFI appeared to have a minimal impact. A disposal mound
was created which gradually spread during the postdisposal period. There were
minor changes in the chemistry of the water column. These appeared to be as-
sociated with a transitory increase in suspended particulate material, and, as
soon as this material had settled, values for chemical parameters returned to
predisposal conditions.
There was no significant uptake of PCBs or metals by organisms inhabiting
the disposal area or by caged animals which were held in close proximity to
the disposed material for up to 3 weeks. Some changes were noted in the
abundance, diversity, and species composition of benthic invertebrates in the
disposal area; however, similar changes in the reference area populations make
it unlikely that disposal was wholly responsible for the changes.
APPLICATION AND REGULATION
The conceptual problem of toxicants associated with sediments must be
evaluated in light of valid chemical and biological data describing the avail-
ability of toxicants to organisms and the water column prior to determining
effects of such toxicants (2). Information must then be gained as to the
effects of specific substances on organism survival and function. Many mater-
ials previously regarded as toxicants are not readily desorbed or released
from sediment attachment and are thus less toxic than in the free or soluble
state, on which most toxicity data are based.
Prater and Anderson (19), using a 96-hr bioassay technique with four
different species or organisms, evaluated the toxicity of sediments from the
Ouluth, Minnesota-Superior, Wisconsin harbor. Sediments could be broadly
classified on an arbitrarily selected scale as nonpolluted, moderately pol-
luted, and heavily polluted using the bioassay. The results of an array of
chemical analyses also led to an arbitrary designation of nonpolluted, moder-
ately polluted, and heavily polluted sediments. In 75 percent of the cases
chemical analyses supported bioassay results, but they were unable to identify
the causal chemical factor for mortality. Concentrations of chemicals thought
to be pollutants varied from one station to another and were not always high-
est at stations producing highest mortalities. Toxic properties of sediments
could have been due to the action of one or more pollutants acting together
(synergism) or to unidentified contaminants, particularly organic compounds.
This strongly argues for the use of a whole-sediment bioassay to determine
potential toxicity of dredged material for disposal (20). Although the sug-
gested procedures have yet to be fully evaluated under a wide spectrum of
environmental conditions, experience will undoubtedly validate this type of
test over the long term.
352
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There are now cogent reasons for rejecting many of the conceptualized im-
pacts of disposed dredged material regarding potential toxicity based on clas-
sical bulk analysis determinations. It is invalid to use total sediment con-
centration to estimate contaminant levels in organisms since only a variable
and undetermined amount of sediment-associated contaminants is biologically
available. Although a few instances of uptake of possible ecological conse-
quence have been seen, the fact that uptake depends on species, contaminants
salinity, sediment type, etc., argues strongly that bulk analysis does not
provide a reliable index of contaminant availability and potential ecological
impact of dredged material.
REFERENCES
1. Fpurth Annual Report: Dredged Material Research Program, Environmental
Laboratory, USAE Waterways Experiment Station, Vicksburg, MS, Jan 77.
2. Hirsch, N. D. , DiSalvo, L. H. , and Peddicord, R., 1978. "Effects of
Dredging and Disposal on Aquatic Organisms," Tech. Rept. DS-78-5, USAE
Waterways Experiment Station, Vicksburg, MS.
3. Wright, T. D. , "Aquatic Dredged Material Disposal Impacts," Tech. Rept.
DS-78-1, 1978, USAE Waterways Experiment Station, Vicksburg, MS.
4. Neff, J. W. , Foster, R. S., and Slowey, J. F. "Availability of Sediment-
adsorbed Heavy Metals to Benthos with Particular Emphasis on Deposit
Feeding Benthos," Tech. Rept. D-78-42, 1978, USAE Waterways Experiment
Station, Vicksburg, MS.
5. DiSalvo, L. H. , et al. , "Assessment and Significance of Sediment-associa-
ted Oil and Grease in Aquatic Environments," 1977. Tech. Rept. D-77-26,
USAE Waterways Experiment Station, Vicksburg, MS.
6. Brannon, J. M. , "Evaluation of Dredged Material Pollution Potential,"
Tech. Rept. DS-78-6, USAE Waterways Experiment Station, Vicksburg, MS.
7. Anderlini, V. C. , Chapman, J. W. , Girvin, D. C. , McCormick, S. J. ,
Newton, A. S. , and Risebrough, R. W. , "Heavy Metal Uptake Study, Dredge
Disposal Study, San Francisco Bay and Estuary, Appendix H: Pollutant Up-
take Study," 1976, U.S. Army Engineer District, San Francisco, CA.
8. Simms, R. R. , Jr., and Presley, B. J. , "Heavy Metal Concentrations in
Organisms from an Actively Dredged Texas Bay," Bull. Environ. Contam.
Tpxicol., Vol 16, No. 5, pp 520-527.
9. Peddicord, R. K. , and McFarland, V. A., "Effects of Suspended Dredged
Material on Aquatic Animals," Tech. Rept. D-78-29, July 1978, by Bodega
Marine Laboratory, University of California, under contract to USAE
Waterways Experiment Station, Vicksburg, MS.
10. Peddicord, R. K. , McFarland, V. A., Belfiori, D. P., and Byrd, T. E. ,
"Effects of Suspended Solids on San Francisco Bay Organisms," 1975,
353
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Dredge Disposal Study, San Francisco Bay and Estuary, Appendix G: Physi-
cal Impact Study. U.S. Army Engineer District, San Francisco, CA.
11. DiSalvo, L. H. , Guard, H. E. , Hirsch, N. D. , and Ng, J. , "Assessment and M
Significance of Sediment-Associated Oil and Grease in Aquatic Environ-
ments," Tech. Rept. D-77-26, November 1977, prepared by Naval Biosciences
Laboratory, Naval Supply Center, Oakland, CA, under contract to USAE
Waterways Experiment Station, Vicksburg, MS.
12. DiSalvo, L. H. , Guard, H. E. , and Hunter, L., "Tissue Hydrocarbon Burden
of Mussels as a Potential Monitor of Environmental Hydrocarbon Insult,"
Environ. Sci. Techno!. , 1975, Vol 9, pp 247-251.
13. Nathans, N. W. , and Bechtel, T. J. , "Availability of Sediment-Adsorbed
Selected Pesticides to Benthos with Particular Emphasis on Deposit-Feed-
ing Infauna," Tech. Rept. D-77-34, Nov 77, prepared by LFE Corporation,
Environmental Analysis Laboratories, Richmond, CA, under contract to USAE
Waterways Experiment Station, Vicksburg, MS.
14. Fulk, R. , Gruber, D. , and Wullschleger, R., "Laboratory Study of the Re-
lease of Pesticide and PCB Materials to the Water Column During Dredging
and Disposal Operations," Contract Rept. D-75-6, Dec 75, prepared by
Envirex, Inc., Environmental Sciences Division, Milwaukee, WI, under con-
tract to USAE Waterways Experiment Station, Vicksburg, MS.
15. Anderlini, V. C., Chapman, J. W., Newton, A. S., Risebrough, R. W., "Pol-
lutant Availability Study, Dredge Disposal Study, San Francisco Bay and
Estuary, Appendix I: Pollutant Availability," 1976, U.S. Army Engineer
District, San Francisco, CA. A
16. Sweeney, R. A., "Aquatic Disposal Field Investigations Ashtabula River
Disposal Site, Ohio," Tech. Rept. D-77-42, 1977, USAE Waterways Experi-
ment Station, Vicksburg, MS.
17. Blazevich, J. N., et al. , "Monitoring of Trace Constituents During PCB
Recovery Dredging Operation - Duwamish Waterway," 1977, U.S. Environmen-
tal Protection Agency Rept. 910/9-077-039, Region X, Seattle, WA.
18. Tatem, H. E. , and Johnson, L. H. , "Aquatic Disposal Field Investigations
Duwamish Waterway Disposal Site, Puget Sound, Washington," Tech. Rept.
D-77-24, 1977, USAE Waterways Experiment Station, Vicksburg, MS.
19. Prater, B. L. , and Anderson, M. A. , "A 96-hour Sediment Bioassay of
Duluth and Superior Harbor Basins (Minnesota) Using Hexagenia 1imbata,
Asellus commum's, Daphnia magna, and Pimephales promelas as Test Organ-
isms," Bull. Environ. Contam. Toxicol., Vol 18, No. 2, pp 159-169.
20. EPA/CE Technical Committee on Criteria for Dredged and Fill Material,
"Ecological Evaluation of Proposed Discharge of Dredged Material into
Ocean Waters; Implementation Manual for Section 103 of Public Law 92-532
(Marine Protection, Research, and Sanctuaries Act of 1972)," Jul 77, pub-
lished by the Environmental Laboratory, USAE Waterways Experiment Sta-
tion, Vicksburg, MS.
354
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MANAGEMENT OF CONTAINMENT AREAS TO
PROMOTE DEWATERING AND SOLIDIFICATION
C. C. Calhoun, Jr.
Environmental Laboratory
U.S. Army Engineer Waterways Experiment Station
Vicksburg, Mississippi 39180
ABSTRACT
Methods developed by the Dredged Material Resarch Program to manage
dredged material containment areas to increase their service lives are dis-
cussed. Emphasis is placed on dewatering fine-grained dredged material by
making maximum use of evaporation. Results of laboratory and a major field
study are given. Methods of predicting dewatering attainable from evaporation
are depicted.
BACKGROUND
In papers presented at the previous two meetings (1, 2), information was
given on research being conducted as part of the U.S. Army Corps of Engineers'
Dredged Material Research Program (DMRP) on methods to dewater/densify dredged
material. These papers were prepared at a time when the research was in
progress and consequently complete results, conclusions, and recommendations
could not be given. The 5-year $33 million DMRP was successfully completed in
March and more definitive information can now be given on the results of these
studies.
The results of the DMRP are being published in over 200 technical re-
ports. However, final results and guidelines from the program are being pub-
lished in a series of 21 concise synthesis reports and most of the synthesis
reports will also be published as Corps of Engineers' Engineering Manuals.
Each synthesis report presents guidelines in one specific area addressed by
the DMRP. One of these reports (3) represents the final DMRP guidelines on
the management of disposal areas to maximize their service lives through de-
watering/densifying the dredged material. As pointed out in the earlier
papers (1, 2), the primary purpose of densifying the material is to gain the
additional capacity of the site that would have been otherwise occupied by
water. Since dewatering coarse-grained material and silts of low plasticity
yield little or no additional volume reduction of the material, emphasis in
the program was placed on dewatering fine-grained material. Although the
specific purpose of dewatering (in the DMRP context) is to reduce the volume
of and not to stabilize the material, dewatering usually results in the mater-
ial having greatly improved engineering properties (e.g., higher strength, low
355
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compressibility, etc.)- Consequently, in many cases, dewatering/densifying
dredged material is synonymous with stabilizing the material.
GENERAL MANAGEMENT CONCEPTS
INTRODUCTION
Most concepts involving long-term disposal site management will result in
increased capital construction and manpower/administrative cost. However, in
most instances, the unit disposal cost of operating the site over the design
life will be equal to or lower than cost for an unplanned operation. Thus,
when incorporating the subsequently described procedures in an overall plan,
the total cost, both short- and long-term, of concept implementation should be
considered.
Application of any general concept to a given disposal site is a site-
specific design problem. Whether or not any concept will prove feasible can
only be determined after careful planning and study, not only of the concept
itself, but of the alternatives to and constraints involved in concept imple-
mentation.
THIN LIFE PLACEMENT
The most economical dewatering mechanism is Mother Nature, through the
evaporative process (4). The rates at which various soils will dewater
through evaporation were studied in detail (5). The depth to which a layer of
fine-grained dredged material will dewater is a function of the net evapora-
tion at the site. The net evaporation is equal to the total evaporation over
a given period of time minus the precipitation during that same period. In
many areas the net evaporation is small and in fact is negative in areas where
precipitation exceeds evaporation. The latter condition is common in many
coastal areas.
In order for dredged material to dewater with no active dewatering tech-
niques applied, the thickness of the lift placed in the containment area in
general should not exceed the water loss available from about half of the net
evaporation during the period from deposition to placement of the next lift.
In some areas net evaporation available at particular times during the total
period should be considered. For instance if the lift is to remain in the
disposal area for one year before another lift is placed there may be several
months where the net evaporation is considerably greater than the average for
the entire year. During this time a desiccation crust on fine-grained dredged
material will develop. Once a crust forms, subsequent wetting will not cause
the crust to revert to the original near liquid state. Consequently, there
may be crust formation and thus dewatering/densification in areas where the
average net evaporation is low or negative.
It is recognized that in most instances it is not possible to place
dredged material in extremely thin lifts because of the limited land area
available for containing relatively large volumes of dredged material. In
some cases the situation can be improved through such techniques as carefullly
selecting the time of year (maximum net evaporation) for placement, the use of
356
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compartments within the area to increase the length of time the material will
be in the area prior to placement of the next lift. These and other tech-
niques are discussed in detail in References 3 and 6. In subsequent parts of
this paper methods for taking advantage of rates approaching the total evapo-
ration rate will be discussed.
OTHER MANAGEMENT CONCEPTS
Thin lift placement of fine-grained dredged material is the most economi-
cal management scheme when specific site conditions prmit. As man's input of
energy into the system increases, costs also increase. As part of the DMRP,
several techniques for dewatering fine-grained dredged material were consid-
ered and evaluated to varying degrees. The controlling factor in establishing
feasibility was almost always economics. If the cost of dewatering the mater-
ial exceeds the cost of constructing and using a new site, the dewatering
technique is in general not feasible. However, this is a site-specific factor
and what is not economically feasible in one area may be feasible in another
area. In some instances, environmental concerns are paramount and costs are
secondary to assuring the dredged material is contained in a specific area.
In the earlier papers (References 1 and 2), the dewatering techniques
being considered in the DMRP were discussed in some detail and indepth discus-
sion of all of the techniques will not be given here. Techniques considered
were:
1. Progressive Trenching
2. Vacuum Wellpoints
3. Windmill Power Feasibility of Vacuum Wellpoints
4. Sand Slurry Injection
5. Natural Freezing and Thawing
6. Mechanical Crust Stabilization
7. Underdrainage
8. Low Voltage Gradient Electro-Osmosis
9. Vegetation Dewatering
10. Capillary Wicks
All of the techniques were successful to varying degrees. Details of the
various studies and results are presented in References 7 and 8. The most
universally applicable technique appeared to be progressive trenching where
trenches are placed in the fine-grained dredged material to rapidly remove
surface water plus increasing the effective evaporation rate.
EVAPORATION DRYING
During the early phases of the DMRP it was noted that a relatively thin
crust usually developed over the underlying soft, wet fine-grained dredged
material confined to a disposal area. It was assumed that this crust devel-
oped and retarded or eliminated any further evaporative drying by sealing the
underlying material from the evaporative processes. It was noted, however,
that in some instances the crust developed to relatively great depths and in
some cases the crust would be as much as 15 feet thick (9).
357
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A close evaluation of the site revealed that the confined disposal areas
generally acted as "bath tubs" and water entering them through precipitation
or other sources could not be removed except through evaporation. It was ^
further noted that in areas where the net evaporation was high or where sur- fl
face water was allowed to drain the crust thicknesses were much greater. As a
result of these observations an extensive study of the mechanisms of crust
development were made (5).
The laboratory and controlled field studies (5) revealed that the crust
in fine-grained dredged material did not seal off the underlying soft material
from the evaporative process. As the desiccation crust develops, cracks also
develop. In most cases water would continue to be removed from these cracks
by the evaporative process and the cracks will continue to develop as long as
the water supplied by capillarity was less than the evaporative demand.
Consequently, the desiccation cracks can extend to considerable depths and
dewatering of the fine-grained dredged material will also continue to these
depths.
When fine-grained dredged material is placed hydraulically in a contain-
ment area approximately four volumes of make-up water are required for a given
volume of i_n situ sediment. Most of this water is drawn off the area through
some type of sluice. In studies of fine-grained dredged material exhibiting
various engineering properties, it was found that after the surface water was
removed cracks would begin to develop as the water content of the material
reached approximately 1.8 times the Atterberg liquid limit (LL) (5). This
condition is referred to as the "decant point." The 1.8 LL is a statistical
average and of course can vary from material to material.
As the desiccation cracks develop the average water content of the re- I
suiting polygons was found to be approximately 1.2 times the Atterberg plastic
limit (PL). Again, the 1.2 PL is only a statistical average and may vary. As
shown in Figure 1, the volume reduction through removal of water is linear and
the slope of the straight line is the coefficient of shrinkage, C . The
relation remains linear until the water content approaches the Atterberg
shrinkage limit (SL). The desiccation cracks were found to account for as
much as 20 percent of the total volume change. The rate of water loss through
evaporation was found to vary depending on whether the dredged material was
derived from marine or freshwater sediments. For marine or saltwater dredged
material the estimated water loss in inches, centimeters, etc., is equal to
about 35 percent of the effective evaporation rate while for freshwater the
loss is approximately 50 percent of the effective evaporation rate. In order
to take maximum advantage of evaporative drying, surface water must be re-
moved. This includes removal of surface water that is held in the desiccation
cracks. A technique for removing surface water was developed by the DMRP and
will be discussed in detail in this paper.
PROGRESSIVE TRENCHING
BASIC CONCEPT
The desiccation cracks formed in fine-grained dredged material are inter-
connecting and thus a system of trenches within a disposal area will remove
358
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Figure 1. Typical linear shrinkage curve for dredged material tested (from
Reference 4).
water from both the surface and from the cracks if the flow "line of the
trenches is below the bottom of the cracks. Since the material underlying the
crust is at or above its LL a trench much deeper than the crust thickness
cannot be maintained. Consequently, as the desiccation cracks deepen the
trenches must also be progressively deepened to assure the water in the cracks
will be drained.
The progressive trenching concept lowers the surface elevation of the
dredged material through three mechanisms. The first is through shrinkage of
the upper material in the crust. Second, the progressive lowering of the
perched water table in the containment area increases the effective stress
acting on the soft underlying dredged material thereby causing it to consoli-
date. The third mechanism depends on the foundation material and water table
conditions. If the foundation material is relatively soft and the perched
water table connects with the foundation water table, the increased effective
stresses from lowering the perched water table will cause the foundation to
consolidate.
TRENCHING TECHNIQUES
The major problem associated with the progressive trenching concept is
the construction of the trenches themselves. At the decant point the material
is too soft to support conventional equipment such as draglines. Equipment
for operation in disposal areas was evaluated as part of the DMRP (10). Only
one piece of equipment was found that could operate in the soft dredged mater-
ial and rapidly produce trenches. The Riverine Utility Craft or RUC (Figure
2) was found to be suitable if not ideal for use. The RUC produces
trenches with the tracks formed by the rotors. The RUC was described in
detail in an earlier paper (2).
In many respects the RUC is similar in appearance and operational charac-
teristics with the Dutch-made Amphirol. However, the RUC is a much heavier
vehicle and the rotors are over three times larger, making the RUC a much more
effective trenching tool. The Dutch use the Amphirol in the "ripening" proc-
359
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ess of dredged material placed in polders (11). The ripening process is
similar to the progressive trenching technique.
In the progressive trenching technique initial shallow trenches are made
after the material reaches the decant point. The trenches are progressively
deepened as required with the RUC until the trenches are about two feet deep,
the limit of the RUC's effectiveness. With two feet of crust other more
conventional equipment can be selected using procedures outlined in Reference
10 to continue the deepening process. Details of the trenching techniques are
given in Reference 3.
FIELD TESTS
The progressive trenching technique was field evaluated at the Upper
Polecat Bay (UPB) disposal site in Mobile, Albania (4). The 85-acre site
filled with 8 to 12 feet of fine-grained dredged material was described in
Reference 2 along with the general plan of tests.
Computations were made based on extensive data collected at UPB to pre-
dict the dredged material surface settlement or volume gain in the site. The
perched water table at the UPB site did not connect with the foundation water
table. Consequently foundation consolidation was not considered and because
of the soft nature of the material, rebound of the foundation was not expected
and did not occur as the perched water table was lowered. Containment area
volume gain was expected only from shrinkage of the crust and dredged material
consolidation.
Average data used to predict shrinkage and consolidation are shown in
Figure 3. The settlement due to shrinkage was determined from the following
relationship:
AH = Hr^ (1)
s
Where AH = Settlement due to shrinkage.
H = Thickness of strata.
Aw = Average change in water content, percent.
C = Coefficient of shrinkage.
Since the dredged material had been placed several years prior to initiating
dewatering, the water content of the material was at about its LL. Also, data
indicated that average water content of the polygons would be about at the PL
(as opposed to the statistical average of 1.2 PL discussed earlier). Aw
was then taken to be equal to LL-PL. The average C was 2.34. Predicted
shrinkage as a function of drawdown is shown in Figure 4.
Conventional theories were used to compute expected settlement from
consolidation of the soft dredged material (4). The resulting consolidation
as a function of drawdown is shown in Figure 5. The coefficient of consolida-
tion of the material was computed to be 0.3 cm2/sec which indicates that
dredged material consolidation would reach 90 percent of total primary consol-
idation approximately two months following imposition of load.
361
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ro T3
!-> en
C 3
ai in
+-> s-
o ai
Q- >
CD
S-
a>
363
-------
Total predicted settlement is shown in Figure 6. Because of the rela-
tively short time required for the material to consolidate, total settlement
was the sum of that from shrinkage and consolidation at a given drawdown.
Field data (also plotted on Figure 6) show that the predicted settlements were
less than those observed in the field. The difference in the predicted and
observed behavior was not great and the predicted values were on the conserva-
tive side. Therefore, the analytical technique appears acceptable.
PREDICTION EQUATIONS
The following equations have been developed to predict dewatering effects
once the dredged material has reached the decant point. The approximate
thickness, in feet, of dredged material at the end of the decant phase
when surface drainage improvement should be initiated, is given by
H
dm'
dm
cs
% sand
100
["
43
% sand\
100 ;
,560Ads
w ,-i
cd
WcsJ
(2)
where
V = volume of channel sediment to be dredged, cu yd.
sana = percentage of sand in the channel sediment.
w , = average water content of the dredged material at the end of
the decant phase, percent.
w
,cs
= average water content of the channel sediment, percent.
A , = area of the disposal site, acres.
In lieu of better data, especially if the calculation is made prior to dredg-
ing, w , may be taken at 1.8 x LL, and Equation 2 may be written as
(3)
Effect of evaporative dewatering
The estimated water loss, in inches, from evaporative dewatering AW is
given by the relationship
u - p7\/
dm cs
% sand
100
/1 % sand^
[(1 100 '
1.8 LL
w
cs J
43.560A
ds
0.35Ep
for saltwater dredged material and by
AW = 0.50Er
(4)
(5)
for freshwater dredged material, where Ep is the Class A Pan Evaporation (see
Reference 3) for the dewatering interval.
The depth, in inches, to which the initial thickness of dredged material
will be dewatered H. is given by
364
-------
AVERAGE FIELD SETTLEMENT
STA. 10 + 00 to 24+00
PREDICTED SETTLEMENT
I
I 2 3
DRAWDOWN IN FEET
Figure 6. Potential settlement versus drawdown and field results.
w
H. =
w
cr
AW
cr
O.Olw
cd s
(6)
where w = average water content of the dewatered dredged material
cr
(crust), percent.
G - specific gravity of the channel sediment/dredged material
sol ids.
In the absence of better data, w , may
assumed as 1.2 x PL. In such a case,
be assumed as 1.8 x LL, while wrio may be
Equation 6 becomes
cr
H-l-5^
AW
(1.5^ - 1)
(1
0.018LLG2
(7)
365
-------
Vertical subsidence, in inches of the dredged material surface H is
computed as
HS =
AW
dc
100
(8)
where P , is the percentage of total dewatering volume gain due to the vol
of the space between desiccation cracks. In lieu of better data, P^ may
taken as 20 percent, and Equation 8 becomes
ume
dc may be
M *-*"
Hs ~ T72
The crust thickness, in inches, formed by desiccation H is given by
H = H. - H (10)
cr i s ^ /
The estimated volume gain, in cubic yards, from evaporative dewatering
shrinkage V , is computed by
u - A AW
gd " AdsAW
43>560
100 ' 12(27)
Effect of increase effective stress consolidation
(11)
P
Gs(l
1 +
+0.01wcd)
O.Olw ,G
cd s
* k - H.
*w / dm i
12 I 2 "i
The average initial effective stress, in pounds (force) per square foot,
at the center of the undewatered dredged material (subcrust) layer P. is
estimated as ]
(12)
where y is the unit weight of sale or freshwater, in pounds (force) per cubic
foot. In lieu of better data, w , may be taken as 1.8 x LL, and Equation 12
becomes
(13)
The increase in effective stress, in pounds (force) per square foot, from
water table lowering Ap is approximated by
Ap = HiYw (14)
The approximate consolidation settlement, in inches, resulting from
increased effective H is approximated by
D
r -
G (1 + 0.018LL)
s 1
1 + 0.018LLG
Yw fdm Hi ,
12 I 2 Hi
- VCc
c 1 + 0.01wcdGs
log
(15)
366
-------
where C is the compression index for the dredged material. If better data
are notc available, w . may be taken as 1.8 x LL, and Equation 15 becomes
(Hdm - H.)CC p. + Ap
Hc = 1 + 0.018LLG log - (16)
s
Additional disposal volume gain, in cubic yards, from subcrust consolida-
tion V is computed from
-HA n - % sancS 43,560
gc cAds (1 ~~m') T2(27)
Total settlement, in inches, of the dredged material surface from de-
watering H, is thus
H. = H + H (18)
t s c '
Total disposal area volume gain, in cubic yards, from dewatering V . is
given as ^
V = V + V (19s)
gt gd V v'y;
The thickness, in inches, of subcrust remaining to be dewatered H is
given by
H = H . - H- - H (20)
r dm i c v '
The volume, in cubic yards, of dredged material available for removal and
productive use V is estimated as
p ds
sand,"! , ,, % sand
cr v' 100 ' dm 100
]
H
43,560
12(27)
,_.
uu
More detailed information on the use of these equations and other re-
quired computation is given in Reference 3 which also contains example prob-
lems. A computer program has been developed to assist with the analyses (12).
SUMMARY
The proper management of disposal areas can increase the service lives of
areas containing fine-grained dredged material. Guidelines have been devel-
oped during the DMRP to aid in developing management plans (3, 13). Work will
continue under the Corps of Engineers1 Dredging Operations Technical Support
program to verify and refine the methodologies.
REFERENCES
1. Calhoun, C. C. , Jr. "Dredged Material Densification and Treatment of
Contaminated Dredged Material," Management of Bottom Sediments Containing
Toxic Substances - Proceedings of the Second U.S.-Japan Experts Meeting,
367
-------
October 1976, Tokyo, Japan. hPA hcological Research Series 600/3-77-U83,
July 1977, EPA Environmental Research Laboratory, Corvallis, Oregon.
2. Calhoun, C. C., Jr. "Densification, Treatment, and Management of Dredged
Material Disposal Areas," Management of Bottom Sediments Containing Toxic
Substances - Proceedings of the Third U.S.-Japan Experts Meeting, Novem-
1977, Tokyo, Japan. EPA Ecological Research Series 600/3-78-084, EPA
Environmental Research Laboratory, Corvallis, Oregon.
3. Haliburton, T. A. "Guidelines for Dewatering/Densifying Confined Dredged
Material," Technical Report DS-78-11, September 1978, U.S. Army Engineer
Waterways Experiment Station, Vicksburg, Mississippi.
4. Palermo, M. R. "An Evaluation of Progressive Trenching as a Technique
for Dewatering Fine-Grained Dredged Material," Miscellaneous Paper
D-77-4, December 1977, U.S. Army Engineer Waterways Experiment Station,
Vicksburg, Mississippi.
5. Brown, K. W. , and Thompson, L. J. "Feasibility Study of General Crust
Management as a Technique for Increasing Capacity of Dredged Material
Containment Areas," Technical Report D-77-17, October 1977, prepared by
Texas A&M Research Foundation, Texas A&M University, College Station,
Texas, for the Environmental Laboratory, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, Mississippi.
6. Bartos, M. J. , Jr. "Containment Area Management to Promote Natural
Dewatering of Fine-Grained Dredged Material," Technical Report D-77-19,
October 1977, Environmental Laboratory, U.S. Army Engineer Waterways
Experiment Station, Vicksburg, Mississippi.
7. Haliburton, T. A. "Dredged Material Dewatering Field Demonstrations at
Upper Polecat Bay Disposal Area, Mobile, Alabama," Technical Report (in
press), U.S. Army Engineer Waterways Experiment Station, Vicksburg,
Mi ssissippi.
8. Chamberlain, D. J. , and Blouin, S. E. "Freeze-Thaw Enhancement of the
Drainage and Consolidation of Fine-Grained Dredged Material in Confined
Disposal Areas," Technical Report D-77-16, October 1977, prepared by
Foundations and Materials Research Branch, U.S. Army Cold Regions Re-
search and Engineering Laboratory, Hanover, New Hampshire, for the En-
vironmental Laboratory, U.S. Army Engineer Waterways Experiment Station,
Vicksburg, Mississippi.
9. Johnson, S. J. e_t al. "State-of-the-Art Applicability of Conventional
Densification Techniques to Increase Disposal Area Storage Capacity,"
Technical Report D-77-4 (Appendices A-C on microfiche), April 1977,
prepared by the Soils and Pavements Laboratory for Environmental Labora-
tory, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Missis-
sippi.
10. Willoughby, W. E. "Assessment of Low-Ground-Pressure Vehicles for Use in
Containment Area Operations and Maintenance," Technical Report D-78-9,
July 1978, U.S. Army Engineer Waterways Experiment Station, Vicksburg,
Mississippi.
368
-------
11. Adriaan Volker Dredging Company. "European Dredging Practices," Techni-
cal Report (in press), U.S. Army Engineer Waterways Experiment Station,
Vicksburg, Mississippi.
12. Hayden, M. L. "Prediction of Volumetric Requirements for Dredged Mater-
ial Containment Areas," Technical Report D-78-41, August 1978, U.S. Army
Engineer Waterways Experiment Station, Vicksburg, Mississippi.
13. Montgomery, R. L. et _a11. "Guidelines for Designing, Operating, and
Managing Dredged Material Containment Areas," Technical Report DS-78-10
(in press), U.S. Army Engineer Waterways Experiment Station, Vicksburg,
Mississippi.
369
-------
IMPACTS OF OIL SPILL AND CLEAN-UP ON THE EUROPEAN COAST: AMOCO CADIZ
William P. Davis
Chief, Bears Bluff Field Station
Gulf Breeze Environmental Research Laboratory
U.S. Environmental Protection Agency
Wadmalaw Island, S.C.
INTRODUCTION
Accidental release of petroleum
transport or transfer from ships will
pollution control and abatement efforts.
Amoco Cadiz wreck on the Brittany coast of
spill resulting from man's
or other hazardous substances during
continue to be a major focal point of
At the time of this writing the
France (Figure 1) represents
actitivies. It occurred on one of
the
the
and
for
largest oil
world's most productive sea coasts in a nation where both technological
scientific skills abound. Heavy weather contributed to both the causes
the wreck and the subsequent spread of the petroleum to over 200 linear kilo-
meters of biologically rich, high energy coastal habitats. From the moment
the French realized the existence of the impending disaster there was a public
mobilization of fishermen, farmers, students, scientists, and clean-up equip-
ment; all attempting to take action appropriate to prepare for the coming of
the "black tide" or "maree noire".
This report attempts to summarize highlights of impacts, ecological
effects, and evolving response efforts of interest to persons living or work-
ing along the shores of the world's oceans. LESSEPTIUES
KERLOUAN
PORTSALL.
ILE d'OUESSANT
LE CONOUET
PTE. deST MATHIEU
PUXJESCAT
A4LABER WRAC'H
L'ABER BENOIT
COB-CNEXO
BREST
Coast of Brittany, showing location
of spilled oil (from Hess, 1978).
371
-------
CHRONOLOGY OF SPILL EVENTS
The Amoco Cadiz (Figure 2) hit rocks one mile (1.6 km) offshore from the
town of Portsall, France on 16 March 1978. The ship's steerage had been lost
and attempts to pull her from the rocks failed as several tow lines parted.
Winds of 40-50 knots contributed to these failures; within six hours the ship
began breaking up, resulting in the release of 216,000 tons of Iranian and
Arabian light crude oil, plus 4,000 tons of fuel into the ocean. During the
next week heavy seas emulsified the escaping petroleum into a stinking
'mousse" and spread the spill over 200 kilometers of the Brittany coast.
ฃf
1,095.91 FT.-
BREAK
BREAK
REGISTRY MONROVIA LIBERIA
OWNER AMOCO TRANSPORT CO
CAU/OFF Nฐ A8AN/4773
POWER 2SA 8CYL DIESEL , 980mm * 2.000mm
22,678Kw/30,400 BMP (SINGLE SCREW)
SPEED 15 25 KTS
MAX DRAFT 65 FT /19 8] M
CAPACITY 233,690 DWT
109,700 GRT
91,000 NET/TONS
ABOVE DATA PER LLOYDS REGISTER
TANK LAYOUT AND VESSEL
DRAWINGS NOT AVAILABLE
Figure 2. General layout and dimensions of Amoco Cadiz showing
locations of breaks (from Hann et aj. , 1978).
Geologically, the Brittany coast is a shield shoreline, underlain by
igneous and metamorphic rock complexes, with headlands, crenulate bays, small
and large beaches, rocky islands, tidal flats, marshes, all representing
widely varied ecological habitats. Although no major rivers enter the area, a
number of "abers" or small rivers are found. Initially, wind moved the petro-
leum in an easterly direction piling oil up against every westward facing
coastal feature, or concentrated it into estuaries with westward facing mouths
or entrances. These westerly winter winds are part of the annual weather
pattern for this part of the ocean, Manche, also known as the English Channel.
372
-------
In early April winds typically swing around and become northeasterly.
The shift in wind direction occurred about 3-4 April, 1978 (Figures 3a,b and
4a, b). The shift -redistributed much petroleum to previously shielded sec-
tions of the Brittany coast.
In addition, the highest spring tides of the season (9-meter tide range)
occurred within the two-week span after the wreck (Figure 5). This resulted
in wide exposure of coastal intertidal habitats to oil, necessitating con-
siderable ingenuity by the people of Brittany in attempting to clean their
impacted coast.
The Ministry of Interior and the French Navy directed much of the effort
to disperse oil at sea with chemical agents. Little information is available
on just what chemical dispersants were employed, where they were used or in
what quantities. Apparently over 50 tons of dispersants were sprayed during
18-22 March. Four ships were observed spraying sheen, not mousse, on 8 April
1978. These ships had been making daily sorties since 18 March from the port
of Brest, France. Interviews with petroleum company officials revealed that
at least four different chemical agents, plus chalk, had been applied but no
useful documentation was available.
The NOAA/EPA Special Report: "The Amoco Cadiz Oil Spill - A Preliminary
Scientific Report" (Hess, 1978) provides a valuable summary of initial events,
responses and assessment of the spill. Subsequently, a French-United States
special commission has been established, co-chaired by Dr. Lucien Laubier,
Director of Centre Oceanologique de Bretagne (COB) of the Centre National pout
I1Exploration des Oceans (CNEXO), and Dr. Wilmot N. Hess, Director of NOAA
Environmental Research Laboratories (ERL). This commission meets each six
months to review scientific activities for assessing effects of the spill, and
to award funds for specific research grants to consider the long-term effects
of petroleum from the spill.
Oil spills are a challenge to pollution-oriented ecologists. Even after
a number of international symposia which have produced extensive reports
(Bates, 1978), one gets the impression that the ecologist faces a desperate
struggle when oil spill catastrophes occur. The magnitude of these events,
particularly from ships the size of Amoco Cadiz is simply beyond the scale of
experience of most scientists and planners. Furthermore, the emergency atmos-
phere surrounding clean-up operations has rarely incorporated much considera-
tion or realization of need for scientific assessment. The Amoco Cadiz oil
spill has spurred efforts in the United States to initiate ecological impact
assessment combining physical oceanography, coastal dynamics, and habitat
assessment, ecological/behavioral effects with chemical analyses. Multina-
tional teams brought together in Brittany by the Amoco Cadiz incident have
been developing and exchanging newly created ideas (Conan et al. 1978), tech-
niques and strategies to use scientific methods for impact assessment, estima-
tion of damage to marine ecosystems and eventually, procedures for habitat
restoration.
Events following the Amoco Cadiz oil spill have provided quantities of
material for the press, sociologists, economic strategists, and politicians.
With regard to the ecology, the assessment of effects still continues.
373
-------
SECTION H
vWRECK SITE
KERSAINT
Awc-2 FIRST STUDY PERIOD
'PORTSALL
AMC-I -----Area Exposed at Low Tide
0 2km
Figure 3a. Locations of observation stations in Section II, the Portsall area,
during the first study period (March 19 to April 2). Heavy oil
accumulations are indicated by the dark-stippled pattern.
SECTION II
WRECK SITE
SECOND STUDY PERIOD J
jPORTSALL f
AMC"' ..-- Area Exposed at Low Tide ~N~
0 2km II
KERSAINT
Figure 3b. Oil distribution for Section II for second study session, April 20
to 28. Heavy and light oil coverage are indicated by the plus and
light-dot patterns, respectively (from Gundlach and Hayes, 1978).
374
-------
.. -. .^PRIMEL TREGASTEL
147
/>~CD':- n
, . /I3l2n x-*; < \i
FIRST STUDY PERIOD
0 24 6km
MORLAIX
Figure 4a. Location of stations in Section VII, Roscoff to Pointe de Plestin
(F-142). Oil distribution during the first study session, March
19 to April 2, is indicated by the dark-stippled pattern.
147'
PRIMELTREGASTEL
SECOND STUDY PERIOD
024 6km
-N-
Figure 4b. Oil distribution along the coastline of Section VII during
the second study session, April 20-28. Heavy ana light oil
coverage are indicated by the plus and light-dot patterns,
respectively (Gundlach and Hayes, 1978).
375
-------
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376
-------
BIOLOGICAL-ECOLOGICAL EFFECTS
Initially, some 4000 or more birds perished, including puffins, guille-
mots, and razorbill auks which are considered endangered species in this
region. Additionally, cormorant species (shag), loons and other migrating
diving birds were severely affected. Certain intertidal organisms including
species of molluscs, echinoderms, crabs, worms, algae, Crustacea, and fishes
were also killed.
In one case, oil contamination of the shoreline caused mass death of sea
urchins (Echinocardium) and several associated species of molluscs. In this
particular situation it was evident that organisms which are normally burrow-
ing forms had surfaced, apparently driven from the substrate by petroleum
components which penetrated up to 30 cm into the sandy bottom habitats.
Whether this event is related to use of dispersants or storm-induced mixing of
seawater, sediment and petroleum is not yet understood.
Bretagne benthic organisms have been studied for a number of years. The
amphipod crustaceans comprise 90% of the species diversity and 40% of the
biomass in fine sediments. Normally amphipods are present in numbers of
15,000/m2 in summer, and 8,000/m2 in winter. Within a fortnight of the wreck,
the population dropped to 2-5/m2, the number of species from the normal 23 to
only 7 (Cabioch, personal communication; NOVA, 1979). These organisms repre-
sent the principal food for commercial fishes including sole, sea bream and
others. Molluscs and polychaete worms at these particular stations were not
so dramatically affected.
A calcareous algae, Lithothamnion, forms "brush" piles, or areas with
high amounts of interstitial space. Such habitats have become benthic entrap-
ments for oil-sediment mixtures. This phenomenon has not been extensively
studied and needs careful evaluation to determine potential ecological im-
pacts.
Dr. Claude Chasse' has conducted extensive benthic biological surveys at
Morlaix, and other bays including the Bay of Lannion, where in the aformen-
tioned example early effects of oil and/or dispersants to benthic organisms
was most dramatic. His research (Chasse', 1972) spans ten years of study of
the macrobenthos between St. Efflam and Michel-en-Greve. At this site, 3-7 km
of beach were covered with five windrows of sea urchins, razor clams and other
organisms. Continuation of ecological assessments at this site, Lannion,
Morlaix, and others are of extreme importance to better understanding of
long-term effects of petroleum on benthic organisms.
Through the University of West Brittany, students were organized into
survey cadres. During initial phases of the spill some 150-200 students
visited intertidal areas (during low spring tide) and counted benthic organ-
isms using printed survey sheets. These sheets were collected and compiled by
Drs. Chasse' and Glemarec. More than 600 students took part in repeating the
"body counts" of dead organisms. The results of these repetitive visits and
subsequent assessment of benthic populations will be invaluable to ecological
comprehension of oil-organism interactions and mechanisms.
377
-------
FIRST TWO WEEKS
OIL TRANSPORT
WIND _,
v heavny
oiled
headlands
AFTER ONE MONTH
WIND
Figure 6. (Top) Oil pushed by strong
westerly winds during the
first two weeks was mainly
deposited along westerly-
facing headland areas.
Interior embayments gen-
erally remained free of oil.
(Bottom) A wind shift during
the beginning of April
spread a light layer of oil
deep into the embayments.
Previously deposited oil
along the exposed headlands
was greatly reduced in quan-
tity (Gundlach and Hayes,
1978).
WIND
ROCKY
HEADLAND
CRENULATE BAYS
WAVES
.LONGSHORE
TRANSPORT
dunes
Figure 7a. Entrapment of oil by
crenulate bays. Gener-
ally, the southerly
section of each bay
remained free of oil.
Figure 7b. Illustration of the
tombolo effect causing
localized oil deposition
behind offshore rocks
(Gundlach and Hayes, 1978).
378
-------
Many small marsh areas were impacted, but the one surrounding the embay-
ment south of Isle Grande represents one of the most heavily damaged. Here
the configuration of the coast entrapped oil and winds-forced the oil onto a
Juneus and Spartina marsh (Figures 6 and 7). Oil depth over the marsh surface
varied with specific circumstances, but was as deep as 15 cm in some areas.
Effects on biota were devastating; polychaetes and other mobile invertebrates
littered isolated pools of water by the thousands.
Clean-up of marsh areas was given high priority. However, use of heavy
equipment without restriction to single-access work paths further contributed
to destruction of the soils and additional disruption of the habitat. Rela-
tive effects of oil versus clean-up activities will be difficult to assess.
The area poses considerable challenge to planners interested in restoration.
The emotional impact of any oil spill is symbolized by the tragedy of
wild bird deaths. In the case of Amoco Cadiz, the eastward extension of the
spill lashed Les Sept lies (Seizh Enez) (Figure 8) which represents the south-
ernmost nesting colony of the common puffin, an endangered species. The
observation team was escorted to the sanctuary on 2 April by ornithologists
from the Ligue Francaise pour la Protection des Oiseaux (LPO). At sites where
one would normally see approximately 300 pairs of puffins in prenesting court-
ship, only one bird was found. By 14 April "bird hospitals" had recorded over
850 puffin carcasses. Spring migration was still underway so the total impact
of oil on the Sept Isles colony is unclear. Other bird species using this
sanctuary include razorbills (100 pairs), guillemots (300 pairs), kittiwakes
(100 pairs), storm petrels, herring, greater- and lesser- black-backed gulls,
fulmars (100 pairs) and gannets (4,000 pairs).
SEIZH ENEZ * "' ;
(LES SEPT ILES) I ECHtLLA
ILE PLATE
AUX MOINES
CERFS
Figure 8. Islands constituting Les Sept lies (from Milon, 1972).
The species most affected by oil were diving birds (puffins, razorbills,
cormorants, loons); soaring and far-flying species (gulls, gannets) had far
fewer immediate deaths. The word immediate is emphasized to denote acute
toxicity. In the case of gulls, these birds were observed feeding on weakened
molluscs, crabs, and worms. Gannets were seen carrying seaweed back to their
379
-------
nesting sites from areas affected by oil slicks. It is not known whether
contaminated seaweed can cause the kind of mortality which has been demon-
strated experimentally with duck eggs (Albers, 1977) or gull eggs (Patten and
Patten, 1977). By 2 April, three dead gray seals had been recovered from this
area of the Brittany coast.
The impact on birds was noted to be "less than expected" by personnel
working for LPO and Societe pour 1'Etude et la Protection de la Nature in
Bretagne (SEPNB). This observation reflects the important role of specific
circumstances. Did many birds avoid this spill because it was so massive and
contained highly aromatic petroleum components? Were migration patterns
sufficiently different during this year (compared to Torrey Canyon)? Had
populations (as known for puffins, razorbills, and guillemots) already been
decreased by the Torrey Canyon spill, so there were fewer birds to be af-
fected? Answers to these questions will depend on research and better under-
standing, evaluation and knowledge of population dynamics.
FISHERIES AND MARICULTURE
Husbandry and harvesting of the sea is as traditional as farming the land
in Brittany. Coastal waters of the North coast affected by the spill support
a traditional artisan seaweed industry. Many species of algae are harvested
and commercially processed to produce alginates for food, soap and other
products. Other algae, as well as the Laminaria, are harvested by hand (up to
6-7 thousand metric dry tons/year) and used as a supplement to livestock food.
Much of the contaminated algae was removed during clean-up activities,
since these plants acted as natural mops for intertidal oil. The impact upon
the algae industry cannot be assessed with the present data, although harvest-
ing was being carried out during the summer of 1978. It initially appears
that washing by sea action prevented much of the damage.
Rearing of oysters (Crassostrea gigas and Qstrea edulis) is an important
industry in Brittany. A valiant effort was initiated at the onset of the
spill to place numbers of oyster racks in estuaries southwest of the antici-
pated trajectory of the floating oil. Of course there was insufficient time
to remove all the racks. Total assessment of the impact of oil pollution on
oysters is not yet available.
Certain oyster culture areas of Brittany had initially been considered
"spared" from the fate suffered by such westward facing bays as Aber Wrach or
Aber Benoit. Later, Morlaix oysters became petroleum tainted and considered
unfit to eat, even though the surface mousse never came to that area.
Mussel culture is also practiced, but the effects of the Amoco Cadiz oil
spill have not yet been assessed. Part of the problem is related to the
distribution and effects of the oil-sediment mixture which has been trans-
ported by tidal currents to areas not significantly impacted by the surface
mousse (e.g., Morlaix). The benthic oil poses particular threats to crab,
scallop, and commercial fish species, emphasizing the need for comprehensive
chemical-ecological studies of the food webs of coastal fishery populations.
380
-------
Another issue is whether traditional fishery population study techniques can
adequately discern effects of a massive pollution event such as a major oil
spill. One gets the impression, from both the literature and from discussions
with statisticians, that present methodology does not yet meet these kinds of
ecoloqical assessment needs.
AGRICULTURE
Another impact which emphasizes the environmental interrelationship of
sea, atmosphere, and land is the unassessed effect of airborne contaminants.
On Easter morning, the stench of petroleum was evident 10-20 km downwind from
the coast with the onshore winds blowing at 40-50 knots. Fields rich with
spring crops, including mustard greens, broccoli and cauliflower extended to
the edge of the rocky coast and it was apparent that fields were "browned"
from petroleum-laden mist blown in from the stormy seas. It is hoped that
studies were made to assess the impact on this link in the food chain.
VULNERABILITY OF BRITTANY COASTAL HABITATS
On the basis of experience in the study of earlier petroleum spill, i.e.,
Metu1 a (Straits of Magellan) and Urquiola (Spain), Gundlach and Hayes (1978)
and Gundlach (1979) have classified coastal habitats into a vulnerability
index designed to predict longevity of oil in specific habitats. In this
system, on the scale of 1 to 10, the greater the value, the greater the like-
lihood of long term damage. Table 1, taken directly from Gundlach and Hayes
(1978), includes comments addressing the situation one month after the wreck.
OIL SPILL CLEAN-UP ACTIVITIES
In June, 1977, legislation had been adopted in France to prevent and
control marine pollution from accidents or releases of pollutants. The plan
had become known as "Plan POLMAR" (from "plan contra pollution marin").
Authority from the government of France flows from the national to local level
via bureaucratic networks. Control of pollution was conceived by "Ministry of
the Quality of Life", but executed under "Direction of Equipment" which is
comparable to Departments of Public Works or Corps of Engineers as far as
operational aspects are concerned. Enforcement authority was retained by the
Ministry of the Interior. The first major spill to test Plan POLMAR was Amoco
Cadiz. The maritime prefect at Brest was placed in charge of POLMAR; but the
operational approach was split into marine and coastline responsibilities due
to the "two fronts" requiring action.
Hann e_t al. (1978) summarized the first two months of clean-up activities
directed at Amoco Cadiz petroleum. Probably no other spill has received so
thorough a clean-up, nor been so completely assessed (Figure 9,10 and Appendix).
Over 5,000 French troops were mobilized for shoreline clean-up. Because
of the Easter holidays thousands of students on spring vacation volunteered
for clean-up and ecological survey teams; engineer (road and construction)
381
-------
TABLE 1. THE OIL SPILL VULNERABILITY INDEX WITH PARTICULAR
REFERENCE TO THE AMOCO CADIZ OIL SPILL1
Vulner-
ab i 1 i ty
Index
Shoreline Type; Example
Comments
Exposed rocky headlands;
Douarnenez to Pte. du Raz and
Primel-Tregastel to Locquirec
Eroding wave-cut platforms;
south of Portsall and F-l to
F-82
Fine-grained sand beaches;
stations south of Roscoff
(AMC-9 and 10) and east of
Portsall (AMC-5)
Coarse-grained sand beaches;
AMC-stations 4 (near Portsall)
and 12 (St. Cava) and F-38
Exposed, compacted tidal flats;
La Greve de St. Michel
Mixed sand and gravel beaches;
no really good example of this
beach type
Gravel beaches; stations F-ฃ
95 and 129, also AMC-16
Sheltered rocky coasts; common
throughout the study area
9 Sheltered tidal flats; behind
lie Grande and at Castel Meur
10
Salt marshes, lie Grande marsh
Wave reflection kept most of the oil
offshore; no clean-up was needed.
Exposed to high wave energy; initial
oiling was removed within 10 days.
All only lightly oil-covered after
one month, mainly by new oil swashes.
Oil coverage and burial after one
month remained at moderate levels.
No oil remained on the sand flat but
did cause the enormous mortality of
urchins and bivalves.
The index value is due to rapid oil
burial and penetration; all areas
had compacted subsurface which
inhibited both actions.
Oil penetrated deeply (30 cm) into
the sediment; clean-up by use of
tractors to push gravel into surf
zone seemed effective and not
damaging to the beach.
Thick pools of oil accumulated in
these areas of reduced wave action;
clean-up by hand and high pressure
hoses removed some of the oil (this
process is valid in non-biologically
active areas).
Tidal flats were heavily oiled;
clean-up activities removed major
oil accumulations but left remain-
ing oil deeply churned into the
sediment; biological recovery has
yet to be determined.
Extremely heavily oiled with up to
15 cm of pooled oil on the marsh
surface; clean-up activities removed
the thick oil accumulations but also
trampled much of the area; biological
recovery has yet to be determined.
1 Higher index values indicate greater long-term damage by the spi1!. For
further information, consult Hayes, Brown, and Michel (1976) or Gundlach
and Hayes (1978).
382
-------
EVAPORATION
DISSOLUTION
INTO WATER
DISPERSAL BY
WINDS, WAVES,
AND CURRENTS
SUPRATIDAL
ZONE*
EMULSIFICATION
LIGHT
FRACTIONS
HEAVY
FRACTIONS
ENTRAPMENT
IN AND ON
BEACH
MATERIAL
INTERTIDAL
ZONE
OW f
TIDE'
ENTRAPMENT
IN SEDIMENTS
INTERACTION WITH
SUSPENDED SEDIMENTS
Figure 9a. Mass balance components (Hann et al_. , 1978)
76,000
TONS
20,000 TONS TS,^
CHEMICALLY / >w AT
DISPERSED /6.000 /
t *rs\uc f
74,000 TONS
EVAPORATED
25,000 TONS DISAPPEARED
PERHAPS UNDER BEACH
SAND
80,000 TONS WENT ASHORE
\ 20,000-25,000
\ TONS RECOVERED
\
\
\
230,000
Figure 9b. Estimated fate of oil from Amoco Cadiz (Source:
local newspapers; from Hann et al., 1978).
383
-------
VOLUME OF LOAD
LOADS TO
MOVE MOUSSE
750 GALLONS 188,830
1,800 GALLONS 78,678
noun
252 CU. FT.
1,884 GALLONS
75,170
4,000 GALLONS 35,405
8,000 GALLONS 17,702
Figure 10. Equivalent truck and tank car loads necessary to remove potential
volume of mousse from shore (Hann et al., 1978).
384
-------
cadres and contractors also assisted in the clean-up effort. One of the most
spectacular responses came from the farmers of Brittany with their intrepid
tractors and liquid manure or "honey" wagons. This equipment was particularly
well suited for use in the sandy-rocky coastal areas, for pumping mousse from
wherever it became entrapped, such as in coves, pools, or from man-made en-
trapment basins or oil booms. Hann et al_. (1978) estimated that approximately
190,000 loads of about 3,000 liters each of oil/water emulsion were moved by
"honey wagon" to collection points for transport by truck, tanker, or railroad
to tankers at the port of Brest. Tankers carried the oil/water emulsion to
refineries. Tragedies continued as the small coastal ship, Henrietta Bravo,
sank in heavy seas while transporting 900 tons of oil-contaminated algae which
had been arduously removed from the shoreline of Brittany.
Land activities eventually became divided into four zones, each under the
responsibility of an engineer from Direction of Equipment, with reinforcements
from the Army. Student volunteers were under administrative direction of the
Ministry of Youth and Sports. An effort was made to enlist volunteers who had
adequate protective clothing, shelter, good personal health, and identifica-
tion accountability for assignment to specific cadres under trained foreman.
Such details may seem remote from the focus of this report, but they are
mentioned to indicate the inadequacy of existing systems to respond to spill-
ages of the magnitude of Amoco Cadiz. There are serious problems in dealing
effectively with well-meaning volunteers; advance planning and training are
essential.
Approaches to oil clean-up spanned every possibility. Rapid deteriora-
tion of the ship, combined with weather problems, precluded effective removal
of the cargo at sea. High waves acted as a surge pump, emptying the cargo
into the waters. Inflatable booms were deployed along the coast, but the
incredibly heavy seas, high winds and 8-meter tides overwhelmed these devices
as protective mechanisms. However, the booms did concentrate the oil and help
in controlling it for pumping and removal efforts.
Some downwind areas anticipated the petroleum influx and bulldozed sand
on tourist beaches above the intertidal zone. After the clean-up, beach sand
was graded over the cleaned zone.
Petroleum dispersants were applied offshore with the restriction that
these chemicals not be used in waters less than 50 meters deep. This arbi-
trary depth was probably unrealistic since 50 meters is actually very close to
shore which, combined with the proximity of the slick and onshore winds,
aggravated this strategy of oil spill control and mixed much petroleum into
highly productive coastal waters. Thirty-five boats were ultimately used to
spread dispersants north and east of Roscoff and He de Brehat areas.
Onshore oil was pushed, scraped, sponged, collected in ditches, collected
mixed with algae and wrack resulting in immense disposal and storage problems.
On 6 April, after the change of wind direction, aerial observations revealed
that the volume of floating and entrapped petroleum in the environment was
overwhelming, even compared to the vast clean up efforts being expended. It
has been stated that over $70 million (U.S.) was spent by June 1978 and it
would be at least two years more before "important" areas were completely
cleaned.
385
-------
In the case of village shorelines, as exemplified at Roscoff, limited
detergents and high pressure water spraying was used to clean rocks. Observa-
tions on 21 July revealed evidence of the oiling by both the numerous tar
spots and a notable decrease of molluscs and marine organisms seen at the
earlier (27 March) observations. In July there was an extensive growth of the
alga Enteromorpha which is often associated with nutrient or biostimulant pol-
lutats in coastal marine waters. Bathing beaches along Roscoff were being
scraped and raked and truck loads of the algae hauled away to reduce the or-
ganic decomposition odors and blockage to water access for beach visitors.
Other high energy beaches looked fresh with clean deposits of sand.
Trenches dug 20-60 cm down invariably revealed a deposit layer of brown
mousse, still pungent and sticky. These oil layers will likely be re-
excavated during winter tide cycles and oil will be redistributed by tidal and
surface currents during winter 1979.
The Amoco Cadiz oil spill presented to modern technology, to man's soci-
ety and the ecosystem an awesome and formidable challenge: how to protect
from, or mitigate the effects of very large oil spills. Unlike some other
spills, there were high levels of science, technology, and organization avail-
able at this time and place.
Concentrated study and consideration of all aspects of this event will
help prepare us for the possibility of future accidents. It is clear that the
combinations of circumstances and possible impacts are nearly infinite. Yet,
it is also clear that numerous preparations and steps can be taken to improve
safeguards for both prevention and response.
ACKNOWLEDGMENTS
This summary is compiled from the work of a number of investigators.
Through the generous and patient support of Dr. Lucien Laubier, Director of
the Centre Oceanologique de Bretagne, and many members of his staff including
Dr. G. Conan, Dr. L. d'Ozouville, and Mr. P. de Clarens, it was possible to
study a delicate and complicated situation. Dr. J. Bergerard, Director of the
Station Biologique, 29211, Roscoff, generously assisted. Dr. Louis Cabioch of
Station Biologique spent considerable time with the observation team, shared
data, showed undersea video tapes and provided much insight and research
knowledge on the oil-sediment emulsion and effects on benthic communities.
Dr. Miles 0. Hayes, Jacqueline Michel Hayes and Erich Gundlach generously
shared their time, valuable observations, and data derived from many hours of
study of coastal ecosystem dynamics. The National Oceanographic and Atmo-
spheric Administration's Environmental Research Laboratory Director, Dr.
Wilmot N. Hess is thanked for facilitating the author's second visit to
Brittany and the opportunity to participate as an observer at the Amoco Cadiz
Commission meeting at Brest. I wish to acknowledge the assistance of my
patient spouse who contributed invaluable aid in the preparation of the manu-
script. Ms. Sharon Maier and Douglas Middaugh read and made improvements to
the manuscript.
386
-------
REFERENCES
Anonymous, 1979. Bibliography of Amoco Cadiz Reports. Union of Littoral
Villages of Western Europe. (ULVOE), Brest March 1979.
Bates, C. C. ed. 1978. Conference on Assessment of Ecological Impacts of
Oil Spills. Proc. AIBS Conf. Keystone Col. Am. Inst. Biol. Sci.,
Washington, D.C. 936pp.
Chasse', C. J. M. 1972. Economic, sedimentaire, et biologique (production)
de Bretagne. Ph.D. Thesis Station Biologique de Roscoff, Faculte des
Science de Universite de Brest. 293 pp.
Conan, .Gerard, L. D'Ozouville, m. Marchand (ed.). 1978. Amoco Cadiz Prelim-
inary Observations of the Oil Spill Impact on the Marine Environment.
Proc. Conf. Amoco Cadiz, Brest France 7 June 1978. Publ. du C.N.E.X.O.
Act. de Colloque No. 6 Centre Oceanologique de Bretagne 29273 Brest
CEDEX.
Cross, F. A., W. P. Davis, D. E. Hoss, and D. A. Wolfe. 1978. Biological
Observations. In: The Amoco Cadiz Oil Spill. W. N. Hess ed. NOAA/EPA
Spec. Report. Supt. Documents, LI.S.G.P.O. Washington, D.C. 20402. p.
197-215 + plates.
Gundlach, Erick R. and Miles 0. Hayes. 1978. Investigations of Beach Pro-
cesses. In: The Amoco Cadiz Oil Spill. W. N. Hess ed. NOAA/EPA Spec.
Report. Supt. Documents, U.S.G.P.O. Washington, D.C. 20402. p. 85-196 +
plates.
Gundlach, E. R. 1979. Oil Spill Impact on Temperate Shoreline Environments,
Based on Study of the Urquiola (May 1976) and Amoco Cadiz (March 1978)
Oil Spills. Ph.D. Doctoral Dissertation; Dept. Geology, Univ. So.
Carolina. 238 pp.
Hann, Roy W. , Les Rice, Marie-Claire Trujillo, and Harry N. Young, Jr. 1978.
Oil Spill Cleanup Activities. In: The Amoco Cadiz Oil Spill. W. N.
Hess ed. NOAA/EPA Spec. Report. Supt. Documents, U.S.G.P.O. Washington,
D.C. 20402. p. 229-275 + plates.
Hess, Wilmot N. , ed. 1978. The Amoco Cadiz Oil Spill: A Preliminary Scien-
tific Report. NOAA/EPA Special" Report. Supt. Documents U.S. Gov't
Printing Office, Washington, D.C. 20402. 283 pp. i-vi; 66 plates.
Hoebeke, Lionel. 1978. Le guide de la France Polluee. Fayoll, Paris 75101,
France; 175 pp.
Hyland, Jeffrey L. 1978. Onshore Survey of Macrobenthos. In: The Amoco
Cadiz Oil Spill. W. H. Hess ed. NOAA/EPA Spec. Report. Supt. Documents
U.S.G.P.O. Wash., D.C. 20402: p 216-228.
Milon, P. 1972. La Mort sur 1'ile. Crepin - Le Blond et Cie Paris, France,
107 pp.
387
-------
NOVA. 1979. Black Tide. P.B.S. Television Documentary Text From WGBH Educa-
tional Foundation Boston, Mass. 19 pp.
Patten, S. M. , Jr. and L. R. Patten. 1977. Effects of petroleum exposure on
hatching success and incubation behavior of the Gulf of Alaska herring
gull group (Larus argentatus x Laurs glaucenscens). NOAA Env. Res. Labs
OCSEAP Reports Boulder Colo. 22 pp.
Pinot, J. P. 1976. La mer et la Peche; La crise de la Peche en Bretagne in
Geographic de la Bretagne; Editor SKOL VREIZ Rennes, France: 118-138.
Szaro, R. C. and P. H. Albers. 1977. Effects of external application of No.
2 fuel oil on common eider eggs. In: Fate and effects of petroleum
hydrocarbons on marine organisms and ecosystems. D. A. Wolfe, ed.
Pergamon Press, N.Y. 164-167.
388
-------
APPENDIX
1 1
1 SECTEUR dt
| ST. RENAN
1
SECTEUR dt
LANNILIS
1
1
1
AT SEA | |S
ACTIVITIES \^J FINISTERE
COAST ~]
PC. POL MAR
MARINE
, ,
STUDIES CHEMISTRY
EVALUATION OF
METHODS
SECTEUR dt
ROSCOFF
1
P.C PLOUDALMEZEAU
FINISTERE
1
PORT
ACTIVITIES
SECTEUR dt
PLOUGASNOU
FIN
cot
SECTEUR dt
L ANN ION
STERE J
1ST
P.C.ZONE RENNES
COTES-DU-NORD
LOGISTICS a
METHODS
SECTEUR dt
ST BRIEUC
CONSTRUCTION OF
ULTIMATE SOLID
WASTE STORAGE SYSTEMS
Approximate organization of the response effort.
OIL RELEASED
AT SEA
I1
WIND a WAVES ACT
ON THE OIL TO
FORM AN EMULSION
WITH WATER
i r
EMULSIO
WATER C(
INCREAJ
i
N IS
BY SURF;
)NTENT
>ES
NO
OIL REMAINS AT SEA ^ -s. /"7s IT~"\ /""iS lf~^~\
UNTIL DISPERSED N0 /ruf^ni,^ YES /APPROACHING \ ROCKY /STRANDED IN\
BY NATURAL "* V GO ASHORE/ \ A ROCKY OR, J *"(pOOLS,
FORCES. yw^A&HUKty ^ANDYAREAX \ '
EMULSION IS SI
OUTGOING TIC
EMULSION IS /" HAS THE^\ .... X"lS
REFLOATED ^ "" /MOUSSPS SP. GRA^ "ฐ / ABOVI
*- BY OUTGOING ^ V EXCEEDED 1 V HIGH
TIDE \^J.OE4?^X \^LfN
YES
SANDY
"HANDED BY
)E
IT ^S. _- EMULSIO
: NEXT\ TC' ^ rOMTFMl
WATER / , DECREA
f-f^y TO WEA
ON ROCKS
YES
N WATER
r
SES DUE
THERINO
YES /REMOVED BY\
FUTURE TIDES,/
REMAINS ON/IN
BEACH UNTIL DEGRADED
BY NATURAL PROCESSES
Possible pathways of oil spilled from Amoco Cadiz.
389
-------
O>
SOLID
PICK-UP
BY
HAND
LOAD ONTO
FARM
WAGONS
TRANSFER
TO DUMP
TRUCKS
DELIVER TO
INTERIM OR FINAL
SOLID MATERIAL DISPOSAL
CUT VEGETATION
AT GROUND WITH
SHOVEL OR
MECHANICAL MEANS
DRAIN
"^VEGETATION!
MOUSSE
NO
PUTIN
BUCKETS
YES
TRANSPORT BY
HAND, FARM
WAGON OR FRONT
END LOADER
IS
'MECHANICAL
EQUIPMENT
^AVAILABLE?;
LOAD INTO HONEY
WAGONS AND/OR
VACUUM TRUCKS
DISCHARGE AT
INTERIM MOUSS
STORAGE
NOTES- I) ATTEMPT MADE TO DAM OFF MARSH TO CONTAIN MOUSSE BUT
SPRING TIDES BROKE THE DAM.
2) SPRINKLERS WERE USED IN SOME AREAS TO KEEP OIL OFF OF
CLEANED AREAS.
Unit process: Cleaning of He Grande marsh.
DELIVER
WATER TO
BOOST
PRESSURE
yes
IN
TRUCK
DELIVER
WATER IN
WITH FIRE
TRUCK
FIRE OR
VACUUM TRUCK
SPRAY
COBBLES
WITH
D1SPERSANT
ALLOW
DRINKING
TIME
PICK UP
COBBLES WITH
FRONT END
LOADER
TRANSPORT AND
DISCHARGE AT
LOWER BEACH
LEVEL
COUNT ON SURF
ACTION TO
CLEAN AND
RETURN COBBLES
Unit process: Cleaning of walls, rockfaces, and cobbles.
390
-------
PROCESS
A
MOUSSE
SEAWEED
^l\ ,,,
TRANSPORT \N
FARM WAGON OR
DUMP TRUCK
DISCHARGE INTO
INTERIM BULK
SOLID WASTE
STORAGE
MOUSSE
TRANSPORT IN
TANK TRUCK
DISCHARGE IN
INTERIM MOUSSE
STORAGE
COLLECT MOUSSE
BY HAND
IN BUCKETS
TRANSFER BY
HAND TO 30
GAL. GARBAGE
CANS
COLLECT OIL
FROM GARBAGE
CANS WITH
VACUUM TRUCKS
COLLECT MOUSSE
WITH SKIMMER
TRANSFER TO
TANK TRUCK
-
Unit process: Removal of mousse from water surface to interim storage.
seawe
mousse
ed
TRANSPORT
BY DUMP
TRUCK OR
WAGON
DISCHARGE
INTO INTERIM
BULK SOLID
WASTE STORAGE
Unit process: Removal of mousse from rocky areas to interim storage.
391
-------
PLACE MOUSSE
OR OILED
SAND IN
PLASTIC BAGS
PLACE OILED
SEAWEED OR
DETRITUS IN
PLASTIC BAGS
CARRY BY
HAMD TO
CENTRAL
POINT
LOAD BY HAND
ONTO WAGON
OR FRONT
END LOADER
DELIVER TO
INTERIM BAG
STORAGE
Unit process: Removal of oiled sand, seaweed, and detritus
to interim storage.
NO MOUSSE/ SEAWEED SEPARATOR
LOAD 1 NTO
DUMP
TRUCKS
DISCHARGE INTO
INTERIM MOUSSE
STORAGE
Unit process: Removal of stranded mousse from beach to interim storage.
392
-------
NO SEPARATION
DISCHARGE IN
ULTIMATE DISPOSAL
PITS BREST HARBOR
DISCHARGE IN
ULTIMATE DISPOSAL
PITS-TRB5ASTLE
Unit process: Movement of mousse and oiled material from
interim storage to disposal.
393
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO.
EPA-600/3-79-102
4. TITLE AND SUBTITLE
3 RECIPIENT'S ACCESSION NO.
Management of Bottom Sediments Containing Toxic Substanc
Proceedings of the Fourth U.S.-Japan Experts' Meeting
October 1978--Tokyo, Japan
5 REPORT DATE
September 1979 issuing dafr
>. PERFORMING ORGANIZATION CODE
7 AUTHOR(S)
Spencer A. Peterson and Karen K. Randolph, editors
8 PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Research Laboratory--Corvallis, OR
Office of Research and Development
U.S. Environmental Protection Agency
Corvallis, Oregon 97330
10. PROGRAM ELEMENT NO.
1BA608
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
same
13. TYPE OF REPORT AND PERIOD COVERED
in-house
14. SPONSORING AGENCY CODE
EPA/600/02
1i SUPPLEMENTARY NOTES .
Proceedings of the Second and Third U.S. -Japan Experts meeting on bottom sediments
^
-6
PEPA's Ecological Research Series as EPA-600/3-77-083 and
respectively:
16. ABSTRACT
The United States-Japan Ministerial Agreement of May 1974 provided for the exchange
of environmental information in several areas of mutual concern. This report is the
compilation of papers presented at the Fourth U.S.-Japan Experts' Meeting on the
Management of Bottom Sediments Containing Toxic Substances, one of the 10 identified
problem areas.
The first meeting was held in Corvallis, Oregon in November 1975. The second meeting
was hosted by the Japanese Government in October 1976. The third session was convened
in November 1977 in Easton, Maryland and the fourth session (at which these papers
we^e presented) in Tokyo.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
water reclamation
sanitary engineering
contaminants
water pollution
ocean bottom sediments
freshwater bottom sediments
b.IDENTIFIERS/OPEN ENDED TERMS
toxic sediments
mercury, PCB contamina-
tion
water pollution control
dredging
dredged materials
c. COSATI Held/Group
06/F
08/A,C,J,H
13/B,J
18 DISTRIBUTION STATEMENT
Release to Public
19 SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES
400
20 SECURITY CLASS (This page)
unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
394
irUS GOVERNMENT PRINTING OFFICE 1979699-843/20
------- |