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EPA-905/9-79-003
January 1979
CHEMICAL EFFECTS OF RED CLAYS ON
WESTERN LAKE SUPERIOR
By
Donald A. Bahnick, Thomas P. Markee and Ronald K. Roubal
Center For Lake Superior Environmental Studies
University of Wisconsin
Superior, Wisconsin 54880
Grant Number R005169-01
Project Officer
Anthony G. Kizlauskas
U.S. Environmental Protection Agency
Region V
Great Lakes National Program Office
Chicago, Illinois 60605
GREAT LAKES NATIONAL PROGRAM OFFICE
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION V
CHICAGO, ILLINOIS 60605
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DISCLAIMER
This report has been reviewed by the Great Lakes National Program Office,
U.S. Environmental Protection Agency (U.S.EPA), Region V, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or rec-
ommendation for use.
ii
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FOREWORD
The U.S. Environmental Protection Agency (EPA) was created because of
Increasing public and governmental concern about the dangers of pollution to
the health and welfare of the American people. Noxious air, foul vater, and
spoiled land are tragic testimony to the deterioration of our natural envi-
ronment .
The Great Lakes National Program Office CGLNPO) of the U.S. EPA was
established in Region V, Chicago, to provide a specific focus on the water
quality concerns of the Great Lakes. GLNPO provides funding and personnel
support to the International Joint Commission activities under the U.S.-
Canada Great Lakes Water Quality Agreement.
Several water quality studies have been funded to support the Upper
Lakes Reference Group (ULRG) under the Agreement to address specific objec-
tives related to pollution in the Upper Lakes (Lake Superior and Lake Huron).
This report describes some of the work supported by this Office to carry out
ULRG study objectives.
We hope that the information and data contained herein will help
planners and managers of pollution control agencies make better decisions
for carrying forward their pollution control responsibilities.
Dr. Edith J. Tebo
Director
Great Lakes National Program Office
ill
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PREFACE
This study was carried out during 1975 with the goal of providing infor-
mation on the effects of red clay erosion on sediment transport and chemical
inputs to Lake Superior. A draft final report was prepared in late 1975 at
the conclusion of the project. A decision to publish this report was made
in early 1978 at which time the authors commenced revisions. The report has
been written in the context of information available at the beginning of 1976-
iv
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ABSTRACT
The southwestern shoreline area of Lake Superior is subjected to exten-
sive erosion of glacial-lacustrine red clay deposits. Clay bluff from the
shoreline contains a large percentage of clay-size particles which remain
suspended in Lake Superior for days to weeks. The clay-size particles under-
go solubilization and exchange processes in the lake water. This investiga-
tion measures inputs of chemical parameters from clay particles in Lake Su-
perior water as of a function of time. Comparisons of the chemical input
magnitudes from shoreline erosion, sediment resuspension,and river particu-
late transport are made. Monitoring of Bayfield County, Wisconsin streams
for sediment transport was done for the spring runoff period. The chemical
characteristics of a near-shoreline Lake Superior site was studied as a func-
tion of water turbidity.
The results show that shoreline erosion is the principal mechanism for
chemical transport to Lake Superior from clay particles as compared to stream
particulate and sediment resuspension inputs. The suspended particles have
the capability of removing chemical species such as heavy metals and many or-
ganic chemicals from the aqueous phase. The sediment input from Bayfield
County, Wisconsin streams is small compared to the input from streams of
Douglas County, Wisconsin. Insufficient data was obtained to warrant con-
clusions on the field studies of turbidity and water chemistry relationships.
This report was submitted in fulfillment of Grant No. R005169-01 by the
University of Wisconsin, Superior under sponsorship of the U.S. Environmental
Protection Agency. This report covers a period from October 1, 1974 to De-
cember 31, 1975 and the work was completed as of October 30, 1978.
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CONTENTS
Foreword ..............................
Preface ............................... iv
Abstract ............................... v
Figures ............................... vii
Tables ............................... vlli
Acknowledgement ........................... ix
1. Introduction ......................... 1
2. Conclusions ......................... 4
3. Recommendations ........................ 5
4. Dissolution of Soil and Sediment Samples ........... 6
General Procedures .................... 6
Results and Discussion ................. 13
5. Water-Sediment Parameter Exchange and Sediment
Interstitial Water Characteristics ............. 27
General Procedures ................... 27
Results ........................ 29
Chemical Inputs from Interstitial Water
of Resuspended Sediments ................ 39
6. Sorptive Characteristics of Clays .............. 42
General Procedures ................... 42
Orthophosphate Studies ................. 42
Metal Leaching and Exchange .............. 46
Exchange of Phenolics with Clays ............ 54
7. Chemistry of Lake Superior Water Samples As
Related to Turbidity .................... 58
General Procedures ................... 58
Results and Discussion ................. 58
8. River Monitoring for Sediment Loads ............. 65
General Procedures ................... 65
Results and Discussion ................. 65
9. Summary of Chemical Inputs to Lake Superior ......... 71
References
Appendices
A. Data for seven-week clay leaching experiments
as described in Section 4 .................. 77
B. EPA-University of Wisconsin analytical quality
control results and their impact on the chemical
loading estimates ...................... 92
C. Methods of analyses for sediments and water samples ..... 106
vi
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FIGURES
Page
Number,
1 Sample collection points within study area 7
2 Comparison of the chemistry of overlying and interstitial
waters for the Superior entry-area core after initial removal
from Lake Superior (A) and after storage for 31 days at 4 C (B). . 37
3 Comparison of the chemistry of overlying and interstitial
waters for the Dutchman's Creek-area core after initial removal
from Lake Superior (A) and storage for 31 days at 4 C (B) M
4 Sorption isotherms for soil samples. . .
47
5 Sorption isotherm for sediment
6 Copper sorption isotherm for clay soil in Lake Superior water. . . 52
7 Manganese sorption isotherm for clay soil in Lake Superior water . 53
vii
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TABLES
Number Page
1 Sediment and Soil Samples 8
2 Samples and Conditions for Seven-Week Leaching Experiments .... 12
3 Samples and Conditions for Silica Leaching Studies 14
4 Four-Month Clay Sediment Leachate Results 15
5 Summary of Clay Soil-Water Chemical Exchanges in MG of Parameter
Per G of Clay 17
6 Clay Sediment and River Particulate Chemical Exchanges in MG of
Parameter Per G of Clay 18
7 Total Corrected Release of Silica in MG of Si02 Per G of Clay. . . 19
8 Total Corrected Chemical Exchanges from Clay Soil and Sediment
Samples 20
9 Particle-Size Distribution in Clay-Containing Samples 24
10 Chemical Releases and Inputs to Lake Superior from Shoreline and
River Erosion 26
11 Sediment Core Analysis 30
12 Particle Size Analysis 31
13 Chemical Analysis of Superior Entry Lake Superior Core and Nemadji
River Soil Sample 32
14 Chemical Analyses of Nemadji River Sediment Core and Overlying
Water 33
15 Chemical Analyses of Superior Entry Area Core and Overlying Water. 34
16 Chemical Analyses of Bardon Creek Area Core and Overlying Water. . 35
17 Chemical Analyses of Dutchman's Creek Area Core and Overlying
Waters 36
18 Estimates of Chemical Inputs in Lake Superior Due to Interstitial
Waters of Resuspended Sediment 41
19 Metal Leaching of Clay Samples 50
20 Metal Inputs from Shoreline Erosion and Sediment Resuspension. . . 51
21 Total Phenolics in Natural Waters 56
22 Interactions of Clay with Phenolics 57
23 Lake Superior Bardon Creek Area Suspended Solids Profiles 60
24 Lake Monitoring in Poplar River - Bardon Creek Area 61
25 Lake Monitoring in Poplar River - Bardon Creek Area 62
26 Lake Monitoring in Poplar River - Bardon Creek Area 63
27 Lake Monitoring in Poplar River - Bardon Creek Area 64
28 Discharges and Sediment Loads of Lake Superior Tributaries (1975). 67
29 Chemical Inputs Due to Leaching of Resuspended Sediment. ..... 72
30 Chemical Inputs to Lake Superior Due to Soil Erosion, River
Particulates and Sediment Resuspension 73
viii
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ACKNOWLEDGMENTS
We gratefully acknowledge Dr. Gary Glass and Dr. John Poldoski from the
U.S. Environmental Protection Agency (U.S.EPA) Environmental Research Labora-
tory, Duluth, Minnesota, for technical assistance during the course of the
study and for providing space and equipment for certain aspects of the work, and
to Dr. Michael Sydor, University of Minnesota-Duluth,for helpful discussions.
We are indebted to Dr. David Armstrong, University of Wisconsin-Madison,
for loan of the Benthos Gravity Corer.
We appreciate the efforts of Dr. Wayland Swain, U.S.EPA Large Lakes
Research Station, Grosse lie, Michigan, in providing reference materials per-
taining to the study.
We acknowledge the contribution of Anthony G. Kizlauskas, U.S.EPA
Great Lakes National Program Office, Region V, Chicago, Illinois, in coordi-
nating the study and the analytical quality control program.
We are most appreciative of the leadership role of Cheryl A. Anderson
and contributions of William Doucette, Lily Mulyadi, Esther Hui, Carol
Nordgren, Mary Ann Rondeau, Lilian Chan, Fred Meyer, Paul Sandvick, Dave
Fritzler, Molly McConnell, and Robert Horton in the collection and analysis
of samples and data processing.
ix
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SECTION 1
INTRODUCTION
The water quality of western Lake Superior is directly affected by ex-
tensive erosion of glacial-lacustrine red clay deposits located primarily in
northern Wisconsin. These clay deposits were formed in an early stage of
present-day Lake Superior and now form a mantle of unconsolidated material
averaging 100 feet (30 m) in depth. The depth increases westward from about
33 feet (10 m) near Port Wing, Wisconsin to more than 570 feet (174 m) at
one point in the city of Superior, Wisconsin. The red clay drainage area of
Wisconsin encompasses 890,000 acres (3600 km2) located in Ashland, Bayfield,
Douglas,and Iron counties.1 Exposure of the red clay deposits occurs along
105 miles (169 km) of shoreline,of which 15% of the exposure has been clas-
sified by the Great Lakes Basin Commission as being under critical erosion.
Eroded red clay is the major source of turbidity problems associated with
rivers'draining the clay deposits and the shoreline area of southwestern
Lake Superior. A considerable portion of the eroded material disperses into
the water as fine particles (less than 2 microns) and thus forms suspensions
of lengthy stability. The suspended material may be carried for long dis-
tances in Lake Superior before deposition on the bottom. The clay material
which is deposited out to 70 feet (21 m) in depth is susceptible to resus-
pension during certain wind events, particularly when the southwestern part
of the lake is under isothermal conditions (late spring and fall).2*3
The most pertinent information relating to the red clay input into the
lake and its resuspension is contained in several available reports.
Sydor2'3 has examined the available data on red clay erosion into Lake Supe-
rior and concluded that the lake turbidity is primarily due to shore ero-
sion and resuspension. Based on stream-monitoring data (see Section 8 for
Bayfield County, Wisconsin data), measurements of fine suspended solids in
the lake and particle-size distribution analysis of soil samples, Sydor con-
cludes that the total stream erosion of soils amounts to 5.9 x 105 metric
tons of material in Douglas County, of which 3.2 x 105 (or 54%) represents
material which is carried into Lake Superior. The Nemadji River is the
principle source of sediment load to Lake Superior, contributing 89% of the
eroded material from streams in Douglas and Bayfield Counties. Rivers in
Douglas and Bayfield Counties account for 80% of the Wisconsin Lake Superior
tributary stream banks which are classified as under very severe or severe
erosion.
The amount of eroded clay material entering Lake Superior due to shore-
line erosive processes has been considered by Hess.5 Using available aer-
ial photographs in conjunction with shoreline observations, the recent rate
of erosion is 2.5 x 10° cubic yards (1.9 x 106 m3) per year for the coastal
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area extending from Superior entry (Superior, Wisconsin) to Bark Point, a few
miles west of Cornucopia, Wisconsin. This shoreline distance is slightly
greater than 50 miles (80 km). Using a clay density of 120 Ibs/cubic foot
(1920 kg/m-3), the above volume of clay is equivalent to 3.7 x 106 metric
tons. Hess estimates that this value accounts for somewhat less than half
of the total erosion on Wisconsin's Lake Superior shoreline. Consequently,
an estimate of the total eroded material along the shoreline is 8 x 106
metric tons per year. Sydor3 has used ERTS images, settling rates, particle-
size data, and lake sampling and arrived at a comparable figure in terms of
erosion along the shoreline in Douglas County, Wisconsin. He determined
that 2.3 x 10b metric tons of red clay is eroded from the shoreline in
Douglas County. Since the Douglas County shoreline distance is slightly
greater than one half the shoreline distance studied by Hess, the results of
the two investigators are in good agreement.
Evidence that resuspension of fine sediment material from the lake
bottom contributes significantly to lake turbidity is summarized by Sydor2,3.
The available data now indicate that approximately 5.6 x 105 metric tons/
year of lake-bottom sediment undergoes resuspension due to currents and in
times of turbulent lake conditions in the shoreline regions of southwestern
Lake Superior during the May-to-November period. An additional 10$ metric
tons/year is subject to resuspension during the December-through-April peri-
od. This accounts for a total yearly resuspension contribution to lake tur-
bidity of 1.6 x 10° metric tons although this value includes material which
has been disturbed more than once. Resuspension involves sediments deposited
at depths up to 70 feet (21 m).
A major part of this study involves an investigation of the degree to
which naturally occurring red clay material affects the concentrations of
major and minor nutrients in this Lake Superior area. Some information on
removal of organic pollutants by suspended clay particles constitutes a
further phase of the project. Clay effects on water chemistry result from
solubilization, exchange,and adsorptive processes. Representative clay-
bearing material consisting of soil samples from shoreline and tributary clay
banks, particulate material from the Nemadji River and Lake Superior have
been employed in this chemical study. The major chemical parameters in aque-
ous systems investigated in this project included dissolved solids, dissolved
oxygen, total Kjeldahl nitrogen, nitrate, total soluble phosphate, inorganic
soluble phosphate, alkalinity, silica, sodium, potassium, magnesium, calci-
um, iron, manganese, zinc, copper, lead, nickel, chromium, selenium, arsen-
ic, mercury, chloride, phenolics, chlorinated hydrocarbons,and PCBs.
Another phase of this project involved aiding Dr. Michael Sydor, Univer-
sity of Minnesota-Duluth, in determining with more accuracy the magnitude of
tributary sediment-load discharge in Lake Superior by monitoring river spring
runoff of suspended solids. Lake Superior monitoring in a high-turbidity re-
gion was done over the period from spring to the end of August in order to
provide information on settling and transport of the suspended material and to
obtain chemical data as related to turbidity and weather events.
The erosion of red clay results in property loss, turbidity in drinking
water intakes, a decrease in aesthetic value of the southwestern shoreline
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area of the lake,and some recognized adverse effects on fish life such as
clogging of gravel beds necessary for fish reproduction and changing fish
feeding habits, distribution,and mortality rates.
It is the purpose of this study to determine the chemical effects of
red clay erosion on the southwestern portion of Lake Superior through a
study of the solubilization and sorptive properties of the clay materials
in the forms of soils (clay bluff), river particulates, and sediments. In
order to obtain meaningful results, information pertaining to the magnitudes
of shoreline and river erosion and resuspension of clay sediments and the
transport of the material must be known. Consequently this project is a
cooperative effort with Dr. Michael Sydor, University of Minnesota-Duluth,
whose research efforts are concentrating on determining magnitudes of the
contributions of the erosion and resuspension factors to Lake Superior tur-
bidity and the transport of the material in the lake (EPA Grant No.
R005175-1).
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SECTION 2
CONCLUSIONS
The erosion of red clay material results in inputs of many chemical
parameters to the southwestern Lake Superior area. For those parameters
considered in this study, chemical release from particles entering Lake
Superior due to shoreline erosion of clay bluff is the largest source of
chemical imputs (when compared to releases from river particulates and re-
suspension of sediments). The transport of river particulates to the lake
and resuspension of bottom sediments during periods of high waves are sec-
ondary processes resulting in chemical releases to the lake.
Upon suspension of red clay containing bluff, sediment, and river par-
ticulate material in Lake Superior water, measurable releases of dissolved
solids, total alkalinity, orthophosphate, total soluble phosphorus, and sil-
ica were found. The metals which are released in detectable quantities
were sodium, potassium, calcium, magnesium, iron, aluminum, and manganese.
Within the accuracy of the experiments, no detectable releases of chloride,
TKN, nitrate, copper, cadmium, zinc, lead, chromium, nickel, mercury,
arsenic, and selenium occurred. However, among the metals only potassium
and calcium were studied for possible release from river particulates.
Suspended red clay bluff particles have the capacity for removing chem-
ical species from Lake Superior water. Specific results on aqueous copper
(II) and manganese (II) show that the suspended particles would remove cop-
per from the water if its aqueous concentration reaches levels of about
1 pg/1 or greater. Manganese removal by suspended bluff material from Lake
Superior water would occur if its aqueous concentration increased to about
4 yg/1 or more. The suspended clay particles also will remove phenolic type
compounds from lake or river water.
The sediment load of rivers in Bayfield County, Wisconsin is small com-
pared to the total sediment load of Douglas County, Wisconsin rivers.
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SECTION 3
RECOMMENDATIONS
The magnitude of the chemical inputs to Lake Superior directly associa-
ted with release from eroded and resuspended red clay material should be
compared to inputs from other water or airborne sources associated with an-
thopogenic activities.
The rate of dissolution of red clay bluff or sediment material in Lake
Superior water should be determined from data in this report. In addition,
sediment fluxes for a number of major chemical species should be computed.
The transport to Lake Superior of chemical species associated with
suspended particulates and the bioavailability of these species should be
investigated for metals and organic compounds. The large sediment load of
the Nemadji River which passes through portions of the Duluth-Superior Har-
bor before entering Lake Superior should in particular be studied for chemi-
cal transport to the lake and its effect on the Lake Superior fishery.
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SECTION 4
DISSOLUTION OF SOIL AND SEDIMENT SAMPLES
GENERAL PROCEDURES
Sediment and soil samples were collected for subsequent use in leaching
and exchange experiments. The sediment samples were obtained using a
Peterson dredge and placed in five-quart (4.7 1) plastic containers. The
sealed containers were stored at approximately 4°C in the dark until their
use in the leaching and exchange experiments. Soil samples were taken from
exposed clay bluff deposits along the banks of the Bois Brule and Nemadji
Rivers and from several locations along the shoreline of Lake Superior.
These samples were also stored in five-quart plastic containers at room tem-
perature. All soil samples except the Bardon Creek area samples were air-
dried at room temperature before use in the experiments.
One river particulate sample consisting of suspended solids from the
Nemadji River was used in the leaching-exchange studies. The sample was
collected by filling 5-gallon (18.9 1) plastic carboys with Nemadji River
water obtained with a Van Dorn water sampler. The water was put into four
modified one-liter plastic polyethylene bottles and centrifuged for one hour
at 2400 rpms (1,580 X g), at which point most of the suspended material had
settled. The lower layer of the concentrated suspension was then filtered
through 0.45 micron membrane filters. The filtered material was transferred
to a pre-weighed plastic bottle with a plastic spatula. Approximately five
minutes of filtering time was required per liter of river water processed.
Approximately 35 liters of river water yielded 5 grams of wet solid material.
The sample locations, type of sample, and date collected are summarized
in Table 1, and the sample locations have been indicated in Figure 1.
On the day of collection of the four sediment samples (SE-1, DS-1, AR-1
and SE-2), approximately one gram of each sample was added to one liter of
Lake Superior water. The mixture was stirred for four months at room tem-
perature. The water was then analyzed for dissolved oxygen, alkalinity,
conductivity and pH while filtered portions (0.45 micron pore) were analyzed
for calcium, magnesium, sodium, nitrate, chloride, silica, aluminum, cadmium,
chromium, copper, iron, lead, manganese, arsenic, nickel, selenium and zinc.
Most of the heavy metals were analyzed by both the EPA, Region V Laboratory,
Chicago and the UWS laboratory. This experiment indicates which parameters
might show larger concentration changes over long periods of time, although
container adsorption or leaching effects would mask the true magnitudes of
changes caused by clay-lake water interactions.
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Figure 1. Sample collection points within study area.
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TABLE 1: SEDIMENT AND SOIL SAMPLES
Deslg-
nation
SE-1
DS-1
AR-1
DS-2
B-l
B-2
N-l
N-2
LS-1
LS-2
Sample
Type
Sediment
Sediment
Sediment
Sediment
Soil
Soil
Soil
Soil
Soil
Soil
LS-3
Soil
Sample Location
3/4 mile from Superior
entry lighthouse (60-
foot depth)
2-1/3 miles from the
mouth of Dutchman's
Creek (60-foot depth)
6-2/3 miles from the
mouth of the Amnicon
River (125-foot depth)
7-1/3 miles from the
mouth of Dutchman's
Creek
North of Highway 13
near fisherman's park-
ing lot on banks of
Bois Brule River
Bois Brule River banks
40 feet to north of B-l
200 yards upstream of
Woodland Road bridge
on the banks of the
Nemadji River
Nemadji River banks
15 yards upstream of
N-l
Lake Superior shoreline
100 yards west of the
mouth of the Amnicon
River (gray clay)
Lake Superior shoreline
20 yards west of LS-1
from the face of eroded
cliff
Lake Superior shoreline
taken below LS-2 on the
same cliff
Date Collected
12/14/74
12/14/74
12/14/74
12/14/74
12/6/74
12/6/74
12/6/74
12/6/74
12/6/74
12/6/74
12/6/74
8
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TABLE 1: SEDIMENT AND SOIL SAMPLES (CONTINUED)
Desig- Sample
nation Type Sample Location Date Collected
LS-4 Soil Lake Superior shore- 12/6/74
line exposed clay bank
150 yards west of the
mouth of Dutchman's
Creek
LS-5 Soil Lake Superior shore- 12/6/74
line exposed clay bank
15 yards west of LS-4
BC-1 Soil Lake Superior shore- 6/4/75
line one mile west of
Bardon Creek 50 feet
above shoreline
BC-2 Soil Lake Superior shore- 6/4/75
line one mile west of
Bardon Creek 5 feet
above shoreline
BC-3 Soil Lake Superior shore- 6/4/75
line 20 yards east of
BC-2 just above the
sand beach
NP-1 River Nemadji River water 6/4/75
Particulate sample obtained at
Woodland Road bridge
site
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Two seven-week leaching experiments were performed using soil or sedi-
ment samples in Lake Superior or distilled water using a procedure similar
to that used by Plumb.0 The aqueous suspensions were equilibrated under
various conditions with respect to temperature, PH, dissolved oxygen and
degree of agitation. The general procedure for soils consisted of using ap-
proximately five grams of the air-dried soil sample in 10 liters of water in
a Pyrex container. Small chunks of each clay sample were placed on a #230
standard sieve (62.5y pore) and spray washed through the sieve using lake
water. The clay-water suspension was rinsed into the 10-liter flask and an
appropriate amount of water was added to bring the water volume to 10 liters
The residue and sieves were dried at 115°C for one hour and the weight of
residue was determined. This procedure removed the sand-size particles from
the sample and allowed a calculation of the weight of silt-clay size materi-
al in the flasks. Blanks containing only Lake Superior or deionized water
were also prepared. One liter of the water sample was removed by siphoning
(after allowing some settling of particles for stirred samples). The si-
phoning was performed using glass tubing in the apparatus and was begun em-
ploying a short spurt of purified air from an oil-less, dried, filtered,
compressed air source. After removing one liter of water, an additional
liter of Lake Superior water was added to bring the water volume back to 10
liters. The lake water used was obtained from the lake intake at the Envi-
ronmental Research Laboratory (ERL), Duluth, Minnesota. This experiment was
conducted at room temperature (23 to 28°C).
For the net removal and addition of one liter of water, 1.065 liters of
water was removed. Of this 1.065 liters, 65 ml was directly siphoned into a
65 ml dissolved oxygen bottle with the remaining liter put into a plastic
container. The one liter was centrifuged at approximately 2400 rpms
(1,580 X g) for approximately 30 minutes and 945 ml of the supernatant was
siphoned at the ERL for analysis. The remaining 65 ml, which contained the
large majority of the suspended material, was returned to the leaching flasks
along with 1 liter of lake water. Most of the supernatant liquid was then
filtered through either 0.1 micron or 0.45 micron membrane filters. Any
suspended material on the filters was rinsed back into the leaching flasks
with part of the liter of water. Of the 945 ml of water sample, approximate-
ly 150 ml was not filtered, this portion being used for conductivity and al-
kalinity measurements. The sample blanks were also subjected to the water
removal and addition procedure. The Lake Superior water used in portions of
the experiments was filtered before addition to the flasks. The water re-
ferred to as "distilled" was purified by passing tap water through a reverse
osmosis, adsorption-ion exchange process (Milli Q-2, Q-3 systems).
The experiments involving Lake Superior sediments were carried out using
procedures identical to those enumerated for the soil samples with the fol-
lowing modification. The sediment samples were not dried but moist subsamples
were weighed, divided in half, and one half of the sample was wet-sieved into
the flask. The other half of the sub-sample was dried at 100-105°C for a
dry weight determination.
10
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Low-oxygen water conditions were obtained by flushing the water for 20
minutes with pre-purified N2> employing a gas dispersion tube and N£ flushing
of the space above the solutions. Lowering the pH of certain of the solu-
tions was accomplished by saturating the water with C(>2 and monitoring the
pH upon removing a sample for analysis. The leaching at 4°C was performed
in a constant temperature room at the ERL, Duluth.
The parameters measured in the aqueous suspensions as a function of
time were total Kjeldahl nitrogen, orthophosphate, total soluble phosphorus
(phosphorus contained in a sample after it has been filtered through a 0.45
micron filter and digested in acid), nitrate, chloride, alkalinity, calcium,
magnesium, potassium, sodium,and conductivity. In addition, measurements of
temperature, pH,and dissolved oxygen were made. Analyses for these para-
meters were performed at the initiation of the experiments and one day, one
week, three weeks, five weeks,and seven weeks after initiation. The samples
and conditions used in these leaching experiments are listed in Table 2.
The clay-to-solution ratio used in these seven-week leaching experi-
ments (5 grams per 10 liters of water) result in suspended solid concentra-
tions which are of the same magnitude (500 mg/1) as could occur in Lake
Superior following intense weather events in the shoreline area. Tributary
rivers reach suspended solid concentrations of 1000 mg/1 for brief times
during high-flow periods. Using a higher clay-to-solution ratio could re-
sult in changes in the relative particle-size distributions toward higher
percentages of larger particles. Consequently the 500 mg/1 suspensions were
used. However, changes in the values of some of the parameters with time
were small (particularly sodium, potassium, magnesium,and calcium). Con-
sequently, the errors associated with the analytical determinations of these
parameters resulted in large uncertainties in their release magnitudes from
the clay. In order to achieve greater aqueous concentration changes in
these parameters with time [and decrease the per cent uncertainty in the
parameter release values as computed by equation (1)], the clay-to-solution
weight ratio was increased in a separate dissolution study. Two samples
were used in this leaching experiment, namely LS-5 (soil) and the upper
layer of the Dutchman's Creek-area core sample (sediment) as described in
Section 5 of this report. The clay-to-solution ratio was approximately one
gram per 500 ml of lake water or 2000 mg/1. The clay samples were weighed
into separate polypropylene one-liter containers. Twelve "identical" sus-
pensions for both the soil and sediment sample, along with six lake-water
blanks,were prepared. Duplicate suspensions of the soil and sediment sam-
ples were analyzed after one day, one week, three weeks, five weeks, seven
weeks and nine weeks. In preparing the suspensions, the clay samples were
wet-sieved into the sample containers to remove sand-size particles and,in
the case of the sediment suspensions, they were prepared under a nitrogen
atmosphere in a dry box,thus preventing exposure of the sediment to air in
the atmosphere. The suspensions were agitated by periodically shaking the
plastic containers.
In addition, a three-month separate leaching study was carried out for
silica,using plastic containers. The clay-solution ratio for the suspen-
sions was approximately 2000 mg/1. The suspensions were leached under both
11
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TABLE 2: SAMPLES AND CONDITIONS FOR SEVEN-WEEK LEACHING EXPERIMENTS*
Sample
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Sample
B-2 Soil
B-2 Soil
N-l Soil
N-l Soil
LS-1 Soil
LS-1 Soil
LS-5 Soil
None
SE-1 Sediment
SE-1 Sediment
DS-1 Sediment
None
N-l Soil
N-l Soil
LS-5 Soil
LS-5 Soil
None
NP-1 Particulate
LS-5 Soil
LS-5 Soil
None
DS-1 Sediment
LS-5 Soil
None
LS-5 Soil
LS-5 Soil
DS-1 Sediment
None
LS-5 Soil
LS-5 Soil
DS-1 Sediment
None
n2
°2
°2
high
high
high
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
high 02
low 02,
low 02,
low 02,
low pH,
low pH,
low pH,
low pH,
high 02
high 02
high 02
high 02
Conditions**
stirred
stirred
stirred
stirred
stirred
stirred
stirred
stirred
stirred
stirred
stirred
unstirred
unstirred
unstirred
unstirred
unstirred
stirred
stirred
stirred
, stirred
, stirred
stirred
stirred
stirred
high 02,
high 02, unstirred
high 02, stirred
high 02, unstirred
, stirred, 4°C
unstirred
, stirred, 4°C
, stirred, 4°C
, stirred, 4°C
*Clay-to-solution ratio is approximately 500 mg/1.
**A11 samples run at room temperature (23 to 27°C) at the normal pH of lake
water or deionized water unless indicated otherwise. Lake Superior water was
used in all systems except for sample numbers 19, 20, and 21, for which deion-
ized water was used.
12
-------
high -oxygen and low-oxygen water conditions employing both Lake Superior
water and deionized water as the leaching media. The conditions and samples
used in this study are summarized in Table 3.
RESULTS AND DISCUSSION
Four-Month Preliminary Leaching Experiments
The results of the four-month leaching study are shown in Table 4. This
study was intended as a longer-term leaching experiment on sediments to give
some estimate of those parameters which may be expected to show larger con-
centration changes in Lake Superior waters over this time period. The lake
water was not analyzed at the initiation of the experiment, and no Lake
Superior water blank was run concurrently with the samples. In addition,
adsorption affects on the walls of the containers might seriously affect
concentrations particularly of the soluble heavy metals. The values re-
ported here have not been used in any of the calculations of inputs given in
this report. However, since these data may be of some general interest, the
values have been tabulated. It can be conjectured from these data that in-
creases in alkalinity and specific conductance occurred particularly for
samples SE-1 and DS-1. The values of specific conductance for samples SE-1
and DS-1 had increased from the values normal for Lake Superior water by ap-
proximately 35 micromhos/ cm, which is equivalent to about 21 mg/1 of dis-
solved solids. The lake water in contact with sediment samples AR-1 and
DS-2 showed lower oxygen content, perhaps indicative of the presence of larg-
er amounts of oxygen-demanding material, although the 13.4 mg/1 oxygen value
for SE-1 is certainly questionable. Silica exhibited a three to sixfold in-
crease in the four leaching systems.
Seven-Week Leaching Experiments
The data for the seven-week leaching experiments pertaining to the sys-
tems summarized in Table 2 was treated by calculating the total release of
the particular parameter from the clay material with time (when applicable).
Using a leaching water volume of ten liters and noting that one liter of
water is removed and a new liter of water (lake or deionized) is added for
each analysis time, the total release in milligrams or micrograms is calcu-
lated by equation (1):
Rn = 10 1 - ] + 1<0 j X± - X^1] (1)
1-1 1-1
where ^ = concentration of the parameter in mg/1 or ug/1 in the leaching
water for the nth analysis
%Q - initial concentration of the parameter in the leaching water at
zero time
X1 = concentration of the parameter in the one liter of water added on
the day of analysis
13
-------
TABLE 3: SAMPLES AND CONDITIONS FOR SILICA-LEACHING STUDIES*
Sample
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Sample
SE-1 sediment
SE-1 sediment
SE-1 sediment
SE-1 sediment
None
SE-1 sediment
SE-1 sediment
SE-1 sediment
SE-1 sediment
None
LS-5 soil
LS-5 soil
None
LS-5 soil
LS-5 soil
None
LS-5 soil
LS-5 soil
None
Conditions**
high 02, unstirred
high 02, unstirred
low Qny unstirred
low 02, unstirred
low 02, unstirred
high 02, stirred
high 02, stirred
low 02, stirred
low 02, stirred
low 02, stirred
high 02, stirred
high 02, stirred
high 02, stirred
high 02, unstirred
high 02, unstirred
high 02, unstirred
high 02, stirred
high 02, stirred
high 02, stirred
*Clay-to-solution ratio is approximately 2000 mg/1.
**A11 samples run at room temperature (23 to 27°C) and at the normal pH of
lake water or deionized water.
Leaching Water Type
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Lake Superior Water
Deionized Water
Deionized Water
Deionized Water
14
-------
TABLE 4: FOUR-MONTH CLAY SEDIMENT LEACHATE RESULTS
Sample*
SE-1
DS-1
AR-1
DS-2
Copper
(yg/D
7
4
7
8
Aluminum
(ye/D
-------
and Rn = total release in milligrams or micrograms for the nth analysis
In order to correct for changes in the values of a particular parameter
with time due to effects not associated with clay interactions (such as
leaching from the walls or adsorption from the container walls), Rn values
were computed for the blanks containing no clay samples. The appropriate
Rn blank value was subtracted from the Rn value of the parameter in the clay-
water systems at the same conditions as the blank. The resulting difference
was divided by the dry weight of the clay sample and these values tabulated
in mg or ug of the parameter released per gram of the clay samples as a
function of time. The data was grouped according to all samples leached for
each parameter. This data along with the pH, specific conductance, and dis-
solved oxygen versus time values are listed in Tables A-l through A-14 in
Appendix A. Summaries of the data for leaching the soil, sediment, and river
particulate samples at two leaching times (one day and seven weeks) are giv-
en in Tables 5 and 6.
Similarly, the total corrected release values for the silica-leaching
experiments (Table 3) were computed and tabulated in Table 7. The addition-
al experiment involving leaching of one clay soil and one clay sediment sam-
ple in plastic containers at solid-to-solution ratios of about 2000 mg/1 are
listed in Table 8 in terms of total corrected releases. These results will
be summarized according to the changes found for each parameter as tabulated
in these tables.
Dissolved Solids—
The amount of dissolved solids in the soil-water systems progressively
increased with time under all conditions. The amount of dissolved solids
increase was twice as large under highly oxygenated water conditions com-
pared to low-oxygen conditions. Lowering the pH to approximately 5.5 (from
the normal pH of Lake Superior water) resulted in a sixfold increase in dis-
solved solids. Twice as much solid material dissolved from soil samples in
deionized water as found for Lake Superior water. Temperature had only a
small effect on the amount of dissolved solids.
The sediments released smaller amounts of dissolved solids in water
than the soil samples. In particular, the sediments did not show the large
initial dissolution of solids as exhibited by the soils, but a steady disso-
lution with time did occur. However, under low-x>xygen water conditions, no
release of solids from the sediments was detected. Release of dissolved
solids from the Nemadji River particulate sample was similar to that found
for soil samples.
Alkalinity-
Soil samples exhibited alkalinity releases equivalent to 12 to 140 mg
of CaCC>3 per gram depending on conditions. The samples at a low pH gave the
greatest releases while leaching under low-oxygen water conditions gave the
smallest. When deionized water was used as the leaching agent in place of
Lake Superior water, the alkalinity increase was more than doubled. Alka-
linity release was the same within experimental error at 4°C as at room
temperature.
16
-------
TABLE 5: SUMMARY OF CLAY SOII^WATER CHEMICAL EXCHANGES* IN MG OF PARAMETER PER G OF CLAY
Samples
Conditions
Leaching Time
Parameter
Dissolved Solids
Alkalinity
Orthophosphate
(P04)
Total Soluble P
Nitrate
Chloride
Total Kjeldahl N
Sodium
Potassium
Calcium
Magnesium
1 through 7
Stirred, high 02,
Lake Superior wa-
ter, 23-26°C
One Day
12.3
(1.0)
11.7
(1.6)
.029
(.008)
0.008
(0.005)
0.03
(0.07)
0.41
(0.30)
0.12
(0.06)
0.24
(0.11)
0.41
(0.04)
1.52
(0.67)
0.80
(0.51)
7 Weeks
24.4
(2.0)
23.2
(1.5)
.016
(.008)
0.036
(0.021)
0.06
(0.15)
0.27
(0.72)
-0.02
(0.07)
0.23
(0.65)
0.42
(0.15)
6.13
(1.40)
0.92
(0.39)
13 through 16
19 and 20 23 25 and 26
29 and 30
Unstirred, high 02, Stirred, high 02, Stirred, low 02, Unstirred, high 02, Hlgh 0^ 8tlrred
Lake Superior wa- Deionized water, Lake Superior wa- lower pH, Lake Supe- Lake Superior wa-
ter, 23-26°C 23-26°C ter 23-26°C rior water, 23-26OC ter, 4°C
One Day
10.6
(0.6)
7.6
(0.6)
0.022
(0.006)
0.010
(0.003)
0.03
(0.08)
-0.40
(0.18)
0.04
(0.03)
0.16
(0.11)
0.33
(0.12)
2.13
(0.80)
0.93
(0.27)
7 Weeks
23.8
(0.2)
20.2
(0.8)
0.033
(0.009)
0.009
(0.004)
-0.06
(0.13)
-0.29
(0.21)
0.38
(0.12)
0.16
(0.02)
3.89
(2.56)
1.12
(0.13)
One Day
42.6
(0.5)
32.8
(1.8)
0.056
(0.007)
0.023
(0.021)
0.19
(0.04)
0.06
(0.04)
-0.25
(0.03)
0.14
(0.11)
0.40
(0.00)
10.41
(0.16)
2.49
(0.06)
7 Weeks One Day
61.0 6.7
(0.9)
50.9 7.6
(1.6)
0.042 0.027
(0.002)
0.013 0.008
(0.002)
0.13 -0.12
(0.007)
-0.47 -0.21
(0.28)
-0.14
0.74 0.10
(0.00)
0.45 0.29
(0.08)
16.16 2.30
(0.30)
3.45 0.94
(0.02)
7 Weeks One Day
12.2 87.4
(5.9)
14.1 79.4
(1.2)
0.029 0.067
(0.005)
0.004 0.017
(0.014)
-0.98 0.18
(0.11)
-0.12 0.21
(0.14)
t\ A1
— — — O.OJ
(0.04)
0.79 0.41
(0.18)
0.11 0.32
(0.03)
2.64 20.27
(3.11)
0.51 2.17
(0.06)
7 Weeks
139.1
(8.3)
139.5
(6.8)
0.063
(0.010)
0.014
(0.015)
0.15
(0.04)
-0.08
(0.02)
0.14
(0.06)
-0.03
(0.26)
0.37
(0.02)
26.24
(2.86)
2.65
(0.08)
One Day
15.9
(0.02)
14.6
(1.6)
0.015
(2x10-5)
0.014
(0.003)
-0.10
(0.17)
-0.09
(0.03)
-0.06
(0.03)
0.47
(0.03)
0.15
(0.01)
3.19
(0.72)
0.98
(0.04)
7 Weeks
30.0
(15.2)
33.5
(9.6)
0.032
(0.0004)
0.012
(0.003)
0.14
(0.06)
-0.14
(0.11)
-0.01
(0.24)
0.34
(0.02)
0.58
(0.42)
6.85
(3.13)
1.04
(0.09)
*Posltlve values
deviations. See
denote release from the clay while negative values
Table 2 for sample Identification.
indicate uptake by the clay. Values in parentheses represent stands
-------
00
TABLE 6: CLAY SEDIMENT AND RIVER FARTICULATF, CHEMICAL EXCHANGES IN MG OF
27
PARAMETER PER G OF CLAY
31
18
Samples*
Conditions
Leaching Time
Parameter
Dissolved Solids
Alkalinity
Orthophosphate
Total Soluble P
Nitrate
Chloride
Total Kjeldahl N
Sodium
Potassium
Calcium
Magnesium
9 through 11 22
Stirred sediment,
high 02, Lake Supe-
rior water, 23-27°C
One Day
0.41
(0.36)
0.51
(1.41)
0.016
(0.014)
0.006
(0.005)
0.15
(0.04)
-0.63
(0.62)
0.01
(0.06)
0.20
(0.17)
0.06
(0.06)
-0.097
(0.37)
0.14
(0.13)
7 Weeks
12.8
(1.6)
10.3
(0.8)
0.063
(0.027)
0.023
(0.002)
0.38
(0.19)
-0.21
(0.11)
0.97
(0.32)
0.24
(0.11)
-0.54
(2.65)
1.89
(0.25)
Stirred sediment, Stirred sediment, Stirred sediment, Nemadji River par-
low 02 Lake Superior low pH, high 02, Lake high 02, Lake Su- ticulate, stirred,
water 23-27°C Superior water, 23-27°C perior water, 4°0 high 02, Lake Supe-
' rior water, 23-27°C
One Day 7 Weeks One Day 7 Weeks One Day 7 Weeks One Day 7 Weeks
-3.0 -1.8 15-5 19.4 0.5 1.8 1-7 39.4
_2.! +2.2 19.3 26.5 -1.2 2.9 0.5 34.8
0.004 0.063 0.074 0.079 0.011 0.028 0.043 0.132
O.oil 0.014 0.033 0.028 0.011 0.007 0.048 0.042
-0.10 -0.43 0.26 0.02 -0.24 0.04 0.05 3.1
0.01 -0.20 0.46 -0.15 -0.12 -0.14 0.80 0.37
n ,, — 0 0.24 -0.07 -0.30 -0.11 0.48
— U . <-l
_0.14 0.54 -0.04 0.46 0.51 0.18 0.19 0.10
0.20 0.24 0.15 0.40 0.03 0.21 0.24 0.24
-0.70 -0.84 7.6 3.6 0.28 -0.98 0 1.6
0.02 -0.27 1-37 1.47 0.17 0.51 0.34 1.37
*See Table 2 for sample identification.
-------
TABLE 7: TOTAL CORRECTED RELEASE OF SILICA IN MG OF S102 PER G OF CLAY
Days
Leached
Sample*
1
2
3
4
6
7
8
9
11
12
14
15
17
18
1
0.04
0.01
0.11
0.15
-0.01
Q.O-/
0.16
0.14
0.56
0.72
0.61
0.51
8
0.22
0.15
0.79
0.40
0.61
0.41
0.34
0.74
0.70
1.18
0.31
0.47
15
0.51
0.47
0.93
0.88
0.46
0.46
0.72
0.67
1.20
1.21
0.99
0.97
1.17
1.18
22
0.84
0.72
1.01
0.96
0.81
0.42
0.75
0.75
1.14
1.07
1.04
0.96
1.32
1.48
36
0.90
1.18
1.35
1.30
1.05
1.12
1.02
1.17
1.53
1.52
0.99
0.94
1.45
1.44
44
1.29
1.19
0.92
1.65
0.97
1.09
1.34
1.04
1.68
1.38
1.19
1.21
1.69
2.02
53
1.29
1.56
1.09
2.02
1.03
1.08
1.32
1.62
1.31
1.46
1.24
1.14
1.69
1.89
64
1.95
1.98
2.22
2.32
1.44
1.47
2.16
1.83
1.54
1.55
1.26
1.28
1.91
2.22
78
2.31
2.30
2.36
2.32
1.17
1.63
2.57
2.06
1.62
1.75
1.51
1.48
2.10
2.52
93
2.82
2.84
3.15
2.88
2.41
2.47
3.18
2.39
1.82
1.74
1.41
1.32
2.28
2.61
*Samples and Experimental conditions are described in Table 3.
-------
TABLE 8: TOTAL CORRECTED CHEMICAL EXCHANGES FROM CLAY SOIL AND SEDIMENT
SAMPLES
A. Sample: LS-5 Soil Sample in Lake Superior Water
Days Leached
Calcium
Magnesium
Sodium
Potassium
B. Sample:
Days Leached
Calcium
Magnesium
Sodium
Potassium
1 7
-0.52 1.13
0.55 0.35
0.15 0.14
0.17 0.20
Lake Superior Sediment
Sediment in
CHEMICAL
1 7
-0.24 0.11
0.05 0.13
0.05 0.04
-0.02 0.05
21
0.70
0.38
0.11
0.18
35
1.94
0.50
0.15
0.20
49
1.65
0.46
0.17
0.21
63
1.49
0.71
0.18
0.20
- Upper Layer of Dutchman's Creek-Area
Lake Superior Water
EXCHANGES (mg
21
-0.17
0.18
-0.04
0.05
parameter/g of clay)
35
0.58
0.30
0.04
0.12
49
0.79
0.26
0.06
0.13
63
0.58
0.36
0.07
0.05
20
-------
Sediments in water under the same conditions as the soils gave smaller
alkalinity releases. Little or no alkalinity change was found in Lake Supe-
rior water under low-oxygen conditions. A smaller increase in alkalinity
was found at a lower temperature (4°C) but this conclusion is based on only
one sample. The alkalinity release for the Nemadji River particulate sam-
ple was larger than that found for soils.
Orthophosphate and Total Soluble Phosphorus—
The releases of orthophosphate amounted to 20 to 40 micrograms of PO^
per gram of solid for soils in Lake Superior water. A rapid initial re-
lease occurred followed by a possible slight decline after a time of about
one day. Use of deionized water in place of Lake Superior water resulted in
increased releases as did lowering the pH. Little effect was noted with
temperature or oxic conditions of the water. A more detailed study of the
soil-orthophosphate systems is given in Section 6. The release values for
total soluble phosphorus showed more scatter than the orthophosphate data
with time. Releases ranged from 10 to 60 micrograms of phosphorus per gram
of soil under Lake Superior conditions. An apparent lower release was noted
under low-oxygen conditions with no definite conclusions possible from the
data on pH and temperature effects.
Sediment releases of soluble phosphorus are comparable to those for
soils (10 to 25 micrograms of P per gram of sediment) under normal Lake
Superior water conditions. Lowering the pH increased the release somewhat.
The Nemadji River particulate sample gave a larger release than any of the
soil or sediment samples (about 70 micrograms of P per gram of particulate
matter). The orthophosphate release was greater for sediment samples than
for soil samples with the release occurring over a longer time period. A
lower pH increased the rate and total release of orthophosphate. The pH
effect on total phosphorus release is inconclusive due to the scatter in
the data. The Nemadji River particulate sample gave the largest orthophos-
phate release (about 150 micrograms of P04 per gram of particulate matter)
over the seven-week period. This larger release is discussed further in
Section 6.
Nitrate—
The data in Appendix A show that the release values for nitrate are
small. Under well-oxygenated Lake Superior water conditions, soil samples
tended to show some release of nitrate on the order of 0.1 mg of N03 per
gram of soil. Under low-oxygen water conditions a loss of nitrate from the
lake water was found. The scatter in the release values for the sediment
samples results in no definite conclusions except that the nitrate exchange
is relatively small. The Nemadji River particulate sample showed a compara-
tively large net release of nitrate on the order of 3 mg of N03 per gram of
particulate material.
Chloride—
As for nitrate, there is little change in chloride with time within the
experimental accuracy as reflected in the fluctuations in the release values.
It is concluded that soils have little effect on the chloride concentrations
in Lake Superior water. The values listed for samples 1 through 7 in Table
5 are influenced by a relatively large release for sample 1 which may have
21
-------
been contaminated. If this sample is ignored, the data indicates a total
release of chloride of less than one mg per gram of clay. Sediment-water
exchange of chloride was also small.
Total Kjeldahl Nitrogen— , .«.
The data indicate clay effects on the ammonia and organic nitrogen
levels in Lake Superior were small. The low levels of ammonia and organic
nitrogen in the lake water cause difficulty in detecting removal of organic
material containing nitrogen. Experiments carried out at higher concentra-
tion levels of the nitrogen-containing compounds would be necessary to in-
dicate the occurrence of clay adsorption or decomposition at the particle
surface. There was no indication of organic containing nitrogen being re-
leased by the soil or sediments at levels above 0.2 mg of N per gram of clay.
Sodium and Potassium—
Although the data for sodium shows more scatter than that for potassium,
the results show that both sodium and potassium are released from the clay
soils. The release was relatively rapid in the case of soils and the con-
centrations of these parameters in lake water assumed steady values after
the first day of leaching. The average release of sodium for the soil sam-
ples is 0.23 mg of Na per gram of soil for the 500 mg/1 suspensions. A
greater release was found in deioiiized water (about 0.7 mg per gram of soil).
The data for the one sample under low oxygen conditions was inclusive. A
somewhat smaller release was shown in Table 8 for the 2000 mg/1 suspensions.
This decrease in release with increase in clay-to-solution ratio is also
seen for potassium, calcium,and magnesium. This may result from a greater
exposed surface area per gram of clay in the lower clay-water ratio suspen-
sions due to a smaller degree of particle flocculation. The release of
potassium was somewhat higher than that for sodium. Thus a 0.4 mg of potas-
sium per gram of clay soil was recorded for the 500 mg/1 suspensions and
about 0.2 mg released in the 2000 mg/1 suspensions. Little or no difference
was found for potassium release in deionized water as compared to Lake Supe-
rior water A smaller release was indicated under low-oxygen conditions
(only one sample) while lowering the PH had little effect on potassium re-
lease from soils.
The data in Table 6 for sodium release from sediments is inconclusive
because of large variations in the releases with time. However the data in
Table 8 show a smaller release for sodium in sediments than soils (0.07 mg
or less of sodium per gram of sediment). Similarly, potassium exchange
values were smaller for the sediments (about 0.2 mg of potassium for 500
mg/1 and 0.1 mg of potassium for 2000 mg/1 suspensions). Release of potas-
sium from the Nemadji River particulate sample was similar in magnitude to
that for sediments.
3 C The data indicate an approximate release of 6 mg of calcium per gram of
soil in Lake Superior water (500 mg/1 suspensions). This value is two to
three times greater in deionized water and lower under low-oxygen conditions.
A lower PH caused a greater flux of calcium to the solution (about 25_mg of
Ca per gram of soil). No significant difference was found with changing
temperature.
22
-------
The sediment data showed a much smaller release and possibly a removal
of calcium from solution although the results are not conclusive. Data in
Section 5 indicate some flux of calcium from sediments to the lake water.
The Nemadji River particulate sample released less than 6 mg of Ca per gram
of particulate material.
Magnesium—
Lake Superior water removed about 0.9 mg of Mg per gram of soil in the
500 mg/1 suspensions while a removal of about 0.6 mg occurred in the 2000
mg/1 suspensions. The release is quadrupled in deionized water (about 3.4
mg of Mg) but little difference is shown for changes in oxygen content of
the water. A lower pH (about 5.5) triples the release in lake water. A
temperature change from about 25°C to 4°c shows no detectable effect.
The data in Table 6 indicates a greater release for sediments than
soils but the data in Table 8 shows a smaller release. We conclude that the
sediments do provide magnesium to the lake water in the range of 0.5 to 2.0
mg of Mg per gram of dry sediment for the 500 mg/1 level and the magnitude
of the release is still increasing after seven weeks. The Nemadji River
particulate sample releases 1.0 to 1.5 mg of Mg per gram.
Silica—
The data in Table 7 indicate progressive releases of silica over the 93-
day period for both the soil and sediment samples under both high-and low-
oxygen water conditions. The sediment samples release more silica than
found for the soils (about 3 mg of Si02 per gram of sediment and 1.8 mg of
Si02 per gram of soil). Using deionized water as the leaching medium re-
sulted in a 25% increase in dissolved silica.
Projection of Release Values to Lake Superior Chemical Inputs
The magnitudes of the chemical parameter inputs to Lake Superior from
shoreline erosion (for those parameters considered thus far) may be estima-
ted from the data presented in Table 5 (seven-week leaching) and Table 8
(3-month leaching). Particle-size distributions for some soil samples are
shown in Table 9. For a number of these samples, only the sand-size parti-
cle percentages were determined during the wet-sieving process. The data
for LS-2, BC-1, BC-3, B-l, N-l and LS-5 indicate that generally less than
10% of the soil sample consists of sand-size particles. Sample BC-2 was
collected at a point 5 feet from Lake Superior and some of the fine materi-
al may have been washed out of the soil by wave action before it was col-
lected. Consequently, approximately 90% of the material in the soil samples
were used in the seven-week leaching experiments and silica-leaching studies.
As stated in the introduction, the total amount of eroded material entering
Lake Superior in Wisconsin due to shoreline erosion is estimated at 8 x 10"
metric tons. Due to the small percentage of sand contained in the samples
and the uncertainty of the shoreline erosion estimate, this figure will be
used to estimate chemical inputs.
The results of the estimated inputs of the chemical parameters to Lake
Superior is summarized in Table 10. The shoreline erosion contribution was
computed by using the value of 8 x 106 metric tons of eroded material per
23
-------
TABLE 9: PARTICLE-SIZE DISTRIBUTION IN CLAY-CONTAINING SAMPLES
% Silt % Coarse
% Sand 3.9 to Clay 1.1
>62.5y 62. 5y to 3.9y
5 57 35
6 36 51
31 31 31
9 19 64
13
6
4
4
0.1
% Fine
Clay
<1.4y
3
7
7
9
Sample*
LS-2
BC-1
BC-2
BC-3
B-l
N-l
LS-1
LS-5
NP-1
*Samples are described in Table 1.
24
-------
year. The values for dissolved solids, alkalinity, and silica are denoted
as being lower limits because of the continued increase of these parameters
with time. The release of many of the parameters were initially large and
then assumed a smaller steady increase with time (dissolved solids, alkalin-
ity, and silica) while others reached steady values or even decreased at
longer time periods. The time of suspension of the particulate material in
Lake Superior water is not well known but since most of the fine material
eventually is deposited in deeper regions of the lake (at which point the
release from the clays would be associated with flux from the lake sedi-
ments), these seven-week leaching studies (93 days for silica) could be con-
sidered as reasonable estimates of contributions by suspended clay particles
from shoreline erosion. Another factor to be considered is the possible in-
creased releases per unit weight of suspended material in lower solid-to-
water suspension ratios. In addition, leaching in large volumes of water,
in which case the value of the parameter does not significantly increase in
the water, could result in larger releases for some of the parameters.
The estimated inputs for the Nemadji River were computed by using a
value of 2.8 x 10^ metric tons of material as an annual suspended solids
load. This represents predominately fine-sized material in the river and
assumes that 54% of the 5.1 x 105 metric tons is carried into Lake Superior.3
In terms of the contributions from all Wisconsin streams due to suspended-
clay particles, the values in Table 10 would be approximately 35% higher
since the Nemadji accounts for 86% of the sediment load from Douglas and
Bayfield Counties and the river banks in these counties include 80% of the
total stream banks which are classified under very severe or severe erosion.
Estimates would assume that particles from the Nemadji River are similar in
properties to those from other rivers.
25
-------
TABLE 10: CHEMICAL RELEASES AND INPUTS TO LAKE SUPERIOR FROM SHORELINE AND RIVER EROSION
K>
Chemical Release From Clays
(mg parameter per gram of sample)
River
Soils Particulates
Inputs to Lake Superior From Erosion
(metric tons per year)
Nemadjl River
Shoreline Erosion Particulates
Dissolved Solids*
Alkalinity* (CaCOj)
Orthophosphate*** (P0$)
Total Soluble P
Nitrate (N03)
Chloride
Total KJeldahl N
Sodium
Potassium
Calcium
Magnesium
Silica*
24 + 3**
23 + 2
0.030 + 0.010
0.036 + 0.020
0.05 + 0.05
< 0.1
< 0.2
0.25 + 0.20
0.42 + 0.15
6 + 3
0.9 + 0.4
1.8 + 0.4
40 + 5
35 + 5
0.150 + 0.050
0.060 + 0.030
3 + 1.5
< 0.5
0.25 + 0.20
1.5 + 1.0
192,000 + 40,000
184,000 + 40,000
240 + 80
280 + 160
400 + 400
<• of\n
< oUU
< 1,600
2,000 + 1,600
3,400 + 1,200
48,000 + 24,000
7,200 + 3,200
14,400 + 3,200
11,000 + 1,400
9,800 + 1,400
43 + 13
17 + 9
840 + 430
< 130
69 + 55
430 + 280
*Lower limits since the values were still increasing at the termination of the experiments.
**The uncertainties are estimated from consideration of standard deviations for the soil samples (Table 5), interlaboratory
analytical comparisons, and fluctuations in the analysis of the parameter with time (Appendixes A and B and Table 7).
***See also Section 6.
-------
SECTION 5
WATER-SEDIMENT CHEMICAL PARAMETER EXCHANGE AND
SEDIMENT-INTERSTITIAL WATER CHARACTERISTICS
GENERAL PROCEDURES
The chemical characteristics of the interstitial waters in near-shore-
line and river sediments containing clay minerals in conjunction with infor-
mation pertaining to the degree and rate of exchange of chemical components
across the sediment-water interface is important in understanding the effects
of sediment leaching and sediment resuspension on the chemical composition of
the lake waters. Information on sediment leaching and resuspension effects
was obtained by collecting core samples thought to be characteristic of red
clay-containing river or lake bottom. Chemical analysis was performed on the
interstitial water and water overlying the sediment along with certain analy-
sis of the sediment itself. Sediment cores from the same locations as those
analyzed at the time of collection were stored at 4°C and the interstitial
and overlying water reanalyzed at one month and in some cases two-month peri-
ods.
Four sampling locations were chosen for obtaining core samples (Figure
1). Five or six cores at each location were collected in 2-1/2 inch i.d.
(6.3 cm) cellulose acetate butyrate core liners which were 4 feet (1.2 m) in
length. One set of cores was taken from the bed of the Nemadji River at ap-
proximately a 10-foot (3.0 m) depth. This set of cores was obtained by a
diver. The clay material in these cores is probably characteristic of the
original glacially deposited lacustrine red clay which is being eroded by the
river flow. A second set of cores was collected from the near-shoreline re-
gion of Lake Superior approximately one mile (1.6 km) west of Bardon Creek
in a water depth of one foot (0.3 m). The clay material in these cores also
could be representative of originally deposited clay but in addition might
contain contributions from clay material which had entered the lake from
shoreline erosion upon the collapse of a section of clay bank. The appear-
ance and consistency of the solid material was that of hard-packed red clay
with some interdispersal of gray clay. A third sampling location was approx-
imately 1/2 mile (0.8 km) east of the Superior entry to the Superior Harbor
(Superior, Wisconsin) at a water depth of 72 to 75 feet (22 to 23 m) at a 3~
mile (4.8 km) perpendicular distance from the Lake Superior shoreline. Cores
at this location were obtained using a Benthos-type 217 gravity corer. The
sediment was loosely packed material characteristic of recently sedimented
particulates. The fourth location was approximately 1/2 mile (0.8 km) east
of Dutchman's Creek at a water depth of 68 to 72 feet (21 to 22 m) at a
27
-------
perpendicular distance of approximately four miles (6.4 km) from the Lake
Superior shoreline. These sediments also contained recently deposited mate-
rial.
Attempts to obtain core samples containing significant quantities of
deposited clay from shallower regions of the lake were unsuccessful. At
these shallower regions, the sediment consisted of sand and gravel although
a fine layer of clay covered the fine sand at certain locations. This indi-
cates that the large majority of clay-sized particles entering Lake Superior
from erosion are transported to deeper areas of the lake.
The cores consisted of material which occupied from seven to fifteen
inches of the core liner with the remainder of the space filled with over-
lying Lake Superior water. Generally, the smaller clay cores were obtained
from the hard-packed material from the Nemadji River and Bardon Creek area
sampling location of Lake Superior.
Upon obtaining the cores, the solid material contained in one core from
each location was analyzed for Eh, pH, total volatile solids, chemical oxy-
gen demand, total phosphorus, total iron, Kjeldahl nitrogen,and particle-
size (pipet-sedimentation method). All analyses except Eh and pH were per-
formed on two sections of the core (upper layer near the sediment-water in-
terface and a lower layer). The specific analytical procedures are summa-
rized in Appendix C. The remaining cores were stored at 4°C in a constant-
temperature room (Environmental Research Laboratory, Duluth, Minnesota).
Within two days of sampling, the overlying and interstitial water in the sed-
iment was chemically analyzed. This analysis procedure was repeated at a
one-month interval for cores from each location and at a two-month period
for the Nemadji River and Dutchman's Creek-area cores.
The method for obtaining the overlying and interstitial water was simi-
lar to the procedure used by Glass and Poldoski.7'8 The overlying water was
sectioned into four zones above the sediment. For a given section, a sample
was siphoned for a dissolved oxygen sample with the remainder siphoned into
an acid-washed polypropylene bottle. A small layer in the lower section
(approximately one inch) of water was left above the sediment. The core
liner was transferred to a nitrogen glove bag and the system flushed with
nitrogen. The remaining one inch of water above the sediment was removed by
pipet and added to the lowest section of the overlying water. The sediment
was then pushed up the liner and 1-1/2-inch sections were sliced and placed
in Whirl Pak bags. Generally, three 1-1/2-inch sections were obtained. The
sediments in the bags were homogenized and the contents of each were trans-
ferred to interstitial water preparation cells.7 The cells were pressurized
with nitrogen (40 psi), centrifuged at 4°C at 2400 rpms (1,580 X g) for 1/2
hour, repressurized twice,and centrifuged for two more 1/2-hour periods.
The water preparation cells were returned to the glove bag and the extracted
interstitial water was filtered using 0.1 micron membrane filters directly
into acid-conditioned polypropylene bottles.
Unfiltered portions of the overlying water were analyzed for pH, spe-
cific conductance, dissolved oxygen, and alkalinity while filtered portions
(0.45 micron filters) were analyzed for orthophosphate, silica, sodium,
28
-------
potassium, calcium, magnesium, copper, manganese, cadmium, zinc, iron, alu-
minum, lead, chromium,and nickel. The interstitial water was analyzed for
the same parameters except pH, alkalinity, specific conductance,and dissolved
oxygen. In addition, interstitial water from one Dutchman's Creek-area core
and one Superior entry-area core was sent to the EPA, Region V Laboratories,
Chicago, for mercury, arsenic, and selenium measurements.
Upper and lower-layer sediment samples from a Superior entry-area core
were sent to ABC Analytical Biochemistry Laboratories, Columbia, Missouri.
These samples were analyzed for chlorinated hydrocarbons, PCBs, arsenic,
cadmium, zinc, lead, selenium,and mercury.
RESULTS
The analysis of the core samples for a number of parameters is summa-
rized in Tables 11 and 12. The particle-size analysis shows that the cores
composed of glacially deposited material (Nemadji River and Bardon Creek)
contained higher percentages of finer-sized particles than the Lake Superior
sediment cores (Superior entry and Dutchman's Creek). The percentages desig-
nated as A represent the distribution of material into particle sizes if it
was dispersed in water while those percentages designated as B were meas-
ured using a peptizer (Calgon) and are representative of the actual particle-
size distribution in the samples. The Superior entry and Dutchman's Creek
cores contained large amounts of fine sand-size particles and only about 10%
in the clay-size range. Consequently upon resuspension, only about 10% of
the material in the sediment would remain suspended for relatively longer
time periods. For example, all particles greater than 3.9 microns settle a
distance of about 4 feet (1.2 m) in 24 hours at 20°C in still waters. The
Bardon Creek area core contained high percentages of clay-size particles
which are the source of much of the continual water turbidity near the Bardon
Creek to Amnicon River shoreline area.'
The Dutchman's Creek-area Lake Superior core contained a much higher
percentage of phosphorus in comparison to the others. The Nemadji River
core had the highest percentage of oxygen-demanding material. The Lake Supe-
rior sediments contained smaller percentages of iron than those cores repre-
sentative of the glacially deposited material.
Chemical analysis for chlorinated hydrocarbons and certain metals (by
ABC Analytical Biochemistry Laboratories, Columbia, Missouri) on the Superi-
or entry core and one clay soil sample obtained from clay banks along the
Nemadji River is tabulated in Table 13. The results for the chlorinated hy-
drocarbons show that only aldrin was detectable in any of the samples within
the limits of measurement. The upper layer of the Superior entry sediment
sample was higher than the lower layer in all detectable metals. There were
no large differences between the levels of metals in the soil and sediment
samples.
The results of the analysis of the interstitial and overlying water in
the cores from the four areas are tabulated in Tables 14, 15, 16 and 17.
The data from two of these areas have been plotted in Figures 2 and 3.
29
-------
TABLE 11: SEDIMENT CORE ANALYSIS
Parameter
Sample
Nemad j i
River
Superior
Entry
Bardon
Creek
Dutchman
Creek
Depth*
(Cm) PH
3.8
6.2
8.9
3.8
6.6
8.0
2.2
7.0
7.9
1.6
6.3
7.3
Total
Solids
61.5
62.4
x=61.9
66.8
74.2
x=70.5
58.8
63.8
x=61.3
70.4
67.3
x=68.9
COD**
(ppm)
34,450
35,900
x=35,150
18,650
7,050
x-12,850
10,650
6,750
x=8,700
10,300
7,700
x=9,000
Total P**
(ppm)
18.4
15.7
x-17.1
17.1
24.2
x-20.7
2.3
5.2
x-3.8
65.8
45.7
x=55.8
Total
Fe**
2.7
2.7
x=2.7
1.7
2.1
x-1.9
4.8
5.1
x=5.0
1.6
2.4
x=2.0
Kjeldahl
N**
(ppm)
480
450
x- 465
304
540
x-422
210
208
x-209
220
165
x-193
Eh (mv)
+460 at 0.25 cm
4-
+405 at 4.1 cm
+20 at 0.64 cm
-161 at 4.4 cm
+55 at 0.63 cm
•t
+60 at 3.8 cm
+136 at 0.64 cm
+173 at 3.8 cm
*Value given is midpoint of depth of core sample analyzed from top. Complete sample includes between 1.3 to 2.5 cm on
either side of depth value.
**Value based on sample dried at 105°C.
-------
TABLE 12: PARTICLE-SIZE ANALYSIS
% Coarse
Parameter
Sample
Nemadji
River
Superior
Entry
Bardon
Creek
Dutchman
Creek
Depth
(Cm)
3.8
8.9
3.8
8.0
2.2
7.9
1.6
7.3
% Sand
(>62.5y)
A* B*
9 9
10 9
74 65
79 82
6 9
14 9
81 68
71
% Silt
(3.9-62.
A*
74
71
15
8
50
31
12
15
5y)
B*
65
76
19
7
14
11
9
Clay
(1.4-3.
A*
6
8
9
7
20
18
6
8
9y)
B*
9
4
4
9
39
11
9
% Fine
<<1.
A*
11
11
2
4
24
38
1
6
Clay
4v)
B*
17
11
12
2
38
69
13
*A refers to sample dispersed in distilled water and B refers to sample
dispersed in distilled water with peptizer added.
31
-------
CO
NJ
TABLE 13: CHEMICAL ANALYSIS* OF SUPERIOR ENTRY LAKE SUPERIOR CORE AND NEMADJI RIVER SOIL SAMPLE
Endrin,
o.p-DDT,
, ^ p.p-DEE, p.p-DDE,
Sample** PCB Aldrin Dieldrin P.p'-DDT Pb H£ Zn Se As Cd
Superior Entry,
Se^imenT" °f <0'04 <0-°°2 <0-°°4 <0'01 8'6 «-"3 3L» <0-01 12.2 0.23
Superior Entry,
S^iLntyer0f <0'04 <0-°°2 <0-°°4 <0'01 3'2 0-">4 22.1 <0.01 9.0 0.03
Nemadji River
Soil Sample <0.04 0.003 <0.004
<0.01 7.2 0.202 38.2 <0.01 11.1 0.16
**Samples contained 46.8, 30.3 and 30.2Z water, respectively.
-------
TABLE 14: CHEMICAL ANALYSES OF NEMADJI RIVER SEDIMENT CORE AND OVERLYING WATER
Distance From Dn,
Sediment-Water
Interface (cm)
62
Day
Values
30
Day
W
OJ
Values
Initial
Values
75-100
50-75
25-50
0-25
0
0-3.8
3.8-7.6
7.6-11.4
75-100
50-75
25-50
0-25
0
0-3.8
3.8-7.6
7.6-11.4
50-100
0-50
0
0-3.8
3.8-7.6
7.6-11.4
£H
7.35
7.40
7.41
7.42
7.50
7.51
7.51
7.82
6.2
S.C.*
272
272
272
272
255
255
255
267
°2
mg/1
8.1
8.4
8.1
5.9
5.8
6.0
6.9
8.7
7.6
t \Jlj
Pg
P04/1
11
9
12
32
154
835
10
2
12
12
35
38
138
236
471
Alk**
134
131
131
134
118
118
121
153
S102
mg/1
11.6
11.1
11.6
11.4
S e d
15.9
10.6
10.6
10.7
11.2
S e d
18.3
15.2
10.1
10.3
S e d
19.6
23.1
26.8
Na
mg/1
4.7
4.9
4.9
5.3
i m e n
6.3
10.5
3.8
3.7
3.7
4.5
1 m e n
6.1
4.2
4.1
i m e n
6.5
6.7
>10
K
mg/1
1.32
1.41
1.39
1.33
t - W a
1.91
1.99
1.16
1.14
1.16
1.08
t - W a
1.89
1.25
1.31
t - W a
1.80
1.80
1.80
Ca
mg/1
42.3
39.0
39.3
38.1
t e r
51.0
72.0
33
33
34
38
t e r
37.8
34.6
29.8
t e r
32
32
35
Mg
mg/1
10.1
10.3
10.1
9.9
I n t
12.1
12.4
8.5
8.5
8.5
13.0
I n t
11.9
9.5
9.7
I n t
10.8
10.5
11.8
Cu
yg/i
4.6
5.0
5.2
6.0
e r f a
5.8
24.2
3
3
4
2
e r f a
8
40
10
5
e r f a
10
15
20
Mn
yg/i
2.8
3.1
3.9
10.1
c e
1590
820
8.0
6.2
10.2
90
c e
1000
380
24.0
22.7
c e
2000
3000
5000
Cd
yg/i
0.15
0.14
<0.1
<0.1
0.4
0.7
<0.1
<0.1
<0.1
<0.1
0.2
3.5
0.1
0.1
1.0
1.0
1.0
Zn
yg/1
3.4
3.3
4.0
1.9
42
57
5.8
4.4
5.2
2.5
13.4
83
13.0
5.8
26
35
35
Fe
yg/1
166
231
171
102
82
35
260
240
260
66
210
100
200
193
Al
ug/1
36
28
33
25
12
274
92
90
42
42
200
Pb
yg/1
<0.1
<0.1
0.2
0.3
0.7
6.1
2.0
1.5
1.5
0.5
2.5
3.2
<1
<1
13.3
15.2
24.4
*Specific Conductance in micromhos/cm.
**Alkallnity in mg of CaC03 per liter.
-------
TABLE 15: CHEMICAL ANALYSES OF SUPERIOR ENTRY AREA CORE AND OVERLYING WATER
OJ
Distance From
Sediment-Water
Interface (cm) pH
31
Day
Values
Initial
Values
75-100 7.07
50-75 7.09
25-50 7.08
0-25 7.03
0
0-3.8
3.8-7.6
7. 6-11. A
0-100 7.32
0
0-3.8 6.60
3.8-7.6
7.6-11.4
P04
02 Mg,
S.C.* mg/1 P
-------
TABLE 16: CHEMICAL ANALYSES OF BARDON CREER-AREA CORE AND OVERLYING WATER
CO
Distance From PO^
Sediment-Water 02 Ug
Interface (cm) pH S.C.* mg/1 P°4/l
30
Dav
Lrnj
Values
Initial
Values
75-100 7.30 121 8.2 9
50-75 7.29 121 8.6 9
25-50 7.30 121 7.4 10
0-25 7.30 122 7.9 16
0
0-3.8 181
3.8-7.6
7.6-11.4
0-100 7.99 107 8.8 10
0
0-3.8 6.9
3.8-7.6
7.6-11.4
S102
Alk** mg/1
56.0 3.19
54.6 3.36
57.5 3.32
56.8 3.39
S e
<4.5
51.5 3.07
S e
Na K
mg/1 mg/1
3.1 0.80
3.2 0.79
3.2 0.79
3.2 0.80
d 1 m e n t
11 1.6
1.9 0.77
d 1 m e n t
Ca
m£/l
15.5
16.3
16.0
16.8
-Wat
37
15.3
-Wat
Mg
mg/1
3.7
3.7
3.7
3.8
e r I
11.5
3.7
e r I
Cu
ug/1
3.5
3.5
2.7
3.5
n t e r
43
13
3.5
n t e r
31
15
Mn
ug/1
3.0
2.3
8.3
4.1
face
115
110
13
face
1250
Cd Zn
Ug/1 Ug/1
<0.1 2.6
<0.1 2.6
<0.1 1.5
<0.1 1.6
1.3 4
4.3 55
0.3 7.6
1.1 13.3
1.0 12.7
Fe
Ug/1
66
42
60
54
42
75
91
234
175
Al
Ug/1
53
36
45
36
56
21
142
166
160
Pb
Ug/1
0.7
0.5
0.3
1.4
0.2
1.0
0.7
4.0
5.0
•Specific Conductance In mlcromho's/cm.
**Alkallnlty In mg of CaC03 per liter.
-------
TABLE 17: CHEMICAL ANALYSES OF DUTCHMAN'S CREEK-AREA CORE AND OVERLYING WATERS
U)
Distance From
Sediment-Water
Interface (cm)
60
Day
Values
31
Day
Values
Initial
Values
75-100
50-75
25-50
0-25
0
0-3.8
3.8-7.6
7.6-11.4
75-100
50-75
25-50
0-25
0
0-3.8
3.8-7.6
7.6-11.4
0-100
0
0-3.8
3.8-7.6
7.6-11.4
jjH
6.94
6.93
6.91
6.88
7.04
7.09
7.10
7.09
7.3
6.3
0? Mg
S.C.* mg/1 PO&/1
108 7.1 3
108 6.6 2
111 6.6 2
116 6.4 23
36
57
1770
106 7.9 3
106 7.7 2
106 7,9 1
107 7.8 6
70
36
44
98 11.4 14
5
40
435
S102
Alk** mg/1
56
55
55
56
S e d 1 m e
49.6 3.41
52.7 3.56
51.6 3.42
53.8 3.52
S e d 1 m e
<9
19
33
44.6 3.15
S e d 1 m e
19.5
33.9
41.0
Ma
1.64
1.69
1.70
1.72
n t - W
3.5
3.4
3.5
1.68
1.84
1.64
1.64
n t - W
3.4
3.6
3.4
1.88
n t - W
3.4
5.2
3.9
K
mg/1
0.62
0.64
0.61
0.60
ate
1.7
1.8
1.7
0.63
0.60
0.61
0.63
ate
1.8
1.9
1.6
0.53
ate
1.7
1.8
1.3
Ca
mg/1
15.6
15.8
15.3
16.4
r I n
37
44
47
16.2
16.3
15.8
14.9
r I n
36
40
28
13.9
r I n
20
25
21
Mg Cu
mg/1 ng/1
3.64 1.9
3.68 1.3
3.74 3.3
3.69 2.5
t e r f a c e
13 3.2
16
16
3.9
3.9
3.8
3.8
t e r
15
12
9.3
3.3
t e r
6.6
7.7
6.6
1.6
2.5
2.3
2.3
3.5
face
9.2
1.9
3.2
2.5
face
3
3
3
Mn
Mg/1
5.8
6.4
99.2
534
4100
7800
7800
3.0
2.1
3.0
5.8
3700
3800
2800
3.4
720
1400
1100
Cd
Mg/1
0.1
0.2
0.1
0.4
0.6
0.1
0.1
<0.1
<0.1
0.2
<0.1
<0.1
<0.1
0.5
0.5
0.3
Zn
Mg/1
7.4
5.9
5.4
5.0
15.5
2.6
1.4
4.9
9.4
9.4
2.5
Fe
Mg/1
31
20
18
49
2800
6200
12600
13
8
14
10
1550
4770
3950
32
94
227
Al
Mg/1
5
7
21
12
81
15
16
60
77
31
Pb
Mg/1
0.6
0.6
1.6
<0. 1
<0.1
<0.1
<0. 1
<0.1
0.7
2.3
0.3
1.0
0.5
6.0
2.0
3.0
*Speclflc Conductance In micromho's/cm.
**Alkalinlty In mg of CaC03 per liter.
-------
100
S 50
01
u
nj
" n
C °S
a -5
it)
3e
«J
6
U.
«, 50
u
«
0
-5
Cu P0«
1 1 F®
B
Overlying V
< Interface
Interstitial
Y
\. v~~^
^ ""
S.C.
• |f Na S102 0^ Ca Alk
o • 9rMg r •
i J Jo I I
\ {if
t
-------
Ul
co
o
OJ
(J
OJ
+J
C
L.
-------
The interstitial waters of the sediments are generally enriched in or-
thophosphate, silica, sodium, potassium, calcium, magnesium, copper, manga-
nese, cadmium, zinc, iron, aluminum,and lead compared to the values for the
overlying water. Parameters in the overlying water which showed an increase
with time are specific conductance (dissolved solids), silica, potassium,
calcium, magnesium,and alkalinity. In some cases, sodium and orthophosphate
also increased in the overlying water with time. Most of the heavy metals
appeared to decrease with time in the overlying water which may reflect ad-
sorption on the container walls or adsorption to particulates in the water
present at the time of collection which subsequently settled to the sediment.
CHEMICAL INPUTS FROM INTERSTITIAL WATER OF RESUSPENDED SEDIMENTS
It is difficult to assess the chemical inputs to Lake Superior from re-
suspension of sediments with the information currently available. One would
need to know the rate of chemical enrichment of the interstitial waters of
the sediments for the various parameters, the total amount of sediment re-
suspended on a yearly basis, and the average time that the particulate matter
remains settled before being resuspended. It would be of interest to deter-
mine the concentrations of the chemical parameters in the interstitial water
in the sediments just prior to spring breakup of ice cover since a particu-
larly heavy load of nutrients and trace metals would be expected to be re-
leased upon disturbing the sediments at this time. The rates of enrichment
of the sediments might be estimated from laboratory studies on cores in
which layers of clay particles are allowed to settle on the surface of the
sediment in the cores and these surface layers analyzed as a function of
time.
From the data currently available, a gross estimate of chemical re-
leases due to resuspension can be made. Sydor3 has reported an estimate of
the amount of fine particulate matter resuspended per year as 1.6 x 10*> met-
ric tons. The portion of the lake bottom resuspended is mainly located in
a 10-to-25 mi* (26-to-65 km*) area of the southwestern end of the lake.
Since much of this is resuspended more than once, a value of 5 x 1(H metric
tons is the approximate amount of fines which is subjected to resuspension.
Considering the sediments from the upper layers of the Superior entry and
Dutchman's Creek areas, the data show an average water content of 39%. Lim-
ited observations on the water content of the upper 0.5 to 1.0 cm of sedi-
ment indicate a water content of about 60%. Consequently, 3.0 x 10-* metric
tons of interstitial water would be associated with 5 x 10^ metric tons of
these upper-layer sediments. Considering the probability that some sediment
material whose particle size is larger than the clay-size particles (fines)
will be distributed under certain turbulence events, the amount of intersti-
tial water associated with resuspension should be somewhat greater than the
value estimated from considering the fines alone. Consequently, a rough es-
timate of the amount of interstitial water associated with resuspension is
5 x 10-* metric tons.
Using the average values of the chemical parameters for the intersti-
tial waters of the upper layers of the Superior Entry and Dutchman's Creek
sediments and the value of 5 x 10^ metric tons of interstitial water
39
-------
dispersed in the lake per year, the estimates of inputs of each parameter
are given in Table 18. These inputs are generally quite small compared to
inputs from other sources. The inputs for orthophosphate, silica, sodium,
potassium, calcium, and magnesium are insignificant compared to those values
for shoreline and river erosion of soils given in Table 10. Input values
for the heavy metals and aluminum are also small. Increasing these inputs
by a factor of ten would still result in relatively small values. However,
additional releases of certain of the parameters due to leaching of the re-
suspended particles would occur. The input values for certain of the heavy
metals and aluminum will be considered further in Section 7 when leaching
studies of soils is considered for these parameters.
-------
TABLE 18: ESTIMATES OF CHEMICAL INPUTS IN LAKE SUPERIOR DUE
TO INTERSTITIAL WATERS OF RESUSPENDED SEDIMENT
Chemical Parameter
Orthophosphate
Silica (Si02)
Sodium
Potassium
Calcium
Magnesium
Manganese
Cadmium
Zinc
Iron
Aluminum
Lead
Copper
Average Value For
Interstitial Water
(mg/1)
Inputs From
Resuspension
(metric tons
per year)
0.009
19.1
4.0
2.1
26
7.1
0.90
0.001
0.008
0.092
0.105
0.007
0.004
0.0045
9.5
2.0
1.0
13
3.6
0.45
0.0005
0.004
0.045
0.05
0.004
0.002
41
-------
SECTION 6
SORPTIVE CHARACTERISTICS OF CLAYS
GENERAL PROCEDURES
The ability of clay-laden soil or sediment samples to control the aque-
ous concentrations of certain chemical species through primarily sorptive
processes was investigated. These studies involve the preparation of clay-
solution suspensions containing a range of concentrations of the particular
chemical parameter under investigation resulting in various chemical para-
meter-clay ratios. After predetermined equilibration times, the aqueous
phase is analyzed for the chemical parameter and the magnitude of concentra-
tion changes due to interactions of the chemical species with the clays is
calculated. These concentration changes with respect to the weights of the
clays in the suspensions are used to calculate sorption isotherms.
The chemical parameters investigated include orthophosphate, phenols,and
certain trace metals. A summary of the experimental methods, conditions, and
results are enumerated below:
ORTHOPHOSPHATE STUDIES
Experimental Procedure
Standard orthophosphate solutions in the range of 0.05 to 0.5 mg/1 were
prepared from dilutions of a 500 mg/1 solution of CaH^PO^. Weighed quan-
tities of the clay sample were added to the standard orthophosphate solu-
tions in duplicate to prepare desired suspended-solid concentrations. The
suspensions were agitated by shaking the Pyrex containers periodically over
a two-hour period.
It had been previously determined that a two-hour period was sufficient
to complete at least 90% of the phosphate exchange with the clays. Lake Su-
perior water obtained from the lake intake at the Environmental Research
Laboratory, Duluth, Minnesota was used in preparing the solutions.
After the two-hour equilibration time, the suspensions were filtered
through 0.45y membrane filters and the aqueous phase analyzed for orthophos-
phate concentrations. Controls containing Lake Superior water spiked with
orthophosphate were run to determine possible losses or gains during glass-
ware contact and filtration. The controls indicated no loss or gain of or-
thophosphate due to these effects.
42
-------
The clay soil samples used in this study had been air-dried at room tem-
perature. The remaining moisture content was determined by heating sub-sam-
ples at 120°C for two hours. The clay sample was ground in a mortar and pes-
tle and sieved through a 120-mesh sieve to remove coarse particles in the
sand-size range.
The sediment sample used was the Lake Superior Dutchman's Creek top-
layer sediment. It was the same sample from which the interstitial water
had been previously removed for analysis in the core-leaching experiments.
The sediment was weighed in the moist state under a nitrogen atmosphere in
a dry box during suspension preparation. Dry weights for the sediment sam-
ples were measured in the same manner as described for the soil samples.
Treatment of Data
The change in orthophosphate concentration (APO^) for the aqueous phase
is calculated in mg per liter by subtracting the average final phosphate
concentration (for duplicate samples) following equilibration with the clay
from the initial phosphate concentration of the solution. Changes in phos-
phate concentration with respect to the clay (mg PC^ sorbed per kg of clay)
are computed using the relationship:
APC-4 clay = "(AP°4 solution) (V) (Ig) (106)
(W) (1000 mg)
where AP04 = change in phosphate concentration in mg/1
V = volume of solution in liters
W = mass of clay in grams
Consequently, negative APO^ clay values represent a net desorption from
the clay and positive values correspond to a net adsorption by the clay.
A plot of APC>4 clay versus the final concentration of orthophosphate in
the solution establishes a sorption isotherm for the particular clay sample.
The slope or slopes of the isotherm is a measure of the buffering capacity
of the clay sample toward orthophosphate. The concentration of orthophos-
phate at which APO^ clay equals zero is referred to as the equilibrium phos-
phate concentration (EPC) for the clay sample and denotes the concentration
of phosphate in the water at which no net phosphate exchange will occur upon
addition of the clay sample to the solution. ^
Results and Discussion
Nine soil samples were studied for their phosphate exchange capacities
toward orthophosphate. These soil samples have been described in Table 1.
The suspensions used in this investigation contained a soil-to-solution
ratio of 1000 mg/1. The temperature for the study was 23 to 25°C. A graph-
ical presentation of the results is given in Figure 4.
43
-------
1-LS-5 5- N-2
2- B-2 6-LS-2
3- N-1 7-LS-3
4-LS-4 8- B-1
9-LS-1
Final Phosphate Concentration (ng/l)
Figure 4. Sorption isotherms for soil samples.
-------
An investigation of one soil sample at various soil suspensions ranging
from 10,000 to 300 mg/1 showed variations in the slopes and EPC values with
the result that the EPC values increase along with an increase in the slope
of the isotherm as the soil-to-solution ratio decreases. Consequently, the
data in Figure 4 would only approximate sorption behavior under conditions
when the concentrations of particles in Lake Superior water are lower than
1000 mg/1.
The EPC values lie in the range of 0.06 to 0.21 mg/1 for the samples.
The gray clay sample (LS-1) has the largest EPC value along with the lowest
slope for the isotherm. Since the concentration of orthophosphate in Lake
Superior water is well below these EPC values (about 0.005 mg/1 or less),
there would be a net input of orthophosphate into Lake Superior upon erosion
of these soils. At a final orthophosphate solution concentration of 0.005
(approximating Lake Superior), the APO^ values range from about -18 to -30.
Considering the -30 value, an amount of 30 tons of orthophosphate would be
released to Lake Superior waters per megaton of eroded material. Using the
previously listed value of 8 x 10° metric tons per year of shoreline-eroded
soil material, an estimate of the annual orthophosphate input to Lake Supe-
rior can be made.
P04 input - (8 x 106 tons soil) ( 3° tons P04 ) = 24Q tong
106 tons soil
Since the fine material will attain low soil-to-solution ratios upon
its erosion and dispersal in the lake water and our studies indicate a larg-
er negative value of APO^ under lower soil-to-solution ratio conditions, the
PO/ input value listed above would only be a lower limit to the -actual input
However, obtaining isotherms at low soil-to-solution ratios is difficult
since small errors in the determination of orthophosphate concentrations in
the solutions result in relatively large errors in the APO^ values, compared
to higher soil-to-solution ratios. In addition, the clay particles do ex-
hibit a buffering effect in that uptake of orthophosphate by organisms in
the water (thereby lowering its concentration) could result in a further re-
lease of orthophosphate to the waters. It is also possible that some organ-
isms may directly remove orthophosphate upon contact with the clay parti-
cles. In view of these factors, we could not estimate the upper limit to
the orthophosphate input to the water and organisms due to shoreline erosion.
In comparison to the 240 metric tons of PO^ from shoreline erosion,
Plumb and Lee have estimated an influx of about 1800 metric tons of ortho-
phosphate into the western arm of Lake Superior mainly from the Duluth-Supe-
rior Harbor.10
Erosion of clay material into the rivers can result in a release or up-
take of orthophosphate depending upon the concentration already in the water.
For example, the data for samples N-l and N-2 indicate that Nemadji River
water containing orthophosphate levels above the 0.07 to 0.10 ppm range will
exhibit a reduction in orthophosphate whereas the opposite is true for wa-
ters containing lower orthophosphate values. The eroded material would
45
-------
result in a net input of orthophosphate into the river water during lower
flow periods but probably remove orthophosphate following extensive land
drainage and possible sewage overflows following storm activity. An uptake
of orthophosphate by the clay particles will increase their EPC values, and
if these particles enter Lake Superior, a larger release of orthophosphate
would result than if the particles had not been subjected to river water ex-
posure under higher orthophosphate concentration conditions. This has been
shown by the higher orthophosphate release of the Nemadji particulate sample
(Section 4).
In order to determine if any large differences in exchange characteris-
tics occur with temperature, one soil sample was investigated at both room
temperature and 4°C. The latter temperature would be characteristic of Lake
Superior shoreline area waters at certain times of the year. The result
showed little difference in the EPC value of the sorption isotherm (0.090 at
4°C and 0.088 at 23°C). Some decrease (^30%) in the slope occurred in the
higher final orthophosphate concentration region of the isotherm, although
in the low final orthophosphate region the isotherms were very close. Thus
the conclusions stated above are unchanged. This study does indicate that
the clay material will remove less orthophosphate from waters containing high
levels of the nutrient at lower water temperatures.
The results of the investigation of the upper layer of the Lake Superi-
or Dutchman's Creek area sediment is summarized by the data shown in Figure
5. The EPC value of 0.05 indicates that there will be a net input of ortho-
phosphate from the sediment into Lake Superior. Upon resuspension of the
material into the lake water, about 32 tons of orthophosphate would be re-
leased per megaton of sediment. Using the value of 1.5 x 10° metric tons
per year as the amount of clay-sized material resuspended,an estimate of
about 50 tons of orthophosphate is released per year due to currents and
wave action,causing resuspension in the shoreline regions of the lake. This
estimate is based on only one sample,which is assumed to be characteristic
of the material resuspended and consequently only a rough estimate. However,
the magnitude of the value should be correct. As discussed earlier for
soils, smaller clay-to-solution ratios than used in this experiment and up-
take of orthophosphate by organisms could increase the orthophosphate con-
tribution from the sediment.
The previously discussed undisturbed core-leaching experiments (Section
5) indicate only a very small contribution of orthophosphate from the inter-
stitial waters of the lake sediments.
METAL LEACHING AND EXCHANGE
Experimental Procedure
Leaching and exchange studies involving certain metals in clay-water
systems were carried out using plastic containers, shorter suspension equil-
ibration times, and, in some cases, a higher solid-to-solution ratio than that
employed in the seven-week leaching studies described in Section 1. The
46
-------
I 120
o>
JO
O
<*•
O
Q.
80
40
0
-20
«
0.10 0.20 0.30
Final Phosphate Concentration (mg/l)
0.40
Figure 5. Sorption isotherm for sediment.
-------
shorter equilibration times were chosen in order to minimize losses of the
metals on the container surfaces.
One phase of these studies involved leaching of a soil sample (LS-5) as
a function of time for a 24-hour period. Approximately one gram samples of
the soil were dispersed into 500 ml of Lake Superior water in acid-presoaked
bottles. The suspensions were shaken for a fixed time using a laboratory
shaker. The suspensions were filtered through either 0.1 or 0.45-micron
membrane filters and acidified with HN03 until analysis. The clay-solution
contact times ranged from a few minutes to 24 hours. All metal analyses
were performed by flameless atomic-absorption spectroscopy.
A second phase consisted of leaching some of the sediment samples used
in the core-leaching experiments (Section 5) and the LS-5 soil sample for
two hours. The same basic procedure was used except that the suspensions
containing sediments were prepared under nitrogen to avoid chemical changes
due to air exposure. Oxygenated Lake Superior water was used to prepare the
suspensions. The sediment samples employed were the upper layer of the Su-
perior entry-area sediment and the upper and lower layers of the Dutchman's
Creek-area sediment. These were the same sediments from which the intersti-
tial water was removed for analysis (Section 5). Some of these leachates
were sent to the EPA Region V Laboratories, Chicago,for mercury, arsenic,
and selenium analysis.
Data has also been obtained on a project under the Sea Grant Program,
University of Wisconsin, involving an investigation of the ability of the
suspended clay particles to remove metals from aqueous solution. Some of
the results will be listed here,as they complement the information obtained
in this project. These studies are focused on clay-water suspensions in
which various amounts of a particular metal have been added. The suspen-
sions are analyzed after a fixed time for the concentrations of metals re-
maining in the solution. Sorption isotherms for the clay-metal interactions
in the aqueous systems are prepared from this data. The agitated suspen-
sions containing approximately one gram of the LS-5 soil sample per 500 ml
of Lake Superior water were analyzed after three minutes, half hour, one
hour, two hours, six hours, twenty hours and twenty-four hours of soil solu-
tion contact. The results indicated that certain of the metals were being
adsorbed on the walls of the polypropylene containers or being readsorbed by
the particulates over this time period (particularly aluminum, iron,and
lead). As the metals seemed to reach maximum concentrations in the solu-
tion within two hours, this time of soil-solution equilibrium was used in
leaching studies involving the LS-5 soil sample and the sediment samples.
The exchange of certain of the metals with clay soil particles in aque-
ous suspensions in experiments in which the suspensions were spiked with
varying amounts of the particular metal gives further information on the
sorption of the metals. Soil suspensions containing Lake Superior filtered
water were prepared in polypropylene bottles and the appropriate metal was
added by pipetting sufficient volumes of concentrated standard into the sus-
pension. The initial concentrations of the metals in the spiked suspen-
sions ranged from 10 to 200 yg/1. A duplicate was prepared for each suspen-
sion. In addition, two bottles contained suspensions which were not spiked
48
-------
with the metal and two bottles containing only Lake Superior water and 200
Mg/1 of the metal were prepared. The latter two bottles were used to check
on metal losses due to container adsorption or filtering. All bottles were
agitated for one hour in a shaker water bath at 23°C,after which the suspen-
sions were allowed to settle for five minutes. Each sample was filtered
using 0.45-micron membrane filters, and the filtrate immediately acidified to
0.05% in HN03 until analysis. The filtrates were then analyzed by flameless
atomic absorption in order to determine metal exchanges with the suspended
clays.
Results and Discussion
The increase in concentrations of the various metals in the leachates
compared to the values in lake water are shown in Table 19. The largest in-
creases are found for manganese, aluminum,and iron. The lower layer of the
Dutchman's Creek-area sediment released the largest amounts of the metals
except for copper. The capacity of the sediments to remove metals from a-
queous solutions containing higher concentrations of the metals is shown by
the system which was spiked with 200 yg/1 each of copper, zinc, cadmium, lead
and manganese. All of these metals except iron were reduced to low levels
upon interaction with the suspended sediment.
From the data for the LS-5 soil sample and the value of 8 x 106 metric
tons of shoreline material eroded annually, estimates of the inputs of metals
to Lake Superior were computed and are tabulated in Table 20. Assuming a
total of 1.6 x 10" metric tons of resuspended sediment annually, estimates
of the metal releases due to this process are also listed in Table 20. The
sediment resuspension inputs are based on the average releases for the upper
layers of the Superior entry and Dutchman's Creek-area sediments. Since the
increases in concentrations of many of the metals after the two-hour clay-
water equilibration times were very small to undetectable, only releases of
manganese, iron,and aluminum could be determined with some certainty. How-
ever, upper limits of metal releases for other metals could be estimated. If
the resuspension contribution to metal inputs were ten times higher than
listed in Table 20, they would still be less than those due to soil erosion.
The resuspension contribution from dispersion of the sediments is much larg-
er than that estimated from the content of the interstitial waters (Section
5) and consequently desorption or solubilization of metals from the suspend-
ed particles would be the major mechanisms for the metal inputs.
Figures 6 and 7 show results of the exchange studies for copper and man-
ganese. The gain or release of the metal as a function of the concentration
of the metal in the aqueous system is plotted versus the final concentration
of metal in the aqueous solution. The "delta metal" values give the mg of
metal exchanged with the soil-per-kilogram of the soil. The data shown for
copper pertain to 1000 ppm soil suspensions while that for manganese refers
to 10,000 ppm suspensions. The "delta metal" values are computed in a simi-
lar manner to those for orthophosphate,which is discussed earlier in this
section. Negative values of "delta metal" refer to release of the metal
from the clay, whereas positive values refer to adsorption of the metal from
the solution.
49
-------
TABLE 19: METAL LEACHING OF CLAY SAMPLES
Sample
Lake Water1
LS-5 Soil
Cu
Mn
1.9 0.2
2.9 5.9
Cd
0.01
0.01
1.0
Pb Cr
Ni
Al
94
Fe
81
Hg
Af. Se^
<2 <5
<2 <5
Superior Entry
Sediment
(upper layer)
1.9 2.3 <.05
<10 49 38 <0.1 <2 <5
Dutchman's Creek
Sediment
(upper layer)
6.1 3.6 <.05
<10 62 125
Oi
O
Dutchman's Creek
Sediment
(lower layer)
0.2 310 <.05
115 520
Dutchman's Creek
Sediment
(upper layer)2
4.1
5.9
2.5
12
148
Concentration of metals in the Lake Superior water used in the leaching experiments. The other values in the table represent
increases in concentration over that in lake water. All metal concentrations in vg/1.
2Lake Superior water was spiked with 200 ug/1 each of copper, zinc, cadmium, lead,and manganese.
-------
TABLE 20: METAL INPUTS FROM SHORELINE EROSION AND SEDIMENT RESUSPENSION
Shoreline* Sediment
Erosion Resuspension
(metric tons (metric tons
per year) per year)
Copper <2.0 <1.0
Manganese 56** 0.4
Cadmium <0.008 <0.01
Zinc <8 <0-6
Lead <1 <0.2
Chromium <0.1
Nickel <8
-------
400
300
O
O)
\
O)
~ 200
O
100
~0 10 20 30
Final Copper Concentration (ug/l)
Figure 6. Copper sorption Isotherm for clay soil in Lake Superior water.
52
-------
10 20
Final Mn Concentration Cug/l)
30
Figure 7. Manganese sorption isotherm for clay soil in Lake Superior water.
53
-------
The data in Figure 6 show that copper has little tendency to be re-
leased from the clay. This particular sample would remove copper from solu-
tion in lake water down to approximately one yg/1 in copper concentration.
The data in Table 20 shows a possible small release of copper projected from
the leaching of the LS-5 soil sample. This indicates that the value in Table
20 for copper is very sensitive to errors in the copper determination,as a
change of 2 yg/1 in concentration of the leachate could change the indicated
release to an apparent adsorption by the clay. The data in Figure 6 also
shows the ability of the clay particles to remove copper from Lake Superior
water under conditions of higher copper ion concentration. For example, the
soil sample suspended in Lake Superior water at a concentration of 10 yg/1
copper would result in a removal of 350 grams of copper per ton of the clay.
This ability of the soil to remove copper was also demonstrated by the data
in Table 19.
The data in Figure 7 shows that the clay soil sample will remove manga-
nese from solution if the concentration of the manganese is greater than
about 4 yg/1. Since Lake Superior water contains about 0.2 yg/1 of manga-
nese, a net release of manganese from the soil should occur. At a lake water
concentration of 0.2 yg/1, the data indicates a release of about 7 grams of
manganese per metric ton of clay. For 8 x 10" metric tons of eroded soil,
the total release would be 56 metric tons. The exchange-studies method
(Figure 7) gives a manganese release value as if the clay were leached in
0.2 yg/1 manganese solution without any increase in concentration as it is
released and this situation would better approximate lake conditions. How-
ever, if the concentration of manganese in the water is greater than 0.2yg/1,
then the release would be a lesser amount. Some limited data on iron ex-
change with clay in aqueous suspensions indicates that the value in Table 20
is not too small.
The values in Table 20 should give the magnitudes of release expected
for the various metals from the clay samples. In general the releases are
small and,in many cases, they could only be listed as "less than" values.
In order to obtain more accurate values on the metal exchange capacity with
clay samples, much data would have to be collected using a more sensitive
analytical technique in order to allow a statistical treatment for confi-
dence levels. Also, data would have to be collected on the effects of clay-
to-solution ratio in the exchange capacity of the clays.
EXCHANGE OF PHENOLICS WITH CLAYS
Experimental Procedure
This phase of the study focused on the ability of clay particles to af-
fect the concentrations of phenolic-type compounds in aqueous solution. In
the study area, phenolics are particularly associated with the St. Louis
River (largest Lake Superior tributary whose waters enter the lake at Duluth,
Minnesota) and the Duluth-Superior Harbor area. Two sampling surveys of the
St. Louis River and Duluth-Superior Harbor were enacted in order to establish
the total phenolic levels for these waters. Samples from a site exhibiting
the highest phenolic concentration were spiked with various amounts of clay
54
-------
soil (LS-5), and the decrease in total phenolics compared to a sample blank
(no clay) was measured. Measurements of the clay interactions with the phe-
nolic-type components of the natural waters was also studied as a function
of time.
2,4-dichlorophenol was used as a representative phenolic-type compound
in further investigations of clay-phenol interactions. These interactions
were studied as a function of time, initial concentration of 2,4-dichlorophe-
nol, and soil-to-solution ratio.
Results and Discussion
The results of the two surveys for total phenolics are given in Table
21. Values in the 20 to 114 vg/1 range were found for the two sampling dates,
with the Interstate 35 sampling site near Cloquet, Minnesota showing the
highest values for each survey.
Water obtained on July 22 from the Interstate 35 sampling site was used
in a study of the interactions of the LS-5 soil sample with the phenolics in
the sample. Various amounts of clay (0.2 to 1.2 g) were added to 500 ml of
the river water. The suspensions were shaken for 30 minutes and filtered
through Gelman type-A glass fiber filters and analyzed for total phenolics.
The results are shown in Table 22.
Studies involving the addition of approximately 0.42 grams of clay soil
to 500 ml solutions of 0.5 mg/1 2,4-dichlorophenol were carried out by ana-
lyzing the suspensions for 2,4-dichlorophenol as a function of time. The
results showed no difference in phenol concentration between 30-minute, 90-
minute, and 150-minute equilibration times. Consequently, a 30-minute equil-
ibration time was used in the studies. 500 ml solutions containing an ini-
tial concentration of 0.5 mg/1 2,4-dichlorophenol were spiked with clay soil
in the range of 0.2 g to 0.8 g. After an equilibration time of 30 minutes,
the solutions were analyzed for 2,4-dichlorophenol. The experiment was re-
peated using an initial concentration of one mg/1 2,4-dichlorophenol. These
data are also shown in Table 22.
The data in Table 22 indicate a significant reduction in total phenolic
concentration with the addition of clay soil to the water. A solution which
is about 400 mg/1 in clay results in a 11% phenolic reduction (expressed as
weight of phenol) whereas the 2400 mg/1 clay suspension experiences a 81%
reduction. Similar reductions in the concentration of 2,4-dichlorophenol
occur. In this case, there is an increased reduction by weight but a simi-
lar reduction in terms of equivalent moles of phenol. A slightly greater
amount of 2,4-dichlorophenol is removed from the one mg/1 solution than the
0.5 mg/1 solution.
It is concluded that the suspended clay particles do decrease the con-
centration of phenolic-type compounds in aqueous solution. The fate of the
adsorbed phenolic molecules in terms of possible decomposition or transport
has not been considered here.
55
-------
TABLE 21: TOTAL PHENOLICS IN NATURAL WATERS
Sample Location
Superior Harbor Entry (Superior, WI)
Barker's Island (Superior Harbor)
Arrowhead Bridge (St. Louis Harbor)
Huron Cement (Superior Harbor)
Blatnik Bridge (St. Louis Harbor)
Drill's Marina (St. Louis River)
Interstate 35-Cloquet (St. Louis River)
yg per liter of total phenolics
June 17, 1975 July 22, 1975
30
37
20
34
35.5
51
70.5
31
41
90
62
39
55
114
56
-------
TABLE 22: INTERACTIONS OF CLAY WITH PHENOLICS*
Sample: St. Louis River Water-Interstate 35 Near Cloquet
Initial Final Micrograms
Total Total Kienol
IT ^ K«- ~f Phenolics Phenolics Adsorbed per
Weight of ™en°, *°S r,,o/i^ gram of Soil
Clay (g)
0.2007 H6 103 H
0.4003 116 82 %
0-6027 116 ".5
0.8044 116 47.5 gg
1.0024 H6 f 7g
1.2054 H6 LL
Sample: 500 yg/1 2,4-dichlorophenol 2,4-dichlor"henol
FinaL2 4-dichlorophenol £?£&_
(g)
0.2022 435
0.2057 460 I"
0-2033 456 108
0.2082 455 *»•
0.3008 410 "
0.3017 405 «
0-4119 363
0.4133 384 ^"
0.5028 329 170
0.5053 330
0.7192 280
0.7006 286
168
153
153
Sample: 1000 yg/l 2,4-dichlorophenol 2,4-dichlorophenol
Weight of Final 2,4-dichlorophenol Adsorbed per
Clay (g) Concentration (yg/1) *ram of Soil
0.2054 920 190
0.2080 915 200
0.4038 848 190
0.4109 840 195
0.6050 763 196
0.6012 775 187
0.8058 720 174
*A11 solutions were 500 ml in volume.
57
-------
SECTION 7
CHEMISTRY OF LAKE SUPERIOR WATER SAMPLES AS RELATED TO TURBIDITY
GENERAL PROCEDURES
A sampling network was chosen in a near-shoreline region of western Lake
Superior for monitoring suspended solids and numerous chemical parameters.
The region selected was approximately one mile (1.6 km) west of Bardon Creek
(Figure 1). This sampling location is approximately 15 miles (24 km) from
the Duluth-Superior metropolitan area and thus the water composition should
be minimally influenced by any point source discharge from this area. Water
sampling was carried out as a function of depth at 10, 20, 40, 60, and 80-foot
depth profiles. In addition, sediment coring was attempted in this region.
The cores obtained showed that the lake bottom in this region is mainly com-
posed of sand, even out to an 80-foot (24.4 m) depth. Consequently only a
few cores were taken in this region.
The purpose of this sampling network was to monitor suspended solids and
water chemistry as a function of weather events. This monitoring would pro-
vide additional information relating to the degree of turbidity of the water
resulting from different types of wind and precipitation events and data on
settling times for the suspended matter. The water chemistry would give
field observations relating to chemical changes which occurred during periods
of high turbidity.
The water samples were obtained using a Van Dorn-type plastic water sam-
pler. The sampling network consisted of sampling at five feet below the sur-
face at a 10-foot water depth (sample 10-5); at 3 and 18 feet below the sur-
face at a 20-foot water depth (samples 20-3 and 20-18); at 3, 20, and 38 feet
below the surface at a 40-foot water depth (samples 40-3, 40-20, and 40-38);
at 3, 30, and 58 feet below the surface at a 60-foot water depth (samples 60-3,
60-30, and 60-58); and at 3, 40, and 78 feet below the surface at an 80-foot
water depth (samples 80-3, 80-40, and 80-78). At the 80-foot depth profiles,
the perpendicular distance to the shoreline was approximately four miles.
RESULTS AND DISCUSSION
The only significant weather event occurred at the beginning of June.
This event consisted of strong easterly winds (10 to 25 mph) with less than
0.5 inches (1.3 cm) of precipitation on June 4 and 2.5 inches (6.4 cm) of
rain over the period June 11 to June 12. The remainder of the summer was
void of any significant weather events which would cause high turbidity
58
-------
levels on the lake. Consequently only two water samplings were obtained un-
der turbid water conditions, and this turbidity was confined to the near-
shoreline region of the lake. A total of eight samplings were carried out at
the Bardon Creek^rea Lake Superior site in June, July, and August. Except
for the June 6 and June 14 sampling times, the waters were relatively low in
suspended solids. The suspended-solid values found for the sampling grid
pertaining to these eight surveys are summarized in Table 23 A comparison
of the June 26 suspended-solid values to those obtained on June 14 indicates
that the concentration of suspended solids had decreased in the area by a
factor of 2 to 4 in 12 days. This is an approximate agreement with the ob-
servations reported by Sydor2 for particle settling under laboratory condi-
tions.
Chemical analyses were performed on water samples obtained on June 6,
June 26, July 17,and August 15. These results are presented in Tables 24
through 27. Most of these water samples contained relatively low suspended-
solids concentrations with only one sample containing greater than 100 mg/1
concentration. Therefore the differences in suspended solids in the samples
are not large enough to make accurate correlations of water chemistry to
turbidity. At this time, no statistical analysis of the data has been per-
formed. A general survey of the data would indicate an increase in total
dissolved solids, total phosphorus, total soluble phosphorus, orthophosphate,
particulate iron, and sodium at times when the waters contain higher suspended
solids. No doubt, the degree of mixing of the waters and currents is im-
portant in determining the values of most of the chemical parameters.
Previous work along the shoreline region of Northern Wisconsin has in-
dicated generally higher values for specific conductance, alkalinity, hard-
ness, calcium, magnesium, sodium, iron, orthophosphate, and chemical oxygen
demand in this area compared to Minnesota shoreline values.^ A chemical
analysis of the waters the day following a severe weather event (wind and/or
wind-precipitation) would be needed to establish values of the chemical para-
meters under high-turbidity conditions. Most of the data Presented here
would serve to establish chemical values at lower suspended solid conditions.
59
-------
TABLE 23: LAKE SUPERIOR BARDON CREEK-AREA SUSPENDED SOLIDS PROFILES
SUSPENDED SOLIDS (ng/1)
DATE 10-5 20-3 20-17 40-3 40-20 40-37 60-3 60-30 60-57 80-3 80-40 80-77
6/6
6/14
6/26
7/5
7/9
7/17
7/24
8/15
122
80
21.5
14
15
6
9
7
62
33
11
15
16
6
4
3
35
23
11.5
20
13
6
1
3
—
13
8.
4
4
2
2.5
2
13
17
6
11
4
2
1
1
5
21
6
9
2
2
2
4
3
5
8
1
2
2
2
1
2
39
2
2
4
2
2
2
1.5
11 0.5 8 12
2 __ ___
211 3
231 1
121 2
1 1 .5 2
212 2
-------
TABLE 24: LAKE MONITORING IN POPLAR RIVER - BARDON CREEK AREA
DATE: June 6, 1975
Profile (ft.)
Depth (ft.)
Suspended Solids (mg/1)
pH
Specific Conductance*
Dissolved Oxygen (mg/1)
Total P (yg/1)
Total Soluble P (yg/1)
Orthophosphate (yg PO^/l)
Alkalinity (mg CaC03/l)
Silica (mg/1)
Nitrate (mg/1)
Kjeldahl N (mg/1)
Colorimetric Soluble Fe (yg/1)
Atomic Absorption Soluble Fe (yg/1)
Particulate Fe (yg/1)
Sodium (mg/1)
Potassium (mg/1)
Calcium (mg/1)
Magnesium (mg/1)
Chloride (mg/1)
Copper (ug/1)
Manganese (yg/1)
Cadmium (ug/1)
Zinc (yg/1)
Lead (Mg/D
*Mlcromhos/cm
10
5
122
7.75
105.3
9.6
29
16
27
47.2
3.14
0.84
0.25
86
1420
2.6
0.72
12.7
3.4
3.4
5
8.3
0.3
7
2
20
3
62
7.54
105.0
10.2
26
8
16
44.4
3.46
0.95
0.42
69
124
1030
3.3
0.71
12.8
3.4
2.0
5
6.7
0.2
1
<1
20
18
35
7.53
103
9.6
14
2
8
42.9
3.06
0.85
0.2
54
45
750
2.3
0.69
15.8
3.2
2.0
5
5.3
0.1
3
40
3
7.51
98.6
10.8
10
3
10
40.7
3.16
0.91
0.27
53
140
2.9
0.67
11.9.
3.3
4.6
5
5.1
0.1
6
7
40
20
13
7.42
98.6
10.9
15
<1
3
41.0
3.20
0.87
0.10
47
170
2.3
0.60
12.8
3.0
3.3
5
4.2
0.2
6
3
40
38
5
7.38
96.6
10.9
8
5
7
41.6
3.27
0.93
0.23
42
200
2.0
0.72
13.5
3.1
1.8
4
2.4
0.1
2
<1
60
3
3
7.38
98.9
11.4
12
3
1
41.0
3.04
0.97
0.16
37
43
1.9
0.62
15.1
3.1
1.8
6
2.5
0.1
3
3
60
30
2
7.42
96.3
11.5
8
4
4
40.8
3.26
1.02
0.05
24
70
2.0
0.58
11.4
3.1
1.7
5
3.4
0.2
1
60
58
1.5
7.39
96.6
11.5
5
<1
2
40.8
3.24
1.23
0.27
24
100
3.4
0.63
12.6
3.1
1.7
4
2.6
0.3
8
7
-------
TABLE 25: LAKE MONITORING IN POPLAR RIVER - BARDON CREEK AREA
DATE: June 26, 1975
Profile (ft.) 10 20 20 40 40 40 60 60 60
D 5 3 18 3 20 38 3 30 58
Suspended Solids (mg/1) 21 11 11 8 66 822
pH 7.48 7.45 7.46 7.49 7.42 7.41 7.49 7 47 7 44
Specific Conductance* 102.7 101.7 102.0 100.0 100.0 100.0 100 8 98 6 98 3
Dissolved Oxygen (mg/1) 10.9 11.0 10.9 11.0 11.4 11.2 10 9 12*0 12*1
Total P (pg/1) 28 23 39 9 18 13 21 ll' S
Total Soluble P (pg/1) 1 <1 5 5 <1 3 5 3 4
Orthophosphate (pg P04/l) 11 4 2 6 11 6 7 4 11
Alkalinity (rag CaC03/l) 45.4 44.6 44.5 44.3 45.4 44.4 44.4 43 8 44 6
Silica (mg/l) 2.81 3.17 2.88 2.98 2.91 2.92 2.93 2*75 2*26
Nitrate (mg/1) 0.97 0.92 0.96 0.90 0.99 0.96 0.95 1.02 I'oO
Kjeldahl N (mg/1) 0.03 0.07 0 10
Colorimetric Soluble Fe (ug/1) 36 30 41 52 30 34 63' 55 8
Particulate Fe (ug/1) 440 280 330 270 180 120 140 62
Sodium (mg/1) 1.4 1.3 1.7 2.0 1.6 1.9 19 13 17
Potassium (rag/1) 0.63 0.75 0.72 0.67 0.65 0.71 0.7] 0.64 O.'s4
S Calcium (mg/1) 14.0 13.8 14.5 14.0 14.2 14.2 14.9 14.6 13 9
Magnesium (mg/1) 3.4 3.4 3.4 3>4 3 A 3 4 3 4 3 3 3'3
Chloride (mg/1) 1.5 1.5 Ii7 2.0 1.7 1.6 17 If, 12
Copper (pg/1) 22 22 1 1.5 1 1 l'
Manganese (pg/1) 2.8 1.5 2.0 1.9 1.9 1.5 2.5 2.1 0.5
Cadmium (pg/1) <0.1 <0.1 <0.1
Zinc (pg/1) 22 72 2' 2 ? 1 •)
Lead (pg/1) <1
-------
TABLE 26: LAKE MONITORING IN POPLAR RIVER - BARDON CREEK AREA
DATE: July 17, 1975
Profile (ft.)
Depth (ft.)
Suspended Solids (mg/1)
pH
Specific Conductance*
Dissolved Oxygen (mg/1)
Total P (Mg/1)
Total Soluble P (Mg/1)
Orthophosphate (yg PO^/1)
Alkalinity (rag CaC03/l)
Silica (mg/1)
Nitrate (mg/1)
Kjeldahl N (mg/1)
Atomic Absorption Soluble Fe (Mg/1)
Colorimetric Soluble Fe (ug/1)
Particulate Fe (Mg/1)
Sodium (mg/1)
w Potassium (mg/1)
Calcium (mg/1)
Magnesium (mg/1)
Chloride (mg/1)
Copper (yg/1)
Manganese (Mg/1)
Zinc (ng/1)
Cadmium (Mg/1)
Lead (Mg/D
*Micromhos/cm
10
5
6
7.61
101.2
15
3
8
43.1
2.82
0.92
0.12
68
74
145
2.0
0.86
14.2
3.6
1.9
11
5
17
1.3
2.5
20
3
6
7.58
100.5
9.2
10
6
<1
43.3
2.93
0.76
0.15
74
79
165
1.8
0.83
14.1
3.5
1.8
8
7
10
0.5
1.5
20
18
6
7.59
100.8
8.7
5
2
3
3.06
0.90
62
65
135
1.7
0.82
14.3
3.5
1.7
6
6
11
0.7
1.5
40
3
2
7.69
99.8
9.0
6
10
<1
44.0
2.68
62
55
67
2.2
0.73
14.1
3.6
1.7
3
20
7
0.3
2
40
20
2
7.70
100.1
9.0
5
8
12
44.6
2.74
0.79
0.05
57
93
1.9
0.78
14.5
3.6
1.5
3
2
4
0.1
0.5
40
38
2
7.40
98.9
10.3
3
5
2
44.6
3.08
1.21
44
55
1.8
0.75
14.5
3.5
1.4
4
1
4
0.3
2
60
3
2
7.61
100.5
9.1
5
_
<1
43.1
2.77
0.89
QQ
oy
72
76
1.8
0.80
14.0
3.5
1.8
5
4
10
0.2
1.5
60
30
2
7.40
98.6
10.1
17
3
10
44.2
2.80
1.01
0.11
27
100
2.2
0.77
14.2
3.4
1.5
4
3
8
0.2
1
60
58
1
7.43
95.7
1
<1
4
43.3
3.05
1.23
14
64
1.7
0.73
14.0
3.4
1.3
4
3
4
0.2
<0.5
80
3
2
7.79
100.1
10
<1
6
44.8
2.76
0.84
7£
/ O
75
76
2.0
0.77
14.0
3.5
1.8
3
5
6
0.1
0.5
80
40
1
7.35
96.0
11.8
3
<1
20
44.3
3.11
1.14
14
90
1.4
0.72
13.9
3.3
1.2
3
2
4
0.2
0.5
80
78
2
7.40
96.3
11.6
<1
<1
<1
43.6
2.91
1.26
11
92
1.5
0.73
14.4
3.4
1.3
3
3
8
0.2
0.5
-------
TABLE 27: LAKE MONITORING IN POPLAR RIVER - BARDON CREEK AREA
DATE: August 15, 1975
Profile (ft.)
Depth (ft.)
Suspended Solids (rag/I)
pH
Specific Conductance*
Dissolved Oxygen (mg/1)
Total P (ug/1)
Total Soluble P (ug/1)
Orthophosphate (ug PO^/1)
Alkalinity («g CaCO,/l)
Silica (ng/1)
Nitrate («g/l)
Kjeldahl N (ng/1)
Total Fe (ug/1)
Atomic Absorption Soluble Fe (ug/1)
Sodium (mg/1)
Potassium (mg/1)
Calcium (rag/1)
Magnesium (mg/1)
Chloride (mg/1)
Copper (ug/D
Manganese (ug/1)
Zinc (ug/1)
Cadmium (ug/1)
Lead (ug/1)
Aluminum (ug/1)
*Mlcromhos/cm
10
5
7
7.73
99.5
5.1
12
5
7
49.0
2.49
0.67
0.27
202
50
1.6
0.62
14.0
3.3
1.6
4
8
6
0.05
<0.2
19
20
3
3
7.73
98.1
6.0
9
5
14
48.0
2.52
0.78
0.24
119
57
1.7
0.60
13.3
3.3
1.3
2
4
3
0.06
<0.2
31
20
18
3
7.62
98.1
11.0
7
4
11
48.2
2.44
0.64
0.26
112
42
1.7
0.59
14.0
3.3
1.6
2
3
3
0.07
0.8
22
40
3
2
7.77
96.3
8.2
5
3
9
46.0
2.52
0.83
0.19
275
20
1.7
0.58
13.9
3.3
1.6
3
1
3
0.02
<0.2
5
40
20
1
7.78
96.0
9.6
7
3
10
46.7
2.47
0.70
34
23
1.7
0.58
13.5
3.3
1.4
2
3
2
0.05
<0.2
11
40
38
4
7.43
98.6
7.6
9
5
5
48.7
2.85
0.87
0.18
108
37
1.6
0.60
14.0
3.3
1.5
2
2
2
0.02
<0.2
23
60
3
1
7.75
96.0
9.6
5
3
6
46.8
2.61
0.72
0.18
48
33
1.6
0.57
13.5
3.3
1.4
2
2
2
0.02
<0.2
9
60
30
2
7.58
96.0
9.0
7
3
6
47.9
2.71
0.73
68
32
1.6
0.59
13.4
3.3
1.5
2
1
3
0.15
<0.2
12
60
58
2
7.48
96.0
6.8
9
6
9
45.7
2.88
1.05
0.15
70
20
1.5
0.57
13.5
3.2
1.3
2
1
3
0.02
<0.2
11
80
3
1.5
7.75
96.3
9.1
6
3
5
50.0
2.55
0.86
0.18
102
21
1.6
0.58
14.0
3.3
1.4
2
1
2
0.02
0.3
5
80
40
2
7.60
96.7
11.0
9
4
12
48.2
2.81
0.97
97
34
1.6
0.57
13.3
3.3
1.4
3
7
3
0.05
0.2
15
80
78
2
7.39
95.8
12.1
8
5
9
44.3
3.20
0.99
60
13
1.4
0.58
13.2
3.2
1.3
1
2
1
0.02
<0.2
10
-------
SECTION 8
RIVER MONITORING FOR SEDIMENT LOADS
GENERAL PROCEDURES
In cooperation with Dr. Michael Sydor, this phase of the study focused
on spring monitoring of river discharges, concentrations and particle-size
distributions of sediment loads, and a determination of the sediment input to
Lake Superior from northern Wisconsin streams during spring runoff. The
study area included Lake Superior tributaries from Superior, Wisconsin to
Cornucopia, Wisconsin (Figure 1). The eastern half of this shoreline area
was monitored by University of Wisconsin-Superior staff while the western
half was sampled by staff from the University of Minnesota-Duluth. In this
section, a summary of the results of the University of Wisconsin study will
be given.
Sampling sites on the streams were established at accessible points close
to the stream mouths but at a distance from Lake Superior, which would avoid
backwash from the lake during seiche conditions. Suspended-solid measure-
ments were made by obtaining depth-integrated samples at vertical profiles
across the river or creek (U.S. DH-48 or U.S. DH-59 samplers were used).
Stream-velocity measurements were obtained at two depths along each profile
using a Gurley meter. Cross-sectional area parameters (depths, width of
stream) were measured at each time of sampling. Suspended solids in the wa-
ter samples were measured by collecting the solids on tared 0.45-micron mem-
brane filters. Turbidity measurements were made by the staff at the Univer-
sity of Minnesota-Duluth.
RESULTS
The discharge and sediment load data for Bayfield County, Wisconsin
streams are summarized in Table 28. These data have been used by Dr. Sydor
in conjunction with other data to estimate the total annual tributary input
of suspended solids to Lake Superior for Douglas and Bayfield Counties. These
estimates have been summarized in the introduction of this report (Section 1).
The major conclusion drawn from these runoff data is that the input of
suspended solids from Bayfield County streams is much smaller compared to the
Douglas County input. The Nemadji River (Douglas County) contributes 89% of
the total stream eroded material in the two counties.3 For Bayfield County
streams investigated in this study, the Bois Brule, Iron, Flag, and Cranberry
Rivers contribute the highest sediment loads during spring runoff. The Flag
65
-------
River showed the highest sediment load on a given day (416 metric tons/day
on April 23).
66
-------
TABLE 28: DISCHARGES AND SEDIMENT LOADS OF LAKE SUPERIOR TRIBUTARIES (1975)
Brule River at Bridge East of Highway 13
Date
April 11
April 14
April 17
April 22
April 24
April 28
April 30
May 2
May 7
Cross-Sectional
Area (nr)
9.2
9.9
12.3
12.5
12.8
13.8
12.3
13.6
12.6
Total Discharge
(m3/sec)
7.0
10.2
17.6
17.7
20.2
17.5
17.8
19.0
14.0
Suspended Solids
Load (tons/day)
6.1
60
102
82
58
40
47
32
31
Cranberry River 1/2 mile From Mouth
Date
April 10
April 13
April 16
April 21
April 23
April 25
April 29
May 1
May 5
May 9
Cross-Sectional
Area (m*)
1.7
3.0
4.1
3.5
5.7
2.2
3.3
2.5
2.5
1.8
Total Discharge
(m^/sec)
1.5
1.8
3.3
2.4
5.1
1.4
1.8
1.4
1.5
1.3
Suspended Solids
Load (tons/day)
0.4
5.7
25.4
8.9
262
5.0
12.5
4.2
3.9
1.6
First Creek East of Flag River
Date
April 13
April 16
April 21
April 23
April 25
April 29
May 1
May 5
Cros s-Sect ional
Area (m2)
0.06
0.20
0.13
0.20
0.12
0.12
0.09
0.06
Total Discharge
(m^/sec)
0.07
0.25
0.12
0.25
0.09
0.11
0.03
0.02
Suspended Solids
Load (tons/day)
<0.5
5.3
0.9
16.4
0.6
1.7
0.2
0.1
67
-------
TABLE 28: DISCHARGES AND SEDIMENT LOADS OF LAKE SUPERIOR TRIBUTARIES (1975)
(CONTINUED)
Fish Creek On Highway 13
Date
April 14
April 17
April 22
April 24
April 29
May 1
May 7
Date
April 11
April 17
April 22
April 24
April 28
May 7
Date
April 13
April 16
April 21
April 23
April 25
April 29
May 1
May 5
Cross-Sectional
Area (m2)
Total Discharge
(nrVsec)
13.7
14.0
16.9
12.0
14.1
Cross-Sectional
Area (m2)
91.5
77.8
93.9
87.1
95
First
Cross-Sectional
Area (m2)
0.77
0.74
0.43
0.64
0.36
0.53
0.22
0.23
ice covered
ice covered
1.7
1.9
2.6
0.5
<0.2
Iron River
Total Discharge
(nrVsec)
ice covered
27.5
17.0
5.0
12.1
<1.0
Creek East of Jardines
Total Discharge
(m3/sec)
0.17
0.59
0.32
0.57
0.11
0.29
0.33
0.07
Suspended Solids
Load (tons/day)
9.4
21
26
2.0
<0.5
Suspended Solids
Load (tons/day)
270
104
25.3
76.5
<5
Suspended Solids
Load (tons/day)
0.6
3.5
0.6
2.3
0.2
0.8
0.2
0.1
68
-------
TABLE 28: DISCHARGES AND SEDIMENT LOADS OF LAKE SUPERIOR TRIBUTARIES (1975)
(CONTINUED)
Flag River On Highway 13
Date
April 10
April 13
April 16
April 21
April 23
April 25
April 29
May 1
May 5
May 9
Date
April 15
April 18
April 23
April 25
April 30
May 2
May 9
Cross-Sectional
Area (nr)
Total Discharge
(m3/sec)
5.3
8.7
14.3
8.8
14.6
5.7
9.5
6.0
6.0
4.9
Cross-Sectional
Area (m2)
1.2
0.77
1.9
1.4
2.3
1.2
0.77
1.6
3.5
9.8
4.7
12.8
2.5
7.8
3.2
2.2
1.3
Haukkala Creek
Total Discharge
(nH/sec)
2.3
1.5
0.74
0.26
0.98
0.26
0.03
Suspended Solids
Load (tons/day)
1.2
29
100
34
416
13
112
30
10
2.6
Suspended Solids
Load (tons/day)
53
36
7.3
1.8
3.1
1.3
0.2
Jardines Creek On Highway 13
Date
April 13
April 16
April 21
April 23
April 25
April 29
May 1
May 5
Cross-Sectional
Area (m2)
1.2
2.7
2.3
4.0
1.7
2.1
1.3
1.3
Total Discharge
(m^/sec)
0.89
2.9
0.62
1.8
0.68
1.4
0.64
0.30
Suspended Solids
Load (tons/day)
4.8
17.2
2.9
14.1
2.1
11.7
0.9
0.8
69
-------
TABLE 28: DISCHARGES AND SEDIMENT LOADS OF LAKE SUPERIOR TRIBUTARIES (1975)
(CONTINUED)
Nelson Creek On Highway 13
Date
April 10
April 14
April 15
April 18
April 23
April 25
April 30
May 2
May 9
Cross-Sectional
Area (nr)
1.7
1.3
1.3
1.0
1.1
0.77
0.58
Total Discharge
(m-Vsec)
ice covered
ice covered
1.3
1.8
0.85
0.38
0.52
0.21
0.07
Suspended Solids
Load (tons/day)
6.9
20.6
3.8
1.1
2.2
0.5
0.3
Reefer Creek On Highway 13
Date
April 14
April 17
April 22
April 24
April 28
May 1
May 7
Cross-Sectional
Area (nr)
15.1
15.5
18.5
14.3
15.0
Total Discharge
(m-Vsec)
ice covered
ice covered
2.1
3.7
1.0
0.75
Suspended Solids
Load (tons/day)
13.9
22.9
7.4
3.5
<0.5
Trask Creek On Highway 13
Date
April 11
April 14
April 18
April 22
April 24
April 28
April 30
May 2
May 7
Cross-Sectional
r\
Area (nr)
3.8
9.0
2.6
3.3
2.7
3.6
2.8
2.4
Total Discharge
ice covered
2.2
2.3
0.88
1.2
0.73
1.1
0.24
0.10
Suspended Solids
Load (tons/day)
10
56.4
5.9
4.8
5.1
9.0
1.1
0.3
70
-------
SECTION 9
SUMMARY OF CHEMICAL INPUTS TO LAKE SUPERIOR
The phase of this study dealing with the chemical inputs to Lake Supe-
rior from the red clays by soil leaching, sediment resuspension, and river
particulate leaching has been reported in the previous sections of this re-
port. This information will be summarized here with a brief discussion of
the results.
The chemical input to Lake Superior due to leaching of resuspended sedi-
ments has not been previously tabulated for some of the parameters, and this
information is listed here in Table 29. These results are based on the data
in Table 6 with the uncertainties estimated from the statistical analysis
presented in Appendix B.
The total inputs of the chemical parameters determined during the course
of this study are given in Table 30 along with the contributions from the
various sources. The contributions from leaching of resuspended sediments
are not included in the total inputs listed since much of this contribution
would occur even without resuspension due to the normal flux from the sedi-
ments. In addition, the values for shoreline erosion include contributions
from seven weeks of leaching (for the parameters down to magnesium in Table
30 and 3 months for silica) and therefore it is difficult to separate into a
soil and sediment contribution because of the uncertainty when the suspended
particles become sediment. Also there is a fairly large uncertainty in the
amount of resuspended material particularly during the winter months.-*
The uncertainties in the inputs listed in Table 30 are based on uncer-
tainties in the chemical analysis (see Appendix B) and assume no errors in
the amounts of clay material eroded. If the values for the magnitude of par-
ticulate material carried into Lake Superior are revised, the values in Table
30 could also be easily corrected.
The results indicate conclusively that shoreline erosion of clay soils
makes a larger contribution than sediment resuspension and river particulates
to chemical inputs to Lake Superior for all parameters for which values are
obtained. Data was not obtained in this study for leaching of Nemadji River
particulates in terms of trace metals, iron, and aluminum although in most
cases the values probably are not large compared to inputs from soil erosion.
The data shows that although the interstitial water of the clay-bearing sedi-
ments are enriched in certain of the chemical parameters, the contribution
of the release of this water during turbulence events is not important in
terms of enriching Lake Superior waters in the chemical parameters. However,
71
-------
TABLE 29: CHEMICAL INPUTS DUE TO LEACHING OF RESUSPENDED SEDIMENT*
Parameter
Chemical Release
(mg parameter per
gram of sediment)
Inputs to
Lake Superior
(metric tons/year)
Dissolved Solids**
Alkalinity**
Orthophosphate (P04>**
Total Soluble P**
Nitrate**
Total Kjeldahl N***
Sodium"'"
Potassium**
Calcium"1"
Magnesium"'"
Silica"1"1"
12.8 + 1.6
10.3 +0.8
0.063 + 0.027
0.023 + 0.03
0.38 +0.25
<0.2
0.06 + 0.04
0.24 + 0.11
0.6 + 0.4
0.30 + 0.20
2.76 + 0.50
20,500 + 2,400
16,500 + 1,200
100 + 40
37 + 4
610 + 380
<320
96 + 60
380 + 160
960 + 600
480 + 300
4,500 + 750
*Based on 1.6 x 106 metric tons/yr of suspended sediment.
**Based on data from Table 6.
***Based on lake water and DC-1 sediment leachate sample analysis by EPA
Region V Laboratory after 7 weeks of leaching at 23-27°C and 4°C.
"'"Based on data in Table 8.
"^Based on data in Table 7.
72
-------
TABLE 30: CHEMICAL INPUTS TO LAKE SUPERIOR DUE TO SOIL EROSION, RIVER PARTICULATES,AND SEDIMENT RESUSPENSION1
Parameter
Shoreline Erosion
Sediment
Resuspension
(leachine)4
Sediment
Resuspension
(Interstitial
Waters)5
River
Participates6
Total Inputs7
Dissolved Solids
Alkalinity
Orthophosphate (PO^)
Total Soluble P
Nitrate (N03)
Phi nr-f Ho
\*n J-Ol luc
Total Kjeldahl N
Sodium
Potassium
Calcium
Magnesium
Silica
Copper
Manganese-*
Cadmium
Zinc
Lead
Chromium
Nickel
Aluminum
Iron
Mercury
Arsenic
Selenium
192,000 + 40,000
184,000 + 40,000
240 + 80
280 + 160
400 ± 400
•cflflft
^OUv
<1600
2,000 + 1,600
3,400 + 1,200
48,000 + 24,000
7,200 + 3,200
14,400 + 3,200
<2
56 + 30
<0.008
<8
<1
<0.1
<8
76 + 50
64 + 10
<0.08
<2
<4
20,500 -1- 2,400
16,500 + 1,200
100 + 40
37 + 4
610 + 380
<320
96 + 60
380 + 160
960 -» 600
480 + 300
4,500 + 750
<1.0
0.4
<0.01
<0.6
<0.2
<1.5
<7.5
<11
<0.01
<0.25
<0.7
0.0045
2.0
1.0
13
3.6
9.5
0.002
0.45
0.0005
0.004
0.004
0.05
0.045
14,900 + 1,900
13,000 + 1,900
58 + 17
23 + 12
1,100 + 580
<175
207,000 + 42,000
197,000 + 42,000
298 + 97
303 + 172
1,500 + 1,000
<800
<1800
2,000 + 1,600
3,500 + 1,300
48,000 + 24,000
7,800 + 3,600
14,400 + 3,200
<2
56 + 30
<0.008
<8
<8
76 ± 50
64 + 10
<0.08
<2
<4
'•Metric tons per year.
2From data in Tables 10 and 20.
-'Based on chemical exchange data (Section 6).
^Based on data In Tables 20 and 28.
-"Based on data in Table 18.
6Based on data in Table 10. Values taken as 35% higher than the inputs of Nemadji River.
^Includes inputs from shoreline erosion, sediment resuspension (Interstitial waters), and river particulates.
for heavy metal plus iron and aluminum for river particulates.
No values available
-------
the enrichment may be important in the effects on bottom-feeding species in
Lake Superior.
The values of Table 30 would have to be compared to inputs from indus-
trial, municipal, tributary (chemical parameters dissolved in river waters^
and atmospheric sources along with chemical fluxes from Lake Superior sedi-
ments to determine the significance of chemical inputs on Lake Superior due
to erosion and resuspension of red clay material.
74
-------
REFERENCES
1. Red Clay Interagency Committee. Erosion and Sedimentation in the Lake
Superior Basin. University of Wisconsin Extension, Madison, Wisconsin,
1972. 81 pp.
2. Sydor, M. Preliminary Evaluation of Red Clay Turbidity Sources for West-
ern Lake Superior. University of Minnesota, Duluth, Minnesota, 1975.
54 pp.
3. Sydor, M. Red Clay Turbidity and Its Transport in Western Lake Superior-
Draft Report. U.S. EPA R-005175-01, 1975. Pages not numbered.
4. Swenson, W.A. Influence of Turbidity on Fish Abundance in Western Lake
Superior, Progress Report, U.S. EPA R-802455-02. University of Wiscon-
sin, Superior, Wisconsin, 1973. 51 pp.
5. Hess, C. Study of Shoreline Erosion on the Western Arm of Lake Superior.
Report from Geology Dept., University of Wisconsin, Madison, Wisconsin,
1973. 51 pp.
6. Plumb, R.H. Jr. A Study of the Potential Effects of the Discharge of
Taconite Tailings on Water Quality in Lake Superior. Ph.D. thesis,
University of Wisconsin, Madison, Wisconsin, 1973. 550 pp.
7. Glass, G.E. and J.E. Poldoski. Interstitial Water Components and Ex-
change Across the Water-Sediment Interface of Western Lake Superior.
Verh. Internat. Verein. Limnol., 19: 405-420, 1975.
8. Poldoski, J.E. and G.E. Glass. Methodological Considerations in Western
Lake Superior Water-Sediment Exchange Studies of Some Trace Elements.
7th Materials Research Symposium: Accuracy in Trace Analysis, NBS,
Gaithersburg, MD, October 7-11, 1974.
9. Taylor, A.W. and H.M. Kunishi. Phosphate Equilibria on Stream Sediment
and Soil in a Watershed Draining An Agricultural Region. J. Agric.
Food Chem. 19: 827-831, 1971.
10. Plumb, R.H. Jr. and G.F. Lee. Phosphate, Algae and Taconite Tailings
in the Western Arm of Lake Superior. In: Proceedings 17th Conference
on Great Lakes Research, International Association For Great Lakes
Research, pp. 823-836, 1974.
75
-------
11 American Public Health Association. Standard Methods for the Examina-
tion of Water and Wastewater, 13th ed. APHA, New York, 1971. 874 pp.
12. Bahnick, D.A., J.W. Horton, R.K. Roubal and A.B. Dickas. Effects of
South Shore Drainage Basins and Clay Erosion on the Physical and Chemi-
cal Limnology of Western Lake Superior. In: Proceedings 15th Confer-
ence on Great Lakes Research, International Association For Great Lakes
Research, pp 237-248, 1972.
13. Day, R.A. and A.L. Underwood. Quantitative Analysis. Prentice-Hall,
Inc. Eagleton Cliffs, N.J., 1967. 482 pp.
14. Fuller, F.D. (ed.). Chemical Laboratory Manual of Bottom Sediments.
Compiled by Great Lakes Region Committee on Analytical Methods, Lake
Michigan Basin Office (currently EPA Region V Office). Chicago,
Illinois, 1969. 101 pp.
15. Royse, C.F. Jr. Introduction to Sediment Analysis. Arizona State Uni-
versity Press, Tempe, Arizona, 1970. 180 pp.
16 Strickland, J.D.H. and T.R. Parsons. A Manual of Sea Water Analysis.
Fisheries Research Board of Canada. Bulletin No. 125, 2nd ed., Ottawa,
Canada, 1965. 203 pp.
76
-------
APPENDIX A
Data For Seven-Week Clay-Leaching
Experiments as Described in Section
77
-------
TABLE A-l: pH OF CLAY LEACHATES AND SAMPLE BLANKS
DAYS LEACHED
Sample*
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Initial
7.35
7.35
7.35
7.35
7.35
7.35
7.35
7.35
7.41
7.41
7.41
7.41
7.41
7.41
7.41
7.41
7.40
7.40
5.90
5.90
5.90
7.40
7.40
7.40
5.99
5.70
5.43
5.39
7.44
7.44
7.44
7.44
1
7.70
7.77
7.75
7.73
7.73
7.76
7.79
7.50
7.38
7.43
7.44
7.50
7.65
7.63
7.71
7.72
7.60
7.50
8.79
8.71
6.00
7.57
7.79
7.60
5.99
5.70
5.43
5.39
7.58
7.70
7.50
7.50
7
7.68
7.72
7.72
7.70
7.75
7.76
7.81
7.55
7.13
7.48
7.40
7.46
7.55
7.62
7.64
7.69
7.55
7.51
8.27
8.59
6.11
7.63
7.80
7.70
6.01
5.99
7.50*
5.61
7.62
7.69
7.50
7.50
21
7.60
7.68
7.71
7.70
7.79
7.79
7.79
7.60
7.59
7.59
7.50
7.49
7.75
7.79
7.79
7.80
7.40
7.49
8.60
8.59
5.89
7.50
7.73
7.64
5.69
5.71
5.30
5.04
7.61
7.70
7.47
7.47
35
7.59
7.63
7.74
7.71
7.75
7.75
7.79
7.50
7.55
7.50
7.55
7.40
7.60
7.70
7.70
7.62
7.53
7.62
8.26
8.42
6.02
7.65
7.79
7.73
5.66
5.71
5.39
5.38
7.55
7.59
7.53
7.54
49
7.60
7.70
7.73
7.73
7.75
7.75
7.77
7.54
7.58
7.60
7.59
7.56
7.70
7.70
7.70
7.70
7.59
7.70
7.95
7.70
6.45
7.77
7.79
7.79
5.78
5.62
5.51
5.20
7.65
7.74
7.49
7.50
* Samples are described in Table 2.
COj was lost from flask.
78
-------
TABLE A-2: SPECIFIC CONDUCTANCE OF CLAY LEACHATES AND SAMPLE BLANKS
DAYS LEACHED
Sample
1
2
3
_4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Initial
92.7
92.7
92.7
92.7
92.7
92.7
92.7
92.7
95.0
95.0
95.0
95.0
95.0
95.0
95.0
95.0
96.0
96.0
1.0
1.0
1.0
96.0
96.0
96.0
96.1
96.1
96.1
96.1
96.1
96.1
96.1
96.1
1
102.7
103.6
103.3
103.0
102.0
104.3
104.6
93.0
95.7
95.2
95.5
95.2
104.6
104.3
103.3
104.0
95.7
96.3
34.8
34.8
1.3
97.7
105.2
99.9
167.4
173.7
105.7
98.9
108.8
108.8
96.3
96.0
7
105.3
106.7
106.0
105.0
106.0
107.0
107.0
95.5
98.9
98.6
97.2
95.8
107.0
106.7
107.4
106.4
97.7
101.1
33.8
34.7
1.7
99.8
107.8
101.4
197.9
206.6
100.8
96.3
109.2
108.8
94.4
94.4
21
108.1
109.1
108.1
108.1
107.3
108.1
108.1
95.1
101.7
103.0
99.2
95.9
108.1
108.5
108.1
108.1
95.8
104.3
34.7
35.5
1.6
95.2
103.6
96.3
190.9
200.3
105.0
97.8
110.7
108.8
95.7
35
108.1
108.6
108.6
108.5
108.6
108.6
108.6
93.0
103.3
104.0
98.6
94.6
108.8
108.6
108.5
108.8
95.2
106.7
34.7
35.9
1.6
95.7
103.0
95.8
178.4
184.5
102.3
97.5
116.6
109.6
93.6
95.2
49
112.2
109.6
112.6
108.5
113.0
113.0
112.6
96.0
102.0
104.3
98.6
93.6
108.8
108.8
108.8
108.8
94.0
105.0
35.5
36.3
1.3
93.3
101.1
94.1
171.8
177.4
102.7
96.6
120.9
104.6
96.0
93.6
79
-------
TABLE A-3: DISSOLVED OXYGEN OF CLAY LEACHATES AND SAMPLE BLANKS
DAYS L BACHED
Sample
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Initial
8.6
8.6
8.6
8.6
8.6
8.6
8.6
8.6
7.8
7.8
7.8
7.8
7.8
7.8
7.8
7.8
9.1
9.1
5.8
5.8
5.8
1.6
2.5
4.1
4.2
2.3
4.7
2.0
8.7
8.7
8.7
8.7
1
8.7
8.7
8.6
8.9
8.3
9.1
9.0
9.0
7.7
7.9
7.6
8.6
9.5
9.1
9.3
8.9
7.3
7.7
7.7
7.8
7.3
1.6
2.5
4.1
4.2
2.3
4.7
2.0
10.4
10.4
10.3
10.3
7
7.9
8.0
8.2
8.1
7.6
8.0
8.0
8.1
7.5
7.3
6.7
7.2
7.8
8.4
7.9
7.9
6.7
6.1
6.6
6.8
7.3
0.7
2.8
0.4
1.6
1.2
7.3
1.2
10.7
10.8
10.5
11.3
21
8.0
8.1
8.2
7.9
8.2
8.6
8.3
8.2
11.7
4.0
7.8
7.9
7.7
8.4
8.4
7.8
6.4
10.9
6.7
11.2
8.3
1.0
0.8
1.4
1.6
1.5
2.8
5.7
10.2
10.5
15.1
35
8.3
7.8
8.2
8.6
8.6
8.5
8.5
8.8
8.7
8.4
8.2
7.9
8.8
8.4
10.5
7.0
6.6
6.8
4.9
7.2
7.5
0.6
0.6
0.5
1.2
1.3
1.2
1.3
10.1
10.2
10.7
10.7
49
8.6
8.4
7.8
8.2
9.6
8.5
8.5
8.4
8.2
8.4
8.6
8.2
8.2
8.6
8.6
8.5
6.6
7.1
6.8
7.1
7.5
0.7
1.1
0.9
1.3
1.6
1.2
1.6
13.2
13.1
13.2
13.2
80
-------
TABLE A-4: TOTAL CORRECTED RELEASE OF DISSOLVED SOLIDS IN mg PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
11.3
12.5
12.3
11.9
10.6
13.5
13.8
0.7
0
0.52
11.4
10.9
9.6
10.5
1.7
42.7
42.6
-3.0
6.7
83.2
91.5
15.5
15.9
15.9
0.5
7
12.7
14.4
13.9
12.6
13.5
15.2
15.2
4.0
3.3
2.7
14.7
14.2
14.8
13.8
11.6
45.2
46.2
-2.5
8.7
131.7
144.3
11.8
20.2
19.8
0.2
21
16.9
19.0
18.1
17.9
16.7
18.2
18.2
7.7
8.4
6.6
17.2
17.5
16.9
17.0
26.3
50.6
51.6
-0.8
10.8
133.9
148.3
19.2
23.2
20.9
1.7
35
21.5
22.6
22.8
22.4
22.2
22.9
22.9
11.6
11.4
7.8
20.6
20.3
19.8
20.4
37.6
54.8
56.4
-0.7
11.7
130.3
141.8
16.2
30.1
21.1
-3.5
49
24.5
22.0
25.8
20.6
25.6
26.3
25.9
12.8
14.4
11.2
24.0
23.9
23.6
23.8
39.4
60.3
61.6
-1.8
12.2
133.2
144.9
19.4
40.4
18.9
1.8
81
-------
TABLE A-5: TOTAL CORRECTED RELEASE OF ALKALINITY IN mg OF CaC03 PER g OF CLAY
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
9.2
12.3
11.5
11.3
12.1
10.9
14.6
-0.4
-0.2
2.1
7.7
6.7
7.8
8.2
0.5
31.6
34.1
-2.2
7.6
80.2
78.5
19.3
15.7
13.4
-1.1
7
11.3
11.6
14.7
13.5
12.0
13.6
15.1
1.6
4.8
9.9
9.2
8.5
11.8
11.4
6.0
31.9
34.5
-2.6
11.4
127.1
127.0
20.4
20.7
19.7
-3.3
21
15.2
15.9
17.4
14.9
17.1
16.0
18.0
7.9
5.7
14.8
13.0
13.7
14.4
20.6
28.9
25.0
-2.4
11.3
119.0
140.1
8.5
22.3
24.2
1.5
35
16.1
17.7
16.2
17.3
14.8
18.3
18.7
6.0
9.4
4.7
15.5
15.8
16.1
13.1
28.7
43.7
45.9
-0.4
10.1
111.6
136.3
21.1
29.0
24.6
4.5
49
25.3
22.3
22.8
21.6
22.2
22.7
25.4
9.5
10.2
11.2
20.0
19.9
21.4
19.5
34.8
49.7
52.0
2.2
14.0
134.7
144.3
26.5
40.3
26.7
2.9
82
-------
TABLE A-6: TOTAL CORRECTED RELEASE OF ORTHOPHOSPHATE IN yg OF P04 PER g
OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
19
32
23
21
38
42
32
25
24
0
19
15
26
28
43
51
62
4
27
63
71
74
15
15
11
7
21
21
26
21
36
36
24
39
45
30
15
11
6
9
153
26
41
25
45
49
38
69
29
46
34
21
13
21
11
14
39
35
23
73
71
41
23
12
24
23
133
47
55
5
14
50
43
78
26
28
27
35
22
26
10
19
40
45
28
81
76
47
15
13
24
20
185
54
40
36
6
77
60
75
26
33
26
49
14
23
6
13
24
9
9
63
89
36
43
22
37
28
132
44
41
63
29
70
56
80
32
32
28
83
-------
TABLE A-7: TOTAL CORRECTED RELEASE OF TOTAL SOLUBLE P IN yg OF P PER g
OF CLAY
D AYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
2
12
2
4
9
15
9
9
8
0
9
6
12
13
49
38
9
11
8
7
27
33
17
12
11
7
4
3
8
5
7
10
4
20
12
4
8
2
—
5
74
37
43
—
—
44
26
50
23
34
13
21
18
22
-0.5
20
33
30
22
18
19
3
10
—
8
5
70
24
10
—
5
24
31
45
25
10
10
35
3
9
11
5
12
14
6
22
22
17
1
3
7
5
65
14
29
19
7
25
24
30
14
14
11
49
59
64
3
20
43
31
31
25
23
21
5
10
7
13
42
14
12
14
4
24
4
28
14
10
7
84
-------
TABLE A-8: TOTAL CORRECTED RELEASE OF NITRATE IN mg PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
0.09
0.12
0.08
0.05
-0.06
-0.02
-0.04
0.18
0.15
0.11
0.14
-0.02
0.01
-0.02
0.05
0.16
0.22
-0.10
-0.12
0.26
0.10
0.26
-0.22
0.02
-0.24
7
0.11
0.19
0.09
0.04
0.05
0.02
0.00
0.25
0.20
•0.16
0.06
-0.04
0.03
-0.08
0.56
0.07
0.12
-0.21
-0.23
-0.05
0.01
-0.34
0.15
0.14
-0.27
21
0.01
0.11
-0.05
0.01
-0.14
-0.02
-0.11
-0.16
-0.13
0.04
0.09
-0.03
0.04
-0.06
2.45
0.10
0.11
-0.10
-0.47
-0.15
0.10
-0.24
-0.32
0.08
-0.54
35
0.05
0.07
-0.01
-0.02
-0.03
-0.03
-0.03
0.36
0.48
0.36
0.00
0.03
0.03
0.05
2.90
0.09
0.08
-0.30
-0.73
0.06
-0.06
0.01
0.56
0.23
-0.49
49
0.08
0.20
0.03
0.07
0.24
-0.21
0.01
0.17
0.47
0.51
-0.10
-0.09
-0.17
0.12
3.09
0.13
0.12
-0.43
-0.98
0.12
0.18
0.02
0.18
0.10
0.04
85
-------
TABLE A-9: TOTAL CORRECTED RELEASE OF CHLORIDE IN rag PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
0.98
0.57
0.42
0.32
0.36
0.25
0.00
-0.03
-0.58
-1.27
-0.66
-0.36
-0.30
-0.26
0.80
0.03
0.08
0.01
-0.21
0.31
0.11
0.46
-0.07
-0.11
-0.12
7
0.35
0.10
0.24
-0.21
-0.12
-0.18
-0.22
0.53
0.25
1.52
1.28
0.84
0.24
1.71
0.37
0.33
-0.03
0.13
-0.10
-0.11
-0.05
0.08
0.29
0.39
-0.06
21
2.47
0.68
0.50
-0.04
0.16
0.10
-0.13
0.22
-0.90
0.45
-0.51
-0.74
-0.74
-1.08
0.39
0.06
0.03
0.72
0.66
-0.00
-0.11
0.18
0.03
-0.03
-0.42
35
1.68
0.31
0.29
-0.46
-0.36
-0.18
-0.32
-1.07
-0.47
-0.29
-0.50
-0.72
-1.41
-1.15
-0.44
0.07
-0.05
-0.13
-0.19
-0.16
-0.02
0.23
-0.01
0.03
0.02
49
1.83
-0.23
0.06
0.47
0.02
-0.18
-0.05
-0.31
-0.24
-0.09
-0.05
-0.18
-0.54
-0.38
0.37
-0.27
-0.66
-0.20
-0.12
-0.09
-0.06
-0.15
-0.06
-0.22
-0.14
86
-------
TABLE A-10: TOTAL CORRECTED RELEASE OF TOTAL KJELDAHL N IN mg OF N PER g
OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
0.16
0.21
0.18
0.09
0.09
0.06
0.04
0.07
0.02
-0.05
0.07
0.04
0.00
0.03
-0.11
-0.23
-0.27
-0.21
-0.14
0.06
0.00
0.00
-0.04
-0.08
-0.07
7
-0.14
-0.12
-0.09
0.15
0.02
0.02
-0.04
0.01
-0.03
-0.06
-0.03
-0.09
-0.10
-0.08
0.40
0.14
0.26
-0.01
-0.04
0.02
0.01
0.24
-0.08
-0.19
-0.16
21
0.36
0.13
0.25
0.15
-0.07
-0.12
-0.14
-1.07
-0.63
-1.27
-0.58
0.13
-0.05
-0.16
-0.23
0.03
-0.08
0.14
-0.01
0.01
0.06
0.21
0.04
-0.01
-0.02
35
0.05
-0.06
-0.12
-0.13
-0.04
-0.10
0.05
0.02
-0.21
-0.08
-0.14
-0.21
-0.27
-0.39
0.02
0.19
-0.04
0.10
-0.23
0.13
-0.21
-0.20
-0.47
-0.45
-0.72
49
-0.04
-0.03
-0.04
-0.09
0.13
-0.05
0.00
—
—
—
—
—
—
—
0.48
—
—
—
—
0.18
0.09
0.24
0.16
-0.18
-0.30
87
-------
TABLE A-ll: TOTAL CORRECTED RELEASE OF SODIUM IN mg PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
0.39
0.19
0.24
0.08
0.18
0.37
0.24
0.39
0.09
0.12
0.30
0.08
0.20
0.06
0.19
0.21
0.06
-0.14
0.10
0.54
0.28
-0.04
0.49
0.45
0.51
7
0.56
0.45
0.06
-0.05
0.19
1.93
0.08
0.12
-0.08
4.50
0.15
0.19
0.18
0.43
2.72
0.44
1.54
0.20
0.18
2.38
0.11
-0.54
0.93
0.68
0.11
21
-0.20
-0.09
-0.51
-0.63
0.91
—
—
1.88
0.16
3.33
1.02
1.14
3.15
1.96
4.49
0.74
0.45
0.15
-0.06
1.05
0.18
-0.06
0.17
1.47
0.42
35
2.04
0.53
0.65
-0.69
-0.07
-0.61
0.15
1.11
0.13
0.00
-0.18
0.97
0.17
0.30
-0.59
0.76
0.69
0.07
-0.58
0.30
-0.17
0.10
0.41
0.39
0.20
49
1.62
0.25
-0.12
-0.01
0.28
-0.34
-0.10
0.91
1.32
0.69
0.32
0.55
0.27
0.38
0.10
0.74
0.74
0.54
0.79
0.16
-0.21
0.46
0.35
0.32
0.18
88
-------
TABLE A-12: TOTAL CORRECTED RELEASE OF POTASSIUM IN mg PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
0.37
0.39
0.36
0.45
0.47
0.41
0.45
0.06
0.00
0.12
0.26
0.22
0.35
0.48
0.24
0.40
0.40
0.20
0.29
0.34
0.30
0.15
0.16
0.14
0.03
7
0.25
0.15
0.35
0.34
0.38
0.38
0.34
0.07
0.13
0.14
0.26
0.36
0.41
0.45
0.16
0.31
0.44
0.32
0.05
0.58
0.31
0.21
0.22
0.47
0.31
21
0.06
0.06
0.01
0.08
0.12
0.11
0.15
0.24
0.26
-0.01
0.17
0.13
0.23
0.32
0.19
0.36
0.42
-0.11
-0.18
0.43
0.38
0.26
0.28
0.37
0.26
35
-0.04
0.02
-0.18
-0.04
0.24
0.04
—
0.63
0.51
0.27
0.48
0.40
0.77
0.79
0.35
0.45
0.55
0.22
0.15
0.34
0.31
0.40
0.31
0.34
0.15
49
0.48
0.21
0.34
0.42
0.55
0.63
0.31
0.33
0.28
0.12
0.15
0.18
0.14
0.16
0.24
0.39
0.51
0.24
0.11
0.35
0.38
0.40
0.28
0.88
0.21
89
-------
TABLE A-13: TOTAL CORRECTED RELEASE OF CALCIUM IN mg PER g OF CLAY
DAYS LEACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
1.17
0.97
2.18
2.37
1.37
1.97
0.59
-0.41
-0.19
0.31
2.78
2.58
2.16
0.99
0.00
10.52
10.30
-0.70
2.30
18.07
22.47
7.60
3.70
2.68
0.28
7
1.86
2.43
3.43
2.81
3.84
4.33
3.60
0.78
0.54
0.95
3.86
3.63
3.16
2.87
2.41
13.05
12.59
-2.63
0.65
28.11
32.81
4.94
4.44
4.14
-0.31
21
0.10
0.14
0.42
1.29
2.46
2.19
1.99
-0.16
1.16
1.66
0.83
2.97
2.28
1.17
5.55
14.88
15.00
-3.12
0.06
26.32
31.62
5.36
4.87
3.73
-1.99
35
__
—
-1.96
7.10
10.85
9.04
7.85
1.46
4.27
-1.88
4.23
3.81
1.67
3.03
-1.16
16.35
14.81
-3.16
0.88
27.71
27.16
6.92
5.71
4.47
-2.06
49
4.82
5.31
6.72
6.76
8.54
6.32
4.45
-0.86
2.25
-3.02
7.59
3.11
3.14
1.70
1.59
16.37
15.95
-0.84
2.64
24.22
28.26
3.65
9.06
4.63
-0.98
90
-------
TABLE A-14: TOTAL CORRECTED RELEASE OF MAGNESIUM IN mg PER g OF CLAY
DAYS L E ACHED
Sample
1
2
3
4
5
6
7
9
10
11
13
14
15
16
18
19
20
22
23
25
26
27
29
30
31
1
1.18
1.22
0.79
0.91
-0.02
0.24
1.26
0.02
0.13
0.28
0.78
0.63
1.18
1.13
0.34
2.53
2.44
0.02
0.94
2.13
2.21
1.37
1.01
0.95
0.17
7
1.03
1.11
0.63
0.66
0.13
0.07
1.37
0.48
0.35
0.27
0.73
0.80
1.28
1.26
0.90
2.59
2.51
-0.18
0.83
2.08
2.10
1.20
1.11
1.15
0.30
21
1.24
1.33
0.89
1.06
0.40
0.61
1.12
1.08
1.21
1.13
0.96
0.89
1.35
1.44
1.47
2.70
2.57
-0.18
0.69
2.39
2.45
1.31
0.92
0.98
0.27
35
1.50
1.89
1.26
0.91
0.54
0.53
1.89
1.04
1.19
1.24
0.66
0.37
1.07
1.24
1.70
3.02
2.99
-0.03
1.06
2.29
2.36
2.06
0.34
0.44
-0.33
49
1.25
1.27
0.87
0.90
0.35
0.46
1.32
1.72
1.77
2.18
1.14
0.94
1.22
1.19
1.37
3.46
3.43
-0.27
0.51
2.59
2.71
1.47
1.10
0.97
0.51
91
-------
APPENDIX B
U.S. EPA - University of Wisconsin
Analytical Quality Control Results
and Their Impact on the
Chemical Loading Estimates
92
-------
INTRALAB COMPARISONS
An analytical quality control (AQC) program was carried out during the
course of the study. This program consisted of University of Wisconsin,
Superior (UWS) analysis of reference samples provided by the EPA and analysis
of split samples by both laboratories. The split samples were chosen at
random from those analyzed by the University of Wisconsin and generally con-
sisted of Lake Superior water samples which had been obtained during the
leaching and exchange studies or from the Lake Superior water-sampling phase.
The results of the AQC comparisons are shown in Table B-l according to
the parameters analyzed. Those samples which do not have UWS sample numbers
are reference samples provided by the EPA Region V Laboratories, Chicago,
Illinois (CRL) while those which do have UWS sample numbers are the split-
water samples.
The comparisons shown in Table B-l were tested for significant differences
between the results of the two laboratories for those samples which were com-
patible with a statistical analysis. The null hypothesis assuming the two
"means" for a particular analysis are identical at a 95% probability level
was used by employing the expression.13
_.,
Vni
n2
where X-^ and X» are the two means in question, S is the standard deviation
in the determination of the means (assuming it is the same for both laborato-
ries), and ni and n2 are the number of individual results obtained by the
two laboratories in determining the mean values. The t value determined is
compared to tabulated values according to the degrees of freedom (n-^ + ^ - 2)
at the desired probability level. If the t value computed is less than the
tabulated t value at the appropriate probability level (95% is used here),
then the two means are identical within the level tested.
Each analysis was not performed in multiplate due to time, budget, and
manpower limitations and thus standard deviations are not available for each
individual determination. During the course of this study, many of the ana-
lytical determinations of each parameter were performed in duplicate, and
these replicate determinations have been used to establish average standard
deviation values for the UWS analysis of these parameters. Standard devia-
tions were calculated for the analysis of samples having parameter values
of the same magnitude as those used in the loading to Lake Superior calcula-
tions. The average standard-deviation values for a large number of repli-
93
-------
TABLE B-lt SUMMARY OF E.P.A.-UNIVERSITY OF WISCONSIN AQC PROGRAM
Date
1975
6/4
6/4
5/30
6/7
6/7
6/25
7/7
7/23
7/23
Al
1 concentrations are in me/1.
Sample No. Orthophosphate-P
UW-S
^^^
—
1
357
323
13
L.W.
9
13
CRL
Nutrient
Ref Cone 1
Nutrient
Ref Cone 2
10755
10771
10773
11001
8209
8221
8222
UW-S
0.024
0.395
0.033
0.001
0.001
0.018
0.001
0.031
0.020
CRL
0.021
0.393
<0.007
<0.007
<0.007
<0.007
<0.007
<0.007
<0.007
Date
1975
4/25
4/25
4/25
4/25
6/4
6/4
5/30
6/7
6/7
6/25
7/7
7/23
7/23
Sample No. Total Soluble-P
UW-S
__
—
—
—
—
—
2
357
323
13
L.W.
9
13
CRL
ULRG#5 #43
ULRG#5 #44
ULRG#5 #45
ULRG#5 #46
Nutrient
Ref Cone 3
Nutrient
Ref Cone 4
10756
10771
10773
11001
8209
8221
8222
UW-S
1.37
1.65
0.128
0.149
0.093
0.767
0.012
0.003
0.005
0.003
<0.001
0.014
0.014
CRL
1.46
1.69
0.18
0.17
0.142
0.713
0.010
<0.007
<0.007
<0.007
<0.007
<0.007
<0.007
Continued
94
-------
TABLE B-l (continued)
Date
1975
4/25
4/25
4/25
4/25
6/4
6/4
5/30
6/7
6/7
6/25
6/25
6/25
7/7
7/7
7/23
7/23
8/6
8/6
8/15
8/15
8/15
8/15
8/15
8/15
8/15
Sample No.
UW-S CRL
ULRG#5 #43
ULRG#5 #44
ULRG#5 #45
—
__
—
3
317
320
11
12
L.W.
L.W.
8
10
14
13
15
2
13
15
16
316
320
349
ULRG#5 #46
Nutrient
Ref Cone 3
Nutrient
Ref Cone 4
10757
10773
10780
11003
11004
11005
8211
8212
8224
8225
8242
8243
8249
8250
8251
8252
8254
8256
8258
TKN
UW-S
3.40
3.87
5.30
4.
0.
0.
0.
0.
0.
0.
0.
0.
0.
<0.
0.
0.
0.
<0.
0.
0.
0.
0.
0.
0.
0.
62
102
332*
0
06
25*
01
04
02
04
01
033
063
03
01
22
39
21
28
18
18
24
CRL
4.03
4.85
6.51
5.85
0.35
5.80
0.21
0.28
0.69
0.27
0.31
0.25
0.11
0.08
0.12
0.08
0.10
0.10
0.16
0.12
0.11
0.12
0.05
0.07
0.09
Date
1975
6/4
6/4
5/30
6/7
6/7
6/25
7/7
7/23
7/23
8/6
8/6
8/15
8/15
8/15
8/15
8/15
8/15
8/15
Sample No. Nitrate
UW-S CRL UW-S CRL
Nutrient 0.368 0.20
Ref Cone 1
Nutrient 1.170 1.11
Ref Cone 2
4 10758 0.22* 0.31
337
317
14
L.W.
15
11
9
14
2
13
15
16
316
320
349
10776
10777
11007
8213
8226
8227
8240
8241
8249
8250
8251
8252
8253
8255
8257
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
22*
23*
25*
24*
20*
22*
24*
26
32*
23*
23*
21*
19*
20*
18*
0.28
0.28
0.28
0.28
0.28
0.28
0.27
0.26
0.39
0.29
0.31
0.31
0.22
0.29
0.21
* Differences between laboratories are statistically significant.
Continued
95
-------
TABLE B-l (continued)
Date
1975
4/30
4/30
4/30
4/30
4/30
4/30
6/7
6/7
6/25
6/25
6/25
7/7
7/7
7/7
7/23
7/23
7/23
8/6
8/6
8/6
8/15
8/15
8/15
Sample No.
UW-S CRL
ULRG//6 #51
—
__
—
—
—
362
320
3
10
17
1
5
14
9
10
16
5
10
15
319
341
362
ULRG#6 #52
ULRG#6 #53
ULRG#6 #54
ULRG#6 #55
ULRG#6 #56
10783
10784
11009
11010
11011
8216
8217
8218
8231
8232
8233
8245
8246
8247
8260
8261
8262
Silica
UW-S CRL
2.4 2.3
2
1
1
0
0
3
3
3
2
2
4
2
4
5
3
3
2
2
4
2
2
2
.3
.2
.0
.2
.3
.24
.15
.7*
.8
.7
.97
.84
.60
.6*
.0
.0
.90
.80*
.80
.52
.81
.70
2.
1.
1.
0.
0.
2.
2.
4.
2.
2.
4.
2.
4.
4.
2.
2.
2.
0.
4.
2.
2.
2.
2
1
0
2
2
89
98
63
6
8
63
51
02
78
71
70
65
36
17
33
54
50
Date Sample No.
1975 UW-S CRL
4/30 — ULRG#6 #51
4/30 —
4/30 --
4/30 —
4/30 —
4/30 —
5/30 5
6/7 362
6/7 320
6/25 16
7/7 L.W.
7/23 13
7/23 16
ULRG#6 #52
ULRG//6 #53
ULRG#6 #54
ULRG#6 #55
ULRG#6 #56
10760
10783
10784
11008
8215
8229
8230
Chloride
UW-S CRL
1.1 1.2
1.
5.
4.
7.
8.
1.
1.
3.
1.
1.
1.
1.
7
3
8
4
5
59
70
42*
45
09
19
19
1.8
5.3
4.8
7.4
8.2
1.6
1.6
3.2
1.4
1.2
1.3
1.3
* Differences between laboratories are statistically significant.
Continued
96
-------
TABLE B-l (continued)
Date
1975
5/30
5/30
6/7
6/7
6/7
6/7
6/7
6/25
7/7
7/23
7/23
8/4
8/4
8/4
8/6
8/6
8/15
8/15
Sample No.
UW-S CRL
6 10761
7
341
1
316
320
362
9
L.W.
12
13
7
8
9
10
16
142
337
10761
10790
10791
10792
10794
10795
11012
8219
8234
8235
8243
8244
8245
8237
8238
8272
8273
Calcium
UW-S CRL
15.0 15.1
11.9
12.2*
12.8
14.5
14.6*
14.3*
15.6*
23.9*
13.4
14.0
13.4
12.8
15.1
12.9
14.9
11.6
11.8
13.7
26.9
13.0
12.8
13.2
Magnesium
UW-S CRL
3.10* 3.3
3.28*
3.33
3.04
3.46
3.36*
3.4*
3.7*
4.19*
3.36*
3.35*
3.27*
2.99
3.25
3.00
3.5
2.8
2.8
3.3
5.8
3.0
3.0
3.1
Potassium
UW-S CRL
0.63
0.67
0.73*
0.60
0.72
0.42*
0.52
0.66
0.72*
0.60*
0.59*
0.57
0.65
0.60
0.63
0.58
0.66
0.52
0.59
0.68
0.64
0.51
0.48
0.51
Sodium
UW-S CRL
2.11*
2.90*
3.07*
2.30*
1.86*
1.13*
1.20*
1.05*
1.46*
1.48
1.73*
1.62*
1.0
1.55
1.41
1.53
1.7
1.48
1.63
1.34
1.3
1.4
1.4
1.4
* Differences between laboratories are statistically significant.
Continued
97
-------
TABLE B-l (continued)
Date
1975
4/16
4/16
4/16
4/16
6/7
6/7
6/7
6/7
6/7
6/7
8/4
8/4
8/4
8/15
8/15
8/15
8/15
8/15
8/15
8/15
Sample No.
UW-S
__
—
—
—
337
349
349
347
320
362
7
8
9
1
2
3
4
317
343
357
CRL
10601
10602
10603
10604
10785
10786
10787
10788
10794
10795
8243
8244
8245
8264
8265
8266
8267
8268
8269
8270
Copper
UW-S
7
4
7*
8*
5
5
1.8
4
4
2.5
2.7
4.0
3.5
3.5
1.3
2.3
CRL
8
4
3
4
7
4
3
4
4
2.0
2.5
2.5
2.0
1.5
0.5
1.0
Iron Lead
UW-S
28
20
20
32
1097
803
54
69
30
260
62
13
4770
3950
11
CRL UW-S CRL
20 <1 1
10 <1 <1
<10 <1 <1
<10 <1 <1
810
570
70
90
44 <1 <1
300 2 1
70 <1 <1
<5
4600
2900
<5
<1 <2
<1 <2
<1 <2
Manganese
UW-S
1.4
0.8
1.0
1.4
8.3
2.6
1.5
10.0*
4.2*
3.0*
3760
4770
5.8*
8.0*
2.3
3.0*
CRL
1.4
1.0
1.4
1.2
8.5
2.5
1.0
5.8
10
1.1
4900
2900
3.5
3.5
1.0
1.2
* Differences between laboratories are statistically significant.
Continued
98
-------
TABLE B-l (continued)
Date
1975
4/16
4/16
4/16
4/16
6/7
6/7
6/7
6/7
6/7
6/7
8/4
8/4
8/4
8/15
8/15
8/15
8/15
8/15
8/15
8/15
Sample No. Nickel
UW-S CRL UW-S CRL
__
— —
—
—
337
349
349
347
320
362
7
8
9
1
2
3
4
317
343
357
10601 <20 <20
10602 <20 <20
10603 <20 <20
10604 <20 <20
10785
10786
10787
10788
10794
10795
8243
8244
8245
8264
8265
8266
8267
8268
8269
8270
Zinc
UW-S CRL
12
7
6
6
7.
7.
2
6
13
7.
8.
6.
5.
6.
0.
2.
0
9
4
0
4
0
1
9
4
11
7
5
5
6.0
13.0
<5
<5
<5
<5
<5
14
<5
<5
<5
<5
Cadmium
UW-S CRL
1.
0.
0.
0.
0.
1.
<0.
<0.
<0.
0.
0.
0.
0.
0.
0.
0.
0
2
2
2
3
3
1
1
1
09
01*
03*
05
05
02
05
0.
<0.
<0.
<0.
0.
1.
-------
cates are listed in Table B-2,together with the range of concentration of the
parameter in those samples which were used in the calculations.
In the calculation of the t values, it is assumed that the standard de-
viation values for the two laboratories are the same as listed in Table B-2.
The values for nL and n2 are taken as two since at most two determinations
were made on the individual analysis of a particular parameter and the same
situation is assumed to exist for the EPA results. Consequently, the ex-
pression for the t values reduces to:
xl ~ X2
and these computed values are compared to a Student's t value of 4.3 for two
degrees of freedom.13
This test for significant differences in the analytical determinations
of the parameters does not indicate which results are the more correct re-
sults but will indicate potential systematic errors in their determinations.
This information coupled with the degree of agreement between the two lab-
oratories will assist in the estimates of uncertainties in the loadings for
the various parameters.
Those individual determinations in which there are significant differ-
ences between the data of the two laboratories are indicated by asterisks
assigned to the UWS values in Table B-l. The results show that there are
significant differences occurring for some of the parameters, but for others
the agreement is within those limits predicted by assuming only random fluc-
tuations in the data. It should be stressed that there is up to a three-
month time difference in the analysis of the split samples between the two
laboratories.
The comparisons for orthophosphate -P and total soluble phosphorus are
limited because of sample stability and the low values of these parameters
in the lake-water samples. The only valid comparisons for orthophosphate
pertain to the results for nutrient reference samples in which the values
are in good agreement. For total soluble phosphorus, the reference samples
were too concentrated for comparisons at the levels at which standard devi-
ations were established. However, comparisons of those reference samples
appear to be fairly good. Only one sample (CRL-10756) was statistically
tested and there is no significant difference between the values.
All total Kjeldahl nitrogen values were tested statistically except for
the high-concentration samples (CKL #43, #44, #45, #46). There are signif-
icant differences in two of the comparison values, with one being extremely
large. The standard deviation for total Kjeldahl nitrogen for the Univer-
sity of Wisconsin determinations is relatively large (0.067 mg/1), and con-
sequently the statistical test would indicate no significant differences at
the low-concentration levels found in the soil and sediment-leaching samples
in Lake Superior water. UWS replicate results indicate that there is a
100
-------
TABLE B-2: UNIVERSITY OF WISCONSIN AVERAGE STANDARD-DEVIATIONS
FOR REPLICATE ANALYSIS
Parameter
Orthophosphate -p
Total Soluble Phosphorus
Alkalinity
Specific Conductance
PH
Calcium
Magnesium
Sodium
Potassium
Chloride
Nitrate - NO-
Kjeldahl -N
Silica (Si02)
Aluminum
Copper
Cadmium
Manganese
Zinc
Iron
Average Standard
Deviation*
0.0020
0.0015
0.38
0.44
0.02
0.26
0.036
0.0325
0.017
0.031
0.005
0.067
0.17
7.1
0.76
0.03
0.36
2.5
15
Concentration Range
0.005 - 0.034 mg/1
0.006 - 0.017 mg/1
20 - 50 mg/1
92 - 272 ymhos
7.5 - 8.3
12 - 17 mg/1
3.3 - 4.3 mg/1
0.3 - 3.7 mg/1
0.5 - 1.0 mg/1
1.0 - 4.6 mg/1
0.8 - 1.3 mg/1
0.03 - 0.4 mg/1
2.6 - 3.2 mg/1
50 - 100 yg/1
1-10 yg/1
0.15 - 1.25 yg/1
1-10 yg/1
1-14 yg/1
30 - 150 yg/1
* The units are the same as those listed under the concentration range.
101
-------
significant degree of uncertainty in the UWS values. Therefore, the EPA re-
sults were heavily relied upon as a basis for the conclusions regarding total
Kjeldahl nitrogen inputs Csummarized in Section 9).
The statistical testing of the nitrate -N values for the water samples
showed that nearly all the values were significantly different. This is a
direct result of the small standard deviation in replicate determinations for
the University of Wisconsin analysis (0.005 mg/1), as any difference greater
than 0.02 mg/1 between the two laboratories is significant. All of the
University of Wisconsin values for the water samples are lower (except for
the one value in which there was agreement) by an average of 0.06 mg N per
liter or approximately 20% of the value determined. However, since there is
good internal agreement within the UWS data, and the concentrations of NO3 in
the samples and Lake Superior water blanks have similar values, the proce-
dure of subtracting the apparent release in a lake-water blank from the ap-
parent release in the sample should largely cancel out a possible systematic
error in both values. For example, if both the sample and lake-water blank
values for nitrate were low by 0.06 mg/1, the correct difference in the
samples would be obtained in the subtraction process. Consequently, the
statistical comparison analysis would indicate the release values should be
valid within reasonably small uncertainties, even though there are differences
on the order of 20% in the determinations by the two laboratories.
The statistical comparisons of the silica data show only three signifi-
cant differences out of 19 samples tested. There was an obvious mistake in
one sample (CRL-8246), as this was listed as being a Lake Superior water
sample and could not possibly contain 0.36 mg/1 of Si02. Consequently, this
comparison was disregarded. The overall agreement with respect to silica is
reasonably good.
The agreement for chloride is very good, with only one sample showing a
significant difference,and the difference for this sample is only 0.22 mg/1
out of 3.4 mg/1.
The statistical tests for calcium showed that five of the twelve com-
parisons were significantly different. The University of Wisconsin values
were generally higher than the EPA results. Similarly, five out of twelve
potassium values and nine out of twelve comparisons for magnesium were sig-
nificantly different. However, the standard deviations for UWS determina-
tions of potassium and magnesium are small (0.016 and 0.036 mg/1 respective-
ly), and the actual agreement for most of the samples was reasonably good.
A larger uncertainty exists in the sodium determinations. Only one of
the twelve values compared showed statistical agreement. The first four
listed values showed extremely large discrepancies in the values from the
two labs. These particular values were not used in any of the loading cal-
culations, as these determinations were made in the earlier phase of the
analytical work before the leaching experiments were begun. The latter
values show better agreement, but significant differences remain. The
standard deviation in the UWS replicate analysis is small (0.14 mg/1) com-
pared to the differences in the results between the two labs. These
differences will be considered in the loading estimate uncertainties.
102
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There are no significant differences in the aluminum, iron, and zinc
values, although there is only one comparison for aluminum and the standard
deviations for zinc and aluminum are higher than those for most of the other
trace metals. Copper, lead, and cadmium agreements are good as is the agree-
ment for manganese at lower concentration levels. The data is insufficient
to allow comparisons on nickel and chromium.
PROJECTION OF AQC PROGRAM TO LOADING UNCERTAINTIES
The results of the AQC program should provide a basis for the estima-
tion of uncertainties in the chemical-loading parameters. Average standard
deviations for the EPA-UWS comparison values (Table B-l) were calculated for
the data pairs corresponding to the same concentration ranges as used in the
loading estimates. These computed values are listed in Table B-3.
The projection of the AQC program to loading uncertainties was accom-
plished by considering the AQC standard deviations in the mathematical
expressions used for calculating the chemical releases.
The chemical releases determined by the seven-week leaching studies
(Section 4) were computed by an expression of the form
R _ 10Xn - 10X1 +
where Xn, X-"- and X^ are concentrations in mg/1 or ug/1 and the denominator
(5) represents the approximate dry weight of the soil or sediment sample in
grams. The coefficient 5 for X^ represents the five one-liter additions of
lake water during the seven-week experiments. Since the X values represent
water concentrations in the same concentration range, they are all assumed
to have uncertainties S, represented by the data listed in Table B-2.
SR, the standard deviation in the result R (mg of leached parameter per gram
of soil or sediment) is given by the square root of the sum of the standard
deviations in the three terms used to calulate R:
SR =
This expression reduces to:
SR = 3S1
The standard deviations computed using this expression are listed in Table
B-3 according to parameter under the heading "Standard Deviations in Soil
or Sediment Releases."
For the leaching of river particulates, approximately two grams of par-
ticulate matter (dry weight) was used per 10 liters of lake water. Conse-
quently, the uncertainty in the particulate releases due to the uncertainties
indicated by the AQC comparisons is calculated by considering the expression
10X - 10X1 + 5X,
R = n t
103
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and SR is given by
S =* 7.5 S
These standard deviations are also listed in Table B-3 under the heading
"Standard Deviations in Particulate Releases."
The standard deviations in the interstitial water concentrations are
the same as those listed for the "Average Standard Deviations" in Table B-3,
since only one value for each parameter is used in the loading calculations.
However, the magnitudes of the parameters in the interstitial waters varied
substantially in some cases from their magnitudes in lake water and thus the
standard deviations in Table B-3 would not directly apply to the concentra-
tions of these parameters without a correction for these differences.
The chemical inputs of trace metals due to soil erosion and leaching of
resuspended sediments has been listed in Table 20 and summarized in Section
9. The releases in this case are computed from data obtained on changes in
metal concentrations in 500 ml of a water sample containing approximately
one gram of solid sample. The expression for the release is of the form
R =
0.5 Xx - 0.5 XQ
1
where X^ and XQ are final and initial concentrations of the metal respective-
ly. Thus, the standard deviation in R is given by
= [(0.
SR = |(0.5 Sn)" + 0.5 (Sn)T= 0.71
where it has been assumed that the standard deviation in X and X are the
same. These standard deviation values for the releases of cadmium, copper,
iron, manganese,and zinc are listed in Table B-3 under the heading "Standard
Deviations in Soil or Sediment Releases".
The values listed in Table B-3 were used to estimate the magnitude of
uncertainty in the estimates of the chemical inputs to Lake Superior sum-
marized in Section 9.
104
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TABLE B-3: INTERLABORATORY COMPARISONS AND LOADING UNCERTAINTIES
Parameter
Orthophosphate -PO^
Total Soluble P
Nitrate -NO
Silica -S02
Chloride
Calcium
Magnesium
Potassium
Sodium
Cadmium
Copper
Iron1
Manganese
Zinc
Average
Standard
Deviation
(mg/1)
0.0054
0.035
0.15
0.26
0.072
0.87
0.20
0.047
0.18
0.000055
0.00093
0.010
0.0012
0.0017
Standard
Deviations
in Soil or
Sediment
Releases
(mg/g)
0.015
0.45
0.78
0.21
2.6
0.6
0.14
0.56
0.00004
0.0007
0.007
0.008
0.0012
Standard
Deviations in
Particulate
Releases
(mg/g)
0.040
0.26
1.1
0.54
6.5
1.5
0.35
1.3
Computed for a 0.038 to 0.148 mg/1 comparison range.
105
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APPENDIX C
Methods of Analyses For
Sediments and Water Samples
106
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A. Sediment Cores
The data for the sediment core analyses was presented in Tables 11 and
12. The specific methods for the analysis of each parameter are described
below:
1. pH. The pH of the sediments was measured by insertion of glass and
silver-silver chloride electrodes one centimeter below the sediment sur-
faces and employing a Corning Model 5 pH meter.
2. Eh. Eh values were obtained by insertion of a platinum and saturated
calomel electrode into the sediment at various depths and reading the
millivolt display on a Corning Model 5 pH meter upon obtaining steady
readings.
3. Total Solids. Tared sediment sub-samples were dried overnight at 103 to
105°C and measured for weight loss.
4. Chemical Oxygen Demand. To a weighed portion of the sample, distilled
water and sulfuric acid were added for preservation. The samples were
refluxed in potassium dichromate and the unreacted dichromate was ti-
trated with standard ferrous ammonium sulfate. The volume of titrant
used for the sample was corrected for dichromate loss utilizating blanks
carried through the same digestion and titration procedure.^
5. Total Phosphorus. The samples were digested using a mixture of nitric
and perchloric acids. The resulting orthophosphate was then determined
colorimetrically using the stannous chloride method.11
6. Total Iron. Ten-gram samples were brought into solution with HNC^,
H202 and NaNC>3. They were evaporated to dryness and ashed in a muffle
furnace at 550°C. The residues were redissolved in 1:1 HC1 and filtered
into 100 ml volumetric flasks. The samples were made alkaline and the
ferric ion reduced to ferrous ion with hydroxylamine hydrochloride.
Acetate buffer and phenanthroline were added. After dilution of each
sample to 100 ml, absorbance measurements were made at 510 nm. The re-
sulting absorbance values were compared to values for known iron solu-
tions in order to quantitate the results.
1' Kjeldahl Nitrogen. The sediment sample was digested for 30 minutes in a
H2S04, Na2S04,and HgS04 aqueous solution. The solution was cooled, wa-
ter was added, followed by addition of a 50% NaOH-Na2S203 solution. The
resulting solution was distilled, using a 27, boric acid solution to col-
lect the distillate. The collected distillate was titrated with stand-
ard H2S04. The results for the samples were corrected by running blanks
through the same procedure.1^
107
-------
Particle-Size Analysis. The pipet-sedimentation method was used in
which the sample is dispersed through a #230 mesh sieve into a cylinder
containing distilled water and Calgon. Aliquots of the suspension are
collected by pipet at a distance 10 cm below the surface as a function
of time. The weights of particles in the aliquots are determined by
drying the aliquots at 105°C and are related to the.particle-size distribu-
tion in the sample using Wadell's practical sedimentation formula ta-
bles.15
B. Water Analysis
1. Total Soluble Phosphorus. Filtered water samples were subjected to an
ammonium persulfate digestion,and the amount of orthophosphate was then
measured by forming the molybedum blue complex and utilizing the stan-
nous chloride colorimetric method. •*•
2. Orthophosphate. The orthophosphate content of the filtered, undigested
samples were measured by the stannous chloride colorimetric method. ^
3. Total Alkalinity. An appropriate aliquot of each sample was titrated to
the methyl red end-point with standard sulfuric acid. *•
4. Nitrate. Nitrate concentrations were determined by reduction of nitrate-
to-nitrite using amalgamated cadmium filings and diazotizing the nitrite
with sulfanilamide and coupling with N-(l-naphyl)-ethylenediamine. The
highly colored dye is measured colorimetrically and resulting absorban-
ces are compared to the measured absorbances of nitrate standards car-
ried through the same procedure.11
5. Total Kjeldahl Nitrogen. The unfiltered sample was digested with potas-
sium sulfate, sulfuric acid,and mercuric sulfate as the digesting re-
agent. The ammonia concentration was then determined, either with an am-
monia electrode (Orion) or by distillation into boric acid followed by
nesslerization.H
6. Silica. Formation of the yellow molbdosilicic acid is carried out using
acidic ammonium molybdate followed by its reduction to heteropoly blue
using l-amino-2-naphthol-4-sulfonic acid. The absorbance of the blue
complex is measured at 815 nm and compared to the absorbances of stand-
ards. 1:L
7. Chloride. An appropriate aliquot is titrated with mercuric nitrate using
diphenylcarbazone as the indicator.
8. Sodium and Potassium. These metals were measured by flame emission us-
ing a Perkin-Elmer 306 atomic absorption spectrophotometer.
9. Calcium and Magnesium. Atomic absorption-flame analysis using a Perkin-
Elmer 306 instrument was employed.
108
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10. Zinc, Copper, Cadmium, Lead, Iron, Manganese, Aluminum, Chromium,and
Nickel. The aqueous samples were filtered through 0.45-micron filters.
The concentrations of the above metals were measured using the Perkin-
Elmer 306 atomic absorption spectrophotometer, the Perkin-Elmer HGA 2100
graphite furnace, and a deuterium arc background corrector. For certain
of the samples containing higher concentrations of iron, a colorimetric
method was also used for soluble and particulate iron. These latter
values are listed in Tables 24 through 26 along with the values obtained
by atomic absorption analyses. For the cclorimetric analysis, the iron
is reduced to its ferrous state and reacted with bathophenanthroline to
form a red compound which is extracted with iso-amyl alcohol. Particu-
late iron is computed from the difference in iron values between the
filtered and unfiltered samples. °
11. Dissolved Oxygen. The azide modification of the Winkler Method was
used.11
12. Total Phenolics. The river-water samples were collected in glass bot-
tles and preserved with H3P04 and CuS04 if not analyzed the same day.
The samples were distilled, reacted with 4-aminoantipyrine. The ab-
sorbances of the chloroform extracts were measured at 460 nm and com-
pared to the appropriate standards and blanks.
13. Specific Conductance. The measurements were made in a water bath at 25°C
using Freas-type conductivity cells and an Industrial Instruments Model
RC16B Conductivity Bridge.
•i, U.S. GOVERNMENT PRINTING OFFICE: 1979—652-558/63
109
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA-905/9-79-003
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Chemical Effects of Red Clays on
Western Lake Superior
5. REPORT DATE
January 1979
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Donald A. Bahnick, Thomas P. Markee, Ronald K. Roubal
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Center for Lake Superior Environmental Studies
University of Wisconsin
Superior, Wisconsin 54880
10. PROGRAM ELEMENT NO.
2BA645
11. CONTRACT/GRANT NO.
R005169-01
12. SPONSORING AGENCY NAME AND ADDRESS
Great Lakes National Program Office
U.S. Environmental Protection Agency
Region V, 536 S. Clark St.
Chicago, Illinois 60605
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
Undertaken in support of the Upper Lakes Reference Group studies of pollution in
Lake Superior and Lake Huron.
16. ABSTRACT
The southwestern shoreline area of Lake Superior is subjected to extensive
erosion of glacial-lacustrine red clay deposits. Clay bluff from the shoreline
contains a large percentage of clay-size particles which remain suspended in
Lake Superior for days to weeks. The clay-size particles undergo solubilization
and exchange processes in the lake water. This investigation measures inputs of
chemical parameters from clay particles in Lake Superior water as of a function
of time. Comparisons of the chemical input magnitudes from shoreline erosion,
sediment resuspension, and river particulate transport are made. Monitoring of
Bayfield County, Wisconsin streams for sediment transport was done for the spring
runoff period. The chemical characteristics of a near-shoreline Lake Superior
site was studied as a function of water turbidity.
The results show that shoreline erosion is the principal mechanism for chem-
ical transport to Lake Superior from clay particles as compared to stream partic-
ulate and sediment-resuspension inputs. The suspended particles have the capability
of removing chemical species such as heavy metals and many organic chemicals from
the aqueous phase. The sediment input from Bayfield County, Wisconsin streams is
small compared to the input from streams of Douglas County, Wisconsin. Insufficient
data was obtained to warrant conclusions on the field studies of turbidity and water
chemistry relationships.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Water chemistry
Sorption
Dissolution
Leaching
Water quality
Sediment chemistry
Erosion
Sediment transport
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Red Clay
Lake Superior
Pollutant loading
Upper Lakes Reference
Group
International Joint
Commission
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