PB84-19 537 9
Chemical and Biological Studies Related to the
Water Quality of St. Louis Bay of Lake Superior
(U.S.) Pnvironmental Research Lab.-Duluth, MN
May 84
U.S. Dtpartmffrt of Commerce
flattens! TechrkaJ fefdrnwtion Se« -ic;
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E PA-600/3-34-064
May 1984
Chemical and Biological Studies Related to the Water Quality
of St. Louis Bay of Lake Superior
by
A. R. Carlson and U. A. Thomas
A cooperative effort among the U.S. EPA Environmental Research
Laboratorv-Duluth, University of Wisconsin-Superior and University of
Mi line sot a-Du lutli
U.S. Environmental Protection Agency
Environmental Research Laboratory-Duluth
6201 Congdon Boulevard
Ouluth, Minnesota 55804
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TECHNICAL FJEPORT DATA
{Reate read Jiuzusnaas on we rnsw btftrt
1, REPORT MO. 2.
EPA-600/3-84-064
3. r'tCIPiLNJ'S ACCESSION no.
Twi I 953? 9
*. t;tle and subtitle
Chemical and Biological Studies Related to the Water
Quality of St. Louis Bay of Lake Superior
5. R£POMT DATE
May 1984
6. performing organization code
1. AUTHORISI
A.R. Carlson and N.A. Thomas
a, PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORQANUATION NAME AND ADDRESS
Environmental Research Laboratory
Office of Research and Devalopnent
U.S. Environmental Protection Agency
Duluth, Minnesota 55804
10, PROGRAM ELEMENT NO.
1 CONTRACT/GRANT NO.
12, SPONSORING AGENCY NAME AND ADDRESS
Sane as above
13. TYPE Of REPORT AND PERIOD COVERED
sponsoring agency code
EPA-600/G3
15. SUMtCMfcNTABY NOTES
16. ABSTRACT
This was a cooperative effort among the University of Wisconsin-Superior,
University of Minnesota-Duluth, and U.S. EPA Environmental Research Laboratory-Duluth
to develop and evaluate affluent toxicity screening nethods and test methods and
protocols for deriving site-specific water quality criteria. The principal components
of the study were to include; (1) a chemical characterization of the main discharges
to the St. Louis River and Harbor, (2) persistence of toxic pollutants in the St. Louis
River and Harbor, (3) a description of the exposure times for various components of the
ecosystem, (4) bioassays with St. Louis river water and resident species, (5) an
assessment as to the degradation of the biologic eosnaunity of St. Louis Harbor, and
(6) a modeling framework to address items 1 through 5.
Because persistent toxic pollutant concentrations were not found in the WLSSD
effluent and no persistent open water pollutant problems were apparent, this study was
ended. The Project Report contains a series of reports on work completed.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b. IOE NTI P1 F RS/OPf N 6NOED TERMS
c cos ati Fieid/0*oup
IS. DISTRIBUTION STATEMENT
Release to Public
19. StCUSlTY CLASS (TbaKtporlt
Unclassified
21. NO. OF PAGfcS
/£. k>
20, SECWRI7* CLASS /TXUfMgc/
line lassif i ed
22, PRICS
EPA f-m 2220-1
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NOTICE
This document has been reviewed in accordance with
U.S. Environmental Protection Agency policy and
approved for publication. Mention of trade names
or commercial products does not constitute endorse-
ment or recommendation for use.
ii
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CONl'tNiS
Executive Summary
A Summary u f Results and Conclusions
lnt roducc ion
Water Chemistry in St. Louis Bay — R. B. Cook and J. Ane e L
St, Lou i s Bay ho.ithos Survey — T, Roush
Seasonal Primary Production and Plankton Dynamics in St, Louis River and
Harbor — J. R. Hargis
Site-Specific Acute and Chronic Aquatic Toxicity Testing - Western Lake
Superior Sanitary District .Treatment Plant Effluent Studies —
1). J. Call, L. T. Prook, C, Hortlicott, and 0, E, llammcrmei sce»'
Locomctor and Von*, i Intory Response of Fish Exposed to Final Treated WLSSD
Effluent (A Surrnary) -- R. A. Druramond
Characterization of the Organic Mature of the Western Lake Superior Sanitary
District Effluent - Summer 1982 {k Summary) — R. Caple
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EXECUTIVE SUMHARY
This was a cooperative effort anions; the University of Wisconsin-
Super ior , University of Minnosot a-D-i 1 uLli, and U.S. EPA Environmental Research
Labor atory-Duluth to develop and pvalu.il e effluent toxicity screening inc tiiods
and test methods sn«J protocols for deriving site-specific water quality
criteria. The principal components of the study were to include: (1) a
chemical characterization of the main discharges to the St. Louis River and
Harbor, (2) persistence of toxic pollutants in the St. Louis River and
Harbor, (J) a description of the exposure times for various components of the
ecosystem, (A) bioassays with St, Louis River water and resident species, (5)
an assessment as to the degradation of the biologic community of St. Louis
Harbor, and (6) a modeling framework, to address items 1 through 5,
Because pers i sLent toxic pollutant coneentrat ions were not found in the
WLSSD effhient and no persistent open water pollutant problems were apparent,
this study was ended. Following are a series of reports on work completed.
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A Summary of Results ar.d Conclusions
ST. LOUIS BAY
Water Ch em i a t r v Surveys
At the six sites, in the small embayment near the Western Lake Superior
Sanitary District (WlSSQ) wastewater treatment plant, ammonia, alkalinity,
total phosphorus, and chloride were higher than in the control crnbayment s.
Hie fraction of WLSSD effluent, estimated from chloride concentration,
was 0,20-0.25 in the three sites closest to the discharge pipe- and 0.05-0.10
in the three sites farthest from the discharge pipo.
Ammonia and total phosphorus appear to h.-ive a substantial sediment
source in the small embaymcnt near WLSSD.
Nutrient input budgets for St. Louis Bay revealed that 90% of the
alkalinity, ammonia, and total phosphorus loadings were derived from the St,
Louis River with th« remainder oriqinatLor from WLSSD, However, high
chloride concentrations in the WLSSD effluent contribute .1 *. o f the Cl~
loading to St, Louis Bay, compared Co 571 from the St. Louis River,
Comparison of the total phosphorus input budget for 1982 with a similar
budget for 1972 revealed that the WLSSD sewage treatment plant released
one-fifth the total phosphorus that was released by the nine sewage treatment
plants operating in 1972,
Phenol CO! -enL rat ions decreased from 8 to 9 ^ L~* In the mid-1970s
to 3 k L-1 in J 982.
The mean total phosphorus at site L (downstream from the present WLSSD
plant) decreased from 110 {f4 L-' between 1972 to 1979 lo 75 jig L~*
for 1979 to 1982.
The mean ammonia concentration at site L decreased from 0.259 rag L"1
C pre-1979) to 0,116 mg L~" after 1979.
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Benthie Invertebrate Surveys
The benthie invertebrate surveys demonstrated noticeable differences
between the* WLSSi) discharge bay and two bays (controls) upstream. The
discharge bay contained fewer types of organiams and these are considered
more tolerant of domestic effluents. The differences between the bays were
less noticeable in October than in June or August.
Phytopl ankton and Zooplankton Surveys
The l>uluth-Superior Harbor is a complex system for pelagic sampling.
Not only is the bathymetry complex, with the extensive shallows plus the
deep, dredged ship channels, but the interactive flows of the St. Louis
ind seiche currents from Lake Superior make point samples a function of
variables. In the shallows, particularly, the range of seasonal change
be extreme. Within this context, examination of the plankton data from
Summer 1982 shows no adverse influence of the effluent from the WLSSD p
WI.SS1) EFFLUENT Toxicity AND characterization
ffluent Toxicity
The effluent was intermittently acutely toxic to aquatic organisms
ar;'i invertebrates) in toxicity tests. Behavioral monitoring of fish
continuously exposed to the plant effluent was used to identify periods
effluent toxicity. -Mi
Increases in fish locomotor and respiratory activity correlate with fish
mortality in bioassays of grab samples. Some possible causes of observed
toxicity were thought to be related to elevated total residual chlorine or
carbon dioxide concentrations resulting from changes in wastewater treatment
in response to changes in influent conditions.
vi
River
many
C an
I ant,
C f i sh
of
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It i«j recommenced Lh/iL anv future b ioassavs or WI.SSI) etfluont, or the
effluent f rum other treatment pi ant s , be comp 1 emented with chemical analyses
of total cli lori ii>!, pil ' unmed i at e and after «** tended aer«itiin), carbon
dioxide, alkalinity, ami hardness. If possible, these test# should be
counted with sensitive aquatic organism hch.iv/ iora I monitoring to identify
episodic periods of toxicity.
E f f 1 uent Char.'ict e r i.11 i on
A comparative qualitative analyses was made of the WLSSD effluent and
influent, and a similar analysis was made of* the effluent from the 1 a r;; s t
single contributor of in.hr-. tr i 11 type organic* (a pulp and pacer industry) to
the U'LSSD influent. The i so 1 at ion and cone rnt rut ions in composite samples
were done • t> threes to relloct the "acidic", "neut ra 1", and "basic"
functionalities in t!u* component s analyzed using mass spectroscopy. The mass
of data is present I v He in?, incorporated into a three x three matrix (3
analyses and 1 sample sites) based on functionality. Wiipn casapleted an
interpret .it ion of the mean i ng and significance of the data will be made.
Because ch lorophcnols originating from W'LSSD had been previously traced
within the buy and into Lake Superior, a r,as chromatography with electron
capture detection procedure aimed at sensitivity, and a second procedure with
liquid chro
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and Ls on 1 v av;ii I able from the Na: iorwi I Technical In format ion Service, 5285
Port Royal Read, Sprjnw.f i«ld, Virginia 22161 [Order No. PBS3-261-691
(RPA-600/S j-83-Oc32) I at a cost of $10,00. This report is intended as a tool
for poo pie to i<>eatc specific t y pes of studies conducted within St, Louis Bay
and was an attempt to compile mid review all of the physical, biological, and
chemical studio* related to the bay,
CONCLUSIONS
1, The water quality of the St. Louts Harbor has 'improved. Much of the
improvement can be attributed to the onset of the operation of the
present WLSSD wastewater treatment plant,
2. There was only a slight impact on the henthic invertebrate community frem
the WLSSD outfall.
3, Survey data indicates thui phy» oplankton and woplankton werr not
deraonstratab lv impacted by the WLSSD effluent.-
4. The WLSSD plant is currently treating its waste to a higher degree than
the 1 ma/I, phosphorus limit. The concentration in the main channel
opposite the plant has decrease-.' by a factor of three since 1973.
>, The WLSSD discharge was occasionally acutely toxic. It appears that some
toxic discharges are related to changes in treatment processes and plant
operatiens in response to special wasie treatment needs resulting in high
residual chlorine or carbon dioxide concentrations in the effluent. Rata
indicate that at times the mixtures of the WLSSD plant effluent and bay
would he acutely toxic in the immediate vicinity of the discharge pipe
but not impact the rest of the h iv h*»i wise of a h is»h dilution ratio.
6. The primary objectives of this research project were not attainable at
this site hec ausc persistent toxic pollutants were not found in the WLSSD
effluent and no persistent open water pollutant problems were apparent.
vi i i
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Water Qua I ily _Assessment of St. U lis Bay of Lake Superior
INTRODUCTION
St. Louis Bay of Lake Superior provides a urdquu opportunity to study a
natural ecosystem and related observed response to pollutants to laboratory
testing effect endpo ints arid obscrv.it ions. To understand a pollutant's cause
and effect relationship in such a system, it must be studied in sufficient
depth to under .it and the controlling factors. To this end, -several on site
(field) and laboratory studies were undertaken to quantify possible pollutant
impacts and result iris; biotic responses of th_• bay ecosystem.
Such research is needed to p/ovide a basis for the U.S. Environmental
Protection Agency' <* (EPft) Off Lee of Water to provide guide,ice to the Statej
on the nod i f it at ion of national water rjunlily criteria to site-specific
situations, and the control of coup lex effluents through the Nat iona I
Pollution Discharge System. The EPA fireat Hakes National Program Office also
needs information on the causes of pollution of St. Lou i * Bay and the impact
of the bay on western Lake Superior.
Hie primary objectives of this research project were: (I) tc field tear
the EPA guidelines for deriving site specific water quality criteria, (2) to
obtain data on the relat ionsh i p between toxicity testing of a complex
effluent and receiving water biotic response, nad (3) evaluate the usefulness
of water quality criteria to orotect a fireat Lakes ecosystem.
To meet the above objectives, three conditions oust have existed. The
first i •: that a point source discharge to the bay had to be at least
chronically toxic, the toxic components of the effluent had to be identified
and the bay biota had to be Impacted by the effluent. Because the Western
Lake Superior Sanitary District (WLSSD) discharge, containing both created
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doraest ic and irdustrial wastes, appeared to meet the above cor.dit ions, it was
selected for .nitial udy. It in the largest single patni discharger to the
bay; its final eff'uenis had exhibited toxic icy in the past and some fish
kills had occurred in the embaywent near its di§charjj« pip*;. During 1932
studies to chemically characterise the OT.SSD effluent, determine its toxicity
and trace it# movement in and out of the bay were initiated wh i 1 e other
studies were initiated to provide a iter chemistry and biological baseline
for the hay from which present and future pa Hut ant ispacts on the bay, and
the hay's impact on Lake Superior, could be dott-rrained. A literature search
of all studies relevant to St. Louis Bay was also begun. Information gained
f i'iw, these first year efforts w«re 11 ecu* m a r y to determine if the primary
objectives of this research project were achievable, and if achievable to
plan subsequent studies.
This project was undertaken as a cooperative effort between ihe U.S.
EPA Knvironroental Research Labor.it or y-D:iluth, University of Minnesot a-l'ul oi h ,
and .Un i vers i«. y of Wi scons in-Super ior > Following are reports on i nd ividu.it
research t asks undertaken in 1982,
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WATER CHEMISTRY
IN
ST. LOUIS BAY
June-November, 19R2
(Subtask 1-addendun)
prepared by:
Robert B. Cook
and
J oh:; J, Ameel
Lake Superior Basin Studies Center
214 Research Laboratory Building
University or Minnesota, Duluth
Euluth, Minnesota 55812
February 1983
The University of Minnesota is committed to the policy that all
persons shall have equal access to its programs, facilities, and
employment without regard to race, creed, color, sex, national
origin, cr handicap.
1
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CONTENTS
Page
List of Tables
List of Figures. . . . ,
Introduction ,
St. Louis Bay
"ampling Scheme . ' .
Methods
Sampling Methods,
Analytics 1 Methodos
Results and Discussion
Mixing of WLSSD Effluent with the St. Louis River . .
Nutrient Inputs to St. Louis Bay.
Historical Trends .....
Conclusions
References ................
Figure Captions. .
2
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1
2
3
4
5
6
7
8
9
10
11
12
13
14.
15,
16 ,
17.
LIST OF TABLES
Page
Equivalency of sampling sites
Water depths at each sample collection site. .
Procedures used for water chemistry analysis .
Precision of analytical methods
Water chemistry data for sampler- collected
on 16 June 1982
Water chemistry data for samples collected
on 7 July 1982
Water chemistry data for samples collected
on 2 O July 19P2
Water chemistry data for samples collected
on 3 August 1982
Water chemistry data for samples collected
on 16 August 1962
Water chemistry data for samples collected
on 7 September 1982
Water chemistry data for samples collected
on 21 September 1982
Water chemistry data for samples collected
on 5 October 1982
Water chemistry data for samples collected
on 19 October 1982
Water chemistry data for samples collected
on 2 November 1982
Summary of water chemistry data for samples
collected June-November 1982
Concentrations of alkalinity, tota1 phos-
phate, ammonia, and CI in the WLSSD effluent .
Derivation of formula for calculating the
mixing of WLSSD effluent with the St. Louis
River
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Table 18. Compilation of mixing fractions, f, for each
of the six embayrnent sites, for each san^pl-
inq date . . . -
Table 19. Comparison of predicted alkalinity, total
phosphorus, and ammonia with the observed
mean concentrations in the embayrnent . . , . .
Table 20. Comparison of inputs to Gt. Louis Bay froiu
the St. Louis River and WLSSD effluent dur-
ing 16 June through 2 November 1982
Table 21. Yearly average total phenol concentrations
at site L (Interstate-535, Elatnik High
Or idge}* » • » * ¦ « * « ¦ • * « • * • » • • *
Table 22. Methods of nutrient analyses used by the
five laboratories studying St. Louis Bay . . .
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LIST OF FIGURES
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6,
Figure 7.
Figure 8.
Page
The Duluth-Superior Harbor
The Duluch-Superior Inner Harbor (St. Louis
Bay)
Total phosphorus at site A (Arrowhead
Bridge) between 1972 and 1982.
Total phosphorus at site L (Dlatnik High
Bridge and Burlington Northern Railroad
Bridge) between 1972 and 1982. "
Nitrate/nitrite at site A (Arrowhead Bridge)
between 1972 and 1982. ....
Nitrate/nitrite at site L (DlatniX High
Bridge and Burlington Northern Railroad
Bridge) between 1972 and 1982
Ammonia at site A {Arrowhead Dridce) between
1972 and 1982, .......... I
Ammonia at site L (Blatnik High Bridge and
Burlington Northern Railroad Bridge) between
1972 and 1982.
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INTRODUCTION
The objective of this study was to characterize the water
chemistry of St, Louis Buy with reference to inorganic and organic
constituents omitted iu the effluent stream of the Western Lake
Supsrior Sanitary District (WLSSD) sewage treatment plant, in
this report we present water chemistry data from our study and
discuss the influence of the WLSSD effluent stream on water
chemistry in St. touis Bay.
St. Louis Bay
The Duluth-Superior Harbor is comprised of St. Louis Bay, or
inner Harbor, the Superior Bay or outer Harbor {Figure 1). The
St. Louis River, which flows through the Duluth-Suporior Harbor,
is the third largest tributary to Lake Superior in terms of area
drained and load in.: of total dissolved solids {Thompson 1978).
Average discharge over a fi0-year period was' 6 4,3 m3 sec-1
with a range o£ 2.3 to 1073 rn3 sec-1 {MPCA 1977), although
average discharge during the present study (June through November
1982) was 116 ir.3 soc"^ (Minnesota Power, unpub. data).
The Lake Superior seiche also transports water into Superior
Bay and St. Louis Bay. The seiche reverses Clow in the St. Louis
River up to Fond du Lac, the site of the first river darn (Sydor
and Stortz 1980), The hydraulic flushing time (Harbor volume f
total inflow) for the Harbor was 12 days or 8% per day in 197 9;
the seiche exchanged 6% per day and the river exchanged 2% per day
(Sydor and Stortz 1900). The complex geoinetry of the Ilatbor
(Figure 1) dictates that little Lake Superior water penetrates
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into St. Louis Bay, Also the river Clow in 1982 was larger,
resulting in a river dominated inner Harbor.
The St. Louis River is the most intensively used tributary to
Lake Superior and the Harbor serves as the economic base for the
cities of Duiuth, Minnesota and Superior, Wisconsin.
The WLSSD sewage treatment plant treats domestic sewage from
the cities of Duiuth, Cloquet, Carlton, Wtenshall, Scanlon,
Hermantown, and Proctor as well as industrial wastes from the
Potlach Corporation, a manufacturer of wood products. The plant
started operating in 1979; prior to that time domestic wastes were
treated at nine separate primary sewage treatment plants {EPA
1975).
The W LSSti effluent discharge pipe {P) extends southwes tward
from the small split,near the WLSSD plant (Figure 2).
Sampling Scheme
For this study we chose 12 sampling sites in St. Louis Bay
(Figure 2}. Cite A (U.S. Highway 2, Arrowhead Bridge) is
representative of St. Louis River water entering St, Louis Bay and
site L {Interstate-535, Blatnik High Bridge) is representative of
water leaving St. Louis Bay. Sites D and C near the Minnesota
Power M.L. Hibbard Electric Station are typical of embayments not
affected by the effluent from WLSSD.
Sites D through I provide a grid within the embayment
receiving WLSSD effluent. Samples taken from this grid will show
the spatial distribution of the WLSSD Cf 1 ucnt. Site J was chosen
to represent an area impacted by a small stream flowing into St.
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Louis Bay, as well as by the WLSSD effluent, and site K was chosen
to represent an area near the main channel, but somewhat removed
from the influence of the WuSsu effluent.
Two separate schemes were used for naming water chemistry and
benthos sample collection sites. Six of the water chemistry sites
were also used for benthos sample collection. The six water
chemistry sites and the corresponding designation for the benthos
sample collection sites are presented .n Table 1.
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METHODS
Sampling .Vethods
Water samples were collected at the 12 sites in St. Louis
Bay (Figure 2) twice a month during the period 16 June through 2
November 1982. Samples for analyt'es measured in the laboratory
were taken at a depth of 1 metre with either a van Dorn or
Kerr.merer sampling device. Water column depths at each site are
presented in Table 2. In situ temperature, conductivity, and pH
were measured using portable meters; temperature and conductivity
were measured at 1 metre depth at each location and field pH was
measured at 0.10 metre depth.
Samples for phenol analysis were transferred to glass bot-
tles and were preserved with copper sulfate and phosphoric acid
{Standard Methods 1975). Silica and total suspended solid sam-
ples were transferred to plastic bottles. Sam Pi es for phosphate,
alkalinity, and chloride were transferred to glass bottles.
The samples were returned to the lab within 2 hours of
collection and kept at 5°C until analysis. Camples for dissolved
phosphate and nitrate were filtered through a 0.45 urn pre-washed
membrane filler upon arrival in the laboratory. Filtered samples
were stored in plastic bottles at 5°C until analysis.
Analytical Methods
The analytical methods used in this project are from Stan-
dard Methods (1975) or are modifications of the procedures in
Standard Methods (1975) and are listed in Table 3- All nutrient
samples were analyzed witnin 24 hours of collection and all
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analyses were run within 36 hcurs. Precision for -??ch rthe"'< as
estircatad fron replicate analyses m-ide throughout this study, is
presentee in T-r.biv 4.
Nitrate/nitrite data are incomplete because we encountered
unreliable reduction of nitrate to nitrite with pre-packaged
reagents. After isolating the cause- of the difficulties and
purchasing new reagents, we began analyzing for nitrate/nitrite
on 7 September 1932,
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RESULTS AND DISCUSS ION
Conductivity profiles determined at site A and site L {Cook,
unpub. ilala; Javorski, RPA-Duluth, unpub. data) were vertically
homogeneous and indicate that the 1 metre depth is representative
of the entire water column.
Conductivity profiles in the small embaymont near the WLSSD
plant exhibited limited vertical structure (Javorski, EPA-Ouluth,
unpub. data). This vertical variation in conductivity was much
less than the horizontal variation in conductivity {eg. between
sites 0 and I}. Therefore, at any one site in the embayment, the
water column can be considered vertically well-mixed relative to
the WLSSD effluent.
Water chemistry data for all the sites for each sampling date
are presented in Tables 5 through 14. A summary of the water
chemistry data, consisting of median and mean values and the
range, is presented in Table 15 for each sampling site. Agreement
between the median and mean values was good, except in a few
instances in which the mean was greater due to a single, large
value (eg. TSB at site J and HH3 at site 0).
The primary influence of the WLSSD plant effluent was on
alkalinity, total phosphorus, ammonia, and chloride. The concen-
trations of these parameters in the WLSSD affluent stream (Table
165 were significantly greater than the concentrations in St.
Louis Bay.
Water flowing into St. Louis Bay at site A had a chemical
composition similar to that at site L, located at fchu ouliul Cor
St. Louis Bay. !-!o table exceptions were total phosphorus, for
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which site L was 12% greater than site A, arid chloride, for which
site L was two-fold greater than site A.
In addition to being influenced by the St. Louis River arid
Bay, site L was influenced by the Lake Superior seiche, which
mixes Lake Superior water into Superior Bay. The effect of Lake
Superior water entering the Duluth-Superior Harbor with the seiche
would jc to dilute the Harbor water. The importance of the seiche
at site L was not determined during this study, although the
effect should be small because of the distance between Lake
Superior and site L.
The six sites in the embayment receiving the WLSSD effluent
{sites D through I> had concentrations of nutrients, alkalinity,
and chlorj.de that were greater than the control embayments {sites
B and C). Hie three sites closest to the WLSSD discharge pipe
{sites D, E, and F) had concentrations oC nutrients, alkalinity,
and chloride that were higher than the other three sites in the
embayment {sites G, II, and I).
Site J, the site influenced by a small stream, had concentra-
tions of nutrients, alkalinity, and chloride that were similar to
sites D through 1. Total suspended solids (TSS) at site J,
however, were stongly affected by the small stream flowing into
the embay-ent. After heavy rains on the preceding two days, the
TSS at site J on 7 July 1982 (Table 6) was ten-fold greater than
the' ir.od ian concentration (Table 15). The other six sites in the
embayment were not influenced by this small stream, as indicated
by the much lower TSS on 7 July (Table 6!.
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Mixing of WLSOU Effluent with the St. Louis Rivec
The concentrations o£ nutrients, alkalinity, ami chloride at
sites D tn rough X aft? strongly influenced by the effluent from
WLSSD, To quantify the extent of this influence wo have calcu-
lated the mixing of WLSSD effluent with St. Louis River water.
The derivation of the formula for mixing {Table 17) assumes
that only two water types - St. Louis River and WLSSD effluent -
mix together to produce the embayment water. We used site A
{arrowhead Bridge) for the water composition of the St. Louis
River, For the WLSSD effluent 'we used the concentration of the
effluent on the day before our sampling date, and we assumed that
the effluent released on that date completely mixed with the
embayment within one day. Clearly, mixing in the embaymenu may
take longer than one day or, perhaps, take les<» time. Mixing is
dependent on St. Louis River flow conditions, wind velocity and
direction, and WLSSD effluent discharge rate. These parameters
are all variable with time of year. In addition, the concen-
trations of components in the St. Louis River and the WLSSD
effluent are not constant during the year.
Despite these limitations in the mixing model, the results
obtained are useful Cor describing the water chemistry patterns in
the embayment. In addition, the mixing values allow the results
from toxicity tests run 01 full-strength effluent to be extrapo-
lated to the e nbay.vten t, in which the effluent is diluted by mixing
with river water.
The mixing fraction, £, was deter:-; ned using chloride.
Chloride is conservative (i.e., does not take part in any
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biological reactions) and the only source of chloride is from the
St. Louis r'i vvr and the WL5SD e f£luent. Therefore, the chloride
concentration?; in tho ejsbaymont will only bp influenced by ntixincj.
The fraction of WLSSD effluent that mixed with the river
ranged from 0.10 to 0.43 for the three sampling sites closest to
the effluent discharge pipe (sites O, E, F) and 0.0 3 to 0,10 for
the other three site- Table 18). Mean values during Jane to
November 1982 were t >0.25 for the three sites closest to the
effluent discharge pipe and 0,05 to 0,10 for the other sites.
The nutrient elements and alkalinity are non-conservatijo
{i.e., take part in biological reactions) and are affected by both
mixing and biological activity. To deter.nine the influence of
biological activity we use the n i x i n^ f ract ion<®. ¦( Table 18), along
with the St.-faouia River and WLSSD effluent concentrations to
predict nutrient and alkalinity concentrations in the embayvnent.
When biological uptake takes place the predicted concentration
will be greater than the observed. When biological production
takes place the predicted concentration is less than the observed.
For alkalinity, the predicted and observed concentrations
agree well (Table 19} and indicate no or slight biolog ical
modification of this parameter. Biological modification of:
alkalinity is only important at low values of alkalinity (Coo);
1981) or for high levels of biological activity (Goldman and
Brewer 1980) .
Total phosphorus and ammonia values predicted by the model at
sites D, S, and P are- less than the observed (Tab)e 19} indicating
that total phosphorus and ammonia are produced by biological
-------
activity. The likely source of this production is bacterial
activity in the sediments. The bacteria decompose organic matter
and liberate the nutrients associated wi -.h the organic matter.
These nutrients are then transported out of the sediments, either
by diffusion or by the movement of invertebrate organisms (eg,
tubi t ic ids) {Berner 1980), Hie sediments in the area near sites
D, E, and F are relatively rich in organic matter (D, Barlaz,
Geology Dept., University of Minnesota, Minneapolis, pers. comm.).
This organic matter originated from either the WLSSD sewage
treatment plant or from phytoplankton in the embayment, whose
growth was stimulated by the' nutrients discharged from WLSSD,
Biological production of nutrients from the sediments at sites G,
H, and I does not appear to be a significant source.
Nutrient Inputs to St. Louis Bay
Another method to quantify the influence of the WLSSD
effluent on water chemistry in St. Louis Bay is to make an input
budget for the Bay. Comparison of nutrient, alkalinity, and
chloride inputs from the St. Louis River and the WLSSD effluent
yields information on the relative importance of these two
sources. **"•
The concentration measured at site A (Arrowhead Bridge) is
representative oi the St, Louis River. Discharge at site A was
assumed to be 1L6 sec--*-, the average discharge for this
period at Thomson Dam, 30 km upstream (Minnesota Power, unpub.
data). No other major rivers nor streams enter the St. Louis
River between Thomson Dam and site A, Discharge u -.ta for the
WLSSD effluent were obtained from Duane Long, WLSSD Plant, Duiuth.
-------
A summary of the Inputs to St. Louis Bay are presented in
Table 20. Even though the average flow rate from WLSSD was two
orders o£ magnitude lower than the St. Louis River flow rate,
alkalinity, total phosphorus, and ammonia loadings from WLSSD were
10% of the St. Louis River loadings. Chloride inputs from the two
sources were similar with 43% of the total Cl~ input coming from
the WLSSD input.
Two other sources of nutrients are not considered in this
input budget. The first is the Lake Superior seiche, which
transports relatively dilute Lake Superior water into the Duluth-
Superior Harbor, The seiche also transports Superior Bay water
into St, Louis Bay. The primary influence of the seiche is to
dilute St. Louis Bay water and enhance the flushing of the Bay.
The second source not considered in this budget is the
transport of nutrients out of the bottom sediments and into the
water column of St, Louis Bay. The mixing model (above) showed
that sediments were a significant source of ammonia and phosphorus
in the small embayment near WLSSD. The sediments in other small
embayments in St, Louis Bay may also be a source of nutrients.
The loading of nutrients from the sediments was not determined in
this study.
A similar nutrient input budget for St. Louis Bay was
determined in 1972 (EPA 1975). Comparison of the 1972 and 1982
nutrient input budgets provides information on the influence of
the WLSSD plant, which started treating wastes «i 1979.
In 1972 the P loading was 8.7 x 10^ g day-* of which nearly
50%, or 4-3 x 10* g day"*, was derived from the nine sewage
16
-------
treatment plants in the area (EPA 1975). Curing the period June-
November 1982, the loadinc from the WLSSr- plant was C.8 x !C~g
day""1 (Table 20) or one-fifth the 1972 value for loading from
sewage treatment plants. Thus, the WLSSD sewage treatment plant
removes P more efficiently than the treatment plants that pre-
ceeded it.
The total P loading rates to St. Louis Bay during 1972 and
1982 were similar {@.7 versus 8.5 x 105g day"1, respectively),
despite the lower amount of P discharged from sewage treatment
plantr. in 1982. This similarity is due to the high St. Louis
River P loading in 1982 {7.6 versus 4.4 x 105g day*"1 in 1972),
which in turn is due to the high value for river flow in 1982.
The GO year average for the St. Louis River was 64.3 m^sec-1,
while in 1982 the flow rate was 116 rn^sec-1. Phosphorus concen-
trations in the St. Louis River were very s i n i 1 ar in 1972 and
1982.
The primary conclusion from this budget is that 901 of the
ammonia, total phosphorus, and alkalinity entering St. Louis Bay
during June to November 1982 were derived from the St. Louis
River, from sources upstream of site A (Arrowhead Bridge).
Chloride loading from WLSSD and the St. Louis River were approxi-
mately equal. The WLSSD effluent causes the mean chloride
concentration to increase from 4 mg L~1 a-t site A (Arrowhead
Bridge) to 10 mg L~1 at site L (Blatnik High Bridge) (Table 15).
Although this is a significant increase in chloride concentra-
tion, it does not present a problem with respect to water
quality. The value of 10 mg L"- is much less than the chloride
17
-------
concentration in the- lower Great Lakes (28 mg L-*; Beeton
196 5), and is comparable to values from dilute lakes (Armstrong
and Schindler 1971). In addition, the chloride concentration at
site L is very similar to the mean chloride concentration of the
rivers of the world {Holland 1978).
Historical Trends
To put the data collected during this project in 1982 into
historical perspective, we have compiled water chemistry data for
St, Louis Bay from other projects for the period 1972 through
1982. The other projects that have comparable data on St. Louis
Bay during this period are: Minnesota Pollution Control Agency
(MFCA 1978a,b; MPCA 1981); the Western Lake Superior Sanitary
District (WLSSD)f the Environmental Protection Agency (EPA 1975)?
the Wisconsin Department of Natural Resources {WDNR 1977); and the
Lake Superior BAsin Studies Center Analytical Chemistry Laboratory
(Lsasc).
The sites we have chosen for this comparison are site A, at
the Arrowhead Bridge (U.S. 53), and site L, at the Blatnik High
Bridge (Interstate-535), WLSSD and EPA collected water samples
from the Burlington Horthern Railroad Bridge, which crosses St.
Louis Bay some 500 in upstream from site L (Blatnik High Bridge).
The Burlington Northern Railroad Bridge and site L were considered
equivalent for this comparison.
If multiple sampling depths were repOLl.td for the other
studies we chose the 1 metre or shallower sample to correspond to
our sampling depth.
-------
Data for total phenol were less complete than toc the other
parameters arid v/e present only yearly averages for site L (Blatni>
High Bridge) in Table 21. , Total phenol concentrations decreased
from 8 to 9 ug L_1 in the mid-1970's to about 3 ug L~^ in
1982. The maximum values reported decreased from 20 in 1974 to 5
ug I--1* in 1982. The recommended limit for total phenol in
surface waters is 100 ug L-1, which was never exceeded at any
time in St. louis Bay.
The five laboratories studying St. Louis Bay used the same
analytical method for total phosphorus {Table 22). Four
laboratories used the cadmium reduction method for nitrate and
three laboratories used the nesolerization method for ammonia
(Table 22). A crude comparison of methodology among the five
laboratories can be determined when historical data from the
laboratories overlaps (Figures 3-8 and discussion below).
The values for total phosphorus, alkalinity, nitrate/nitrite,
and ammonia used in this historical comparison are monthly means
for each of the laboratories reporting data.
Total phosphorus at site A (Arrowhead Bridge) ranged from 4 0
to 150 ug over the period 1972-1932 with no historical
trend evident (figure 3).
Total phosphorus at site L (Blatnik High Bridge and Burling-
ton Northern Railroad Bridge) ranged from 30 to 300 ug L~* prior
to the 1979 start-up of the WL3SD sewage treatment plant (Figure
4). After 1979 the values ranged from 30 to 140 ug . The
effect of the WLSSD sewage treatment plant was to decrease the
variability in total phosphorus at site L. The mean value for
-------
total phosphorus between 1972 and 1978 was 110 uy L~^ and
a£ter 1979 was 75 ug L'~^. After the WLSSD plant started
operations in 1979 the mean phosphate concentration decreased by
40%. This decrease is significant at the p £ 0.05 level,
according to BMQP intervention analysis.
Nitrate/nitrite at site A (Arrowhead Bridge) ranged from
0.010 mg L-1 to 0.400 mg L-1 during the period 1972 to
1982 with no trend evident (Figure 5). Data from WLSSD were for
nitrate only. MPCA data, for which separate nitrate and nitrite
values were given, indicated that nitrate/nitrite was 15% greater
than nitrate alone.
Nitrate/nitrite at site L (Blatnik High Bridge and Burlington
Northern Railroad Bridge) ranged from 0.010 to 1.00 mg L-1
prior to .1979 and from 0.10 to 0 .380 mg after 1979 (Figure
6). The variability within any one year decreased after 1979.
Before the start-up of the WLSSD plant nitrate/nitrite averaged
0,191 mg L-1 and after the start-up 0.139 mg L-1.
Ammonia at site A (Arrowhead Bridge) ranged from 0.010 to
0.600 mg L~^ between 1972 and 1982 {Figure 7). There are too
few data points to verify any trends with time.
Ammonia at site L {Blatnik High Bridge and Burlington Northern
Railroad Bridge) ranged from 0.010 to 1,350 mg L-^ prior to
1979 and from 0.020 to 0.380 mg L~^ after 1979 (Figure 8).
Trends with time are difficult: to identify for ammonia primarily
because prior to September, 1978 the limit ot detection for the
MFC A data was 0.200 mg L~* , which is much higher than the
majority of data points from other sources for this period. On
-------
the basis oi the WLSSD data points only the pre-iy79 mean ammonia
concern-ration was 0,259 mg L-1 and post-1979 mean amrronia
concentration was 0,116 mg L_1. Thus there has been a 55%
reduction in ammonia concentration since the WLSSD sewage
treatment plant started operating in 1979,
21
-------
O.'S
At the six sites in the small embaynent near the MLSSV
plant, aninonia, alkalinity, total phosphorus, and
chloride were hig.ier than in the control embayments
(sites 3 and C).
The fraction of WLSSD effluent, estimated from chloride
concentration, was 0.20-0.25 in the three sites closest
to the discharge pipe and 0.05-0,10 in the three sites
farthest from the discharge pipe.
Ammonia and total phosphorus appear to have a
substantial sediment source in the small embayment near
WLSSD.
Nutrient input budgets for St. Louis Bay revealed that
90% of the alkalinity, ammonia, and total phosphorus
loadings were derived from the St. Louis River with the
remainder originating from WLSSD. However, high
chloride concentrations in the WLSSD effluent contribute
43% of the CI"* loading to St. Louis Bay, compared to 57%
from the St. Louis River.
Comparison of the total phosphorus input budget for 1932
with a similar budget for 1972 revealed that the WLSSD
sewage treatment plant released one-fifth the total P
that was released by the nine sewage treatment plants
operating in 1972.
-------
6. Phenol concentrations decreased from 8 to 9 tig in the
raid-1970's to 3 uj L--1 in 1982,
7. The mean total phosphorus at site L decreased from 110 ug
L-1 between 1972 to 1979 to 75 ug for 1979 to
1982.
8. The mean ammonia concentration at site L decreased from 0.259
rag L~^ (pre-1979) to 0.116 mg L-^ after 1979.
23
-------
REFERENCES
Armstrong, F.A.J, and r. W. Schir.dlor. 1971. Preliminary
chemical characterization of" waters in the Experimental
Lakes Area, northwestern Ontario. J. Fish. Res. Bd. Canada
28s171-18?.
Beeton, A.M. 1965. Eutrcphication of the St. Lawrence Great
Lakes. Linnol. Oceanogr, 10:240-254.
Berner, H.A. 190Q. Early Diagenesis: A Theoretical Approach.
Princeton University Press, 237 p.
Cook, R.B. 1981. The biogeochenistry of sulfur in two small
lakes. PhD Dissertation. Columbia University, 248 p.
EPA. 1975. Report on St. Louis Bay, Minnesota and Wisconsin.
U.S. Environmental Protection Agency, National Eutrophica-
tion Survey, Region V, Working Paper No. 123. 43 p.
Goldman, J.C. and P.G. Brewer. 1980. Effect of nitrogen source
and growth rate on phytoplanktcn-mediated changes in
alkalinity, Limnol. .Oceanogr. 25:352-357.
Holland, H.D. 1970. The Chemistry of the Atmosphere and
Oceans. Wiley-Interscience. 351 p.
MPCA. 1977, Study of Minnesota's Tributaries to Lake Superior.
Minnesota Pollution Control Agency, Roseville, KN. 87 p.
M PC A. 1978a. Water Quality Sampling Program, Minnesota Lakes
and Streams 1970-1975. Vol. 8, Part A and B. Minnesota
Pollution Control Agency, Roseville, MM. 1074 p.
MPCA. 1978b. Water Quality Sampling Program, Minnesota Lakes
and Streams October, 1975 - September, 1977. Vol. 9,
Minnesota Pollution Control Agency, Roseville, MN. 483 p.
MPCA. 1981. Water Quality Sampling Program, Minnesota Lakes and
Streams, October, 1977 - September, 1980, Vol. 10.
Minnesota Pollution Control Agency, Roseville, MN. 227 p.
Sta in ton, M. P., M.J. Capael, and F.A.J. Armstrong. 1974. The
Chemical Analysis of Fresh Water. Department of
Environment, Fisheries and Marine Service: Misc. Spec. Pub.
No. 25. Winnipeg, Manitoba. 125 p.
Standard Methods. 1975. Standard Methods for the Examination of
Water and Wastewater. 14 Ed. American Public Health
Association, Washington, D.C. 1193 p.
24
-------
Sfydr-" y jiid K- Stortz. 1980. Sources and transports of coal
-• ihe Duluth-Superior Harbor. U.S. Environmental Pro-
tection- Acency, Duluth, MN'. Publication number LPA-6CO/3-
'.0-0"7. 84 p.
Thompson, M.E. 1978. Major ion loadings to Lake Superior. J.
Great Lakes Rea. 4:361-369.
WDNR. 1977. Superior Harbor Study, Unpublished Data for 1976-
1S77. Wisconsin Department of Natural Resources.
25
-------
Table 1.
Equivalency "of sampling sites. The voter cheaistr;/
aoapling site in the left colunn is the sane aa the
benthos snap 1o collection site in the right colunn.
Benthos sampling
site
designation
IB
MIA
VIC
V2C
Interstate
Water chemistry
sampling site
designation
H
K
26
-------
Table 2. Water depths at each simple collection site.
Sample
Water
Site
Depth
( n)
A
7.5
B
2.-1
C
2.0
0
2.0
E
2. 5
F
3-0
G
2.0
H
2.0
i.
4. 5
J ...
2.2
K
1.5
L
8.0
27
-------
title 7. Procedures used for water chesiatry nr. alyais.
Paraaeter
Technique
Temperature and
Conductivi. ty
Measured a 1 tu with a Y SI
Model 33 f eaparatur«/Con«i-4Ct i-
vity Jieter. Calibrated in the
laboratory.
Field PK
Measured in ai tu using a Graph-
ic Controls cortnbl* pH M « t e r
(model ? II M 810 0). Calibrated
In the field usin« pH4, 7, and
9 buffers.
Laboratory pH
Measured in the laboratory it
roan tenperature. Bee.< a an
Model 3500 Digital pH acter and
Censor ex S30CC cor. binn tior.
elcctrcdc. Calibrated with pH
<5.0 and 7.0 buffers.
Alknlinity
Titration with sulfu:
p H 4.5 and pH 4.2.
I c acid to
Stands rd
Methods (19?5).
pp 279-262.
Dissolved Phosphorus
Filtration
nan U - 6
Molybdenus
method.
through 0.45 un Gel-
membrane filter,
bluo/asccrbic acid
Standard Me t h o i) a
(1975). pp 461 -482,
Total Pnosphorua
Acid-pcrsulfate digestion fol-
lowed by molybdenum blue/ascor-
bic acid analysis. Standard
.Methods (1975). p 476.
n o 3 ~ o 2"
Filtration through 0.45 ua Gel-
man C .N - 6 membrane filter.
Cadmium reduction method.
Standard Hethoda (1975) as
modified by Stairton, e_t a 1
(1974 ). pp 42-48.
NHj
Phenol
Distillation followed by Hes-
slerization. Standard Methods
(1 975). pp 4 10-4 15.
Distillation, chloroform, ex
traction er.d fornation
pyrin® dye. Standard
(1975). pp 577-580.
c f an 11 -
Xe t n od s
28
-------
Table 3 (continued)
Farane te r
Silica
Total Suspended Solids (TSS)
Chloride
Technique
Between 16 June and 22 July
1982 the heteropoljr blue method
was used. Between 3 August and
2 November 198 2, we used aetol
(p-aethylaminophenol sulfate)
as the reducing agent. Stan-
dard Methods (197 5). ptj 4 90-
492-
Suspended solids collected on
Galman A - E glass fiber filter
disk, dried at 103 C and
weighed.
Measured using chloride speci-
fic ion electrode (Graphics
control PR I 91100 UlIra-sensi-
xive C 1 ~ electrode and Orion
Research, Inc. Model 90-02-00
double junction reference elec-
trode )¦.
29
-------
Table. 4. Precision of analytical methods. Precision was
estimated from duplicate analyses run during June-
November 1982. !f is the number of duplicate analyses
and precision is the average relative deviation in
pe rcen t.
4
Parameter H Precision
{% S.D. )
pK
29
0.8
A Ik
28
0.8
Dis. P
34
1.8
T. P.
37
3-2
kh3
84
6.7
1
0
5S
1
O
21
3.4
Phenol
7
15.4
Si
38
52
6. of
0. 35
Cl~
2
7.7
1 % S.D. • n e an ^ x 100 where K is the number of
It
duplicate analyses.
p
For the hcteropoly blue method used between 16 June and 22 July
1982-
' For the netol nethod used between 3 August and 2 November 1982.
30
-------
Table 5- Water chemistry data for sanplea collected on 16 Jun« 1902
Sample Temp. Cond. Field Lab. Alk PC,, TP KO-j/KOt Nil-* Phenol Si TSS CI"
Site (°C) (umho/cn) pK pit (ng,''J "> (ngT/l) (ugP/l) (ugfl/1) (ragM/l) (ug/l) (mg/i) (rag/]) (rag/l)
A
20.1
118
7.5-1
7.28
49-
' 1
92
0.15
2
1
4
11 .
5
B
20.1
112
7.60
7-60
48.5
3
79
<0.02
2
1
4
8
5
C
?0.0
J12
7-97
7.48
46.9
4
79
0.10
1
2
1
0
5
1)
19.0
200
7.22
7.15
49.7
43
174
0.18
1
1
4
16
36
B
19.0
330
6.91
7.03
64.5
80
250
0.24
2
2
7
16
52
F
59.0
350
6.60
7.07
60.2
73
27C
0.24
2
•J
4
17
50
G
19.6
142
7.47
7.20
49.0
21
107
0.00
1
1
4
a
15
H
t?.9
160
6.95
?.<9
31.0
28
119
0.12
2
1
6
e
23
I
17.9
166
7.28
7.15
51-3
32
ijo
c. o
<
1
4
9
23
J
18.6
2?11
7.02
7.14
59-5
55
195
0.23
3
2
5
26
43
•f
19.8
121
7.75
7-50
47-5
16
93
<0.02
2
1
6
11
10
L
17.2
129
7.65
7.43
48.0
10
93
<0. 0
-------
Table 6. Water chemistry data for aa«p"1es collected on 7 July 1982
Sample
. Site
Tenp.
(°c)
Cond.
(uraho/cp)
Field
PH
Lab.
pH
A lk
(nsg/l)
VC43"
(ugP/1)
TP
(ugP/l)
fiO^/KOo
(ugN/lf
Kll-j
Phenol
(ug/1)
Si
(ng/1)
TSS
{ niif /1)
cr
(»g/i)
A
21.7
135
7.7 S
7.77
55.5
3
103
-
<0.02
1
1.2
34
3
B
21.6
139
'7.67
7.70
56.6
4
53
_
0.03
2
1.2
12
5
G
21.0
159
7.72.
7.75
57.1
7
60
-
<0.02
4
1.1
'7
5
D
19-9
300
7.53
7.63
99-6
IB
150
•
0.58
17
1.6
22
•5
E
19-9
365
7.43
7-30
142.6
37
340
0.66
25
3.0
23
23
F
19-9
430
7.47
7.68
123-2
57
270
_
- 0.70
19
2.1
21
20
C
20.0
159
7.71
7.M
01.'J
15
92
-
0,16
4
1.9
12
7
11
20.0
157
7.66
7-69
59-6
8
90
-
0.13
3
1.9
14
a
I
20.0
149
7.64
7.66
60.2
11
73
-
0.12
5
2.1
14
6
J
1H.2
175
7.62
7.63
63.9
5
100
_
0.23
6
3-7
*.26
16
K
20-9
139
7-73
7.GA
56.3
4
66
-
0.03
2
2.4
16
5
L
20.0
141
7.54
7.67
57.0
7
79
-
0.06
3
1.8
10
8
Renarks: Heavy rain on 5. 6 July.
-------
Table 7» Water chomiatry data for samples collected on 20 July 1982
Sample
Site
Temp,
(°c)
Cond.
(umho/cm)
Field
pH
Lab.
pH
Alk
(mfi/l)
mi3~
(ugl/1)
TP
(ugP/1)
MO-j/BOg KM*
(ugll/l) (meH/l)
Phenol
Cvip./l)
Si
(rag/1)
TSS
(ag/l)
CI"
(mg/l)
A
KS1
MS
7.10
7.14
36.6
14
70
0.12
3
3.3
12
3
B
N5
IIS
7-08
7.30
36.6
13
66
0.14
6
3.1
10
3
C
22.1
98
6.61
7.27
36.8
16
71
0.13
3
3.0
12
3-
D
21.1
210
6.45
6.90
80. a
95
302
0.52
8
4.3
19
90
' E
22.0
110
6.45
6.68
54.3
45
168
0.15
3
3-4
12
52
F
21 .0
132
7.15
7.19
39-9
20
07
0.22
4
3.2
10
14
G
22.0
106
6.71
7.26
37-0
15
81
0.16
3
3.1
11
6
11
21.9
105
6.78
7-16
35-4
5 6
71
0.14
4
3-t
10
10
I
21.5
100
6.69
7.29
36,5
15
78
0,15
3
3-3
'0
. 1
J
23.1
120
7-22
7.24
40.2
16
87
0.19
3
3-2
9
13
K
22.1
98
6.62
7.3»
35.9
13
70
0.12
7
3.2
9
4
I
19-9
go
7.15
7.36
37-4
8
148
0.50
4 •
3.0
8
9
1113 - not sampled
-------
Table 8. Water chemistry data for samples collected on 3 August 1982.
Sample Terra. Ccrad. Field Lab. Alk POTP NO*/KOo pHH-j Phenol Si TSS CI"
Si io C°0) (umho/om) plf pH (rag/l) («gP/1) (ugP/l) (ugK/lf (mglf/l) (ug/l) {ng/l} (n.g/l) (mg/l)
A
98
7.22
50.0
41
127
0.12
3
3-6
16
4
B
93
7.40
50.4
47
132
0.09
2
3.4
13
4
C
100
7."32
49.1
20
99
0.12
2
3-4
12 '
4
D
353
7.27
107.0
143
311
0.38
5
3.7
13
65
E
531
7.39
102.7
139
274
0,33
6
3.6
13
65
F
' 408
7.13
117.9
185
364
0.39
*7
3.8
14
79
G
110
7.55
50.3
32
94
0.13
2
2.9
10
10
11
113
7.52
49-2
28
89
0.20
2
2.9
8
8
I
111
7-52
49. l
36
99
0.11
1
2.0
9
7
J
114
7.40
41). 9
78
135
0.13 ¦
%
2.7
13
8
K
103
7.56
40.6
60
124
0.12
\
2.9
11
6
I
109
7-38
48. \
86
0.12
'3
2.7
12
6
-------
Table 9- Water chemistry data for samples collected on 16 August 1982
Sample Temp. Cond. Field Lab. A Ik P045* TP MOv/NOg NH, Phenol Si TS5 CI"
Site (°C) (ucr.ho/cm) pH pH (mg/l) (ugl'/l) (ugP/l) (ugfl/lj {tagfl/l) (ug/l) (mg/l) (mg/l) (rag/l)
A
23.0
135
7.27
6.83
38.4
15
0.14
-------
Table 10. Water chemistry data for samples collected on 7 September 1982
Sample Temp, Cond. Field lab. Alk FO,5" TP NCK/NQp HH-* Phenol Si TSS CI"
Site (°C) (umho/cu) pH pfl (ng/l) (ugF/l) (ugP/l) (upN/l) (mgN/l) (ug/l) {ng/l) (reg/l) {mg/l}
A
20.2
140
7-42
57.0
39
86
83
0.09
4
3-3
10
5
B
20.4
139
7.62
58.2
30
75
95
0,09
2
3-0
6
5
C
20.4
159
7.64
50-7
'53
92
120
0.10
4
3.2
5
D
23.4
396
7.43
104.6
424
610
86
4.43
3
3.4
13
45
8
2?,2
273
7.48
83.2
250
357
140
3.18
1
2.9
9
24
F
24.4
200
7.54
65-0
94
166
184
0.59
6
2.7
7
17
G
21.0
153
7.66
58.8
38
91
129
0.13
1
2.8
5
8
H
21.1
151
- . 7.69
50.2
34
86
148
0.13
3
2.7
6
9
1
21.2
152
7.64
58.1
40
81
01
0.13
<1
2.7
6
9
3
21.1
171
7.61
59.7
48
98
145
0.17
4
2.5
7
12
K
20.6
148
7.65
57.5
32
85
147
0.12
<1
2.8
6
8
L
20.5
148
7.61
57-6
40
¦80
132
0.12
2
2.6
5
9
-------
Table 11. Water chemistry data for samples collected on 21 September 1982
Sample Temp. Cend. Field lab. Alk PO/3" TP KC3/NO2 NH, Phenol Si TSS CI"
Site (°C) (unho/cm) pH pH (ng/l) (ugl'/l) (ucP/l) (ugN/j) (nf,N/l) (ug/l) (ug/l) (wg/l) (r.g/l)
A
14,2
128
7.12
59.3
21
63
127
0.11
1
3-0
6
5
B
14.0
125
7.30
58.8
19
173
108
0.10
1
3-3
4
6
C
13.9
128
7.33
59.0
18
65
113
0."!
1
3.5
7
5
D
15.0
147
T.12
66. .
145
239
54
0.18
2
3.9
10
54
E
15.2
231
7.53
74.6
83
160
131
0.17
2
3.5
10
34
F
14.4
153
7.38
78.8
108
210
90
0.19
1
3-9
10
44
C
15.0
200
7.45
77.0
104
200
91
0.14
2
3-8
7
40
ii
14.5
16?
7.42
67.5
59
134
94
0.15
2
3.5
8
24
i
14-8
158
7.16
60.0
35
102
107
0.13
1
3.4
14
13
j
13.9
152
7.44
62.8
34
95
135
0.16
7
3.4
6
14
K
14-5
179
7.42
63.2
44
136
136
0.15
2
3-5
8
20
L
14.2
140
7.49
50.7
30
78
187
0.14
5
2.9
6
12
-------
Table 12. Water chemistry date for samples collected on 5 October 1982
Sample Temp. Cond. Field Lab. A Ik P04*5~ TP NCK/MOo tlH, Phenol Si TSS CI"
Site (°C) (uoho/cm) p)i pH (mg/l) (ugP/l) (ugP/l) (ugN/lJ (mgN/l) (ug/l) (mg/3) (rag/l) (mg/l)
A
159
7.08
58.8
20
70
66
0.15
1
4.2
9
5
B
158
7.26
58.8
22
74
108
0.14
1
4.1
' 5
5
C
160
7-27
59-6
20
79
92
0.14
1
4.2
7
5
D
441
7.05
89.3
85
193
113
0.37
3
4.4
9
57
E
472
7-05
92.7
92
, 212
79
0.40
3
4.6
c;
66
F
330
7.08
62.9
69
174
98
0.28
3
4.4
9
49
G
266
7.17
71.1
45
127
103
0.24
2
4.2
7
29
H
278
7-19
70.6
49
133
120
0.19
3
4.1
6
27
I
210
7.34
64.7
30
92
117
0.17
2
4.0
7
14
J
255
7.32
69.7
37
111
92
0.15 '
4
4.3
7
23
K
211
7-28
64.7
34
91
87
0.21
3
4.0
j
16
T
J *
184
7.34
62.1
22
85
108
0.15
3
4.0
6
9
-------
fable 15* Water chemistry data for sanples collected on 19 October 1982
Samplu Temp. Cond. Field Lab. Alk FOj^" TP KO^/MQ? N!f r Phenol Si TSS CI"
Sits (°C) (uir.ho/ca) pH pH (mg/l) (ugP/l) (ugP/1) (ugM/lJ (nigH/l) (ug/l) (mg/l) (mg/l) (mp/l)
A
a.s
70
7.16
31.5
7
61
74
0,04
2
3.6
14
3
3
9.0
69
7.22
33.2
11
57
64
0.02
1
3.6
8
3
C
9.1
69
7.19
33-8
11
57
65
0.03
3
3.6
7
3
D
11.9
265
6.98
83-2
77
208
34
0.13
6
4.5
10
70
E
13.0
340
6.99
75.2
77
191
37
0.10
6
4.4
10
60
F
15. <
380
7.00
83.8
96
242
20
0.12
5
4.4
9
78
G
11.8
275
- ¦ 7.04
70.7
69
185
33
0.13
4
4.3
10
56
H
9-5
101
7.21
39.1
19
81
• 53
0.04
3
3-6
9
11
I
9.2
92
7.22
37-3
11
73
61
0.04
3
3.6
11
8
J
10.0
112
7.28
44.0
19
70
73
0.05 '
3
3.8
6
12
K
9-2
68
7.25
32.4
10
60
59
<0.02 ¦
2
3.6
9
3
L
•3.5
80
7.26
35.1
12
69
60
0.05
2
3.6
11
5
-------
Table 14. Water chemistry data for sanpleg collected on 2 November 1982
Sample Temp. Cond. Field Lab. Alk FO.^" TP HO-i/KOo NH< Phenol Si TS3 CI"
Site (°C) ('jmho/Cm) pH pH (ng/l) (ugr/l) (ugP/l) (ugN/l) (tig/l) (ngSi/l) (mg/l) (rafl/l)
A
7.0
82
-
7-34
42.4
13
53
81
0.09
1
3.9
5
4
B
7.0
00
_
7.32
41.0
11
50
88
0.11
2
3.8
4
.4
C
7.0
01
_
7-34
41.4
34
51
80
0.11
1
3.0
4
4
D
8.9
182
_
7.21
81.2
168 '
250
25
0.60
5
4.1
6
62
E
9-5
208
-
7.25
80.4
174
260
39
0.6?
3
,4.2
6
60
P
6.1
149
_
7.24
83-0
190
270
18
0.43
3
4.2
6
64
G
3. <3
166
_
7.26
55.B
53
120
56
0.30
3
3-9
6
31
H
8.0
140
-
7.38
48.6
34.
89
39
o.?3
2
4.0
6
25
I
8.0
142
-
7-36
48.3
27
95
54
0.19
1
3-8
7
31
J
7.9
158
_
7.36
55.5
34
09
70
0. x5
3 .
4.0
4
25
K
7.2
101
-
7.37
40-4
14
54
77
0.09
2
-
4
12
L
7.6
130
_
7-36
45.5
27
81
33
0.18
1
3-6
6
21
-------
Table 15- Summary of water chemistry data for samples collected June - November, 1902
Conductivity Laboratory pH Alkalinity Disaolv#;d PO^-
(unho/cm) ( rr.fi/ 1) (uf;P/l)
Sample
Site Median Heart Range Median Mean Range Median Mean Range Median Kctn Range
k
12a
118
70-159
1.19
7.24
6.6*3-7.77
49-8
47.9
31.5-59.3
14
18
3-41
B
125
11?
69-158
7.31
7.38
7-12-7.70
49.4
49. J
33.2-58.8
14
18
3-47
C
124
116
69-160
7-36
7.42
7.19-7.75 .
51.0
49.5
33.8-59.6
17
17
4-33
D
282
?QR
147-490
7.18
7.20
6.90-7.63
85-3
86.6
80.8-107.0
119
IT f
10-424
E
330
323
110-570
7.20
7-10
6.66-7.53
85 .H
85.0
54.3-142.6
,00
119
37-250
F
286
282
132-430
7.16
7.22
6.84-7.68
80.0
79-2
52.0-123-2
84
94
20-190
C
164
184
106-275
7.33
7.36
7.04-7.66
60.4
59.5
37.0-77.0
42
46
15-104
H
154
200
101-620
7.35
7.33
7.16-7.69
54.6
57.0
35.4-91.2
34
45
8-176
1
150
152
92-245
7.35
7.39
7.15-7.66
54.7
52.6
36.5-60.3
31
27
11-40
J
164
173
112-255
7-38
7.3ft
7.14-7.63
59.6
57.0
40.2-69.7
"54
36
5-78
K
130
136
68-195
7.34
7.40
7.21-7.65
49.9
49-8
32-4-64.7
24
20
4-60
L
132
129
80-184
7.40
7.44
7.26-7.67
50.4
50.2
35.1-62.1
23
21
8-40
-------
Table 15 (continued)
Total Phosphorus
(ugP/1)
Sample
Site Median Mean R_nge
Nitrate/Kitrite
(ugH/l)
Median Mean Range
Ammonia
(r,g?!/l)
Median Mean
Range
Phenol
(ug/l)
Median Mean Range
A
71
81
53-127
83
90
01-127
0.12
0.10
<0.02-0.15
2
2
<1-4
B
74
04
50-173
95
93
64-108
0.10
0.00
<0.C2-0.14
2
2
<1-6
C
71
75
51-99
92
94
65-120
0.11
0.10
<0.02-0.14
2
2
<1-4
0
239
271
150-610
54
62
25-113
0.38
0.76
0.13-4.43
4
5
1-17
E
250
246
160-357
79
85
37-140
0.29
0.61
0.10-3-18
3
6
1-25
P
24?
228
166-364
90
82
53-184
0.26
0.34
0.12-0.78
4
5
1-19
C
107
122
81-200
91
82
33-129
0.15
0 17
0.00-0.24
2
2
<1-4
H
89
99
71-134
94
91
39-148
0.14
0.16
0.04-0.27
3
3
2-4
I
92
91
73-130
81
84
54-117'
0.13
0.13
0.04-0.17
¦ 1
2
<1-5
J
99
109
70-195
92
103
70-145
0.56
0.16
0.05-0.23
4
4
3-7
K
85
87
54-136
87
101
59-147
0.10
0.12
<0.02-0.21
2 _
2
<1-7
L
81
89
69-148
108
114
60-187
0.12
0.14
<0.02-0.50
2
3
1-5
-------
Table 15 (continued)
Sample
Site
Hodian
Silica
(mgSi/l)
Mean Range
Total
Median
Suspended
(fflg/l)
Mean
Solids
Range
Hodian
Chloride
(mg/l)
Mean
Range
A
3.6
3.2
1.2-4.2
10
12
5-34
4
4
3-6
8
3.3
3.0
1.2-4.1
8
8
4-13
5 ¦
5
3-6
C
3.4
3-1
1.1-4.2
to
10
4-17
5
4
3-6
D
3-8
3-5
1.4-4-5
12
13
6-22
60
57
15-90
E
3.6
3-6
2.7-4.6
11
12
6-23
56
51
23-66
F
3.6
3-6
2.7-4.4
to
11
6-21
46-
45
17-79
G
3-2
3.2
1.4-4.3
8
8
6-12
22
24
6-56
H
3.3
3.1
1.6-4.1
8
8
6-14
16
24
8-81
I
3.0
3.2
1.4-4.0
9
10
6-14
11
14
6-31
J
3-4
3.3
2.5-4.3
8
22
4-126
15
20
3-43
K
3.2
3.0
1.6-4.0
a
9
4-16
9
10
3-20
I
3-0
2.9
1.8-4.0
8
8
5-5 2
9
10
5-21
-------
Table 15. Concentrations of alkalinity, total phvSphats,
ammonia, and Cl~ in the WLSSD effluent. Data courtesy
of Duane Long, WLSSD.
Date
Alkalinity
Total
Phosphorus
(mg
Ammonia
L-l)
Chlorid;
15 June
200
0.90
' 1.20
250
6 July
350
0.62
3,00
85
19 July
180
0.48
0.55
205
2 August
220
0.62
<0.10
205
15 August
180
0,48
<0.10
265
6 September
180
1.73
6.20
250
2D September
150
0.96
<0.10
295
4 October
100
0.35
0.65
225
13 October
190
0.55
0.10
250
1 November
220
0.90
1.60
225
Average*
198
0.64
0.56
211
*Volume-weighted average concentrations for the period June-
November 1S32.
44
-------
Table 17. Derivation cf fcrnula f•.r calculating ths nixing of
WLSSD affluent with the "it. L^uis River.
If we assume that the chemical composition in the small embayraent
near the WLSSD plant is a result of the mixing cf Arrowhead
Bridge (site A) water with WLSSD effluent water, then the mixing
fraction {£) can be calculated from:
C = (1-f) A + f W
where:
C = concentration in the embaymcnt
A = concentration at site A (Arrowhead Bridge)
W - concentration of WLSSD effluent
This formula simplifies to
£ = C - A
W - A
For Cl~, with C = 50 mg L-^, A = 3 mg L~^ and W » 250
mg L_1 then f is:
£ = 50-3 = 0.19
250 - 3
Therefore, the concentration of Cl~ in the embayment is
a result cf mixing 19% WLSSD effluent with 81% St.
Louis River water.
45
-------
Table 18. Compilation of mixing fractions, f, for each of the
six e-nbayront sites for each sampling date.
Site
6/16
7/7
7/20
8/3
8/16
9/7
D
0.127"
0.146b
0.431
0.303
0.266c
0.133
E
0.192
0.244
0.243
0.303
0.278
0.078
F
0.184
0.207
0.054
0.373
0.100
0.049
G
0.041
0.049
0.015
0.020
0.103
0.012
H
0.073
0,051
0.035
0.020
0.290
o.cis
I
0.073
0.037
0.020
0.015
0.073
0.015
M21
10/5
10/19
11/2
Averace
d
D
Cf. 175
0.235
0.271
0.252
.255
E
0.104
0.277
0.231
0.253
.227
F
0.139
0.200
0.304
0.271
.193
G
0.125
0.109
0.215
0.122
.097
H
o.osa
0.100
0.032
0.095
.097
I
0.029
0.041
0.020
0.122
.043
aE£fluent values for calculation taken from June 14, 1982.
^Effluent values for calculation taken from July 5, 1932.
cPlant effluent concentrations taken from August 16, 1982.
^Calculated using mean embayment concentraten, mean WLSSO
effluent concentration, and mean Arrowhead Bridge: concentration
(Tables 15 and 16).
'46
-------
Table *9- Conperiron predicted alkalinity, total phosphorus,
and anaonia, with the observed mean concentrations in
the ensb378!CRt. Arrowhead 2ri
-------
Table 20. Comparison of inputs to St. Louis Bay from the St. Louis River and WLSSD effluent during 16 June - 2 November
1982, The average flow for the St. Louis River is calculated from discharge data at the Thomson Dam, some 30
km upstream from St. Louis Bay. Concentrations used in calculating loadings from the St. Louis River are
those measured at site A (Arrowhead Bridge). All average concentrations are volume-weighted averages. The
loading is an average loading rate over the 140 day period between 16 June and 2 November 1982-
Source
Average
Plow
(sir sec *)
Alkalinity
Ave. Loading
Cone
(mg L_1) (107g day"1)
Total Phosphorus
Ave. Loading
Cone
(mg L-1) (105g day"1)
Ave.
Cone
(mg L-1)
Ammonia
Loading
(105g day"1)
Ciilo
Ave.
Cone
(mg L_1)
ride
Loading
(107g day-1)
WLSSD
1.6
198
2.7
.639
0.88
0.556
0.76
211
2.9
St.
Louis
River (at
site A)
11C
46
46
.076
7.6
0.033
8.80
3.9
3.9
Total
Loading
49
8.5
9.6
•
6.8
-------
Table 21. Yearly average total phenyl concentrations at site L
(Interstate-535, Blatnik High Bridge). Early data are
from MPCA (197Sa). N is th3 number of samples
collected during the year.
Average
Year N Total Phenol Range
(mg L*"1)
1973
1
23
-•
1974
15
9.2+6,0
2-20
1975
8
8.0+4.6
4-19
1982
10
2.7+1.2
1-5
49
-------
Table 22. Mat hods c f nutrient analysis used by the five laboratories
studying St. Louis Bay. For details vf analytical methods sec
references in Figures 2 and 3.
Laboratory
Amnonia
no3/no2
Total Phosphorus
LSBSC
Distillation,
Cd Reduction,
Persulfate
Digestion,
Messierization
Azo Dye
Molybdenum
Blue
WIS3D
Phenato
Brucine3
Persulfate
Digestion,
Molybdenum
Blue
EPA
Distillation,
Cd Reduction,
Persulfate
Digestion,
Nesslerization
Azo Dye
Molybdenum
Blue
MPCA
Distillation,
Cd Reduction,
Persulfate
Digestion,
Messier izaticn1
Azo Dye
Molybdenum
Blue
Alkaline Oxidation,
Diazolization^
WDNR
Phenate
Cd Reduction,
Persulfate
Digestion,
Azo Dye
•Molybdenum
Blue
11S72-1977
2197?-1930
¦*NO"J only
50
-------
FIGURE CAPTIONS
Figure 1. The Duluth-Superior Harbor.
Figure 2. The Duluth-Superior Inner Harbor (St. Louis Day).
Locations for water chemistry and plankton sample
collection are designated by A through L. P denotes
the approximate location of the WLSSD discharge pipe.
Figure 3. Total phosphorus at site A (Arrowhead Bridge) between
1972 and 19R2. Depth of sample was £1 metre.
References: LSRSC - this laboratory? WLSSD - Storet
computer printout; EPA-EPA (1975); WDNR-WDNR (1W7) .
Figure 4. Total phosphorus at site L (Elatnik High Bridge and
Burlington Northern Railroad Bridge) between 1972 and
1992. Depth of sample was _£l metre. References as in
Figure 3 and; MPCA-MPCA (1978a, b, 1981).
Figure 5. Nitrate/nitrite at site A (Arrov;head Bridge) between
1972 and 1982. Depth of sample was <_1 metre.
References as in Figure 3.
Figure 6. Nitrate/nitrite at site L (Rlatnik High Bridge and
Burlington Northern Railroad Bridge) between 1972 and
1982, Depth of sample was j_l metre. References as in
Figures 3 and 4.
Figure 7. Ammonia at site A (Arrowhead Bridge) between 1972 and
1982, Depth of sample was _< 1 metre. References as in
Figure 3.
Figure 8. Ammonia at site L (Blatnik High Bridge and Burlington
Northern Railroad Bridge) between 1972 and 1902.
Depth of sample was _<_1 metre. References as in
Fiqures 3 and 4.
51
-------
o
N
Lake
Superior
-------
Figure 2
53
-------
0.7
Figure 3
TOTAL PHOSPHORUS AT ARROWHEAD BRIDGE
a. 0. tt
ut
£
v>
3
EC
o
X
a
v*
o
X
Q.
6.3
0.2
Q-lsgsc
Jh-WiSSD
~ -EP A
O-WDNR
<
h
O
tr*
0-1
4 %
+ \
A,
1972 I <973 I 1»'< | 1975 J 1 9 7 0 1 IS?? I 9 J 8 | 1V70 | 19»0 1 196 1 J 1 5 » 2
YEAR
0.?
Figure 4
TOTAL PHOSPHORUS AT DLATNIK HIGH BRIDGE
— 0.6
? 0.5
E
o.<
co
a
s
O
x
A.
m o.s
0
1
o.
0.2
<
H
o
t- o. I
o° jcta * *»'v C* X'» " ^ »'
* ^ .* * *• * ik%4 - # *
*
-LSESC
A-WLSSD
~ -EPA
©-MFC A
D Ot
\^y*v.. .|s>
197; I l •> 7 3 I 1974 | 1975 | 187S j 18 7 7 | 1 9 7S [ 1979 | 1 9 9 0 j 196 1 j l SSJ
YEAR
54
-------
Figure 5
NITRATE/NITRITE AT ARROWHEAD BRIDGE
(.2
S
z , 0
e»
£
(U 0,1
M
5
5 *¦«
til
I-
< Q,i
cc
^-LSOSC
A-V/LSSD
~ -EP6
O-WDNR
0,1
C C!
j I » 7 3 j UTI j 1975 | I V 78 j 1 9 X 7 j IS 78 | i 87 9 j 1 960 j 1 98 1 j t IB!
YEAR
01
E
i.j
1.0
Figure 6
NITRATE/NITRITE AT BLATNIK HIGH BRIDGE
^-LSSSC
~ -WLSSD
~ -EPA
O-MPCA
IU OB
< 0.4
a
0.2
o D . — * •• Wl.' A.. • /• ,
fta ° ! ,* • S' ». -A*
c ft » f ** * ; • * r V- A ¦ ¦
* *J* 4 A *. A » *
. 0
yf */?
I S 7 V j 16 7 3 j 1971 j 1975 | 1976 | ' S ? 7 j '578 j 1579 | s 9 * S j t J I t | n:." j
YEAR
55
-------
1 :
- ,.0
o e
Figure 7
AMMONIA AT ARROWHEAD BRIDGE
0-LSBSC
A-WLSSD
~ -EPA
O-WOMB
<
X 0.6
O
2
S
< C.4
0,5
CP
* M. J. * J. * *'•
N**4 *«*»¦ » ******
j IS?} j l!H j t»?5 | 1976 J 1S?7 j 1678 | 1979 j I86 0 | Tori | tS£2 [
1972
YEAR
1.*
Figure 0
AMMONIA AT BLATNIK HIGH BRIDGE
x
01
1.2
1.0
c.a
() -LSGSC
A-WLSSD
~ -EPA
©-MPCA
z °#
o
2
S
< 0 *
0.2
* » .« *
• * ¦ • »
° ^ V. • '* . > ."** »' • . ••
°c T T JT ttttt T7 TfHTIf? *\ > *,
.. A ^ ^ WJ
1ST! j 1973 I 1974 | I s;5 j »»r§ | 1977 j t»?» | 1i>7§ | IfSO | tf#» | 1#6 J
YEAH
56
-------
St. Louis Say Benthlc MacroInvertebrate Survey
by
Tbo^. is Rut: ,h
U.S. Knvironnor.t.-il Protection Agency
Jnvironmertcat Research l.aboratory-Dulnth
6201 Congdon Boulevard
Duluch, Minnesota 55804
December 1982
57
-------
Introduct iuii
History — Si. Louis Bay has historically experienced very poor water
quality conditions. A combioat ion of CAccsa cut roph ic at ion presumably due to
nutrients front a waste treatment plant, and fish-tainting chemicals,
presumably from an upstream paper u. 11, combined with the modifications of
navigational dredging and development of the waterfront have been prime
influences for degradation.
The construction of the Western Lake Superior San t ary District (WLSSD)
treatment plant apparently has deviated much of the chemical problems such as
low dissolved oxygen and fish tainting chemicals.
Purpose
With the development of WLSSD and its sewage system, a numbc of waste
streams and their chemicals are now processed though the plant and dinarged
into the lower St. Louis Bay via a diffuser .system. The purpose of this
survey was to determine the pattern of distribution of the benthic
maeroinvertebrales in relation to the WLSSD discharge. This survey was
conducted in conjunct^ . with a number of other fascets of a study program.
Among the other investigations was a survey of the plankton and water
quality, and laboratory measures of acute toxicity, test f i sh responses and
chemical determination of contaminants.
Rat io.iale
The benthic macro invertebrate cummini ty was selected for surveying
because of their sessile habits and integrating exposure to the environmental
conditions in their immediate surroundings. Upstream coves were uscu «js>
controls since they would not. be exposed to chemicals possibly found in the
58
-------
discbarge. Multiple sampling stations rfcrc used In order to estimate spatial
variation within a cove. The transects in the WLSSO discharge cove were used
in order to oore precisely delineate the impacted urea, if indeed art iapaet
was found. Presumably, if the community was adversly affected, differences
in the taxa captured would be found and circumstantially be attributed ta the
WLSSI) discharge. The other investigations would be compared for possible
confirmation.
Station Location
Three bays on the Minnesota side of St. Louis Bay were sampled three
times during 19S3 using mid and quarter-point stations on transects extending
across the bays (Figure 1). Upstream bays were near the Arrowhead Bridge.
In the WLS5D disc barge bay, two 3 station transects were saupled, using the
diffuser station as a common point. Sampling was done on June 15, August 10,
and October 26, 1982» Durim, August and October, an additional station
-------
sorted to rsnove .other orgatisina. The organisms were re-preserved in 70Z
ethanoi.
Sanple Analysis
The organisms were enumerated and identified to convenient taxa using
dissecting and conpound microscopes. Standard taxononic refcerenee were
ut ilized.
Results
Tables 2, 3, and 4 present the number of organisms in each taxonoraic
entity as captured by the combined 3 grabs of the 6" x 6" dredge at each
station. Tables 5 and 6 present the ouaoations when all 3 sampling periods
are combined, along with sfiapie calculated values relative to clarifying the
patterns of distribution. Table ? presents data by sampling period for total
numbers per taxon and percent composition. Table 8 presents the data as
density (nunbers/m ) of organises. Figures 2 and 3 display density and
percent composition data.
A total of 105 grab sample;; captured 2,916 organisms of 22 taxa (18 to
20 each sampling period). 93.4% were oligochae'es and chironomids {90.5 to
961 for individual sampling). Over the three sampling times, 2 to 12 taxa
per station were captured, frequently, the occurrence of a taxon at a
station was represented by one individual.
Overall, the upstrean bays had the fewest oiigochaetes and the largest
number of taxa, VIC, the i.vwt upstrean station in the discharge bay, was
quite similar to the upstream bays, possibly due to the direction of the
water I low. The station by the diffuser (W1A) showed an increase in the
nuniber of taxa during the sumuer while W'23 and U2C remained severely
60
-------
depressed. The patterns of the upstream stations >:ere reasonably consistent,
thus both spatial and tecippral differences were In effect.
The oligochaetas werc not Identified to lower taxonomic entitles and the
numbers even Include a few Individuals of the freshwater polychaete,
Hanayunkia eriensis. Lowest densities were found outside of the discharge
bay. The greatest numbers were found In August. This was the most common
taxon, comprising 65.9% of all irganisns (54.5 to 74.9%, for each sampling).
Chirono.alds were the second most comaon group, 27.52 of all organisms
(19.1 to 36.IX for each period). Eleven genera were captured, with the most
common and widaly dispersed being Proeladlus. Much lower numbers and number
of taxa was found In the discharge bay.
Two genera of Trlchoperg were found. They were raore common in the last
2 samplings and a few were found in the discharge bay during October.
Ephemerapera was represented almost exclusively toy Hexagenla. None were
found in the discharge bay and the October samples contained very small
individuals.
Conclusions
The benthie invertebrates demonstrated noticeable differences between
the WLSSD discharge bay and two bays upstream.
The discharge bay contained fewer types of organisms.
61
-------
Table 1. Sampling areas, scat ions and depth of watrar (meters) for the 1982
St. Louis Bay, Minnesota, benthos survey.
June Aug. Oct.
15 10 26
I. Transect in the bay south of the Minnesota
Power electric generating plant.
1A - Southern station
2.6
3.2
3.1
IS - Midpoint
2.ft
2.5
2,8
1C - Northern station
1.5
3.0
2.2
Transect in the bay north of the
generating plant.
2 A - Southern point
1.8
2.0
Z.5
2B - Midpoint
2.4
2.5
2.5
ZC - Northern point
1.5
2,2
2.1
Pay receiving ULSSD discharge.
W1. Southern transect.
W1A - Close to diffuser
1.5
3.5
3,5
WiB - Midpoint of southern transect
2.1
2.2
2.5
W1C - Close to shipping channel
1.5
2.0
2.7
W2, Northern transect, uses W1A as one end.
W2B - Midpoint of northern transect
2.7
3.0
2.5
W2C - Close to shipping channel
4.3
4.0
4.3
INT - Southwest of discharge bay
N'/A
2.0
2.1
62
-------
Tafol® 2. Results from the Juno 5982, sampling of ttia St, Louis Bay, Minnesota, bentfios survey.
Sampling Stations
1A
IB
1G
2A
28
2C
wu
WIS
WIC
W28
W2C
Total
I) 01!gochg#tes
49
17
5
a
1
2
76
147
71
98
70
540
2) Dlptoro
A J CM ronomldao
a) Tanypodlnsa
Proc!sd!us
20
16
10
17
u
21
3
7
23
4
9
144
Coolotanypus
6
2
3
11
3
35
AtJlahesmy I a
i
1
2
b) CMronominaa
Cryptoch 1 ror.oous
styl1fera
2
1
\
1
5
C ryprocrv 1 ron omu s
nals
5
3
1
1
1
6
17
Glyptotondioas
1
2
2
1
2
8
Tanytarius
1
1
2
Chiron ones
3
1
5
9
Polypod1 1 um
5
1
i
1
10
1
19
Mlcropsectre
Tributes
pupae
3J CoratopCKjonidas
Pa 1 pomia
t
3
. 1
5
C) CulIcidao
Chaoborus
1
1
31 Tricoptora
' PhyI ocentr*3Bus I 1
Oocotis
I
2
2
5
41 EphemeroptoMa
Hoxagani a
I
2
1
1
2
?
Caonls
1
!
5! Mollusco
Sphaori on
4
2
1
1
8
6} Amphipoda
Gamraarus fasela+us 1 1
?) Other
1sopoda
1
»
Hirudins®
2
2
63
-------
Tab to 3. Results from the August 1982, sampling of 1+>o St. Louis 8ay, Minnesota benthos survey.
Sampling Stations
i A
13
IC
2A
29
2C
HI A
W1B
W1C
V28
K2C
INT
Total
I) Ollgochaotos
102
34
30
6
22
46
95
109
93
110
196
30
873
2) Dlptora
A) Chironomldaa
a) Tanypodlnaa
Procladlus
16
4
If)
1
11
16
' 2
31
17
24
25
1
158
Coolotanyaus
3
1
1
5
At>laboS<»yi 8
1
t
1
3
b) CMrcnon Ir.sa
Cryptocft t ronortus
sty 11iera
5
1
1
1
8
Cryptocbiron emus
na 1 s
2
2
1
2
11
9
3
30
6 1 yijfotond I pes
Tanytarsus
1
2
3
Chlronomus
1
3
1
5
Pol yped i 1 urn
1
t
1
3
Mlcroesac+ra
1
1
TrIbalos
1
1
pupa*
3
2
5
B) Coratopogonldae
Pa loomi a
J
1
3
5
C) CutIcidae
Chaotwrus
I
1
2
Triccptora
Phylocontroous
11
3
7
4
6
t
1
Oo;stis
4) Ephemoreptara
Hexagsn1 a
1
2
1.
2
1
7
Caen 1s
5! MolI used
Sphaor 1 un»
1
2
2
1
2
8
6) Amphlpoda
Ganmarus fasclatus
2
1
1
4
7) Other
I sopoda
H1rud1nao
2
i
2
1
2
1»
64
-------
Tebio 4. Results from tha October 1902, sampling of the St, Louis Bay, Minnesota benthos survey.
Sampling Stations
t) 01Iqochaotos
U 19 IC 2A 2B 2C W1A W18 WIC W2B H2C INT Total
56 23 12 15 4 25
74
93 78 35 84
5tC
2) Dlptora
A) Ch Ironomldao
al Tanypcn) Inae
Procladtus
20
8 35 19 67 42 43 10 252
Ceelotafypus
29
Abie's esmyla
bl Chlronomtn##
Ct yptocnIronomus
sty 11 torn
I 2
CryptochIronomus
nal s
GIyptotendI pes
Tsnyrarsus
Chironomus
22
32
PolypcxJi I>jn
MI cropsectra
Tribal OS
pupae
81 Ceratopogonidee
Pal poraia
Z1 CulIcidae
Chaoborus
3) Trlcoptera
Pbylocontropus
2 ! 2
I 1
20
Oncot I »¦
41 Ephenoroptara
Hexagenla
5 »3
2 1
32
Caunls
5 ) Mo II uses
Spfiaer lum
61 Amphlpoda
Gaiwiarus fasclatus
I 1
7} Other
Isoooda
HIrud!nag
65
-------
Tab Is 5. Sunmary results of th« 3 samplings of «>» tw St. Louis ooy, Minnesota bonthos survoy.
SamplIng Stations
IA
IB
IC
2A
28
2C
HI A
W1B
W1C
W2B
K2C
• NT
Tota 1
1) 011gochaotas
201
74
45
29
J.i
73
245
345
242
241
330
41
1525
2) Olptora
A J Ch1ronomldaa
a) Tanypodlnse
Procladlus
56
24
23
18
26
45
40
57
107
70
77
It
554
Coototanypus
It
2
15
8
12
10
5
6
69
AblabasitiY la
3
3
1
1
t
9
b) Chlronointnaa
Cryotochlronomus
sty 11fera
2
1
6
3
3
1
2
4
22
CryptochIronofflus
na 1 s
2
5
2
3
2
4
12
15
3
48
G!yptctond1 pas
1
2
2
5
I
2
9
Tanytarsus
2
t
1
3
7
Chirononus
1
2
4
4
8
22
1
3
1
46
Pol ypad 1 1 u«i
6
2
3
1
>5
2
2
31
Mlcropsoctrs
1
1
Trlbolos 1 1
pupae
3
2
5
3) Coratopoqonidas
Pa I pom la
3
i
2
3
3
1
13
C) CulIcldao
Chaotxsrus
2
1
4
1
1
9
3! Tricoptera
Phylocootreipus
15
7
5
9
5
8
1
2
1
1
54
Oecetis
!
3
2
6
4) Ephemeroptars
Hexagon la
4
7
16
2
5
4
8
46
Caen 1s
5
1
2
51 Hoi 1USCS
Sphaarlum
4
1
1
5
2
1
9
2
25
6J AmpMpoda
¦Gamssargs fssclatus
2
1
3
8
1
I
16
7 > Other
Isopocia 1 I
Hirudlrtaa
6
4
1
2
3
1
2
19
66
-------
Table 6. Summary of the number of taxa and organisms and percent composition of two major taxa from the 1982
St. Louis Bay, Minnesota, benthos survey.
Samp 1 i rig Stations
1A
IB
IC
2A
2B
2C
W1A
Ml B
W1C
M2B
W2C
INT
Total
Number of Taxa
16
13
16
15
16
13
7
10
11
4
5
11
22
Number of Organisms
320
134
125
97
98
163
313
439
405
313
431
78
2916
I 01i^ochaetes
64.7
55-2
36.0
29.9
27.6
44.8
78.3
79.5
59.8
77.0
81.2
52.6
65.9
X 01 i?,och,tfttej + Procladius
82.2
73.1
54.4
48.5
54.1
72.4
91.1
92.5
86.2
99.4
99.1
66.7
84.9
-------
labia 7. Ntrebors of organisms ami percmt compos It ton, by sailing period,
for the 1903 St, Louis Bay, Ml nnssota, benthos survey.
J una
August
Oetetwr
Total
Mo.
i
So.
*
No,
%
No,
1
1) 01tqoehlotos
540
66,4
873
74 ,9
510
5' .5
1923
65.9
2) Clptoro
A) CMrunoraldao
a) Tanvpodlnss
Proc1 ad 1 us
144
17.7
158
13,6
251"
26.9
554
19,0
Coelotanypus
35
4,3
5
0,4
29
3,1
69
2.4
Ablabosmyla
2
0.2
3
0.3
4
0.4
9
0,3
b) CMronomJnao
Cryptoch1ronomus
sty 11fera
5
0,6
a
0.7
9
1.0
22
0.8
Cryptochlronomus
nal s
t7
2,1
30
2*6
t
0,1
48
1.6
Glyptotondlpas
8
1.0
1
0,1
9
0.3
Tanytarsus
2
0,2
3
0.3
2
0,2
7
0,2
Ch 1 rono"im
9
1.1
5
0.4
32
3.4
46
1.6
Pol yped 1 tun
19
2.3
3
C .3
9
t.O
3!
1.1
Mlcropsoctra
1
0.1
1
T
Tr1 Polos
1
0,1
1
T
pupae
5
0.4
5
0.2
8} Corotnpoqon i cjao
PaIpomla
5
0.6
5
0.4
3
0.3
13
0.4
C! CuIiciaaa
Chaoborus
1
o.:
2
0.2
6
0,6
9
0.3
55 Trtcoptora
Phytocantropus
1
0,1
33
2.3
20
2.1
54
1.9
Oocetis
5
0.6
1
0,1
6
0.2
4) fiphortorcptera
HaxagonI a
7
0.9
7
0,6
32
3.4
46
1.6
Caen Is
i
0.1
¦
1
0.1
2
T
5) Pollusca
SphSO>-!u«
8
1 .0
8
0.7
9
1 .0
25
0.9
6> AmpM poOi.
Gamraarus fsselatus
1
0,!
4
0.3
11
1.2
16
0.5
7) Othor
1sopoda
1
0.1
1
T
HI rudlr>a«
2
0,2
11
0.9
6
0.6
19
0,7
Total
013
1165
938
2916
NO,
20
18
t9
22
' HO, • nun^or
68
-------
2
Table 8» Density ! nunhers/T,') of bonthlc macro!nvertobretes col Iect«d during 19BJ
from St. Louis Bay, Minnesota.
1A
19
10
2A
23
2C
WIA
WIG
¦ WIC
W2B
*2 C
INT
1> 01Igochn&tes
989
354
215
139
129
349
1171
1668
1157
1152
16'3
794
2 5 Olptora
A) Chi remoulds©
a J Tanynodinan
d
Procl or) 1 us
263
!! 5
110
86
• 124
715
191
272
51 I
335
368
79
Coolotanypus
53
10
72
38
1?
48
24
<*.3
AMabosmyla
14
14
5
5
b! Chlrorvcvnlnao
Cryu toeh I rono">u s
Sty(!forfl
to
3
29
14
14
5
10
19
Cryptoch1roionus
rial s
to
24
10
14
10
19
57
72
22
GlyototencHpes
5
10
10
5
5'
10
Tanytarsus
10
5
1
14
Ch1 rem omus
5
10
19
19
38
10*.
5
14
5
Po I yeed 11 -im
29
10
14
5
72
10
15
Mlcroosectra
7
Thibolos
c
Pl.OaO
14
10
8>
Csratopoion1daa
Pa loonl n
14
5
10
14
14
5
C)
Cul tel dm
Chaobor 1 rsao
Chaoborus
10
5
5
14
1
7
3! Tr
coptera
Phylocnntrooui
72
33
24
43
24
33
5
10
5
7
Oocotl s
5
14
10
4) Ephfjmerootera
Hexaglnla
19
33
76
10
24
19
62
Coenls
5
5
5) Mollosca
Soha«rlyn
19
5
24
10
5
43
14
6> Amph[poda
Gamnarus fasclatus
10
5
14
3fl
5
5
7) Other
1soaodo
•
5
Hlrudlnao
29
19
5
10
14
5
14
Number of taxa
Density of oroanlEns
16
153!
13
641
16
598
464
15
464
14
""35
8
1512
10
2036
10
1933
4
1497
5
2062
it
5 38
69
-------
Figure 1. Sampling star ions foe the 1982 benthos survey of St. Louis Bay,
MInnetaca.
70
-------
2500
w.
Mi
m
w/.
m
m
m
M,
////.
M
M
yS
#
%
1
VJ//.
Wa
w/
P
'§
W'A
r'^
i
m,
m
m
VA
-------
100
-*4
80
60
c
o
co
o
CL
E
o
o
I 40
o
a>
CL
20
Sa
Vj/A
m
m
fa
Ya
m.
'///
///
' / / ,
M
'///
m
|gl
M
#
w
n
vm
W/
Y/W,
't,
///;
//
:4-
'/A',-
P
-iP
m
W
I
*
M
fj
t
ilpi
If
m
VM
V/.
%
w
///A
w,
'///.
f
I
I
I
m
%
|
IC 2A 2B
2C WIA
Station
WIS WIG W2B W2C INT
¦'//A Chironomidne
//m Oligochaefes
FiBure 3. Percent composition of benthie omcroinvertebrates collected during 1983, St. Louis Bay, Minnesota,
-------
SEASONAL PRIMARY PRODUCTION
AND
PLANKTON DYNAMICS IN THE
ST. LOUIS RIVER AND HARBOR
(Subtasi 3)
prepared by;
Jack R. Hargis
Department of Biology
Lake Superior Basin Studies Center
214 Research Laboratory Building
University of Minnesota, Duluth
Duluth, Minnesota 55812
January, 1983
The University of Minnesota is corrcnitted to the policy that all persons
shall have equal access to its programs, facilities and employment with-
out regard to race, creed, color, sex, national origin or handicap.
73
-------
CONTENTS
List of Figures and Tables
Purpose. .........
Materials and Methods. . .
Results and Discussion
Ph,y top lank ton . . . .
Zooplankton . . . , .
Literat-jre Cited
74
-------
LIST OF FIGURES AND TABLES
EiSa
FIGURE 1, Sample Locations for Uater
Chemistry and Plankton Subtasks , . . .
TABLE 1. Phytoplankton List for Duluth -
Superior Harbtr Study, 1982 ......
TABLE 2a. June Phytoplankton in the
Duluth - Superior Harbor, 1982. , . . .
TABLE 2b. July Phytoplankton in the
Duluth - Superior Harbor, 1982. . . . .
TABLE 2c. August Phytoplankton in the
Duluth - Superior Harbor, 1982
TABLE 3. Chlorophyll a_ Concentrations
from the Duluth - Superior Harbor,
Summer, 1982 (ug/1iter). . . . . . .
TABLE 4. Composite List of Zooplankton
from Six Sites in the Duluth -
Superior Harbor, Sunnier, 1982
TABLE 5. Volumes Filtered in Zooplankton
Collection (liters) at Six Sites
in the Duluth - Superior Harbor during
Summer, 1982
TABLE 6a. June Zooplankton in the Duluth -
Superior Harbor, 1982 (no. per liter) .
TABLE 5b. July Zooplankton in the Duluth -
Superior Harbor, 1932 I no. per 1i terl .
TABLE 6c. August Zooplankton in the Duluth -
Superior Harbor, 1982 (no. per liter) .
75
-------
PUFPOSE
The purpose of this subtask was to document the distribution of plankton
organisms within the Duluth - Superior Harbor, relative to the effluent of
the Western lake Superior Sanitary District (WLSSH). Samples of phyto-
plankton and zooplankton were collected from six sites in the Harbor: two
sites were within the bay where WLSSD effluent is discharged (coded E and
H); two sites were chosen to match these in bays "upstream" and north and
south of the Minnesota Power & Light Company plant (C and B, respectively);
the fifth and sixth sites were located at the Arrowhead Bridge (A) and the
High Bridge (L). These last two sites are located where plankton organisms
would be well-mixed "upstream" (A) and "downstream" (L) relative to conditions
within the WLSSD Bay.
MATERIALS AND METHODS
Samples were collected at two-week intervals at each site, coordinated
with the water quality sampling subtask {Figure 1), Phytoplankton were
taken from the upper meter of water by varlDorn water sampler. Slides wee
made following HcNabb (1950); 15 ml of the Lugol preserved sample were
filtered onto a mi 11 ipore filter using a pressure •• vacuum pump at low
vacuum. The filters were placed on a drop of immersion oil and left to
stand overnight, until clear, A drop of Pennount solution (Fisher Scientific)
was placed on tup of the filter and covered with a cover slip.
Six slides wo re made for each sampling period - one for each of the six
sites. The slides were counted at 400X, using randef. fields, about 50
fields were counted to give a tcf.l of 200 individuals cojsited per slide.
The number of fields varied with the density of organisms on the slides.
Individuals were identified to genus, and to species where possible. A*.
-------
77
-------
the colonies were counted as a single unit. Filaments were counted only if 5 or
more cells appeared in the field of view. Chlorophyll _a concentrations from
each sample were measured by fluorometer {Strickland and Parsons, 1972),
corrected for background fluorescence. All values were read from standard
curves derived from purified chlorophy11 a_ {Sigma Chemica! Company).
Zooplankton were taken by vertical tows at each site with a standard, 80jj tnesh
Wisconsin net. Preservation in 4% formalin plus 60 g/1iter sucrose was used for
tne triplicate samples taken each time. Zooplankton were counted in open
chambers according to the procedures recommended by the International Biological
Programme (Edmondso.) and Winberg, 1971); three hundred organisms, minimum, were
counted at each site, Edmondson {1959) and Pennak (1978) were used for
taxonomi c reference.
RESULTS AND DISCUSSION
The n:j 11jth - Superior Pirbor supports a relatively ricii assemblage of
phytoplo.-ikto.n during sumer. Thirty-three species wtre identified along with
twenty more units identified to genus (Tjble 1). Only twelve species (units)
were found in large enough numbers to be considered comrton. There were not
anomalies in distribution or densities of these common species between control
sites and sites near the outflor of WLSSD (Table 2a~c), except an increase in
the density of Cryptomonas erosa in the proximity of the effluent is indicated.
Diatoms tended to decline as the summer progressed and waters warmed
(Stephanodiscus, Synedra) , as is common (Fogg, 1975'). Green algae fluorished in
the warmer waters and. surprisingly, very few blue-green algae appeared. The
low light intensities in the brown harbor waters may favor the growth of greens
over blue-greens, barring any organic pollution or nitrogen limitation (Wetzel,
1975).
78
-------
Table 1. Phytoplankton List for Duluth-Superior Harbor Study, 1982,
Bacillariophyceae {diatoms)
Achnanthes lanceolata var. rostrada
*
Asterfonella formesa *
Cocconeis spp.*
Coseinodiscus spp.
Cycloiella Meneghiniana*
Cymbella spp.
Oiatoma himenale
Difltoma spp.
Eunotia pectiralis
Fragilaria capucina
Fragilaria crotonensis
Fragilaria spp.
Gomphonema spp.
Melosira distans*
Helosira granulata*
Melosira varians
Melosira spp.*
rteridiori circulare
Navicula cuspidata
Navicula exitjua
Navicula gastrum
Navicula hungarics
Navicula pt>pula
Navicula radiosa
Navicula viridula
Navicula spp.*
Hi tzschia pa lea
Nitzschia tryblionella
Hitzschia spp.
Pinnularla spp.
Rhoicosphenia curvata
Stauroneis crucicula
Stephanodiscus spp.*
Synedra actinastroides
Synedra ulna*
79
Synedra spp.*
Tabellaris fenestrata
unidentified diatoms
Chlorophyta (green algae)
Actinastrum spp.
Ankistrodesmus
Cosmarium
Crucigenia quadrata
Elaktcthrix viridis
Kirchneriella lunar is
Pandorina morum
Pediastrum duplex
Scenedesmus spp.*
unidentified unicells
unidentified colonies
unidentified filaments
Cyanophyta (blue-green algae)
Anabaersa spp.
Anacystis spp.
Aphanocapsa spp.
Euglencphyta
Euglena spp,
Phacus longicauda
Pyrrophyta
Ceratiura hirudinella
Cryptoaonadales
Cryptcmonas erosa"
* Cc..Tion species throughout study.
-------
Table 2a. June Phytoplankton in the Ouluth-Superior Harbor, 1382.
Si tes
Species
A
8
C
E
H
I
*
Asterionella formosa
• 467*
733
800
600
1067
933
Cocconeis spp.
200
133
133
200
133
67
Cyclotella roeneghiniana
1267
733
600
400
400
400
Melosira distans
1533
933
1867
2400
1867
2000
Melosira g<-anu1ata
3467
3933
4600
3267
4000
4200
Melosira spp.
0
200
867
0
800
133
Navicula spp.
400
600
600
267
400
267
Stephanodiscus spp.
1533
533
1400
533
667
267
Synedra ulna
333 '
67
200
200
67
133
Synedra spp.
133
0
600
333
467
333
Scenedesmus spp.
67
67
67
200
67
200
Cryptomonas erosa
2133
2267
3467
2933
2333
2667
~Density, number per liter
80
-------
Table 2b. July Phyto plank tort in the Duluth-Superior Harbor. 1982,
Sites
Species A 0 C E H L
«
Asterionella formosa
133*
67
133
0
333
133
Cocconeis spp.
46?
467
267
200
267
2f>0
Cyclotella meneghiniana
306?
933
1867
933
2733
2133
Helosira distans
306?
1600
1600
267
. 3267
3733
Helosira granulata
867
1667
1267
1067
1733
2131
Helosira spp.
0
67
0
0
0
0
Navicula spp.
400
600
. 800
133
333
200
Stephanodiscus spp.
67
600
600
67
1 33
267
Synedra ylna
333
400
467
200
200
200
Synedra spp.
400
400
600
267
200
67
Scenedesmus spp.
133
200
133
0
267
0
Cryptomonas erosa
1067
4533
4203
88 '0
1067
2133
'Density, number per liter
i
81
-------
Table 2c August Phytoplankton In the Duluth-Superior Harbor, 1982,
Sites
Species
A
B
C
E
H
t
Asterionella forrnosa
67*
133
67
67
67
200
Coccor.jis spp.
6?
67
0
0
67
0
Cyclotella meneghiniana
733
200
133
67
257
600
Melosira distans
600
*1000
1067
1000
1133
1733
Melosira granulata
2867
2667
2067
2000
2867
4200
Melosira spp.
67
333
333
133
467
O
o
Navicula spp.
33*
333
133
67
533
267
3tephanodiscus spp.
133
67
0
0
0
67
Synei'ra ulna
0
0
0
0
0
0
Synedra spp.
0
67
67
0
67
133
Scenedesmus spp.
133
67
200
133
200
67
Cryptomonas erosa
3067
6600
8533
10,400
5133
1733
~Density, number per liter.
82
-------
Table 3. Chlorophyll a Concentrations from the Duluth-Superior Harbor,
Sumraer, 1982 {ug/liter).
June 17 July 22 August 18
Site* '
A 0,90 3.50 0.70
B 1.10 5.00 0.75
C 1.20 4.00 0,70
E 0.90 4.00 1.10
H 0,75 0.20 1.00
L 0.85 3.00 0.60
~Reference Figure 1.
83
-------
Concentrations of Chlorophyll a_ measured from each site are preserved by
date in Table 3. The usual pattern for north temperate waters is seen in the
harbor, as well: Chlorophyll values climb into July and drop quickly as solar
radiation and water temperatures diminish. We conclude once more that all sites
demonstrate the same essential pattern (p .05, two-way ANflVA) as we did from the
species list information (Sokal and Rohif, 1969). The one interesting
departure, site "H" on July 22, shows a value one order of magnii-iine lower than
its companions. This site 1s the offshore site in the WL5SD Bay. All standards
arid procedures were double-checked for this sample - the valw is correctly
reported. This probably indicates the sort of variability that can be expected
when sampling near the dredged channels, the deeper waters of which contain less
chlorophyll than the uppermost layers. Light attenuation, rapidly In the
uppermost layers, must be an extremely important factor influencing
phytoplanktor life in the Harbor.
The zooplankton of the harbor, judging from these six sites, become
dominated oy Bcsmina coregoni {some specimens bear features of longircstns)
as summer progresses. Table 4 displays the thirteen taxonomic categories into
which zooplankton were enumerated. Table 5 illustrates the volumes of Harbor
water filtered per sample at each site during the summer. Triplicate samples
were taken each time. At times, Bosmina so dominated the community that they
appeared to "swarm". Thi s became more prominent later ir. mid-summer as the more
cool-water species like Daphnia galeata and the Diaptorr.us spp. declined. From
Table 6a, o, and c, the clear dominance of just a few species within the
cunmu" «.y can be seen. The pattern persisted tx each of the v'tes sampled.
Further, the same species were domir.art at al 1 six sites at one particular time
tho ,:h the magnitude of this dominance varied. Only eight species figured
importantly ir. the xooDlanktor, corrmunity structure, however, eleven tax; plus a
-------
Table 4. Composite List of Zooplankton from Six Sites in the
Duluth-Superior Harbor, Summer, 1982,
Category 1 - Cladocera
Daphnia galeata
Bosmina coreqoni
Diaphanosoma leuctenLergiarium
leptodora kindtii
Ceriodaphnia megalops
Alona guttata
Category 2 - Copepoda
Diaptomus spp.
Mesocyclops "leucfcarti
Paracyclops fimbriatus
Halieyclops spp.
Orthocyclops modestus
Category 3
Immature copepods (rtauplii & copepodi tes)
Harpact icofda
65
-------
Table 5.
Volumes Filtered In Zocplankten Collection
at Six Sites in the Duluth-Superior Harbor during
Summer, 1982
A B C E H L
June 73.6 24,5 61.4 30.7 24.5 73.6
July 73.6 24.5 15.3 24.5 36.8 73.6
August 73.6 24.5 30.7 36.8 36.8 85.9
86
-------
category of immature copepods (nauplii and eopepodites) were enumerated along
with an occasional errant Harpacticoid copepod-up from the sediments.
The June data (Table 6a) illustrate an interesting phenomenon around
station E, the WLSSD effluent. The production of immature copepods is aheao
here relative to the rest of our sites. I suspect the warmth of the effluent to
be the principal cause. The numbers of immatures are elevated 10 - 15X over
those in the two comparison bays in June. This relationship is still somewhat
apparent in July, but disappears by August. This could be an indirect effect -
the warmth causing accelerated algal growth, algae used as food by the
copepods,
In July (Table 6b) the overall community was quite reduced, but densities
were highest iri the WLSSD Bay. Hal icyclops spp. which pervade the bay were most
abundant at station E, near WLSSD. This genus is known for its tolerance to
brackish-salty conditions (Edmondson, 1959).
87
-------
Table 5a. June looplankton in the Duluth-Superior Harbor,
1932 (no. per liter).
*
Si tes
Zooplankton
A
B
c
E
H
t
Daphnia galeata
6.94
8.41
9.66
3.88
9.59
9.43
Bosmina coregoni
31.89
29.02
49.44
77.04
40.61
178.56
Diaphanoscrrd Icucten bergianum
.34
1.1S
2.10
1.56
.37
3.40
leptodora kindif
.10
.65
.28
.00
.00
.00
Ceriooaphnia megalops
.00
.00
.00
.00
.00
.00
Alcna guttata
.00
.00
.00
.00
.00
.00
Diaptoraus spp.
3.95
2.29
.44
3.68
1.88
1.89
Mesocyclops leuckarti
.42
.24
.73
20.03
10.16
2.27
Paracyclops fimbriatus
.93
.53
1.14
.33
1.31
2.27
Halicyclops spp.
1. S3
2.86
3.93
10.07
.65
4.52
Orthocyclops modestus
.00
.00
.00
.00
.00
.00
Immature copepods
7.82
18.24
24.54
211.50
6.78
71.30
Harpacticoida
.00
.00
.00
.00
.00
.00
88
-------
Table 8b. July Zooplankton in the Duluth-Superior Harbor, 1S82
(no. per liter).'
Sites
Zooplankton
A
8
c
E
H
L
Oaphm'a galeata
.26
.53
78
1.14 .
.24
.61
Bosmina coregoni
.91
2.00
6
60
17,39
2.26
2.02
Diaphanosoma leucten bergianum
.23
.33
92
1.47
.11
.07
Leptodora kindtlf
.00
.00
00
.00
.00
.00
Ceriodaphnia megalops
.04
.04
00
.00
.00
.00
Alona guttata
.01
.04
07
.00
.03
.00
Diaptomus spp.
.15
.37
26
1.35
.38
.57
Me'f cyclops leuckarti
,03
.08
72
.61
.16
.20
Paracyclops fimbriatus
.12
.37
39
2.08
.22
.39
Hallcyclops spp.
.92
5.76
2
35
11.43
.73
1.20
Orthocyclops modestus
.00
.00
00
.00
.05
.10
Immature copepods
5.39
9.63
n
05
54.82
4.65
8.14
Harpacti coi da
.03
.00
00
.00
.00
.01
89
-------
Table 6c. August Zooplankton in the Dulyth-Superior Harbor, 1982
(no. per liter).
Sites
Zooplankton •
A
B
C
E
H
L
Oaphnia galerta
19.35
24.24
13.75
6.36
7.42
3.02
Bosmina coregoni
9.10
29.63
19.71
.7,5.79
17.17
6.29
Diaphanoscma lexteri bergianum
9.46
8.20
5.67
3.34
3,09
Leptodora kindtii
.08
.00
.00
.00
.00
.00
Ceriodaphnia megalaps
.30
1.02
.72
.19
.19
.08
Alona guttata
.00
.00
.00
.00
.00
.00
Oiaptomus spp.
4.16
3.84
4.36
8.07
5.16
4.37
Kesocyclops leuckarti
1.44
4.82
2.61
6.85
3.45
1.70
Paracyclcps fimbriatus
3.70
9.39
4.07
6.85
3.23
1.65
Hali cyclops spp.
3.10
9.47
3.84
7.23
4.27
1.65
Orthocyclops modestus
.00
.00
.00
.00
.00
.00
Immature copepods
18.70
37.39
17.10
25.73
18.67
10,96
Harpacticoida
.00
.00
.00
.00
.00
.00
90
-------
August (Table 6c) shows.J higher densities overall for the zooplankton
in the Harbor. Relatively large gains were made by Oiaphanosoma and Cerio-
daphnia. which made its first appearance in our samples from four of the six
sites. Their densities weye greatest in the open water stations and ttie
control bays (sites A, L and B-. C). The population increases of these spec-
ies probably paralleled the development of adequate bacteria, phytoplankton
or periphyton food supplies.
The Duluth-$uperior Harbor is a complex system for pelagic sampling. Hot
only is the bathymetry complex, with the extensive shallows plus the deep,
dredged ship channels, but the interactive flows of the St. Louis River and
seiche currents from Lake Superior make point samples a function of many
variables. In the shallows, particularly,the range of seasonal change can be
extreme. Within this context, examination of the piankton data from Summer
1982 shows no adverse influence of the effluent from the Western Lake Superior
Sanitary District.
91
-------
Literature Cited
Edmondson, W.T. (ed.). 13S3. Fresh-Water Siclogy, Zr,d Ed. Wi Icy SSons,
New York.
Edmondson, W.T. and G.G. Winberg. 1971. ft manual on methods for the assess-
ment of secondary productivity in freshwaters. ISP Handbook No.¦» 1 7.
BUckwell, Oxford.
Fogg, G.E. 1975. Algal cultures and phytoplankton ecology, 2nd ed. Univer-
sity Wisconsin Press, Madison.
McHafab, C.D. 1980. Enumeration of freshwater phytoplankton concentrated
on the membrane filter. Limnol. Oceanogr. 5:57-61.
Pennak, R.W. 1978. Fresh-Water Invertebrates of the United States, 2nd Ed.
Wiley & Sons, New York.
Sokal, R.R. and F.J. Rohlf. 1969. Biometry, Freeman, San Francisco.
Strickland, J.D.H. and T.R. Parsons. 1972. A practical handbook of seawater
analysis. Bull. 167. Fish. Res. Board Canada.
Wet?el, R.G. 1975. Li mnology. Saunders Company, Philadelphia.
92
-------
Summary
Ventilatory Response of Bluegill Sunfish Exposed to Final Treated
ULSSU Effluent
by
Robert A, Drutanond, Research Aquatic Biologist
U.S. Environmental Protection Agency
Environmental Research Laboratory-Duluth
6201 Congdon Boulevard
Ouluth, Minnesota 55804
December 1982
93
-------
The ventilatory activities (cough and opercular rates) of two bluegllls
exposed to 100% final-Created effluent (continuous flow-through) were
monitored over an extended period of time. A synopsis of this monitoring
effort follows.
TWo fish were installed on August 18, 1982, and allowed to recover from
the effects of transfer for 24-hours. Starting August 19, the fish were
monitored continuously for the next 96-hours and all respiratory data was
recorded on strip-chart records. At least one major period of stress was
noted to occur; at other times the fish appeared normal, i.e., similar to
several hundred controls observed at ERL-D in Lake Superior water.
After 96-hours, fish were monitored nearly every day for the next month.
New fish were installed on August 27 and on September 10, 1982. During this
period, treatment plant operators would turn the strip-chart monitor on for
time slots ranging from 2 to 12 hours per day. Occasionally the fish were
monitored even longer.
Respiratory data were plotted at half-hour intervals on the basis of
relative change from the expected normal. Three categories were designated:
some stress evident, moderate stress, and highly stressed. It was apparent
from these data plots that the effluent was not of consistent quality from
hour-to-hour or day-to-day. At least one period of high stress was
correlated to the presence of residual chlorine. Another period of stress
appeared to be correlated with changes in influent quality as a result of
industrial housekeeping activities. University of Wisconsin personnel
conducting on-site exposures observed mortalities among fathead minnows
during this same period (circa September 1-7). Other peak periods of
response were of unknown cause.
94
-------
All original data plots were turned over to Mr. Quale Long at WLSSD fo
study and comparison of these events with treatment plant operations.
-------
SITE-SPECIFIC ACUTE AND CHRONIC AQUATIC TOXICITY
TESTING-WESTERN LAKE SUPERIOR SANITARY
DISTRICT TREATMENT PLANT EFFLUENT STUDIES
By
Daniel J- Call, Larry T, Brooke,
Carol Northcott, and Dean E. Hammermeister
Center for Lake Superior Environmental Studies
University of Wisconsin-Superior
November 1982
U.S. EPA Cooperative Agreement No. CR80923402
96
-------
SITE-SPECIFIC ACUTE AND CHRONIC AQUATIC TOXICITY
TESTING—WESTERN LAKE SUPERIOR SANITARY
DISTRICT TREATMENT PLANT EFFLUENT STUDIES
INTRODUCTION
A need exists for the characterization of natural waters regarding their
capacities for reducing the toxic effects of discharged wastes to aquatic organisms,
An understanding of effects of naturally occurring ligands in reducing toxicities
of various wastes would facilitate the issuance of variances for discharge permit
limits upon an environmentally sound site-specific basis.
A study was conducted by the University of Wisconsin-Superior, Superior, WI,
to determine the toxicity to aquatic organisms of effluent from the Western Lake
Superior Sanitary District (WLSSD) treatment facility in Ouluth, MN. Exposures
were conducted on site and at the University of Wisconsin-Superior campus with
organisms native to the area and thought to have a high level of sensitivity to
potentially toxic effluent. Water from the St. Louis River upstream from the
WLSSD discharge point and University of Wisconsin laboratory water were used as
the control water.
Bioassays were conducted using static and flowing conditions with grab and
composited samples of two processed waters within the WLSSD treatment plant and
seven species of aquatic organisms. Water samples were collected at various
times throughout the summer of 1982,
97
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METHODS
Test Mater Descriptjcm
MLSSD treatment plant processed waters and St. Louis River water were
employed as test waters. WLSSD water was examined for suspected toxicity while
the river water was used as a 'clean' water control for comparison.
Two types of WLSSD treatment plant processed waters were tested - filtered
and final effluent. Filtered effluent was water which had been fully treated
except for chlorir.ation. This water was called filtered effluent because it is
filtered immediately prior to chlorination. Final effluent was filtered effluent
that had been chlorinated and subsequently dechlorinated before discharge to the
harbor. Filtered effluent was not released to the harbor during this study with-
out chlorination and dechlorination,
St. Louis River water was collected by submerging 5 gal polypropylene car-
boys at a site located at the end of the City of Superior, WI boat landing pier
on the downstream side of the Arrowhead bridge.
Hater Chemistry Determinations
Measurements of pH {Method 424), total alkalinity (Method 403), total
hardness (Method 309 B) and dissolved oxygen (Method 422 B) were made on exposure
water samples according to Standard Methods for the Examination of Water and
Wastewater (APHA, 1 575). Water analysis was performed once either at the start
or during the exposure period for static bioassays. For the flow-through tests,
samples for pH, alkalinity, and hardness were taken every day while dissolved
oxygen was measured at least every other day. Alkalinity and pH determinations
were completed on the same day they were taken or stored at 3 C overnight before
the measurements were made. Samples from the WLSSD treatment plant for hardness
determination required fivefold dilution prior to analysis. Without dilution,
98
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the hardness endpoint was not clear. Chlorine content and pH of the tested
effluents at the time of discharge are available from WLSSD records and not
reported in this report.
Results of final effluent exposure water chemistry measurements made during
the rtudy period were quite variable. The geometric mean pH was 7.76 and ranged
from 6.7 to 8.6. The mean total alkalinity was 214 mg.L"^ as CaCO^ with a range
-1 -1
from 147 to 362 mg-L . The mean value for total hardness was 210 mg-L as
CaCOj, ranging from 121 to 252 mg-L-1. The mean and standard deviation of
dissolved oxygen concentrations were 6.8 t 1.0 mg-L'^ (n=118).
Results of filtered effluent exposure water chemistry determinations were
also highly variable. The geometric mean pH was 7.95 with a range of 6.5 to
8.6 The mean total alkalinity was 193 mg-L""' as CaC03, ranging from 142 to
-1 -1
278 mg-L , Mean total hardness was 235 mg-L as CaCO^ and ranged from 208
to 267 mg-L"^. The mean and standard deviation of dissolved oxygen concentra-
tions were 6.8 ± 0.9 mg.L""' (n=88).
Organisms
Test organisms used during the series of exposures included Daphnia magna,
(water flea), Gaimiarus pseudolimnaeus, Hyalella azteca (amphipods), Pimephales
prone!as (fathead minnow). Piplectrona sp. (caddis fly), Hexagenia sp. and
Stenonema sp. (mayflies). D. magna were cultured at the University of Wisconsin-
Superior with 30 mg of yeast and trout chow (4:1 wt:wt) per 1 iter of water. 6.
pseudolimnaeus were collected from the Eau Claire River upstream of the city
of Gordon, WI on 17 March, 1982. On the same date, H. azteca were collected
from the St. Croix River immediately below the St. Croix Flowage dam near
Gordon, HI. The amphipods were held at 15 C and fed ground, dried, maple leaves
prior to exposure. Fathead minnows were reared in the University of Wisconsin-
-------
Superior culture facilities and fed 48 hr old Arteroia sp, (brine shrimp} until
testing. Diptectrona sp., Hexagenia sp. and Stenoncma sp. wore all collected
on 9 A'jyubL 1982 from Mission Creek at fond "du Lac, MN, the Brule River at the
Wisconsin Ranger Station, Brule, WI and from Interfalls Lake at Pattison Park,
WI, respectively.
During all tests observation for mortalities were made at least once daily.
Static Bioassays
Static tests were conducted on grab samples and on one day arid seven day
composite samples of WLSSD effluent collected at different times throughout tne
summer. The tests were run at the University at room temperature which ranged
from 21-23 C for the exposures.
The 14 June, 1982, effluent was screened for toxicity with five 30 day-old
£.* promelas, six G. pseudolimnaeus and eleven H. azteca. They we all tested
in 1 L beakers containing 900 ml of the grab sample. In addition, five young
P_. promelas and five D_. magna were tested in 250 mL beakers containing 200 ml
of grab sample.
Static exposures performed from 23 June through 2 August, 1982 used grab
and one or seven day composite samples of WLSSD effluent. Quadruplicate ex-
posures of five P_. promelas and five 0. magna in 200 ml of 100% effluent were
made in 250 mL beakers. For each exposure, quadruplicate control exposures were
performed using laboratory water from the University of Wisconsin-Superior.
Grab samplis of WLSSD effluent taken on 8, 9, and 10 September, 1982, were
used to expose !P. promelas. The samples were diluted with St. Louis River water
to provide 0, 25., 50, 75, and 100 percent solutions in duplicate. Ten fish total
were exposed lu each concentration.
100
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Flow-Through System Description,
A continuous flow system was designed to expose various types of organisms
to the WLSSLi treatment plant final effluent and to St. Louis River water.
Temperature control and aeration were provided to the test waters. Organisms
were exposed to 100% final effluent and 100% St. Louis River water. An
identical exposure apparatus was used for each water type. The apparatus con-
sisted of an exposure tank within a larger tank {water bath). Two types of
exposure tanks were employed throughout the three month test period: a large tank
into which two small compartmental inserts were placed and a sinaller exposure tank
with no compartments. Each exposure tank was equipped with a stand pipe and drain
tube. Metering pumps delivered test waters to the exposure tanks via stainless
steel tubing. The point of inflow was always opposite the tank stand pipe. The
WLSSD final effluent diverted to a sampling box was the source of treatment pi ant
test water. St. Louis River water that was collected periodically was pumped
from a 56 L polypropylene reservoir into the other exposure tank. To facilitate
temperature control, a flow-splitting tank distributed cold tap water equally to
each of the two water bath tanks. Adequate oxygenation was supplied by a dual
outlet air pump. An air stone was placed in each exposure tank in the area of
test water inflow.
Flow-Through Bioassays
The first flow-through exposures were conducted with Diplectrona sp.,
Hexagenia sp., P_. promelas, and Stenonema sp. Five each of Dip!ectrona sp.
and Hexagenia sp., and ten each of P_. promelas and Stenonema sp., were exposed
in duplicate. To separate the organisms and expose them in dupl icate, two 3
compartment inserts and two stainless steel mesh cages were used within a large
exposure tank that measured 34.5 x 20.5 x 10.5 cm. The inserts measured
101
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15,0 x 15,4 x 13.8 cm and had two ends covered with 505 ?.m Nytex®mesh to
allow water exchange. The cages weri 9.4 cm long by 4.0 cm in diameter and
closed with a neoprene stopper. Ten Stenoncma sp. were loaded in each of the
cages and positioned in the center of insert compartments. The other organisms
were exposed separately in insert compartments. The tank volume exchange rate
_1
with final effluent was 5.8 volumes-day"'.
In the second flow-through exposure, twenty fathead minnows were placed
into a tank 9.8 x 23 x 11.8 en containing 2.65 I of water, flow was increased
-1
to provide 20 tank volume exchanges-day .
In both exposures a duplicate system was operating using St. Louis River
water, collected daily, as a reference. All chambers were covered with a glass
plate to prevent contamination and evaporation.
RESULTS
Bioassays of WLSSD effluents {prior to chlorination and immediately after
dechlorination) were conducted with waters sampled "14 June through 10 September
1982. Both static and flow-through assays were conducted, with the static tests
performed at the UW-Superior testing facility and the flow-through testing done
at the WLSSD treatment facility.
Static Bioassays
Twenty-three tests were run with WLSSD effluent and St. Louis River
reference water. Four species of aquatic organisms (P. promelas, G. pseudo-
1imnaeus, H. azteca, and D. magna) were included in the tests. Water samples
were collected on thirteen occasions from three sites (St. Louis River, WLSSD
effluent after final filtering prior to chlorination, and final processed water
after chlorination and dechlorination). Some deaths occurred in St, Louis River
102
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reference water in 26,1% of the tests. Similar numbers of deaths in reference
and processed waters precluded the use of bioassay data with Oaphnia for the
composited water samples collected on July 12 and 19 and with P_. promelas for
water samples collected on July 13 and September 9. Filtered effluent from
WLSSD hatj increased toxicity when compared to St, Louis River water in 46,21 of
the remaining tests (Table 1) and the final WLSSD effluent showed increased
toxicity when compared to St. Louis River water in 38.9% of the remaining tests.
However, mortalities of 5-10% represented the deaths of only 1-2 organisms.
The greatest differences in mortalities of organisms in reference and
processed waters were with P. promelas and grab samples of the final effluent
collected on 29 July, 8 September, 3'»d 10 September, On these three dates
{23.1% of sampling dates), mortalities ranged from 33 to 100% in the undiluted
final effluent. A portion of the samples collected on 29 July and 10 September
were held seven days with aeration and retested with P. promelas. Toxicity was
reduced from the initial tests. Mortalities decreased from 40 to 5S for the
29 July grab sample and from 100 to 02 for the 10 September grab sample (Table 1).
Toxicity of the 10 September final effluent was estimated by diluting
the effluent with St. Louis River water and exposing P. promelas for 96 hr.
The dilutions v;ere 25, 50, and 75% of the processed water. A Spearman-Karber
(trimmed) estimate was made of the median lethal concentration (LC^g) for this
water sample (Hamilton, et a]_. 1977). The 96 hr LC^Q was 55.4% of pure processed
water.
Flow-Through Sioassays
Initially, four species of aquatic organisms (P. promelas, tiexagcnia sp.,
Stensncma sp., and Diplectrona sp.) were exposed to St. Louis River water and
WLSSD final effluent for 96 hr starting on August 16. The St. Louis River
103
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TABLE 1. Effects upon Survival of Several Species of Aquatic Organisms Exposed
to St. Louis River Water (Reference) and Two Processed Waters of the
Western Lake Superior Sanitary District (WLSSD) for 96 hr. Processed
Waters were Sampled at the Stated Times by Instantaneous Grabs or by
Compositing with a pump for 1 or 7 Days. Reference Waters were all
Grab Samples. Exposure Water Temperatures were 21-23 C,
Processed Water Collection _ Percent Mortality ,
Date "Time type " Exposed Species Age Re ferine e FiTterlT" Final —
6/14
1430
Grab
Pimephales promelas
3 day
0
0
0
30 day
0
. 0
0
Garrmarus
pseudolimnaeus
adult
0
0
0
Hyalella azteca
adult
0
9.1
0
Daphnia magna
adult
0
0
0
6/23
1455
Grab
Pimephales promelas
9 day
0
10
0
Daphnia magna
adult
0
20
5
6/29
0838
Grab
Pimephales promelas
3 day
0
10
0
6/30 ¦
1115
Grab
Pimephales promelas
5 day
0
8.3
9.8
7/12
7-day
Pimephales promelas
9 day
0
0
N.T.
Composite
Daphnia magna
adult
11.8
5.0
N.T.
7/13
1 day
Pimephales promelas
10 day
5
4.8
5
Composite
7/19
1 day
Pimephales promelas
11 day
0
0
0
Composite
Daphnia magna
adult
11.8
20
10
7/19
7 day
Daphnia magna^
adult
0
5
0
Composite
7/29
1430
Grab
Pimephales promelas
5 day
10
N.T.
40
7/29^
1430
Grab
Pimephales promelas-'13 day
0
N.T.
5
Grab-^
Pimephales promelas
13 day
0
N.T.
5
8/2
a.m.
a /
Pimephales promelas—
5 day
0
0
5
9/8
p.m.
Grab
Pimephales promelas^
0-5 day
10
N.T.
33
9/9
a.m.
Grab
Pimephales promelas^
1-6 day
10
N.T.
9.1
9/10
a .m.
Grab
Pimephales promelas^/
2-7 day
0
N.T.
100
9/10—7
a.m.
Grab
Pimephales promelas^
3-13 day
0
N.T.
0
a7 Fiiter~ls processed water immediately prior to chlorination. final is the chlorinated
— and dechlorinoted processed water as it leaves the treatment facility. Filter water
was aerated during testing, final water was aerated only at stated times
(see footnotes e & g).
b/ N.T. = not tested,
c/ 48 h exposure.
3/ Water collected on 7/29 was held and retested on 8/6.
e/ Continuous aeration during exposure to final processed water.
fj Water collected on 8/2 was aerated and held for testing until 8/7.
g/ Daily 15 minute aeration during exposure.
fiy Water collected on 9/10 held at room temperature and retested on 9/17,
104
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reference water consisted of daily grab samples collected upstream at the
Arrowhead bridge and WI.SSO final effluent pumped continuously from
the treatment plant discharge line. No significant (p<0.05) differences were
observed in mortalities between the two tested waters. However, high mortalities
in the controls occurred with the exception of the Stenonema bipassay, where no
control organisms died. Ten percent mortality occurred in the final effluent
test water with Stenonema.
An extended acute flow-through exposure of P_. promelas to WLSSD final effluent
was then conducted between 1 September and 8 September. The test was designed
to proceed for 30 days to observe fish for possible growth differences. However,
at 192 fir the test was terminated due to mortality of all organisms in the final
effluent test water (Table 2), The reference or control water was St. Louis
River water in which 95% of the fish survived the 192 hr exposure.
TABLE 2. On-Site Flow-Through Extended Acute Bioassay of Western
Lake Superior Sanitary District (WLSSD) .
Final Process Water with Pimephales promelas-
Percent Mortality
St. Louis Final
Date Duration River Effl uent
9/1 24 h 0 0
9/2 48 h 0 0
9/3-6 72-144 h 5 <20-/
¦ 9/7 168 h 5 <50—^
9/8 192 h 5 100
a/ Fathead minnows were 15 days old at the start of the extended acute
exposure.
b/ Effluent was highly colored and percentages are approximations based
on observations of netted fish err 9/7 and 9/8.
105
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DISCUSSION
The processed water discharged from the WLSSD treatment facility is not
continuously toxic to aquatic organisms on an scute basis. However, significant
toxicity does periodically occur. In 23.1% of the samples collected from 14
June to 10 September, 1982, mortalities to fathead minnows in the undiluted
final effluent ranged from 33 to 100%.
The grab sample of final effluent collected on 10 September resulted in
100% mortality. When this effluent was diluted with St. Louis River water, the
resultant LCgQ to fathead minnows was 55.4% of the pure processed water. From
this it would appear that the mixture of WLSSD final effluent and harbor water
would be acutely toxic at times to organisms in the immediate vicinity of the
diffuser pipes where the effluent is discharged. Dependent upon the total volume
of St. Louis River water for dilution of the WLSSD effluent, toxicity would be
diminished as distance from the diffuser pipes increased. The dilution factor
can be determined from other studies.
The observation that acute toxicity of the final processed water from WLSSD
was greatly reduced upon holding with aeration for a period of seven days in-
dicated that the chemical agents responsible for the toxic effects were volatile
or chemically unstable in the water. One possible cause for the observed periodic
toxicity that was examined was the concentration of total residual chlorine in
the final effluent. Records of the chlorine feed rate and chlorine concentrations
in the mixer and final effluent were obtained from WLSSD (Figure 1). Elevated
concentrations of chlorine in the final effluent were recorded on 6 September
and 9-10 September. Grab samples of final effluent collected on 8 and 10 September
resulted in 33 and 100% mortality, respectively, to fathead minnows in static
bioassay. The 96 hr LC^g for total residual chlorine with fathead minnows was
106
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SEPTEMBER, 1982
Figure I. Chlorine feed rate (lbs-day 1) and concentrations of chlorine in the mixer and
final effluent (mg-L-1) at the WLSSD wastewater treatment facility from September 1
to September 10, 1982.
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reported as 130 and 86 pg-L""' in two separate tests (Arthur et al_., 1975},
The 24 hr ICgg for fathead, minnows was 145 and 140 ug-L"^ as determined by the
same authors.
On 6 September, the final effluent chlorine concentration reached a recorded
-1
high value of 180 pg-l and on 9-10 September the concentration for the three
recorded spikes ranged from 270 to 450 pg-L-'', The toxicity of the final effluent
grab sample collected on 10 September may have been caused by elevated concentra-
tions of chlorine on that date. However, possible causes for the mortalities in
the static bioassays conducted with grab samples collected on 29 July and 8
September are not known.
In the extended acute flow-through exposure with young fathead minnows that
started on 1 September, mortalities began occurring between 3 and 6 September,
with complete mortality occurring by 3 September. These mortalities may have
resulted from the elevated chlorine concentration on 6 September.
WLSSD personnel indicated that excess carbon dioxide (CO.,) may occasionally
be present in sufficient concentrations to cause mortality of fathead minnows.
Evidence of high CO^ content of the final effluent does exist, although no COg
measurements were made in this study.
The pH of seme grab samples increased with time. Samples taken on 8, 9 and
10 September 1982 had an initial pH of 6.95, 6.81 and 6.61, respectively (WLSSD
records). They exhibited a gradual increase of pH to 8.12, 8.55 and 8.45,
respectively, when held 1 day for bioassay testing. Five water samples taken
during the period, 1 September to 5 September 1982, had a mean pH of 7.13 and
ranged from 7.05 to 7.21 when measured within 6 hr after sampling. They exhibited
an increase of 0.45 to 0.60 pH units according to plant records of pH for final
effluent discharged during this period. It is not known whether these five
108
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samples would have increased to a pH greater than 8,1 as did samples taken
during the later sampling period.
During the second flew-through bioassay the total alkalinity of bioassay
water was frequently much greater than hardness. For final effluent grab samples
taken on 8, 9, and 10 September and analyzed at the end of acute bioassay
exposures, the total alkalinity was 317, 362 and 236 mg-L"1 as CaCOg, respectively,
_i
Corresponding hardness values were 152, 141, and 121 mg-L as CaCO^, respectively.
The differences between alkalinity and hardness are greater than that of samples
taken earlier in the study. Alkalinity and hardness values for the time period
1 September to 5 September 1982 had a mean of 218 and 174, respectively, with a
range of values from 210 to 235 and 185 to 187, respectively. The interaction
of high pH influent from the Potlatch Corporation with other influent and process
waters already within the plant may result in a temporary buffering of the final
effluent.
Discharge water from the Potlatch Corporation passes through the Cloquet
pumping station and travels to the WLSSD treatment plant where it mixes with
other plant influent waters. Highly alkaline discharge water from the Potlatch
Corporation reached the Cloquet station approximately at 9:00 a.m., 6 September
and continued until termination of our testing on 10 September, 1982. The mean
and range of pH values for Cloquet station effluent was 10.36, and 8.77 to 11.32,
respectively. Approximately 21 hrs later, the beginning of the alkaline water
arrived at the treatment plant influent point, as indicated by a pH increase
from 7.48 to 8.14 in 1 hr. For the period 6 September to 9 September, 1982,
final effluent mean pH was 6.82 and the range of pK was 6.45 to 7.17, In com-
parison, final effluent mean pH was 6.59 and ranged from 6.45 to 6.81 during the
period 1 September to 5 September, 19S2. Alkaline influent was not present then.
1G9
-------
Carbon dioxide is readily dissolved into an alkaline solution and the con-
centration of HCO"3 and COg" are a 11 owed to increase, subsequently increasing
carbonate alkalinity. This is the condition that existed in the Potlatch
effluent from 6 to 10 September, Apparently, in-plarit precipitation, complexation,
and dilution by other influents are sufficient to maintain a final effluent pH
near neutrality with elevated alkalinity during the time highly alkaline Potlatch
effluent is present.
During the secondary treatment process microbial respiration produces some
COg but an excess of free C02 may already have been present in the influent.
This would tend to preserve the high alkalinity of alkaline influent; that is,
it would allow relatively large amounts of CO,, to remain in solution as HC0~3
as C03". When the process waters pass from the region of high free COg concen-
tration to a region of lower concentration, €0^ is evolved according to the
following reactions.
C03(=) + Hz0 i==* HC03^ + 0H(~*
HC03^ + H2(K H2C03 + OH^'V
H2C03r=i H20 + C02
When C02 is evolved, hydroxy! ion (OH") is produced, raising pH of final
effluent. These reactions are probably responsible for the pH increase observed
for the grab samples described earlier.
This mechanism, although simplistic, may explain a probable cause for the
gradual pH increase, marked difference between alkalinity and hardness of final
effluent when alkaline influent was present and possibly, test organism
mortalities. All of the factors which influence C02 concentrations arc net
110
-------
accounted for. High free CO., concentrations may have occurred at other titles
during the study and may be associated with conditions other than alkaline
influent,
REFERENCES
Aiaeric;"! Public Health Association. 1975, Standard Methods for the Examination
of Water and Wastewater (14th ed.). American Public Health Association,
Washington, D.C.
Arthur, J.W., R.W. Andrew, V.R. Hattsoo, D.T. Olson, G.E. Glass, D.J. Hal 1igan,
and C.T. Walbridge. 1975. Comparative toxicity of sewage-effluent dis-
tribution to freshwater aquatic life. U.S. Environmental Protection
Agency, Duluth, MN. Ecological Research Series EPA-600/3-75-012.
Hamilton, M.A., R.C. Russo, and R.V. Thurston. 1977 . Trimmed Spearman-
Karber Method for estimating median lethal concentrations in toxicity
bioasiays. Environ. Sci. Technol. 11:714-719. Correction 12:417(1978).
Ill
-------
Summary
Characterization of the Organic !lature of the Western Lake Superior
Sanitary District Effluent
Summer, 1982 (Subtask 1)
Prepared by
Ronald Caple
Department of Chemistry
Lake Superior Basin Studies Center
214 Research Laboratory Building
University of Mimiesata-Duluth
Duluth, Minnesota 55812
February, 1983
The University of Minnesota is committed to the policy that all persons shall
hove equal access to its programs, facilities and employment without regard
to race, treed, color, sex, national origin or handicap.
112
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The objective of this portion of the project was to identify as many of
the organic components in the Western Lake Superior Sanitary District (WLSSD)
effluent as possible. To make this coiaplex task more meaningful, a similar
analysis was undertaken of the WLSSD affluent, as will as the effluent of the
Potlatch paper mill operations in Cloquet, Minnesota. The latter is
suspected to be the largest single contributor of industrial type organlcs to
the ULSS!) operation.
The qualitative analyses of the above three sites was the result of
coordinated sampling that gave a composite sample at each of those sites
corresponding as closely as possible to the same flow through sample. The
isolation and concentration of the organlcs in these composite samples was
done in threes to reflect the "acidic", "neutral", and "basic"
functionalities in the cooponents. The chemical analyses were done by mass
spectroscopy. The mass of data obtained are presently being incorporated
into a three x three matrix (3 analyses at 3 sample sites) based on
functionality.
A two-pronged approach to the analyses of chlorophenols was developed in
the event this would be useful for future monitoring purposes. The
procedures were complementary in that one was a gas chromatography with
electron capture detection (GC-ECD) approach aimed at sensitivity, and the
second procedure used liquid chromatography (11PLC) with a variable wavelength
detector that, with wavelength ratioing as a tool for identification, would
aid in the identification of chlorophenols in complex mixtures. The GC-ECD
method Involved a prior derlvatlzatlon with acetic anhydride which led to
enhanced extraction efficiencies, whereas the ili'LC analyses, while not as
sensitive without prior concentration, did not require derlvatlzatlon.
113
i
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A procedure has been optimized for the quantitative analysis of trace
phenolic components in environmental samples, Basic solutions that contain
the phenolic compounds as their phenoxide salts are ncetylated with acetic
anhydride. The resulting acetate derivatives of the phenols are readily
extractable from an aqueous solution and are easier to handle by common GC
techniques.
i Led report containing the methods used in effluent characteriza-
tions and raw data, and chlorophenol analyses procedures are available on
request.
114
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