Lake Michigan Mass Balance

LAKE MICHIGAN MASS BUDGET/
MASS BALANCE

WORK PLAN

U.S. Environmental Protection Agency
Great Lakes National Program Office

ACTIVE POOLS

OPEN-LAKE WATER COLUMN STRATEGY

Introduction

Water column samples in the open lake will be collected and analyzed to
produce the calibration data base for the water column portion of the mass
balance model. The open lake data for the chemicals selected for mass
balance will be critical for the transport and hydrodynamic model
components. The sampling plan for the open lake will consider both
nearshore and offshore areas, and the water column will be resolved both
horizontally (spatially) and vertically (with depth). The working definition of
nearshore for this study is based on the movement of bottom sediments by
wave action. A guideline of 25-30 meters depth will be used for
distinguishing nearshore and offshore.

Parameters and Methods

The parameters to be monitored in the water column are listed in Table 7.
Some samples, such as large-volume hydrophobic organic contaminant
(HOC) samples, will be taken as operationally-defined dissolved and
particulate phases. The dissolved phase will be that portion of a water
sample that passes through a 0.7 micron GF/F glass fiber filter, and the
particulate phase will be the material that is retained on the filter.
Particulate-phase organic carbon (POC), dissolved-phase organic carbon (DOC),
and total suspended solids (TSS) will be sampled along with the
large-volume samples. All filtered organic parameters will be sampled with
the same type and pore size filter for consistency. Nutrient concentrations
and traditional water quality parameters, such as pH and alkalinity, will be
monitored in addition to targeted pollutants for mass balance. Nutrient data
are required for the development of the eutrophication model. In addition,
conductivity, temperature, and depth (CTD) profiles for each sampling station
will be obtained by over-board casts (i.e., with a Seabird). Casts using
transmissometry and fluorometry will be used to observe water column
profiles of suspended solids and chlorophyll.

Specific details of sampling and analytical chemistry are covered in the
Quality Assurance Project Plans (QAPjPs) and Standard Operating
Procedures (SOPs) that will be used for the mass balance. The SOPs and
the QAPjPs are initially based on the procedures and quality
assurance/quality control measures that were used in the Green Bay Mass
Balance Study (Swackhamer, 1988), and they are developed by the principal
investigators (PIs) involved in the study. Overall, the SOPs are a combination
of "cook-book" methods, such as the filtering of total suspended solids
(TSS), and performance-based methods, such as the congener-specific
analysis for PCBs. It is important to emphasize uniformity of sampling and
analytical procedures where possible. For that reason, XAD-2 resin will be
used to pre-concentrate dissolved-phase target HOCs, which are PCBs and
trans-nonachlor. This is consistent with the sampling procedures for the
tributary dissolved-phase and atmospheric vapor-phase samples.
Open-lake, dissolved-phase water samples will be obtained by passing the
sample filtrate through XAD-2 resin columns. The resin column volume will
be on the order of 600 cubic centimeters of resin. This relatively large
volume of resin is used to allow sampling flow rates in the range of 1 liter per
minute and to prevent sample breakthrough. Typical dissolved-phase
sample volumes will be in the range of 200 to 300 liters. Particulate-phase
sample volumes will start at 400 liters and are scaled up from there,
depending on the in-lake concentrations of suspended solids and analytical
requirements. Samples for dissolved-phase and particulate-phase PCBs
and trans-nonachlor will be analyzed by gas chromatography (GC) with
electron-capture detection (ECD).

Atrazine and its two major degradation products, de-ethylatrazine (DEA) and
de-isopropylatrazine (DIA), will be sampled using solid-phase extraction
(SPE) with analysis by gas chromatography/mass spectrometry (GC/MS) with
selected ion monitoring (SIM). There is evidence that atrazine exists
primarily (95%) in the dissolved phase in surface waters (Thurman, et. al.,
1992). So, the measurement of atrazine and its major degradation products
will be focused on the dissolved phase. Water samples for atrazine, DEA,
and DIA will be taken separately from those for PCBs and trans-nonachlor.
The sample volume for atrazine will be in the range of 2 to 3 liters due to
breakthrough problems on SPE cartridges. (Thurman, et. al., 1990). Also,
atrazine is not amenable to a full mass balance because it is not measurable
in all media, such as fish tissue. Thus, a bioaccumulation model is not
possible. However, it is expected that a water column mass balance model
is attainable.

Sampling Site Selection

The data quality objectives (DQOs) for the open-lake water column are
based on the best sampling techniques and analytical chemistry available. A
combined sampling and analytical uncertainty of + 20-30% at 90%
confidence is the goal of this component of the mass balance. There are
currently few open-lake data on HOCs in the open lake (Swackhamer and
Armstrong, 1987; Lefkovitz, 1987; Pearson and Swackhamer, 1993;
Anderson, 1994). Therefore, surrogate parameters, such as solids
concentrations, were used to determine the number of open-lake sampling
stations that are required to meet the DQOs. Solids data from approximately
100 stations in 1976-1977 were used (Rockwell, et. al., 1980).

There are 41 sampling stations. Ten of these stations are identified as
master stations where increased resolution sampling will strengthen the
calibration data set. The sampling station locations are shown in Figure 8.
There is a need to have both nearshore (water depth < 25-30 meters) and
offshore stations in order to characterize contaminant concentration
gradients, as well as in-lake processes, such as the occurrence of the
thermal bar. With regard to thermal profiles, remote sensing data for
temperature is planned to augment the ship survey data. This satellite data
will be ground-truthed. In summary, the focus of station location will be on
measuring the concentration gradients.

Other aspects of the station location rationale can be summarized. The
offshore stations were selected near existing GLNPO monitoring stations,
when possible. One master station was located in Green Bay, while two of
the Lake Michigan master stations correspond to existing NOAA weather
buoys. The master station off of Grand Haven, Michigan is a NOAA Great
Lakes Environmental Research Laboratory (GLERL) station that has several
years of existing suspended solids data, as well as other parameters. The
non-master stations have been located near some of the monitored
tributaries, as well as at sites away from tributaries. The two Green Bay
passages with the highest transport of solids are chosen, as well as one site
in the Straits of Mackinaw.

The vertical resolution at the sampling stations will vary. During non-stratified
periods (isothermal), a mid-water column depth will be used. Water-column
transparency profiles will be used to identify any additional vertical resolution
which may be needed. During stratification, all stations will be sampled at the
mid-epilimnion and at a depth in the hypolimnion that corresponds to the
median particle mass, as measured by transmissometry. Continuous
monitoring devices will also be used in some cases to measure the transport
of solids.

The proposed master stations are identified in Figure 8. The master
stations will be sampled at two additional depths during stratification. When
they occur, the deep chlorophyll layer (DCL) and the benthic nepheloid layer
(BNL) will be located using fluorometry and transmissometry, respectively,
and sampled for all parameters. Care must be taken to sample the BNL
without disturbing and/or sampling the bottom sediments. Because of
uncertainties involved with sampling the BNL from a ship platform, the BNL
has been identified as a research area. The BNL may not always exist at the
master stations, and it may also occur during non-stratified periods (Hawley
and Lesht, 1993). Transmissometry will be critical for detection of the BNL.
Investigation of the short-term variability of the BNL using transmissometry
casts is planned. Nearshore master stations have been ruled out, based on
the working definition of nearshore as 25-30 meter depth.

During implementation of this plan, it will be important to coordinate the water
column sampling with sampling for atmospheric contaminants, as well as with
phytoplankton and zooplankton sampling. The air/water exchange flux
calculations will depend upon a close synchronization of the measurement of
the contaminants in the two media. The logistics for performing these tasks
have been considered. The emphasis at this point is that all field data must
be collected in the same yearly hydrologic cycle, and for open water
components, comprehensively during each survey. At a minimum, seasonal
coordination is needed for the open lake and tributary monitoring. There are
nearshore open-lake stations located near the mouths of some of the
monitored tributaries (Figure 8) as mentioned above. Also, the open lake
water and plankton sampling should be coordinated temporally and spatially.

The fluxes of contaminants to/from Green Bay will be determined. The
horizontal and vertical resolution needed to accurately measure this flux will
be estimated based on transmissometry data. A master station in Green Bay
will also be monitored. Data from these stations will be used in conjunction
with the Green Bay Mass Balance Study model to determine the Green
Bay/Lake Michigan fluxes. The fluxes at the Straits of Mackinaw will be
investigated using acoustic Doppler current profilers (ADCPs), if the
procurement and budget constraints of the program will allow it. It has been
noted that the flux from Green Bay is a more critical parameter than the flux
through the Straits of Mackinaw .

Sampling Schedule

The limnological cycle will be the basis for the temporal aspects of the
sampling plan. The planned number of lake surveys is 4 in 1994, and 3 in
1995. The first survey during each year will be at the earliest "ice out" in the
late Winter or early Spring. The second survey in 1994 should capture the
lake in early stages of stratification (late Spring). Surveys in the late Summer
or early Fall, 1994, and perhaps 1995, and late Fall surveys in 1994 and
1995 to measure the lake at late stratification round out the seven major
surveys. The scope of the late Summer/early Fall survey in 1995 is under
discussion at present. The rationale for these time frames is the need to
capture lake events as accurately and precisely as possible. The depth of
the thermocline and the occurrence of overturn are key variables. Previous
GLNPO surveys indicate that Lake Michigan does not turn over until the
middle or end of December. A Winter survey, of limited spatial coverage,
may be included if conditions are such that it is safe to sail. Finally, it will be
important to capture Spring run-off for atrazine due to its present application
schedule.

Open-Lake Water Column Research Areas

The benthic nepheloid layer (BNL) is an area of research. Important questions include:

1. How accurately can we measure contaminant concentrations in the BNL?
2. How accurately can we measure particle transport in the BNL?
3. How is the BNL/food chain connection to be quantified/estimated?
4. How important is the BNL in the offshore transport of particles?
5. What is the short-term variability of the BNL?

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All filterables at 0.7m, Whatman GF/F filters

Figure 8
Open-Lake Sampling Station Locations

BIOLOGY

Summary of Biology Data Needs and Sampling Approaches

Three of the five Management Objectives presented in the Introduction to this Work
Plan directly involve the biota:

• to develop the predictive ability to determine the environmental benefits
  (i.e., reductions in fish tissue concentrations) of specific load
  reduction scenarios for toxic substances and the time required to
  realize those benefits (i.e. trend analysis of organic contaminants in
  fish);
• to develop the ability to evaluate the environmental benefits (i.e.
  reductions in fish tissue concentrations) of load reductions for toxic
  substances that will occur under existing environmental statutes and
  regulations; and
• to improve our understanding of key environmental processes which
  govern the cycling and bioavailability of contaminants within relatively
  closed ecosystems.

To achieve these objectives, a food web model will be constructed and calibrated
for predicting the total body burden of the target contaminants in representative fish
species. The model will be linked to the physical-chemical model for Lake Michigan.

The food web model is intended to predict the concentration of the target chemicals
(PCBs, trans-nonachlor, atrazine) in the fish species of interest (lake trout, coho
salmon, bloater chubs) as a result of contaminant concentrations in the water
column. The results for each species will be dependent on the size or age class of
the species being modeled, concentrations of contaminants in the water, food chain
dynamics, and other seasonally-varying factors that influence the exposure history of
the target species. For example, diet studies indicate that in Lake Michigan coho
salmon consume primarily alewife and some invertebrates, while the diet of lake
trout is more diverse, consisting of alewife, bloater chub, rainbow smelt, sculpin
species, Diporeia spp., and Mysis relicta. The relative percentage and amount
consumed of each forage species in the lake trout coho salmon diets vary, however,
between seasons and between different geographic locations in Lake Michigan. In
order to adequately model the flow of contaminants from the water through each of
the target food chains, data are needed for each of the listed components of the
food chains for each representative area of Lake Michigan for different seasons.

Each of the named species and groups will be collected concurrent with the early
spring, midsummer and late fall surveys of the open water column. Phytoplankton
and zooplankton will be collected at some of the open water sites. Fish collections
will be primarily at three selected locations for the lake trout food chain, i.e., the
so-called “biota boxes” near Saugatuck, MI, the mid-lake reef near Port Washington,
WI, and near Sturgeon Bay, WI (Figure 9). Coho salmon collection sites will vary
seasonally. Diporeia and Mysis will be collected within the lake trout collection
areas and at one additional site northeast of Chicago, IL. Phytoplankton and
zooplankton will be collected at the biota box stations and at some of the open water
master station sites.

In addition, studies will be conducted to further define and quantify food web
interactions. An analysis of the stomach contents of lake trout, coho, bloater chub and
the forage fish species will elucidate the diet of these fish, including quantity, species
consumed and seasonal changes. Phytoplankton and zooplankton species
composition, abundance and biovolume will be determined the biota box sites and at
the open water master stations to support refinements in the modeling of food web
interactions at the lower trophic levels.

A Data Requirements matrix is presented in Table 8 which displays for each species
and group the specifications for age and size, the seasons to be collected, the location
of sampling sites, requirements for coordination with other data elements, and a
reference to a list of measurements to be obtained from each sample. A listing of the
parameters to be measured for each data group is displayed in Table 9, Biology
Measurements and Data Groups.

Figure 9
Lake Michigan Sampling Locations-Biota

TABLE 8
BIOLOGY DATA REQUIREMENTS

1X = 1994 only, XX = 1994 + 1995
2Biota Box Areas are designated Saugatuck, Sturgeon Bay, Port Washington and Chicago.
3Refer to the Table 9 Biology Measurements and Data Groups for a list of data elements to be measured for each Data Group

Table 9
BIOLOGY MEASUREMENTS AND DATA GROUPS

Group A Lake trout; coho salmon from Lake Michigan; bloater chubs > 200 mm
Group B Bloater chubs < 150 mm
Group C Alewife; smelt;sculpin; coho salmon from hatchery(except no gut content analysis)
Group D Mysis; Diporeia
Group E Zooplankton (Cladocera); phytoplankton

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Sampling Locations

Lake trout and forage fish

Three geographic areas of Lake Michigan will be sampled
for lake trout, bloater chubs, alewife, smelt and sculpins (Figure 9). Each area is expected
to contain trout populations representative of different habitat and food chain
characteristics. Trout from an area east of Sturgeon Bay, WI., will represent northern,
nearshore conditions. Those from the mid-lake reef east of Port Washington, WI., will be
typical of those from deep water populations, and those southwest of Saugatuck, Mi., will
represent nearshore, southern basin fish. The bloater chubs and forage fish species will
be collected from within the same biota box areas as for the lake trout.

Coho salmon

Sampling locations for coho salmon were selected to follow the typical
seasonal migration of planted coho. Spring sampling will be conducted in the southeastern
region near St. Joseph, Mi., and in the southwestern region near Waukegon, IL. Young
coho also will be collected directly from the Platte River hatchery, where the majority of
coho are raised or originate. Mid-summer sampling will be conducted in both the east
central and west central regions of the lake. Late fall sampling will be conducted to
coincide with the fall spawning run up Lake Michigan tributaries. Collections will be made
from the returns of mature coho (both age 1+ and 2) to rivers from two general regions of
the lake: the northeastern side in the vicinity of the Platte River, and the western side in the
vicinity of the Kewaunee River. Fall collections will also be made of immature coho from
the southeastern and southwestern regions of the Lake.

Mysis and Diporeia

These crustaceans will be collected by bottom trawls within each of
the lake trout biota box areas. Collections will be made in the vicinity of 40m and 80m
depths in each of the biota boxes and at station No. 5 near Chicago. Biota box stations at
10m generally are too dynamic (wave action) or warm to support large populations of these
macroinvertebrates.

Zooplankton and phytoplankton

These trophic levels will be collected for analysis of
contaminant concentrations at each of three stations within the biota boxes and at station 5
near Chicago. The stations will be located at 10m, 40m and 80m depths. Phytoplankton
and zooplankton will also be collected for quantitative analysis of species identification,
abundance and biovolume at each visit to the 9 biota box stations and to the 10 open water
master stations. Bythotrephes will be collected when abundant during sampling operations
for the predator and forage fish.

Primary productivity

The rate of fixation of carbon by algal populations, i.e., primary
productivity, will be determined by ship-board incubations using the radiotracer C14 at each
visit to the 9 biota box stations and to the 10 open water master stations.

Sampling Schedule

Fish, invertebrates and phytoplankton will be collected at each of the designated sites
during three (3) seasons: early spring, midsummer, and late fall. The invertebrates and
phytoplankton will be sampled at the same time as the corresponding open water survey for
organic contaminants. Collections of fish will be conducted at approximately the same
time, but not necessarily coincidental with the surveys for organics contaminants,
invertebrates and phytoplankton. Given that fully successful collections of biota can be
obtained during the first field season, some reduction of effort can be achieved if a second
field year is required. In that case, fish collections would be conducted during the spring
and fall seasons, but the lower food chain components would continue to be collected
during all three seasons.

Quantity or Biomass of Samples

Quantitative data on the spatial and temporal variability of organic contaminants in the
designated trophic levels in Lake Michigan are not currently available. Experience gained
from the GLNPO monitoring program for fish contaminants and from the results of the
Green Bay Mass Balance Study have been used to design the following sampling
guidelines.

For Contaminant Analysis:

Individual fish: 25 specimens per age grouping per site (biota box) per season,
e.g., 25 lake trout in each of age groupings 2-4 yr, 5-7 yr and 8-10 yr; 25 bloater
chubs in each age group 0-2yr, 4+yr; etc.

Composite fish samples: 5 composite samples per age grouping per site (biota
box) per season, each consisting of 5 fish. However, each composite will contain
only fish of the same age, e.g., 2 yr old, 3 yr old, etc. Some exceptions to the
numbers of fish per composite may be made based upon availability of fish of
certain ages or sizes.

Mysis, Diporeia, Bythotrephes,zooplankton (Daphnia), and phytoplankton:
10 grams, wet weight (drained), per site (each station within the biota boxes) per
season, without accompanying sediment and detritus. Bythotrephes may be
abundant only in late summer or early fall. Ten percent of the samples will be
collected in duplicate for quality control assessment. The required quantity of
biomass may change during the study depending on the concentration of
contaminants found in the samples and on the sensitivity of the laboratory
methodology.

For fish samples, the basic unit for analysis of chemical contaminants will be composites of
5 fish each. Five (5) such composites will be analyzed for each designated size class of
each species from each biota box each season. Appendix 4 displays a summary of the
number of organisms to be collected and the number of analyses to be performed for this
study. Analysis of contaminants in individual fish is recognized to be preferred over the
composite samples in order to assess the variability in contaminant burdens within each
fish population of interest. However, if each fish were analyzed individually, 1350 analyses
would be required for lake trout, coho and chubs alone! The analytical effort needed to
accommodate that number of samples is beyond the scope of this project. Therefore, the
composite fish sample approach appears to be a reasonable compromise. Supporting
studies to estimate the variability in contaminant burdens among fish of similar age/size and
collected from the same area at the same time will be conducted on a limited basis.

For Diet Composition

Quantitative data on the simultaneous diets of the predator fish (lake trout and coho salmon)
and of the forage fish (bloater, alewife, smelt, slimy and deepwater sculpin) in Lake
Michigan are not currently available. Specimens for diet analysis therefore will be taken
concurrently with those for contaminant analysis. Twenty specimens will be collected per
age group per site (biota box) per season, 10 of which will be analyzed for diet
composition. If more than 3 of the 10 specimens in a forage fish group have empty
stomachs, the other specimens will be analyzed. Because of the high percentage of empty
stomachs usually found in the predator fish, all specimens of the predator fish will be
analyzed. Each prey fish from a stomach will be identified to species, measured for total
length if intact, and weighed. Innovative procedures, suchas measuring vertebrae for
cenversion to total length, will be conducted for prey fish not intact. Invertebrate food items
will be sorted into the lowest taxa practicable, and weighed in the aggregate. Then 10
individuals per taxon will be measured (total length) and converted to biomass based on
regressions from the literature. Stomachs of prey fish are weighed before and after food
items are removed to obtain total weight of prey eaten.

Sampling Methodology

A brief summary of collection methods for each species and group follows:

Additional Model Requirements

Not all data inputs to a food web model will be determined from empirical field
measurements. Although laboratory studies on some parameters would provide data to
better define and reduce uncertainty in food chain bioaccumulation models (Thomann &
Connally 1984; Endicott et al. 1992; Connally et al, 1992), such research is beyond the
scope of this project. Therefore, much of the data for physiological and ecological
processes and for contaminant flux rates will be gleaned from the peer reviewed literature
for Lake Michigan (first option), peer reviewed literature for other locations (second option),
or from other reports and unpublished studies (third option). This approach will be taken to obtain values for:

• Rate of uptake of contaminants from the water through the gills (fish) or through the
  whole organism (invertebrates and algae).
• Rate of uptake of contaminants through food ingestion at each trophic level.
• Rate of elimination of contaminants from the organism
• Organism respiration rate
• Other factors related to organism exposure to contaminants through food (diet
  composition) and water
• Fish migration patterns
• Effects of compositing fish samples on estimates of mean and variance of
  contaminant concentrations

MERCURY

Based upon a recommendation of the original Mass Balance Workshop, total mercury was
agreed upon as a target analyte of the LMMB by the Steering Committee in November,
1993. Recognizing the difficulty of achieving modeling results at the level of accuracy
expected for organic contaminants, we will attempt a less extensive data collection and
modeling effort for mercury than for the organochlorine contaminants. A main difficulty in
modeling mercury is the rudimentary state of knowledge of the processes and rates of
conversion of mercury among its several forms, particularly its rate of uptake and
transformation in biota. These are critical research questions which, unfortunately, are
beyond the scope of the LMMBS.

As part of the Enhanced Monitoring Program, mercury was included as a target analyte in
the original parameter list for tributary and atmospheric monitoring. It has received much
attention in the Great Lakes Basin (Sills, et. al., 1992).As stated in the introduction, mercury
is a pollutant of concern based on trends in loadings obtained from sediment cores from
inland lakes, as well as fish tissue concentrations, which require consumption advisories in
some inland waters. After some discussion of the utility and desirability of lead as a
chemical for mass balance, and its eventual removal from the list, the workshop participants
felt that there should be some effort made to obtain the data needed to for a Total Mercury
mass balance model. This model would have less certainty associated with it than will the
mass balances for the other chemicals, because sampling would occur at fewer locations
in the Lake than for the other chemicals, and there are significant research questions to be
answered before the rate and transfer functions needed for the models can be derived.
Because of sampling requirements (clean techniques, clean rooms, etc.) and the cost of
analysis, the inclusion of mercury as a mass balance chemical would require a
considerable increase in expenditure. The decision to whether or not to proceed with a
total mercury mass balance is that of the managers.

The outline of the work necessary for a mass balance for mercury is taken from
conversations with Dr. Ronald Rossman and Mr. Douglas Endicott of U.S. EPA, Large
Lakes Research Station, as well as discussions that took place at the Workshop.

TRIBUTARIES

Monitoring of total mercury in the dissolved and particulate phases, for load calculations, is
planned as part of regular sampling of the tributaries. That is, total mercury samples will be
taken at each sampling visit. Clean techniques will be used, including teflon samplers.
Little or no additional sampling will be required for the mass balance model, as samples will
be taken as a regular part of the intensive monitoring program.

ATMOSPHERE

Total mercury will be monitored at four sites (IIT, South Haven, Sleeping Bear Dunes and
Chiwaukee Prairie or Indiana Dunes). Vapor and particulate phase mercury will be
collected for a period of 24 hours every sixth day. Mercury in precipitation will be a
composite weekly sample. The mercury monitoring conducted for Lake Michigan will be
coordinated with a ten site network which will monitor for vapor and particulate mercury for a
one year period proposed to begin in approximately October 1994. This basin-wide
network will include the five US and Canadian IADN sites and five additional sites.
Sampling frequency will be the same as that proposed for Lake Michigan. Sampling
methods for the mass balance are currently being developed under a research proposal
with EPA-AREAL. Total mercury will be monitored as part of the atmospheric monitoring to
be conducted for load estimates for Lake Michigan.

SEDIMENT

Surficial sediment (top 1 - 2 cm) from all depositional zone box core samples collected as
part of the sediment sampling program (see Sediment section) will be analyzed for total
mercury. It is anticipated that a subset of the (dated) sediment cores to be taken for
analysis of other mass balance chemicals would be analyzed for mercury to determine
historic loading trends. The subset of cores would depend on data quality objectives
determined for the mercury mass balance, but would probably be 10 to 15. A limited
number of sediment trap samples will also be analyzed for mercury to determine current
particulate mercury fluxes.

OPEN LAKE

Total mercury samples (mercury in dissolved and particulate fractions) will be taken at
master stations and at one station in each of the biota boxes on all planned mass balance
surveys. One (unstratified water column) or more (stratified water column) samples will be
taken at each station as part of the Open Lake surveys (see Open Lake Section). Clean
techniques will be used for sample collection, and clean area aboard the R/V Lake
Guardian will be used for sample processing and handling.

BIOTA

Upper Food Chain
A small subset of the lake trout and coho salmon sample collected by NBS and USFWS
will be analyzed for total mercury.

Lower Food Chain
Samples of zooplankton and phytoplankton, taken concurrently with those to be analyzed
for organic contaminants, will be analyzed for total mercury. A subset of the Mysis relicta
and Diporiea samples will also be analyzed.

RESEARCH

There are several areas of research which must receive attention for successful completion
of a mercury mass balance. Most are cogent to the fate and effect (food chain) portion of
the work. Methyl mercury is the chemical specie which is most toxic and most
bioconcentrated. While total mercury will be measured in all media, methyl mercury will
not. Understanding the relationship between methyl mercury and total mercury is important
to the understanding of mercury bioaccumulation in fish. For this purpose, methyl mercury
measurements, along with total mercury, should be made at a research level, to begin to
define both loads of methyl mercury, and concentrations, seasonally in the water. It may
also be necessary to measure several species of mercury in open water and over-water
atmosphere to determine flux of mercury into and out of the water: this is equivalent to work
performed for the Green Bay Mass Balance which has led to a rethinking of role of the Bay
as a source or sink of PCBs. In the case of mercury, several species would be measured,
namely: Hg, Hg²+, total-Hg and methyl-Hg. A final area of research relevant to mercury
uptake by biota is the measurement of selenium.

QUALITY ASSURANCE PROGRAM

The EMP directors and managers will make decisions based upon the interpretive results
of this program. These decisions will depend on qualitative and quantitative measurements
derived from various environmental data collection activities (EDCA) including modeling.
Measurements are never true values and always contain some level of uncertainty.
Therefore, decision makers must be sufficiently comfortable with the uncertainty in data to
risk making an inappropriate decision. This is the basis for the quality assurance program: minimizing the risks of making inappropriate decisions, thereby maximizing the potential for improvement of the environment.

The EMP QA Program's goal is to assure that the data that are produced meet defined
standards of quality within a specified level of confidence. Data quality will be defined,
controlled, and assessed through activities implemented within the various technical
resource groups. The following sections will provide a brief discussion of the major
planning, implementation and assessment aspects of the EMP QA Program. Detailed
information can be found in the EMP QA Program Plan.

THE QA WORKGROUP

The QA workgroup is composed of a coordinator (QAC), a lead from each technical
resource group, various agency QA representatives, principle investigators, and technical
experts, to ensure that data are of acceptable quality. The QA program will also hire
support personnel for the verification and validation of data prior to official acceptance into the main data repository. The QA workgroup serves two functions; support and oversight.
As a support group, the QA workgroup responsibilities will include:

• Assisting in the development of program objectives, data quality objectives,
  and measurement quality objectives;
• Assisting in the development of the EMP Study Plan;
• Developing and implementing the EMP QA Program Plan;
• Providing technical guidance to principle investigators on the development of QA Project Plans; and
• Assisting in the development of verification techniques

Oversight functions include:

• Reviewing and approving QA Project Plans;
• Tracking progress on QA Project Plan development;
• Coordinating and implementing assessments;
• Developing integrated data quality reports; and
• Verifying/validating data.

QA PROGRAM PLANNING

As in all substantive data collection efforts, planning is essential. The QA program will
assist in four major planning/development activities: 1) data quality objectives,
2) measurement quality objectives, 3) the EMP QA Program Plan, and 4) the QA project
plans.

DATA QUALITY OBJECTIVES (DQOs)

Central to a sound QA program is the development of data quality objectives (DQOs).
DQOs are the full set of performance constraints needed to design a project, including a
specification of the level of uncertainty that a decision maker (data user) is willing to accept
in the answers to the questions of the study. This is data that, when evaluated, provides the
decision maker with enough certainty that he/she is willing to risk making an inappropriate decision. Therefore, the data quality attributes that are associated with data are necessary for any educated ecological management decision.

Uncertainty can be illustrated as follows:

So2 = Sp2 + Sm2 (equation 1)
Where:

o= Overall Uncertainty
p= Total Population Uncertainty (spatial and temporal)
m= Measurement Uncertainty (data collection)

The estimate of the allowable overall uncertainty is the DQO. The term "uncertainty" is
used as a generic term to describe the sum of all sources of error associated with a given
portion of the measurement system. Since variance is additive, we can see that every input
to the mass balance model (MBM) will add to the overall uncertainty of the model.
Therefore, the MBM is only as good as the data inputs. At a specific input, confidence in
the estimate of population uncertainty can be controlled through the use of statistical
sampling design techniques. The goal of QA program is to understand and control
measurement uncertainty to an acceptable level through the use of various quality control
and evaluation techniques.

The modeling section and subsequent sections relating to each ecological resource (air,
open lake etc.) have stated that the DQO for each input to the model to be within 20-30% of
the mean at the 95% confidence interval. The QA workgroup will strive to attain a level of
measurement uncertainty that will meet the DQO.

MEASUREMENT QUALITY OBJECTIVES

Equation 1 can be further viewed as:

This equation serves to illustrate that DQOs are the sum of both the population and
measurement uncertainties. The terms data quality objective (DQO) and measurement
quality objective (MQO) have been added to equation 1. This serves to distinguish the fact
that an MQO is not a DQO and that the EMP QA programs main priority is to control and
assess measurement uncertainty by establishing MQOs.

MQOs are addressed in terms of 6 attributes: precision, accuracy, detectability,
completeness, representativeness, and comparability. These attributes are defined in the
EMP QA Program Plan and will be addressed in detail in resource specific QA project
plans.

Comparability of data across the various ecological resources is important for the mass
balance as well as for other uses of the EMP data. Since each resource group will be
measuring primarily the same parameters, it is important that detection limits, accuracy, and
precision are comparable. There are two ways of controlling comparability: 1) requiring the
use of specific methods, or 2) requiring consistent method performance criteria. The QA
workgroup will assist the ecological resource groups on attaining data comparability

THE EMP QA PROGRAM PLAN

The document around which the QA program revolves is the EMP QA Program Plan
(QAPP). The EMP QAPP describes the program's minimum requirements to which all
organizations collecting data must adhere. These minimum requirements are developed in
order to meet the EMP objectives. The goal of the program plan is to present the program,
the data quality objectives (DQOs), and the rational for them, and to establish the consistent
use of QA techniques among the various agencies collecting data for the EMP. In order for
the program to successfully meet the EMP objectives, all cooperators must adhere to the
guidance and policy set forth in the QAPP. Major elements of the QAPP include:

The QAPP will be developed in cooperation with all program workgroups and approved by
the Program Directors.

QA PROJECT PLANS

The EMP requires every EPA funded EDCA to have written and approved quality
assurance project plans (QAPjPs) prior to the start of the EDCA. The purpose of the
QAPjP is to specify the policies, organization, objectives, and the quality evaluation and
quality control activities (QE/QC) needed to achieve the DQOs of the EMP.

Each program cooperator will be provided guidance documentation for the development of
QAPjPs. The QAC and support staff will also be available for one-on-one consultation in
order to assist in the QAPjP development.

QA PROGRAM IMPLEMENTATION

QA program implementation includes the following areas that will subsequently be
addressed:

QA PROJECT PLAN REVIEW AND APPROVAL

Review of the QAPjP will include the principle investigator (PI), the resource workgroup's
QA lead, the EPA Project Officer, and the EPA QA manager (QAM). The EPA QAM will
review each QAPjP for the required elements and the soundness of the planned QA
activities. The QAM will provide written comments within 15 working days from
submission. Data collection may not proceed without an approved QAPjP.

TRAINING/CERTIFICATION

Training is essential to the success of data collection activities. Training enables personnel
to complete each aspect of an EDCA according to design and management objectives and
in a standardized manner.

Prior to the start of any EDCA, a training session shall be conducted. Training will include
practice with each of the SOPs and shall include some level of certification by the trainer
that individuals are performing the EDCA properly.

The resource workgroup QA lead will oversee the training aspects of their resource groups,
attend the training exercises for assessment purposes, and report on the activities
accomplishments.

ASSESSMENTS

An audit or assessment is a formal evaluation of performance to pre-determined standards
and the evaluation and documentation to effect change towards improved performance.
Audits are the principal means to determine compliance and to control systems in a
real-time manner to improve performance. Three types of audits are defined: 1) technical
systems audits (TSAs), 2) data quality audits (DQAs), and
3) performance evaluations (PEs). These audits will be utilized in the EMP.

Technical Systems Audits (TSAs)

Technical systems audits (TSAs) are qualitative on-site evaluations of a complete phase of
an EDCA (i.e., sampling, preparation, analysis). This audit can be performed prior to the
data collection activity, in order to verify the existence and evaluate the adequacy of
equipment, facilities, supplies, personnel, and procedures that have been documented in
the QAPjP. TSAs are also employed during the data collection activity in order to verify and
evaluate the EDCA.

Data Quality Audits (DQAs)

A data quality audit (DQA) focuses on collected data. It is used to determine if enough QA
information exits with the data set to evaluate the quality of the data and whether this quality
satisfies the stated DQOs of the EDCA. It is also used to assess the ability of the QAPjP
to produce data of known and satisfactory quality.

Performance Evaluations (PEs)

Performance evaluations (PEs) are a means of independently verifying and evaluating the
quality of data from a measurement phase, or the overall measurement system. This is
accomplished through the use of samples of known composition and concentration. These
samples can be introduced into the measurement system as single blind (identity is known
but concentration is not) or double blind (concentration and identity unknown). These
samples can be used to control and evaluate accuracy and precision and to determine
whether DQOs or MQOs have been satisfied. PEs can also be used to determine inter-
and intra-laboratory variability and temporal variability over long projects, and to evaluate
laboratories prior to contract awards.

Another performance evaluation method that may be employed in the EMP are
interlaboratory comparisons studies in which reference or a homogenous matrix samples
are sent to all analytical participants in order to determine data comparability.

DATA VERIFICATION/VALIDATION

Data verification is a process used to determine and control measurement uncertainty in
order to produce accurate and reliable data. A method must be developed within each
QAPjP that takes the various QE/QC information that has been included in the QA design
and evaluates this data in a consistent manner. Data not meeting acceptance criteria is
flagged. Depending on the types of flags associated with the routine samples, data may
be reanalyzed (if possible) or flagged in a manner that will inform the user of the data
quality. This process should not be considered as a means to eliminate subjective
decisions made by the principal investigator (PI), but will allow for a consistent data review
using the MQO samples. In fact, if a verification system is properly developed, it should
capture many of the thought processes used by the PI during his/her review of data.

Each resource group will use a consistent set of flag codes. This set contains mandated
standard EPA codes. As new codes are needed, they will be developed and distributed to
all EMP cooperators. PIs developing QAPjPs must identify the codes they will use to flag
data.

Data validation is a process whereby either the PI or the technical workgroup review the
project data and the associated flags in terms of the program requirements and determine
what data will be placed into the central data base to answer the program objectives. At
present this procedure has not been developed. However, once it has, it must remain
consistent throughout the program's duration. If not, all previous data must be processed
through any modified procedure.

QA REPORTING

The following types of QA documentation will be developed during the EMP.

The first three have been discussed in previous chapters and will not be presented here.
More details on all QA documentation is included in the EMP QA Program Plan.

The QA report is a document that describes a project's quality assurance program,
including the verification techniques, and provides an assessment of the quality of the
routine data, based upon the evaluation of measurement quality samples. The QA report is
directed primarily towards the users of the data who will be analyzing the data and making
various interpretive conclusions. Depending on the type of report (interim or final), the QA
report will include the following:

Overview: The time sequence that the report covers, the activities that the report covers, a
brief description of the program and reference to the appropriate QAPjP, and the structure
of the report.

QA Summary: Summary of the QA program, its implementation, and accomplishments,
and a summary of corrective actions taken.

Audits: Results of all audits during the appropriate time span. Actual audit reports should
be included in an appendix.

Data Assessment: Assessment in terms of precision, accuracy, detectability,
representativeness, completeness, and comparability in terms of the DQOs/MQOs,
estimates of overall measurement uncertainty the statistical techniques used to make the
assessments, a discussion of whether the DQOs/MQOs were met, and the resulting impact
on decision making, limitations on the use of the data and identification of invalid data
(flagged data) for the program.

Conclusions: Assessment of the QA program both positive and negative and
recommended changes for improvement of the program.

Each QAPjP will identify the frequency of these reports and the specific content of
progress and final reports.

Lake Michigan Enhanced Monitoring Program
- Data Management Strategy -

The Lake Michigan Mass Balance (LMMB) and Lake Michigan Enhanced Monitoring
projects represents considerable opportunity to improve data management practices for
environmental monitoring information collected under the Great Lakes Program. The data
management mission for these projects is to provide a data entry, storage, access, and
analysis system to meet the needs of mass balance modelers and other potential users of
the data. This document outlines elements of a data management plan for the Lake
Michigan Enhanced Monitoring Program (LMEMP).

Background
Because the LMEMP will involve over 25 investigators in collecting and analyzing samples,
data management and the quality assurance program will be pivotal in maintaining
consistency and comparability across the program. Fortunately, in planning the LMEMP,
the need for rigorous data management was recognized early. Since then, a data
management strategy has been evolving for the LMEMP.

In planning for this project, GLNPO has taken the responsibility to develop and implement a
data management plan for information supporting the LMEMP in cooperation with Region 5
and the States of Illinois, Indiana, Michigan and Wisconsin. These responsibilities include:
data management, data base administration, and development/administration of the system
which houses these data. Project Officers for laboratory contracts and grants which create
data and the LMEMP work groups are responsible for the quality of the data. Staff support
is provided by GLNPO and contract staff, Region 5, and the US Army Corps of Engineers.

LMEMP Data Management Philosophy

The data management plan for this project is being developed under several guiding
principles including:

• Cross-program/project utility and long-term value: The data collected under the
  LMEMP will represent the largest, and highest quality toxics data ever generated in the
  Great Lakes Basin. It is therefore critical to the Great Lakes Program that the data be
  useful to investigators outside the scope of the original project.
  
• Store data of known quality: In order to make the data useful beyond the original
  scope of the project, users have expressed the need to be able to understand the
  quality of each data set in the data base. To support this requirement, the LMEMP data
  base will store information describing the project, the data quality objectives, and the
  quality assurance information associated with each data set.
  
• Avoid duplication of effort: Because the LMEMP includes monitoring of all major
  environmental media (sediment, water, air and biota), there will be a significant
  challenge to make all of these data available within a single system. In fact, there is
  currently no single system which could manage all of these data types. GLNPO has
  therefore formed a partnership with USEPA Office of Water, where the STORET
  Modernization Project is being completed. The STORET Modernization Team shares
  GLNPO’s vision for a comprehensive monitoring database focusing on longevity,
  integration, and data quality. By becoming a pilot project for STORET Modernization.,
  LMEMP is capitalizing on a national-scale user requirements analysis and on the efforts
  to integrate with other major environmental monitoring data systems. GLNPO has
  utilized existing resources wherever they exist in developing this data base.

The LMEMP Data Base

The LMEMP Data Management Plan centers on the use of a relational data base that is
designed to store and organize data so that the data are consistent, and so that redundancy
is eliminated whenever possible. Relational data bases strive to maintain a single copy of
the information and refer to it using pointers that indicate where related information is used.
This helps not only to ensure efficient storage and consistency, but allows quick access to
the data. Relational also means that relationships between different sections of the data
base are not restricted when the data base is created. For example, if sampling and station
information are stored in separate locations in the data base, one can create a query using
both.

Based on an extensive requirements analysis for this multi-media monitoring project, a
relational database has been designed to accommodate all of the information that will be
necessary to utilize these data far into the future. For the first time, GLP data users will
have a comprehensive monitoring data base that will provide information about the project
objectives, the participants, the monitoring stations, the sample collection/analytical
procedures, the analytical results AND the supporting quality assurance/quality control
data. By storing all of this information in a single data base, the data can be used to
support projects beyond the original scope of the LMEMP. Because extensive project
description information will be included in the data base, secondary users will not have to
make phone calls or track down supplemental reports in order to determine whether these
data might be of use in their projects. The useful life of the data will extend beyond the
careers of the scientists that collected the data. As the GLP monitoring program matures,
the LMEMP data base is expected to be expanded to house all major Great Lakes
environmental monitoring project data.

Standardized Data Reporting & Data Entry

Because there are over twenty-five organizations producing data through collection and
analysis of samples, a tremendous amount of forethought was necessary to ensure that
data will be submitted in a consistent and comparable format. For the LMEMP the two
major outside sources for data are the field sampling crews and the analytical laboratories.
For both of these groups of data generators, required formats for data reporting (data
reporting standards) were developed. The data reporting standards are designed to take
ASCII text flat files (like spreadsheets) and convert them to the relational structure of the
data base. Each data standard specifies the formatting rules by which data must be
submitted, and in many cases, allowable values for a given field are defined (i.e.: mercury
shall be reported as "Hg", Atropine shall be reported as "Art", etc.). By requiring
consistency in data reporting, the allowable value lists reduce the amount of processing
necessary upon receipt.

The data reporting standards were designed to minimize the number of data elements
reported from the field crews and lab analysts. All of the “Project” and “Station” data, as
well as any data that can be gleaned from the Quality Assurance Project Plans will be
entered using a data entry application at the Program Office. The data elements and
attributes which are required by either the data reporting standards or the data entry
applications will make up the minimum data requirements for the LMEMP data base. The
minimum data requirements will be particularly useful in determining which additional
monitoring studies can be added to the LMEMP data base.

Data Access

The LMEMP data base is being designed to support a variety of uses. The primary users
will be the LMEMP project team and the environmental modelers associated with the
project. The data base will also be accessible to anyone who can benefit through the use
of high-quality toxic data. Among the anticipated customers are the Lakewide Management
Teams, Remedial Action Plan committees, and government/non-government entities
focused on developing load reduction strategies. The data base will include
documentation of methods, quality assurance, quality control, data quality objectives, and
other information needed for meaningful interpretation.

Clearly, toxic chemical data can be difficult or impossible to interpret for those not trained in
organic chemistry. Therefore, all summary documents and data analyses will be made
available to those who request it both via the Internet and through the mail. GLNPO is
committed to working with State and other customers to improve access to Great Lakes
environmental monitoring information. The LMEMP data base will be a major step toward
fully meeting the needs of Great Lakes data users.

Project Communications and Internet Access

LMEMP work group members can now communicate through Internet electronic mail. A
“listserver” (basically an electronic mailing list) has been established to facilitate group
communications. To communicate via the listserver with project participants owning
Internet addresses, send your email to the following address:

GLIN-LMMB@great-lakes.net

To subscribe to the LMEMP listserver, send an email message to:

GLIN-Majordomo@great-lakes.net

and in the body of the email, simply type:

subscribe GLIN-LMMB .

Members who do not have Internet mailboxes can get one from the Great Lakes
Information Network (GLIN). Ron Emaus at CICNet (313)998-6419 can help provide
electronic mail services or required connectivity to members of LMEMP work groups.

The Great Lakes Information Network includes Internet “Gopher” and “World Wide Web”
servers containing various information about the Great Lakes, including environmental
information and information about environmental activities in the Basin. The Lake Michigan
Mass Balance and Enhanced Monitoring Work Plan and other LMEMP documents/reports
will be posted on the Great Lakes Network and will be available for downloading by
interested parties. The following Internet addresses provide access to the LMEMP and
other Great Lakes information:

http://epawww.ciesin.org/
http://www.great-lakes.net:2200/
gopher://glnpogis2.r05.epa.gov

Additionally, an anonymous FTP site is available at: ftp://glnpogis2.r05.epa.gov .
Please inform the Data Management Committee chair when you have electronic copies of
documents to be posted on the GLIN.

REFERENCES

References (Introduction and Tributary Sections)

• Baker, D.B. 1988. Sediment, nutrient and pesticide transport in selected lower Great lakes
  tributaries. USEPA, Great lakes National Program Office, Chicago, Il. EPA 905/4-88-001.
• Day, R.M. 1989. Estimated loadings from seven Michigan tributaries and recommendations
  for tributary sampling strategies. USEPA, Great Lakes National Program Office, chicago, Il.
• Dolan, D.M., Yui, A.K. and R.D. Geist. 1981. Evaluation of river load estimation methods for
  total phosphorus. J. great lakes Res. 7:207-214.
• Eisenreich, S.J. 1987. The chemical limnology of nonpolar organic contaminants:
  polychlorinated biphenyls in Lake Superior. In Sources and Fates of Aquatic Pollutants,
  ed. R.A. Hites and S.J. Eisenreich, pp. 319-364. Advances in Chemistry 216;American
  Chemical Society, Washington D.C.
• Gilbertson, M. 1988. Epidemics in birds and mammals caused by chemicals in the Great
  Lakes. In Toxic Contamination and Ecosystem Health: A Great Lakes Focus, ed. M.S.
  Evans, pp. 133-152. Toronto: John Wiley and Sons.
• IJC (International Joint Commission). 1989. 1987 report on Great Lakes Water Quality:
  Appendix B Great Lakes Surveillance. Great Lakes Water Quality Board Report to the
  International Joint Commission.
• Mac, M.J. 1988. Toxic substances and survival of Lake Michigan salmonids: field and
  laboratory approaches. In Toxic Contamination and Ecosystem Health: A Great Lakes
  Focus, ed. M.S. Evans, pp. 389-401. Toronto: John Wiley and Sons.
• Miller, M.A. and M.E. Holey. 1992. Diets of lake trout inhabiting nearshore and offshore
  Lake Michigan environments. J. great Lakes Res. 18:61-60.
• Richards, R.P. 1990. Measures of flow variability and a classification of Great Lakes
  tributaries. Water Quality Laboratory, Heidelberg College, Tiffin, Ohio.
• Rockwell, D.C., De Vault, D.S., Palmer, M.F., Marion, C.V., and R.J. Bowden. 1980. Lake
  Michigan intensive survey 1976-1977. USEPA, Great Lakes National Program Office,
  Chicago,Il. EPA-905/4-80-003-A.
• Sorensen, J.A., Glass, G.E., Schmidt,K.W. Huber, J.K., and Rapp, G.R. Jr. 1990.
  Airborne mercury deposition and watershed characteristics in relation to mercury
  concentrations in water, sediments, plankton, and fish of eighty northern Minnesota lakes.
  Environ. Sci. Technol. 24:1716-1727.

References (Atmosphere)

• Achman D.R,, Hornbuckle, K.C., and S.J. Eisenreich, 1993, Volatilization of Polychlorinated
  Biphenyls from Green Bay, Lake Michigan, Environment Science and Technology, 27,
  75 - 86.
• Baker, J.E. and S.J. Eisenreich, 1990, Concentration and Fluxes of Polycyclic Aromatic
  Hydrocarbons adn Polychlorinated Biphenyls across the Air-Water Interface of Lake
  Superior, Environment Science & Technology, 24, 342-352.
• Eisenreich, S.J. and W.M.J. Strachan, 1992, Estimating Atmospheric Deposition of Toxic
  Substances to the Great Lakes, An Update. Workshop Report. Canadian Centre for
  Inland Waters, Burlington, Ontario, January 31 - February 2, 1992.
• Holson, T.M., Noll, K.N., Fang, G., Lee, W., and J. Lin, 1993, Dry Deposition and Particle
  Size Distributions Measured during the Lake Michigan Urban Air Toxics Study,
  Environment Science and Technology, 27, 1327 - 1333.
• Hornbuckle, K.C. Achman, D.R., and S.J. Eisenreich, 1993, Over-Water and Over-Land
  Polychlorinated Biphenyls in Green Bay, Lake Michigan, Environment Science and
  Technology, 27, 87 - 98.
• Keeler, 1993
• Lamey, L and W. Swain, July 1993, Technical Planning Guidance for the Great Waters
  Program, for U.S. Environmental Protection Agency, Office of Air Quality Planning and
  Standards, Durham, North Carolina
• Mackay and Yeun 1983. Mass transfer coefficnent correlations for volatilization of organic
  solutes from water. Environment Science and Technology, 17, 211-217.
• O'Connor, D.J. 1983. Wind Effects on gas-liquid transfer coefficients. J. Environ. Eng.,
  109, 731-752.
• Rockwell, D.C., De Vault, D.S., Palmer, M.F., Marion, C.V. and R.J. Bowen. 1980. Lake
  Michigan Intensive Survey 1976-77. USEPA, Great Lakes National Program Office,
  Chicago, Il. EPA-905/4-80-003A.
• Strachan, W.M.J. and S.J. Eisenreich, 1988, Mass balancing of toxic chemicals in the Great
  Lakes: The role of atmospheric deposition. Report to the International Joint
  Commission: Winsor, Ontario, 113 pp.
• Swackhamer, D.L. 1988. Quality Assurance Plan Green Bay Mass Balance Study I. PCBs
  and Dieldrin. Great Lake National Program Office, U.S. Environmental Protection
  Agency, Chicago, IL. 22 pp.
• U.S. Environmental Protection Agency, 1991, Report of the Great Lakes Air Toxics
  Research Priorities Workshop. Office of Research and Development, Atmospheric
  Research and Exposure Assessment Laboratory, Research Triangle Park, North
  Carolina, March 11 -13, 1991.
• U.S. Environmental Protection Agency, 1992a, Report of the Great Lakes Mass-Balance
  Planning Workshop, Office of Research and Development, Atmospheric Research and
  Exposure Assessment Laboratory, Research Triangle Park, North Carolina, March 31 -
  April 1, 1992.
• U.S. Environmental Protection Agency, 1992b, Report of the Lake Michigan/Lake Superior
  Loading Study Workshop - Review of Air Monitoring Design. Office of Research and
  Development, Atmospheric Research and Exposure Assessment Laboratory,
  Research Triangle Park, North Carolina, September 1 - 3, 1992.

References (Sediment Section)

• [Incomplete; REVIEWERS, please add pertinent references; a compilation will be useful
  to all eventual participants in the program]
• Bierman, V.J. and others 1992. Development and validation of an integrated exposure
  model for toxic chemicals in Green Bay, Lake Michigan. Report to USEPA, Grosse Ile, MI;
  300 p
• Cahill, R.A., 1981. Geochemistry of recent Lake Michigan sediments. Circular 517, Illinois
  Geological Survey, Champaign, IL., 94 p.
• Chambers, R.L. and Eadie, B.J. 1981. Nepheloid and suspended particulate matter in
  south?eastern Lake Michigan. Sedimentology: 28, 439?447.
• Eadie, B.J., Chambers, R.L., Gardner, W.S., and Bell, G.L. 1984. Sediment trap studies in
  Lake Michigan: resuspension and chemical fluxes in the southern basin. J. Great Lakes
  Research: 10, 307?321.
• Eadie, B.J., N.R. Morehead and P.F. Landrum 1990. Three phase partitioning of HOC in
  Great Lakes waters. Chemosphere 20: 161?178
• Edgington, D.N, and J.A. Robbins (1990). Time scales of sediment focusing in large lakes
  as revealed by measurement of fallout Cs?137. pg 210- 223 in M.M. Tilzer and C. Serruya
  (eds.) Large Lakes: Ecological Structure and Function. Springer-Verlag
• Frank, R., R.L. Thomas, H.E. Braun, D.L. Gross, and T.T. Davies. 1981. Organochlorine
  insecticides and PCB in surficial sediments of Lake Michigan (1975). J. Great Lakes
  Research 7:42?50
• Gottlieb, E.S., J.H. Saylor and G.S. Miller 1989. Currents and temperatures observed in
  Lake Michigan from June, 1982 to July, 1983. NOAA Tech Memo ERL-GLERL # 71; 45p.
• Hawley, N. 1991. Preliminary observations of sediment erosion from a bottom resting
  flume. J. Great Lakes Res. 17: 361- 367.
• Hawley, N. and B.M. Lesht 1992. Sediment resuspension in Lake St. Clair. Limnology and