United States
Environmental Protection
Agency
Research and Development
Environmental Research
Laboratory
Duluth MN 55804
•EPA-600/S3-83-094 Dec. 1983
&ER& Project Summary
Environmental Levels of PCB in
Great Lakes Fish
C. P. Straub and J. M. Sprafka
This report reviews and evaluates
previously reported PCB levels in a
variety of fish sampled from various
locations in the Great Lakes. Higher
concentrations in fish appear to be
related to near-shore sampling where
higher exposure to bottom sediments
occurs to the flora and fauna compris-
ing the food chains for the specific fish
collected. Highest concentrations of
PCBs were found in lake trout and fat
trout taken from Lake Superior and in
fish collected from the lower end of
Lake Michigan. There is a need to
identify past and/or present sources
contributing PCB contaminants to the
off-shore areas as well as to identify
major sources of runoff contributing
PCBs to the waters of the Great Lakes
system. Additional information as to
food-chain constituents is needed to
more rapidly assess prey-predator rela-
tionships in the various regions of the
system.
This Project Summary was developed
by EPA's Environmental Research Lab-
oratory, Duluth, MN, to announce key
findings of the research project that is
fully documented in a separate report of
the same title (see Project Report order-
ing information at back).
Introduction
The intent of this review was to identify,
based on available data reported to us,
the major species of fish contributing
PCBs to the human diet and the major
sources of contamination. This review
first identified levels of contamination by
given sampling area in samples of lake
trout in Great Lakes waters, since this
species was most extensively studied; it
then identified levels by location for other
species of fish which form part of the
human diet or may serve as food sources
for fish at higher trophic levels. Our
primary concern was for human exposure,
even though we fully recognized the
importance of a total ecological systems
approach, particularly with respect to
predator-prey relationships. In fact, the
latter are necessary to fully understand
and appreciate the potential for human
exposure through ingestion of fish. One
other facet that is not directly considered
in this review is the potential for infant
exposure to PCBs through breast feeding
and subsequent accumulations of these
agents in fatty tissue.
Conclusions
The following conclusions may be
drawn based upon the data available to
the authors and the assumptions referred
to in the text.
1. There is a dearth of information on
PCB levels in many species of fish
collected from various locations. In
many instances, only one or two
samples were collected annually or
biennially.
2. Where more data were available for
specific fish from given locations, it
was demonstrated that the PCB
concentrations reported varied in a
log-normal manner.
3. Based upon data reported for fish
collected from certain areas of Lake
Superior, the concentrations gener-
ally were lower, whereas near-
shore samples included in these
same areas showed higher bottom
mud and sediment concentrations
in the near-shore areas.
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Recommendations
1. All subsequent investigations of fish
and other sources of PCBs in the
Great Lakes should be coordinated
through a central organization
which can specify the kinds of fish to
be collected, numbers of fish, and
locations for sample collection.
2. There is a greater need for reporting
the portion of the fish examined (i.e.,
the total fish or edible fraction) to
provide a better base for comparing
samples. Similarly, methods used
for analysis should be reported and
a uniform system of quality control
should include all laboratories
carrying out these studies. The
specific standard used for estima-
ting the PCB concentration should
be indicated, and information on the
actual isomers identified should be
reported.
3. With the isolation of areas of higher
fish contamination, a concerted
effort should be made to indicate
whether such contamination levels
reflect current discharges of PCBs
or sources that have accumulated
over time.
4. Stomach contents of the fish caught
should be examined to identify feed-
ing habits in the various parts of the
lake system during different
seasons of the year.
Species of Fish Sampled
The most extensive data available for
study were on lake trout, but data in
variable number were reported for fat
trout, carp, catfish, yellow perch,
whitefish, walleye, sucker, red sucker,
black crappie, brown bullhead, herring.
fresh water drum, bloater, burbot, brown
trout, rainbow trout, muskie, salmon,
Chinook salmon, cisco, and smelt. Similar
species were not sampled from all sites,
probably due to the fact that all species
were not found at all locations. The
species of most interest are those that
have been identified as major food
sources. These, in order of preference as
indicated by preliminary data from the
epidemiological questionnaire on eating
habits of commercial fishermen, are
yellow perch, lake whitefish, lake herring,
and lake trout.
Results
Data are presented in the form of semi-
logarithmic plots of PCB concentration
(log scale) vs. length (arithmetic scale) or
weight (wet) (log scale) vs. length (arith-
metic scale); as logarithmic plots of PCB
concentration (log scale) vs. weight (wet)
(log scale); and as logarithmic probability
plots of PCB concentrations. In addition,
fish body burden (mg) vs. fish weight
(grams) was plotted on log-log paper and
demonstrated a better linear relationship
than that reported by others using an
arithmetic plot.
C. P. Straub andJ. M. Sprafka are with the School of Public Health, University of
Minnesota, Minneapolis, MN 55455.
W. R. Swain is the EPA Project Officer (see below).
The complete report, entitled "Environmental Levels of PCB in Great Lakes Fish,"
{Order No. PB 83-264 481; Cost: $10.00, subject to change) will be available only
from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Environmental Research Laboratory
U.S. Environmental Protection Agency
6201 Congdon Blvd.
Duluth.'MN 55804
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