TATE OF THE GREAT LAKES 200,
CAN WE EAT THE FISH?
Fish Tissue
The Issue: Fish consumption advisories resulting
from chemical pollution are still issued annually by
the eight Great Lakes states and the Province of
Ontario.
• There are health risks associated with
consumption of Great Lakes fish species
carrying elevated concentrations of
contaminants in their tissue.
• Human exposure to pollutants that
accumulate in fish tissue has been linked to
reduced birth weight, developmental
problems, neurological problems, immune
system impairments, and cancer.
• Fish consumption advisories, warning
people to limit their intake of particular fish
species, are currently present in all five Great
Lakes.
The Indicator - SOGI. 2003
This indicator
assesses the extent to
which contaminants
accumulate in fish
tissue and impact
the edibility of Great
Lakes fish.
Contaminants are
ingested by fish.
While some are excreted, lipid (fat)-loving
contaminants are stored in fish tissue. As these
fish are ingested by other fish, the contaminants
accumulate at increasingly higher
concentrations. Large fish, the type most often
desired for human consumption, are often those
carrying the largest amounts of contaminants.
The indicator examines contaminant
concentrations in coho salmon in relation to the
PCBs
Mercury
Toxaphene
Chlordane
Dioxin
PCBs
Mercury
Chlordane
Dioxin
PCBs
Mercury
Toxaphene
Chlordane
Dioxin
f
PCBs
Mercury
Dioxin
PCBs
Mercury
Toxaphene
Dioxin
Mirex
Figure 1. Contaminants that cause fish consumption
advisories in each of the five Great Lakes.
need for fish consumption advisories. Currently,
contaminant concentrations in coho salmon are
examined in relation to a standardized fish
advisory, the "Protocol for a Uniform Great
Lakes Sport Fish Consumption Advisory."
Edible fish are considered those with
contaminant concentrations at levels below this
standardized advisory.
A standardized advisory is used since
consumption advisories vary by Lake and state.
State and provincial agencies establish these
advisories in response to data indicating
elevated tissue concentrations of PCBs, mercury,
and other contaminants (Figure 1).
The Assessment
Many organochlorine contaminants such as
PCBs, chlordane, and toxaphene were banned a
decade to several decades ago. These are
persistent chemicals—able to bioaccumulate in
the fatty portion of fish tissue—that we still
detect in our annual fish tissue surveys.
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CAN WE EAT THE FISH?
PCBs in Lake Superior Coho Salmon
2.5
? 2.01
Q.
S 1.5-
V)
DO 1 n
O
Q.
0.5
0
Do not eat
One meal e
On
P ^ ^ ^ ^ J
Year
iea per week Unlimit
very two months
5 meal per month
5d consumption
1.9
1.0
0.2
0.05
PCBs in Lake Michigan Coho Salmon
2.5
.
S 1.5
8
Q.
One meal every two months
One meal per month
I..I. Ill I..
0.5
0
One meal per week Unlimited consumption
PCBs in Lake Huron Coho Salmon
1.9
1.0
0.2
0.05
One meal every two months
N^ N^ ^ ^ ^ ^l
Year i
One meal per month
1.9
1.0
0.2
0.05
per week
Unlimited consumption
PCBs in Lake Erie Coho Salmon
.
,5 1.5'
5
a.
One meal per week Unlimited consumption
PCBs in Lake Ontario Coho Salmon
2.5
0.5
0
Do not eat
One meal every two months
One meal per month I
One meal per week
Year
1.9
1.0
0.2
0.05
Overall, concentrations of the banned chemicals
are decreasing over time, but they are still
present at levels that could affect humans or
other members of the food chain. As shown in
Figure 2, current PCB concentrations still
exceed health protection limits set by the Great
Lakes Protocol for PCBs in most of the Lakes.
Over time, the hope is that PCBs and other toxic
chemicals will be undetectable in fish species,
thereby removing the need for the present-day
advisories.
As banned organochlorine contaminants
continue to decline, mercury will become a
more important contaminant of concern
regarding the edibility of fish. Also,
unregulated contaminants, such as brominated
flame retardants, are now being measured in
fish tissue at elevated levels. Agencies are
starting to study and monitor these and other
chemicals in the Great Lakes.
The Outlook
Increased regional screening efforts will help to
quickly identify new chemicals of concern. A
coordinated regional approach for data
evaluation and advisory decisions may also
assist to more efficiently and effectively identify
the risks associated with Great Lakes fish
consumption.
For More Information...
Visit the web site, www.binational.net, to
access the State of the Great Lakes 2003 and
other references reporting on the state of the
Great Lakes.
Unlimited consumption
Figure 2. Results of a uniform fish advisory protocol
applied to historical data (PCBs, coho salmon).
12/03
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