Great Lakes' health gets mixed results in environmental
Drinking water ranks high; exotic species, toxins threaten
By JO SANDIN
Article courtesy of the Milwaukee Journal Sentinel
Oct. 5, 2001
The Great Lakes still rank among the world's best sources
of drinking water, but they are under siege from invasive
species, airborne toxins and urban sprawl and, much of
the time, they are not a safe place to swim.
That's the consensus of scientists in the United States
and Canada who jointly released their fourth biennial
assessment of the "State of the Great Lakes."
The 2001 report released this week by the U.S. Environmental
Protection Agency and its Canadian counterpart, Environment
Canada, rates the health of the Great Lakes as measured
by 33 environmental indicators ranging from deformities
and tumors in fish (poor) to contaminants in colonial
nesting birds (good).
"Levels of toxic chemical contamination have dropped
in many fish species," said Thomas Skinner, EPA Region
5 administrator. "However, many fish are still unsafe
to eat. Contaminant levels will need to continue to decline
for many years before advisories can be lifted or modified."
The report - which is the most comprehensive measure
of factors affecting the Great Lakes and their drainage
basins - noted these signs of good health:
- The health and abundance of the walleye fishery, although
catches were highest in Lake Erie and lowest in Lakes
Michigan and Superior.
- A drop of 50% to 90% in concentrations of contaminants
in the eggs of herring gulls since monitoring began
in 1974, although those in Lake Michigan continue to
have high levels of DDE, a degraded product of the now-banned
- The minimal level of chemical contaminants in drinking
water, even before treatment.
Only two symptoms of poor health were cited: deformities
and tumors in fish, particularly in Lake Erie, and continued
invasions from exotic species, which were named as the
greatest biological threat to Great Lakes aquatic systems.
However, beach closings increased and the number of beaches
that experienced no closings decreased.
Moreover, the report noted: "Population growth causing
both increased demands made on sewage treatment plant
capacities and the probability of release of untreated
effluent, as well as more private treatment systems, especially
in resort/vacation areas, may cause an increase of undetected
releases of inadequately treated waste."
No specific lakes or parts of the Great Lakes system
earned "good" ratings, and Lake Michigan's health was
described as mixed with improvement for fish populations
but deterioration for fish habitat.
Numbers of sea lamprey, an exotic predator that was one
of the first to ravage Great Lakes fisheries, have been
relatively stable in Lake Michigan. However, populations
in the north part of the lake have increased because of
an expansion of the large Lake Huron lamprey population.
Although lake trout are reproducing naturally throughout
Lake Superior, natural reproduction remains at very low
levels or is non-existent in the rest of the Great Lakes.
Appeared in the Milwaukee Journal Sentinel on Oct.