The Great Lakes contain 95% of the fresh water in the U.S., and 20% of
the fresh water in the entire world. For 200 years people considered
these lakes too large to pollute; they thought you could dump anything
and it would disappear. Nearly 40% of U.S. industry, and half of
Canada's industry, operates within the Great Lakes basin (the area from
which rainfall drains into the Great Lakes).
In 1970, LIFE magazine declared Lake Erie "dead," mainly due to
phosphorus (from sewage treatment plants and factories) causing the
excessive growth of algae, which used up the available oxygen and
killed off other oxygen users, such as sport fish. Lake Ontario was not
much better. The Cuyahoga River in Ohio became a symbol of industrial
neglect when it caught fire several times in the late '60s.
The U.S. and Canada signed an agreement in 1972 and spent $10 billion
in the next five years cleaning up the lakes. Phosphorus dumped into
the lake was cut 80% by building sewage treatment plants and limiting
the phosphorus in detergents. Water quality began to improve. However,
in 1978 it was obvious that more needed to be done, so a new agreement
was signed, this time to control toxic discharges into the lakes.
Authorities drew up a list of 350 toxics, aiming to keep them out of
the lakes entirely. They identified 11 chemicals as critical
pollutants: lead, mercury, hexachlorobenzene, PCBs, four pesticides
(mirex, DDT, dieldrin and toxaphene), dioxins, furans, and polynuclear
aromatic hydrocarbons (such as benzo[a]pyrene).
Nine years later, in 1987, it was plain that the toxics control program
wasn't working, so a new agreement was signed. "The problem of
persistent toxic substances is the foremost problem confronting the
Great Lakes," says Thomas Brydges, a scientist with Environment Canada
(equivalent to U.S. Environmental Protection Agency).
Wildlife is showing the effects. Fish in the Great Lakes are developing
cancer of the liver. They have other cancers as well, but cancer of the
liver is the most prevalent. As with any medical problem, a cause and
effect relationship between pollution and fish tumors is impossible to
"prove," but John Harshbarger, director of the registry of tumors in
lower animals at the American Museum of Natural History, says the
"circumstantial evidence is so strong it is almost impossible to deny."
In addition to liver tumors, 100% of the Coho salmon in the Great Lakes
have goiters (enlargement of the thyroid gland). "They also lack
secondary sex characteristics, have impaired lipid metabolism, are
unusually small, and 75% of the embryos die," Harshbarger explains.
Birds in the Great Lakes are being born with serious birth defects.
Some Cormorants are born with "crossed bill defect"--the upper and
lower halves of their bills don't meet because the upper bill curves
off to one side; they die within a few weeks because their bills are
useless for catching fish. Hatching success is another measure of the
health of bird populations; a colony of Forster's terns in Green Bay
hatches 52% of its young, compared to 100% in colonies living in
cleaner waters. Populations of mink and river otters are thought to be
declining as a result of toxics interfering with reproduction.
Humans living in the Great Lakes basin accumulate more toxics than
people elsewhere, according to a joint report by the U.S. National
Research Council and Canada's Royal Society. The main route of exposure
is eating fish from the lakes, but beef grown around the lakes also has
high levels of PCBs.
Among women living in the Great Lakes basin, breast milk has high
levels of PCBs. A breast-feeding infant gets six times the daily dose
of PCBs approved by the U.S. Food and Drug Administration (FDA). Babies
born to mothers who eat Great Lakes fish aren't carried to full term,
have low birth weight, have small heads, and show behavior
abnormalities. (See RHWN #61.)
A report by two employees of Environment Canada summarized hundreds of
studies relating levels of toxics in the Great Lakes with the health of
wildlife and people. They point out that human cancer rates in the
Great Lakes basin and the St. Lawrence River Valley are higher than in
many other parts of the U.S. and Canada. Heart disease and birth
defects also seem elevated in the Great Lakes basin. The report has
caused a storm of controversy, but it has also drawn high praise; some
scientists call it "very important, a revolutionary document akin to
SILENT SPRING for people rather than birds." Others of a different
stripe poohpooh the suggestion that chemicals obviously harming
wildlife might also be harming humans.
Back in 1972 when efforts were first begun to clean the Great Lakes,
people thought toxics came from two sources: factories and sewage
treatment plants. Now they recognize six major sources: factories,
sewage plants, runoff from farmland and municipal streets (socalled
non-point sources), contaminated groundwater, contaminated sediments
(old pollution coming back to haunt us), and the atmosphere.
Pollution of the atmosphere results from many legal and generally-
accepted methods of waste disposal: the disposal of sewage sludge on
the land, aeration of toxics in open lagoons, municipal waste
incineration, sewage sludge incineration, and the cleansing of
contaminated groundwater by "air stripping." Obviously, another source
is the 2.4 billion pounds of toxics that American industry reported
releasing into the atmosphere in 1987.
The incineration of municipal solid waste is a major source of lead,
cadmium and mercury. The combustion of coal is also a major source of
these, plus arsenic; and motor fuel combustion is the biggest source
for lead and cadmium. PCBs are evaporating into the atmosphere from
U.S. landfills, where 154,000 tons of PCBs lie buried.
Pesticides banned in the U.S. but still being sold by U.S. companies in
foreign locales may also be coming home to roost in the Great Lakes.
For example, part of the 12,000 tons of DDT used in Latin America rains
down on the Great Lakes each year, entering water, plankton, fish, and
Another source of toxics for the Great Lakes is the 132 Superfund sites
on the U.S. side and 10 major chemical dumps on the Canadian side. And
these are just the "official" big ones. One river, the Niagara, has 164
chemical dumps along its U.S. side. CHEMICAL & ENGINEERING NEWS, a
publication of the American Chemical Society, acknowledges the dilemmas
caused by chemical dumps. "If the material is merely removed from one
site and placed in another so-called secure landfill with a liner, the
liner will eventually fail.... Similarly, active hazardous waste
landfills that comply with current U.S. laws may present problems to
future generations. Some of them are sited along the Great Lakes and
rivers leading into them. When the liners fail, they too may require
very expensive cleanup." The U.S. Geological Survey notes that soils
around the Great Lakes are sand and gravel; leachate travels through
such soils rapidly, entering the lakes.
For all the international concern about the Great Lakes, the toxics
problem is worsening. Control programs are inadequate because the
toxics problem is being treated in piecemeal fashion. The only time
sharp improvement has occurred was when dieldrin, heptachlor, DDT,
PCBs, and mirex were banned within the Great Lakes basin in the early
'70s. It seems clear that until Americans and Canadians REDUCE THEIR
USE OF TOXIC MATERIALS, the Great Lakes will continue to be poisoned
more each year.
Get: Tom Muir and Anne Sudar, TOXIC CHEMICALS IN THE GREAT LAKES BASIN
ECOSYSTEM: SOME OBSERVATIONS (1988); order from Tom Muir, Environment
Canada, P.O. Box 5050, Burlington, Ontario, CN L7R4A6; phone (416) 336-
4951. And see: Bette Hileman, "The Great Lakes Cleanup Effort," C&EN
[CHEMICAL & ENGINEERING NEWS] February 8, 1988, pgs. 22-39.
Descriptor terms: great lakes; water pollution; wildlife; fish;
mammals; pcbs; incineration; landfilling; air pollution;
biomagnification; canada; pesticides; birth defects; developmental
disorders; cancer; teratogens; birds;