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The Great Lakes (Superior, Michigan,
Huron, Erie, and Ontario) are an important part of the physical
and cultural heritage of North America. The magnitude of the
Great Lakes water basin is difficult to appreciate. The lakes
contain some 5,500 cubic miles of water, covering 94,000 square
miles, with a shoreline of over 10,000 miles. The Great Lakes
is the largest system of fresh surface water on earth, comprising
roughly 18 % of the world supply. Only the polar ice caps
contain more fresh water. Approximately 10% of the U.S. population
and 25% of the Canadian population live in the region (US
EPA and Government of Canada, 1995).
For over 200 years, the Great Lakes basin
has been used as a resource for industry, agriculture, shipping,
and recreation. By the early 1960s, the environmental quality
of the Great Lakes had deteriorated. Eutrophication, overfishing,
and the widespread presence of toxic substances all contributed
to the decline. The physical nature of the basin and the long
retention time of chemicals in the lakes combine to make this
huge freshwater resource a repository for chemical and their
by-products. Despite their size, the lakes are especially
sensitive to pollution. Less than one percent of their total
volume flows out of the St. Lawrence River each year, allowing
toxic substances to accumulate in the lake sediment (Hicks,
1996).
Because of the persistence and widespread
occurrence of these Great Lakes pollutants, toxic effects
in wildlife have been demonstrated (Table 1). Epidemiologic
investigations conducted in the late 1970s and early 1980s
suggest that adverse human health effects, i.e., reproductive,
developmental, behavioral, neurologic, and immunologic, may
result from exposure to Great Lakes pollutants (Colborn et
al., 1990; Fein et al., 1984; Jacobson and Jacobson, 1988;
Jacobson, Jacobson, and Humphrey, 1990a, 1990b). Given the
implications of the association between persistent toxic substances
(PTSs) in the Great Lakes and the potential for adverse human
health outcomes, in 1990 the U.S. Congress amended the Great
Lakes Critical Programs Act to investigate this human health
concern.
Initiated in 1992, the Agency for Toxic
Substances and Disease Registry (ATSDR) Great Lakes Human
Health Effects Research Program (GLHHERP) is designed to characterize
exposure to contaminants via consumption of Great Lakes fish,
and investigate the potential for short- and long-term adverse
health effects.
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