‘
?
—'“Ï '
,;w““
;
(
’
'
-
lè
îëga
.
1968—1971, a series of 19 more sessions were held at which state and federal
'
ofcials, scientists, businessmen, and conservaüonists discussed the problems
of the lake. The objective was to formulate a series of recommendations to be
endorsed by the federal government and written into regulations by the four
states surrounding Lake Michigan (Wisconsin, Illinois, Indiana, and Mich—
_
igan).
of. these sessions appear in a 9000—page, 20—v01urhe
series which provides the basis for most of this chapter [l];
Conference speakers docurnented a long list of ills _plaguing the lake,
among them industrial pollutants including cils, phenols, chlorides, sulfates,
polyChlor‘inated biphenyls, phthalate plasticizers, and many other chemicals.
The rising level of phosphate nutrients from municipal sewage and agr‘iCul—
tural runoff already had produced overfertization of inshore Waters, thereby
‘
reducing the dissolved oxygen content in the water and causing widespread
eutr0phic problems. Conditions favorable to eutrophication were intensied
in the summer of 1967 by phosphate nutrientS from the decaying carcasses of
ve billion tons of dead alewives, small sh belonging to an ocean species that
had been introduced into the Great Lakes by man. The alewives adapted only
partially to the freshwater environment
were particularly vulnerable
_
to natural temperature changes. Coho salmon, introduced into Lake Mich—
igan to prey on the alewives and to provide sport shing, had acquired very
,
high levels of DDT which made many of them unt for commercial
[2].
Residue levels of DDT and its breakdown products were also high in Other
_’
‘
species of sh. These problems With sh, “some experts concluded, Were s'ymp—
'
.
toms of serious biological changesbrought about by
industrial, mücipal,‘ -
?
—'“Ï '
,;w““
;
(
’
'
-
lè
îëga
.
1968—1971, a series of 19 more sessions were held at which state and federal
'
ofcials, scientists, businessmen, and conservaüonists discussed the problems
of the lake. The objective was to formulate a series of recommendations to be
endorsed by the federal government and written into regulations by the four
states surrounding Lake Michigan (Wisconsin, Illinois, Indiana, and Mich—
_
igan).
of. these sessions appear in a 9000—page, 20—v01urhe
series which provides the basis for most of this chapter [l];
Conference speakers docurnented a long list of ills _plaguing the lake,
among them industrial pollutants including cils, phenols, chlorides, sulfates,
polyChlor‘inated biphenyls, phthalate plasticizers, and many other chemicals.
The rising level of phosphate nutrients from municipal sewage and agr‘iCul—
tural runoff already had produced overfertization of inshore Waters, thereby
‘
reducing the dissolved oxygen content in the water and causing widespread
eutr0phic problems. Conditions favorable to eutrophication were intensied
in the summer of 1967 by phosphate nutrientS from the decaying carcasses of
ve billion tons of dead alewives, small sh belonging to an ocean species that
had been introduced into the Great Lakes by man. The alewives adapted only
partially to the freshwater environment
were particularly vulnerable
_
to natural temperature changes. Coho salmon, introduced into Lake Mich—
igan to prey on the alewives and to provide sport shing, had acquired very
,
high levels of DDT which made many of them unt for commercial
[2].
Residue levels of DDT and its breakdown products were also high in Other
_’
‘
species of sh. These problems With sh, “some experts concluded, Were s'ymp—
'
.
toms of serious biological changesbrought about by
industrial, mücipal,‘ -