Lake Michigan environmental survey : final report / [edited] by John C. Ayers.

3200 cfs.
From these data the rates of removal of materials have been computed.
The resulting estimates are given in the last three columns of Table C-8. The
Lake Michigan outflow values for the Straits and the Chicago outlet are listed
as a total and separately.
By comparing the total output with the accepted input in this table it
should be possible to estimate the lake's accumulation of each parameter. How-,ever, as indicated by those values marked with an asterisk, the output in three
cases exceeds the input. This may be real, but much more likely it should only
be interpreted as an indication of the poor quality of either the input or output estimates or both.
PESTICIDE INFLUENTS
Despite considerable search we have been unable to find any better information than that given by Dr. Donald I, Mount of the Duluth Laboratory of the
FWQA in testimony before the February 25, 1969 Conference on Pollution of Lake
Michigan and its Tributary Basin (D. I. Mount, pp. 693-761 in "Proceedings,
Conference on Pollution of Lake Michigan and its Tributary Basin, Illinois,
Indiana, Michigan and Wisconsin. Volume 2, Second Session, February 25,
1969, Chicago, Illinois. U. S. Dept. of the Interior, FWPCA"). In this testimony Dr. Mount says bluntly (pp. 729-731), "The Committee (Pesticide Committee,
FWQA, Duluth) has exerted effort to compile information on types, amounts, and
distribution of insecticides applied in the Lake Michigan drainage basin, and
has learned that there are no accurate, consistent compilations of such information. Fragmentary figures are available for some areas and for some insecticides, but extrapolation of these figures into realistic totals for the drainage basin appears impossible at the present time. Even the following general
statements on usage are subject to great error; the values are only general indications and should be used cautiously."
"In 1964 approximately 3.8 million pounds of insecticides were used on
crops in the three lake States of Minnesota, Michigan and Wisconsin (U.S.D.A.,
1968). It is not known what portion of this was applied in the Lake Michigan
watershed. In the lake States the greatest amounts of the insecticides were
used on apples and other deciduous fruits. Aldrin (that converts to dieldrin),
used on the largest acreage on corn, totalled 761,000 pounds on approximately

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