2000 parts per million. Meanwhile, the nesting colonies of the grebes dwindled—f ro m more
than 1000 pairs before the firs t ins ecticide treatment to about 30 pairs in 1960. And eve n the
thirty s eem to have nes ted in vain, for no young grebes have been obs erved on the lake s ince
the las t DDD application.
This whole chain of pois oning, then, s eems to res t on a bas e of minute plants which mus t have
been the original concentrators. But what of the oppos ite end of the food chain—the human
being who, in probable ignorance of all this s equence of events , has rigged his fis hing tackle,
caught a s tring of fis h from the wate rs of Clear Lake, and taken them ho me t o fry for his
s upper? What could a heavy dos e of DDD, or perhaps repeated dos es , do to hi m? Although the
California Department of Public Health professed to see no hazard, nevertheless in 1959 it
requi red that the us e of DDD in the lake be s topped. In view of the s cientific evidence of the
vast biological potency of this chemical, the action seems a minimum safety measure. The
physiological effect of DDD is probably unique among insecticides, for it des troys part of the
adrenal gland— the cells of the outer layer known as the adrenal cortex, which s ecretes the
hormone cortin. This des tructive effect, known s ince 1948, was at firs t believed to be confined
to dogs , becaus e it was not revealed in such experimental animals as monkeys, rats, or rabbits.
It s eemed s ugges tive, however, that DDD produced in dogs a condition very similar to that
occurring in man in the pres ence of Addis on’s dis eas e. Recent medical res earch has revealed
that DDD does s trongly s uppres s the function of the human adre nal cortex. Its cell-des troying
capacity is now clinically utilized in the treatment of a rare type of cancer which develops in the
adrenal gland....
The Clear Lake s ituation brings up a ques tion that the public needs to face: Is it wis e or
des irable to us e s ubs tances with s uch s trong effect on phys iological process es for the control of
ins ects , es pecially when the control measures involve introducing the chemical directly into a
body of water? The fact that the insecticide was applied in very low concentrations is
meaningles s , as its explosive progres s through the natural food chain in the lake de mons trates.
Yet Clear Lake is typical of a large and growing number of situations where solution of an
obvious and often trivial problem creates a far more serious but conveniently less tangible one.
Here the proble m was res olved in favor of thos e annoye d by gnats , and at the expe ns e of an
uns tated, and probably not even clearly unde rs tood, ris k to all who took food or wate r from the
lake. It is an extraordinary fact that the deliberate introduction of poisons into a reservoir is
becoming a fairly common practice. The purpose is usually to promote recreational uses, even
though the wate r mus t then be treate d at s ome expens e to make it fit for its intended use as
drinking wate r. When s ports me n of an area want to ‘improve’ fis hing in a res ervoir, they prevail
on authorities to dump quantities of pois on into it to kill the undes ired fis h, which are then
replaced with hatche ry fis h more s uited to the s ports men’s tas te. The procedure has a s trange,
Alice-in-Wonderland quality. The reservoir was created as a public water supply, yet the
community, probably uncons ulted about the s ports men’s project, is forced either to drink
water containing pois onous res idues or to pay out tax mone y for treatment of the wate r to
remove the pois ons—treatments that are by no mea ns foolproof.
As ground and surface waters are contaminated with pesticides and other chemicals, there is
danger that not only pois onous but als o cancer-producing s ubs tances are being introduce d into
public water s upplies. Dr. W. C. Hueper of the National Cancer Institute has warned that ‘the
danger of cancer hazards from the cons umption of conta minated drinking water will grow
backadmin
(backadmin)
#1