During the seventeen years she worked in the US Fish and Wildlife Service, Rachel Carson learned about the problems of pesticides. Undaunted by the chemical companies' hostility and by the public's high enthusiasm for pesticides, she wrote a book called Silent Spring, which caused a major shift in public consciousness about the environment.
The following is a summary of Silent
Spring by Gino J. Marco in Silent Spring Revisited:
In the first several chapters, Rachel Carson stated that the
large number of chemicals (approximately 500, many were
pesticides) introduced each year was possibly making the earth
unfit for all life. Insecticides were becoming deadlier and
deadlier. Specialists were concerned only about efficacy and
were losing sight of the overall picture. Before World War II,
inorganic chemicals were the main pest controls. Arsenicals
were greatly used, and toxicological problems occurred. Carson
emphasized chlorinated hydrocarbons and organophosphates as the
main problems leading to bird and fish kills, human nervous
system disorders, and deaths. She noted that herbicides were at
one time considered no problem to animals. She explored the
possibility of surface and ground water contamination problems.
She explained that water treatment plants did not remove
chemicals because multiple chemicals in catch basins could
interact to form toxic compounds, and thus cancer hazards from
polluted waters would increase in the future.
Carson stated that chemicals treatment of soils led to the
destruction of beneficial biological species, and that such
destruction resulted in imbalance to the ecosystem. Also,
wildlife that ate chemically killed worms also dies. She noted
the long-term persistence of chlorinated hydrocarbons in soil
and the possible transfer of chemicals into plants grown in
such soils. She stated that government officials had aerially
sprayed areas without notifying the public, and that these
officials underestimated the safety problems of chemicals .
Carson highly praised the desirability and great potential of
using biological controls in place of chemicals, as well as use
of natural products and less toxic chemicals (e.g.,
pyrethrins). She pointed out that scientists' and government
officials' concerns addressed only classical toxicity of
pesticides and that no testing was done on effects to wildlife.
Regarding residues in food, she stated that government
protection through the Food and Drug Administration was minimal
and that tolerances provided a false sense of security, because
usually, only minimal safety data were available.
In human safety, Carson pointed out that exposure to or
ingestion of various products, each at individually safe
levels, taken together, could lead to health problems. Also,
she described the concept of delayed physiological symptoms
(e.g., mental problems and cancer). She also considered
disruption of key metabolic pathways and mutations a high price
to pay to have no mosquitoes. She stated that with safety
knowledge increasing rapidly, what is safe today is not safe
tomorrow. She cited tumors and leukemias brought on by
carbamates, DDT, and aminotriazole as problems.
Carson discussed the resistance of insects to insecticides
at length and indicated that the U.S. Department of
Agriculture's solution at the time was to recommend more
frequent sprays or greater quantities. She sated that DDT
brought on the "age of resistance" and noted that chemical
treatment was a treadmill that , once started, could not be
Carson concluded that our desire of total control of nature
was conceived in arrogance.