For the first time in history, every human being is exposed to dangerous chemicals from the moment they are conceived. These substances have been found everywhere: in organisms in remote lakes, earthworms burrowing in the soil, and humans all over the world. Their production began during WWII and has grown rapidly ever since. New pesticides are incredibly potent, Carson warns, with the ability to affect important processes in the body. If we are to live so closely with them then we had better understand them better.
This is a new era of man – even though these synthetic chemicals have only been in existence for two decades, by using them so extensively we have already changed our environment in subtle but all-pervasive ways, so that all of us have been exposed to these chemicals. It is the public’s responsibility to become educated about the chemicals that have invaded its present, and will continue to shape its future.
Arsenic is chief among the older, inorganic pesticides. It is naturally occurring in small amounts, and highly toxic – a favorite poison since the time of the Borgias, an infamous dynasty from the Italian Renaissance. Arsenic contamination kills many species and has carcinogenic (cancer-causing) effects in humans. Nevertheless, it is sprayed with “supreme carelessness” according to Dr. W.C. Hueper, a leading expert on environmental cancers.
By recalling the use of arsenic by the Borgia family, Carson means to emphasize the chemicals infamous past as a deadly poison and in doing so question how modern people could possibly use it as a pesticide that is sprayed so carelessly. She also introduces what will become a major topic later in the book –the idea that pesticides can cause cancer, a disease that many of her readers will have some experience with.
Modern insecticides are deadlier still. There are the chlorinated hydrocarbons, including DDT, and the organic phosphorus insecticides, including malathion and parathion. They are organic, built from carbon atoms within methane molecules that have been altered in small but significant ways. Normally, for example, methane is composed of one carbon atom and four hydrogen atoms, but scientists have discovered that substituting chlorine for one of the hydrogen atoms creates methyl chloride.
Whereas arsenic occurs naturally in small doses, these new pesticides are a creation of man – and man has outdone himself, manufacturing a range of deadly poisons. On the one hand, Carson seems to celebrate the ingenuity of modern science, but she also underlines the unpredictable nature of the changes created by small alterations in the molecular make-up of these chemicals.
DDT is often thought of as harmless, because it was used in powder form to combat lice during WWII - however, in liquid form it is much more toxic, and can accumulate in the body over time. Scientists disagree about what level of accumulation is tolerable, but studies have shown that a majority of people carry unsafe levels stored in their bodies’ fat cells and vital organs, where it can build up over time. DDT in fat cells is then released over time with exertion, leading to chronic poisoning.
DDT would become a focus of Carson’s followers, who eventually succeeded in getting it banned in 1972. Carson’s focus on the issue of accumulation—in which repeated exposures at a ‘safe’ level build up within the body to produce unsafe levels of exposure – highlights how little we know about the behavior of the chemicals we are using in the real world. Her attitude of cautious skepticism is in line with the precautionary principle.
The chemical is transmitted through the food chain, and even from mother to child. If a crop of alfalfa is dusted with DDT, and then chickens are fed with infected alfalfa, their eggs have been shown to contain DDT afterwards. The same mechanism of transference has been found to function in human mothers who transmit DDT through the placenta during pregnancy or in their breast milk.
The idea that DDT and other toxins can be passed across the ‘germ line,’ which is to say, from generation to generation, raises a new set of moral questions. We are not only poisoning ourselves, but also transferring mutations and toxins to the next generation, who bear no responsibility for their creation.
Chlordane, Heptachlor, Dieldrin, and Aldrin are other pesticides in the same family (chlorinated hydrocarbons) as DDT, and each is widely used in aerial spraying of crops. Each also builds up through food chains and over time, and is many times more toxic than DDT, with evidence of seizures, sterility and death resulting from exposure. In one instance, a group of pesticide sprayers working against malarial mosquitoes substituted Dieldrin for their usual DDT and exposure to the chemical led to seizures and death among the sprayers themselves.
By listing the types of pesticide, Carson underlines their variety and how widespread they are. This anecdote of the poisoned sprayers is particularly evocative; the workers, in their attempt to use the sprays against the mosquitoes, wind up injuring themselves. This mirrors what Carson believes to be happening on a larger scale: humans, in their war against the pests, are poisoning themselves – perhaps fatally.
Endrin is the most toxic pesticide of all; for birds, it is 300 times more toxic than DDT. Carson recounts a series of terrifying anecdotes of its use, including the story of a child who went into a permanent vegetative state and a small family dog that died within hours after they had played on a floor that had been sprayed against insects.
Carson uses the story of the small dog and infant to make the effects of these toxic pesticides tragically real to the reader by demonstrating their ability to harm the most innocent and helpless members of society. Who is responsible? The horrified parents, or the companies who sold the spray?
Organic phosphates, the second group of pesticides, have their origins in German labs, where they were discovered by a chemist named Gerhard Schrader and then weaponized during WWII as nerve gas. They attack the nervous system, destroying enzymes that are vital to the proper transmission of impulses from nerve to nerve. Without this enzyme, an excess of transmitters builds up, causing convulsions and death.
The fact that the development of many pesticides came as a result of weapons research during World War II further supports Carson’s idea of a ‘war against nature,’ and in reminding her readers of this fact Carson also underlines the strangeness of this former weapon being used as though it were completely harmless, highlighting its dangerous effects on the nervous system.
An enzyme in the body naturally protects against the effects of organic phosphates, but repeated exposure in small doses can wear this defensive measure away. Instances of parathion poisoning are increasing in the U.S., and although they are less persistent than other pesticides, organic phosphates’ effects can be extreme.
This point reinforces the idea that pesticides cannot be thought of in terms of individual exposures. The natural defenses of the body are part of that ecological balance developed over millennia that Carson has described, and their disruption has unexpected consequences.
Malathion, another organic phosphate widely used in home gardening, demonstrates another important principle about synthetic chemicals: in combination they can react together in unexpected ways to inhibit natural defenses and become much deadlier. Further, these combinations can happen inside the body from separate exposures that happen over time, since chemicals build up in the body’s tissues.
Another warning that, although individual chemicals can be tested in isolation, the ways that they will interact in the environment – or even within the body itself – are much more difficult to predict. This basic unpredictability is a major reason to follow the precautionary principle.
Systemic insecticides are used to make plants poisonous to the pests that eat them. Carson compares them to the mythical dress that Medea, of ancient Greek mythology, gave to a rival, which when worn caused a violent death. These ‘built-in’ insecticides make all of the tissues of a plant or animal toxic to the insects that prey on them, but this toxicity can also be transferred in uncontrollable ways to living beings other than the targeted pests.
As with her earlier reference to the Borgias, when Carson here compares systemic insecticides to Medea’s deadly dress she is drawing upon a common cultural well of knowledge about poisons. By associating pesticides with this tradition she is challenging their perception as simple, harmless, helpful sprays.
Herbicides, poisons that target plants, are also toxic, and the myth that they are no threat to animal life is false. Many have been banned in England and Australia, although no such restrictions exist in the United States. Dinitro, penta, and amitrol are examples of herbicides with hidden, cancer-causing effects that can sometimes be transferred down the germ line, meaning that their effects carry on from one generation to another. If we are so worried about nuclear radiation, asks Carson, how can we be indifferent to the synthetic chemicals in our environment?
Widening the scope of her argument from pesticides to herbicides, Carson continues this challenge. By comparing the policies of other major countries to the United States’, she legitimates the concern about cancer caused by such sprays. Finally, by comparing the effects of synthetic chemicals to those of nuclear radiation, she takes advantage of an issue – nuclear radiation – that at the time had earned a lot of public attention and concern in order to create urgency.