2023年12月27日发(作者：)

SILENT SPRING

By RACHEL CARSON

(ONE SINGLE BOOK WHICH BROUGHT THE ISSUE OF PESTICIDES

CENTERSTAGE. WITH MASS SCALE POISONING OF THE LAND WITH

PESTICIDES AND WITH THOUSANDS OF FARMERS COMMITTING SUICIDE.

THIS BOOK IS ESSENTIAL FOR PUBLIC RESEARCH IN INDIA.)

Contents

Acknowledgments ix

Foreword xi

1 A Fable for Tomorrow 1

2 The Obligation to Endure 5

3 Elixirs of Death 15

4 Surface Waters and Underground Seas 39

5 Realms of the Soil 53

6 Earth’s Green Mantle 63

7 Needless Havoc 85

8 And No Birds Sing 103

9 Rivers of Death 129

10 Indiscriminately from the Skies 154

11 Beyond the Dreams of the Borgias 173

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12 The Human Price 187

13 Through a Narrow Window 199

14 One in Every Four 219

15 Nature Fights Back 245

16 The Rumblings of an Avalanche 262

17 The Other Road 277

List of Principal Sources 301

Index 357

Acknowledgments

IN A LETTER written in January 1958, Olga Owens Huckins told me of her

own bitter experience of a small world made lifeless, and so brought my

attention sharply back to a problem with which I had long been

concerned. I then realized I must write this book.

During the years since then I have received help and encouragement

from so many people that it is not possible to name them all here. Those

who have freely shared with me the fruits of many years’ experience and

study represent a wide variety of government agencies in this and other

countries, many universities and research institutions, and many

professions. To all of them I express my deepest thanks for time and

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thought so generously given.

In addition my special gratitude goes to those who took time to read

portions of the manuscript and to offer comment and criticism based on

their own expert knowledge. Although the final responsibility for the

accuracy and validity of the text is mine, I could not have completed the

book without the generous help of these specialists: L. G. Bartholomew,

M.D., of the Mayo Clinic, John J. Biesele of the University of Texas, A. W.

A. Brown of the University of Western Ontario, Morton S. Biskind, M.D.,

of Westport, Connecticut, C. J. Briejer of the Plant Protection Service in

Holland, Clarence Cottam of the Rob and Bessie Welder Wildlife

Foundation, George Crile, Jr., M.D., of the Cleveland Clinic, Frank Egler of

Norfolk, Connecticut, Malcolm M. Hargraves, M.D., of the Mayo Clinic, W.

C. Hueper, M.D., of the National Cancer Institute, C. J. Kerswill of the

Fisheries Research Board of Canada, Olaus Murie of the Wilderness

Society, A. D. Pickett of the Canada Department of Agriculture, Thomas G.

Scott of the Illinois Natural History Survey, Clarence Tarzwell of the Taft

Sanitary Engineering Center, and George J. Wallace of Michigan State

University. Every writer of a book based on many diverse facts owes

much to the skill and helpfulness of librarians. I owe such a debt to many,

but especially to Ida K. Johnston of the Department of the Interior

Library and to Thelma Robinson of the Library of the National Institutes

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of Health. As my editor, Paul Brooks has given steadfast encouragement

over the years and has cheerfully accommodated his plans to

postponements and delays. For this, and for his skilled editorial

judgment, I am everlastingly grateful. I have had capable and devoted

assistance in the enormous task of library research from Dorothy Algire,

Jeanne Davis, and Bette Haney Duff. And I could not possibly have

completed the task, under circumstances sometimes difficult, except for

the faithful help of my housekeeper, Ida Sprow.

Finally, I must acknowledge our vast indebtedness to a host of people,

many of them unknown to me personally, who have nevertheless made

the writing of this book seem worthwhile. These are the people who first

spoke out against the reckless and irresponsible poisoning of the world

that man shares with all other creatures, and who are even now fighting

the thousands of small battles that in the end will bring victory for sanity

and common sense in our accommodation to the world that surrounds

us.

Foreword

IN 1958, when Rachel Carson undertook to write the book that became

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Silent Spring, she was fifty years old. She had spent most of her

professional life as a marine biologist and writer with the U.S. Fish and

Wildlife Service. But now she was a world-famous author, thanks to the

fabulous success of The Sea Around Us, published seven years before.

Royalties from this book and its successor, The Edge of the Sea, had

enabled her to devote full time to her own writing.

To most authors this would seem like an ideal situation: an established

reputation, freedom to choose one’s own subject, publishers more than

ready to contract for anything one wrote. It might have been assumed

that her next book would be in a field that offered the same

opportunities, the same joy in research, as did its predecessors. Indeed

she had such projects in mind. But it was not to be.

While working for the government, she and her scientific colleagues had

become alarmed by the widespread use of DDT and other long-lasting

poisons in so-called agricultural control programs. Immediately after the

war, when these dangers had already been recognized, she had tried in

vain to interest some magazine in an article on the subject. A decade

later, when the spraying of pesticides and herbicides (some of them

many times as toxic as DDT) was causing wholesale destruction of

wildlife and its habitat, and clearly endangering human life, she decided

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she had to speak out. Again she tried to interest the magazines in an

article. Though by now she was a well-known writer, the magazine

publishers, fearing to lose advertising, turned her down. For example, a

manufacturer of canned baby food claimed that such an article would

cause “unwarranted fear” to mothers who used his product. (The one

exception was The New Yorker, which would later serialize parts of Silent

Spring in advance of book publication.)

So the only answer was to write a book—book publishers being free of

advertising pressure. Miss Carson tried to find someone else to write it,

but at last she decided that if it were to be done, she would have to do it

herself. Many of her strongest admirers questioned whether she could

write a salable book on such a dreary subject. She shared their doubts,

but she went ahead because she had to. “There would be no peace for

me,” she wrote to a friend, “if I kept silent.”

Silent Spring was over four years in the making. It required a very

different kind of research from her previous books. She could no longer

recount the delights of the laboratories at Woods Hole or of the marine

rock pools at low tide. Joy in the subject itself had to be replaced by a

sense of almost religious dedication. And extraordinary courage: during

the final years she was plagued with what she termed “a whole

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catalogue of illnesses.”

Also she knew very well that she would be attacked by the chemical

industry. It was not simply that she was opposing indiscriminate use of

poisons but—more fundamentally—that she had made clear the basic

irresponsibility of an industrialized, technological society toward the

natural world. When the attack did come, it was probably as bitter and

unscrupulous as anything of the sort since the publication of Charles

Darwin’s Origin of Species a century before. Hundreds of thousands of

dollars were spent by the chemical industry in an attempt to discredit

the book and to malign the author—she was described as an ignorant

and hysterical woman who wanted to turn the earth over to the insects.

These attacks fortunately backfired by creating more publicity than the

publisher possibly could have afforded. A major chemical company tried

to stop publication on the grounds that Miss Carson had made a

misstatement about one of their products. She hadn’t, and publication

proceeded on schedule.

She herself was singularly unmoved by all this furor狂热；激怒. Meanwhile,

as a direct result of the message in Silent Spring, President Kennedy set

up a special panel of his Science Advisory Committee to study the

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problem of pesticides. The panel’s report, when it appeared some

months later, was a complete vindication of her thesis.

Rachel Carson was very modest about her accomplishment. As she wrote

to a close friend when the manuscript was nearing completion: “The

beauty of the living world I was trying to save has always been

uppermost in my mind—that, and anger at the senseless, brutish things

that were Now l can believe I have at least helped a little.”

In fact, her book helped to make ecology, which was an unfamiliar word

in those days, one of the great popular causes of our time. It led to

environmental legislation at every level of government.

Twenty-five years after its original publication, Silent Spring has more

than a historical interest. Such a book bridges the gulf between what C. P.

Snow called “the two cultures.” Rachel Carson was a realistic,

well-trained scientist who possessed the insight and sensitivity of a poet.

She had an emotional response to nature for which she did not apologize.

The more she learned, the greater grew what she termed “the sense of

wonder.” So she succeeded in making a book about death a celebration

of life.

Rereading her book today, one is aware that its implications are far

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broader than the immediate crisis with which it dealt. By awaking us to a

specific danger—the poisoning of the earth with chemicals—she has

helped us to recognize many other ways (some little known in her time)

in which mankind is degrading the quality of life on our planet. And

Silent Spring will continue to remind us that in our overorganized and

overmechanized age, individual initiative and courage still count:

change can be brought about, not through incitement煽动，刺激 to war or

violent revolution, but rather by altering the direction of our thinking

about the world we live in.

1. A Fable for Tomorrow

THERE WAS ONCE a town in the heart of America where all life seemed

to live in harmony with its surroundings. The town lay in the midst of a

checkerboard of prosperous farms, with fields of grain and hillsides of

orchards where, in spring, white clouds of bloom drifted above the green

fields. In autumn, oak and maple（枫树） and birch set up a blaze of

color that flamed and flickered across a backdrop of pines. Then foxes

barked in the hills and deer silently crossed the fields, half hidden in the

mists of the fall mornings.

Along the roads, laurel, viburnum and alder, great ferns and wildflowers

delighted the traveler’s eye through much of the year. Even in winter the

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roadsides were places of beauty, where countless birds came to feed on

the berries and on the seed heads of the dried weeds rising above the

snow. The countryside was, in fact, famous for the abundance and

variety of its bird life, and when the flood of migrants was pouring

through in spring and fall, people traveled from great distances to

observe them. Others came to fish the streams, which flowed clear and

cold out of the hills and contained shady pools where trout lay. So it had

been from the days many years ago when the first settlers raised their

houses, sank their wells, and built their barns.

Then a strange blight crept over the area and everything began to

change. Some evil spell had settled on the community: mysterious

maladies swept the flocks of chickens; the cattle and sheep sickened and

died. Everywhere was a shadow of death. The farmers spoke of much

illness among their families. In the town the doctors had become more

and more puzzled by new kinds of sickness appearing among their

patients. There had been several sudden and unexplained deaths, not

only among adults but even among children, who would be stricken

suddenly while at play and die within a few hours.

There was a strange stillness. The birds, for example—where had they

gone? Many people spoke of them, puzzled and disturbed. The feeding

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stations in the backyards were deserted. The few birds seen anywhere

were moribund; they trembled violently and could not fly. It was a spring

without voices. On the mornings that had once throbbed with the dawn

chorus of robins, catbirds, doves, jays, wrens, and scores of other bird

voices there was now no sound; only silence lay over the fields and

woods and marsh.

On the farms the hens brooded, but no chicks hatched. The farmers

complained that they were unable to raise any pigs—the litters were

small and the young survived only a few days. The apple trees were

coming into bloom but no bees droned among the blossoms, so there

was no pollination and there would be no fruit.

The roadsides, once so attractive, were now lined with browned and

withered vegetation as though swept by fire. These, too, were silent,

deserted by all living things. Even the streams were now lifeless. Anglers

no longer visited them, for all the fish had died.

In the gutters（排水沟） under the eaves（屋檐） and between the

shingles of the roofs, a white granular（颗粒状的） powder still showed

a few patches; Some weeks before it had fallen like snow upon the roofs

and the lawns, the fields and streams. No witchcraft, no enemy action

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had silenced the rebirth of new life in this stricken world. The people had

done it themselves.

This town does not actually exist, but it might easily have a thousand

counterparts in America or elsewhere in the world. I know of no

community that has experienced all the misfortunes I describe. Yet every

one of these disasters has actually happened somewhere, and many real

communities have already suffered a substantial number of them. A grim

specter has crept upon us almost unnoticed, and this imagined tragedy

may easily become a stark reality we all shall know.

What has already silenced the voices of spring in countless towns in

America? This book is an attempt to explain.

2. The Obligation to Endure

THE HISTORY OF LIFE on earth has been a history of interaction

between living things and their surroundings. To a large extent, the

physical form and the habits of the earth’s vegetation and its animal life

have been molded by the environment. Considering the whole span of

earthly time, the opposite effect, in which life actually modifies its

surroundings, has been relatively slight. Only within the moment of time

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represented by the present century has one species—man—acquired

significant power to alter the nature of his world.

During the past quarter century this power has not only increased to

one of disturbing magnitude but it has changed in character. The most

alarming of all man’s assaults upon the environment is the

contamination of air, earth, rivers, and sea with dangerous and even

lethal (deadly) materials. This pollution is for the most part

irrecoverable; the chain of evil it initiates not only in the world that must

support life but in living tissues is for the most part irreversible. In this

now universal contamination of the environment, chemicals are the

sinister and little-recognized partners of radiation in changing the very

nature of the world—the very nature of its life. Strontium 90, released

through nuclear explosions into the air, comes to earth in rain or drifts

down as fallout(放射性尘埃), lodges in soil, enters into the grass or corn

or wheat grown there, and in time takes up its abode in the bones of a

human being, there to remain until his death. Similarly, chemicals

sprayed on croplands or forests or gardens lie long in soil, entering into

living organisms, passing from one to another in a chain of poisoning and

death. Or they pass mysteriously by underground streams until they

emerge and, through the alchemy (magic) of air and sunlight, combine

into new forms that kill vegetation, sicken cattle, and work unknown

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harm on those who drink from once pure wells. As Albert Schweitzer has

said, ‘Man can hardly even recognize the devils of his own creation.’

It took hundreds of millions of years to produce the life that now inhabits

the earth—eons of time in which that developing and evolving and

diversifying life reached a state of adjustment and balance with its

surroundings. The environment, rigorously shaping and directing the life

it supported, contained elements that were hostile as well as supporting.

Certain rocks gave out dangerous radiation; even within the light of the

sun, from which all life draws its energy, there were short-wave

radiations with power to injure. Given time—time not in years but in

millennia—life adjusts, and a balance has been reached. For time is the

essential ingredient; but in the modern world there is no time.

The rapidity of change and the speed with which new situations are

created follow the impetuous (rude, violent) and heedless pace of man

rather than the deliberate pace of nature. Radiation is no longer merely

the background radiation of rocks, the bombardment of cosmic rays, the

ultraviolet (紫外线) of the sun that have existed before there was any life

on earth; Radiation is now the unnatural creation of man’s tampering

(intervene) with the atom. The chemicals to which life is asked to make

its adjustment are no longer merely the calcium and silica and copper

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and all the rest of the minerals washed out of the rocks and carried in

rivers to the sea; they are the synthetic creations of man’s inventive

mind, brewed in his laboratories, and having no counterparts in nature.

To adjust to these chemicals would require time on the scale that is

nature’s; it would require not merely the years of a man’s life but the life

of generations. And even this, were it by some miracle possible, would

be futile, for the new chemicals come from our laboratories in an endless

stream; almost five hundred annually find their way into actual use in

the United States alone. The figure is staggering and its implications are

not easily grasped—500 new chemicals to which the bodies of men and

animals are required somehow to adapt each year, chemicals totally

outside the limits of biologic experience.

Among them are many that are used in man’s war against nature. Since

the mid-1940s over 200 basic chemicals have been created for use in

killing insects, weeds, rodents (n. 啮齿动物，啮齿类),

and other organisms

described in the modern vernacular as ‘pests’; and they are sold under

several thousand different brand names.

These sprays, dusts, and aerosols (气雾剂, 喷雾)are now applied almost

universally to farms, gardens, forests, and homes— nonselective

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chemicals that have the power to kill every insect, the ‘good’ and the

‘bad’, to still the song of birds and the leaping of fish in the streams, to

coat the leaves with a deadly film, and to linger on in soil—all this

though the intended target may be only a few weeds or insects. Can

anyone believe it is possible to lay down such a barrage of poisons on

the surface of the earth without making it unfit for all life? They should

not be called ‘insecticides’, but ‘biocides’.

The whole process of spraying seems caught up in an endless spiral. Since DDT was released for civilian use, a process of escalation (n. 增加；扩大；逐步上升)

has been going on in which ever more toxic

materials must be found. This has happened because insects, in a triumphant vindication of Darwin’s principle of the survival of the fittest, have evolved super races immune to the particular insecticide used, hence a deadlier one has always to be developed—and then a deadlier one than that. It has happened also because, for reasons to be described later, destructive insects often undergo a ‘flareback’, or resurgence, after spraying, in numbers greater than before. Thus the chemical war is never won, and all life is caught in its violent crossfire.

Along with the possibility of the extinction of mankind by nuclear war,

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the central problem of our age has therefore become the

contamination of man’s total environment with such substances of

incredible potential for harm—substances that accumulate in the

tissues of plants and animals and even penetrate the germ cells to

shatter or alter the very material of heredity upon which the shape of

the future depends. Some would-be architects of our future look toward

a time when it will be possible to alter the human germ plasm by design.

But we may easily be doing so now by inadvertence, for many chemicals,

like radiation, bring about gene mutations. It is ironic to think that man

might determine his own future by something so seemingly trivial as

the choice of an insect spray.

All this has been risked—for what? Future historians may well be

amazed by our distorted sense of proportion. How could intelligent

beings seek to control a few unwanted species by a method that

contaminated the entire environment and brought the threat of

disease and death even to their own kind? Yet this is precisely what we

have done. We have done it, moreover, for reasons that collapse the

moment we examine them. We are told that the enormous and

expanding use of pesticides is necessary to maintain farm production.

Yet is our real problem not one of overproduction? Our farms, despite

measures to remove acreages from production, and to pay farmers not

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to produce, have yielded such a staggering excess of crops that the

American taxpayer in 1962 is paying out more than one billion dollars a

year as the total carrying cost of the surplus-food storage program. And

is the situation helped when one branch of the Agriculture Department

tries to reduce production while another states, as it did in 1958, ‘It is

believed generally that reduction of crop acreages under provisions of

the Soil Bank will stimulate interest in use of chemicals to obtain

maximum production on the land retained in crops.’

All this is not to say there is no insect problem and no need of control. I

am saying, rather, that control must be geared to realities, not to

mythical situations, and that the methods employed must be such that

they do not destroy us along with the insects.

The problem whose attempted solution has brought such a train of

disaster in its wake is an accompaniment of our modern way of life. Long

before the age of man, insects inhabited the earth—a group of

extraordinarily varied and adaptable beings. Over the course of time

since man’s advent (n. 到来；出现；基督降临；基督降临节), a small percentage of the

more than half a million species of insects have come into conflict with

human welfare in two principal ways: as competitors for the food supply

and as carriers of human disease.

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Disease-carrying insects become important where human beings are

crowded together, especially under conditions where sanitation is poor,

as in time of natural disaster or war or in situations of extreme poverty

and deprivation. Then control of some sort becomes necessary. It is a

sobering fact, however, as we shall presently see, that the method of

massive chemical control has had only limited success, and also

threatens to worsen the very conditions it is intended to curb

(restrain).

Under primitive agricultural conditions the farmer had few insect

problems. These arose with the intensification of agriculture—the

devotion of immense acreages to a single crop. Such a system set the

stage for explosive increases in specific insect populations. Single-crop

farming does not take advantage of the principles by which nature works;

it is agriculture as an engineer might conceive it to be. Nature has

introduced great variety into the landscape, but man has displayed a

passion for simplifying it. Thus he undoes the built-in checks and

balances by which nature holds the species within bounds. One

important natural check is a limit on the amount of suitable habitat for

each species. Obviously then, an insect that lives on wheat can build up

its population to much higher levels on a farm devoted to wheat than on

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one in which wheat is intermingled with other crops to which the insect

is not adapted.

The same thing happens in other situations. A generation or more ago,

the towns of large areas of the United States lined their streets with the

noble elm tree (榆树). Now the beauty they hopefully created is

threatened with complete destruction as disease sweeps through the

elms, carried by a beetle that would have only limited chance to build up

large populations and to spread from tree to tree if the elms were only

occasional trees in a richly diversified planting.

Another factor in the modern insect problem is one that must be viewed against a background of geologic and human history: the spreading of thousands of different kinds of organisms from their native homes to invade new territories. This worldwide migration has been studied and graphically described by the British ecologist Charles Elton in his recent book The Ecology of Invasions. During the Cretaceous (n. 白垩纪；白垩系adj. 白垩纪的；似白垩的) Period, some hundred million years ago, flooding seas cut many land bridges between continents and living things found themselves confined in what Elton calls ‘colossal separate nature reserves’. There, isolated from others of their kind, they developed many new species. When so20

me of the land masses were joined again, about 15 million years

ago, these species began to move out into new territories—a movement that is not only still in progress but is now receiving considerable assistance from man.

The importation of plants is the primary agent in the modern spread of species, for animals have almost invariably gone along with the plants, quarantine (n. 检疫；隔离；检疫期；封锁vt. 检疫；隔离；使隔离vi. 实行隔离)

being a comparatively recent and not completely effective innovation. The United States Office of Plant Introduction alone has introduced almost 200,000 species and varieties of plants from all over the world. Nearly half of the 180 or so major insect enemies

of plants in the United States are accidental imports from abroad, and most of them have come as hitchhikers on plants.

In new territory, out of reach of the restraining hand of the natural

enemies that kept down its numbers in its native land, an invading plant

or animal is able to become enormously abundant. Thus it is no accident

that our most troublesome insects are introduced species.

These invasions, both the naturally occurring and those dependent on

human assistance, are likely to continue indefinitely. Quarantine and

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massive chemical campaigns are only extremely expensive ways of

buying time. We are faced, according to Dr. Elton, ‘with a life-and-death

need not just to find new technological means of suppressing this plant

or that animal’; instead we need the basic knowledge of animal

populations and their relations to their surroundings that will ‘promote

an even balance and damp down the explosive power of outbreaks and

new invasions.’

Much of the necessary knowledge is now available but we do not use it.

We train ecologists in our universities and even employ them in our

governmental agencies but we seldom take their advice. We allow the

chemical death rain to fall as though there were no alternative, whereas

in fact there are many, and our ingenuity could soon discover many more

if given opportunity.

Have we fallen into a mesmerized (adj. 着迷的v. 施催眠术，迷住，迷惑）state that makes us accept as inevitable that which is inferior or detrimental, as though having lost the will or the vision to demand

that which is good? Such thinking, in the words of the ecologist

Paul Shepard, ‘idealizes life with only its head out of water, inches above the limits of toleration of the corruption of its Why should we tolerate a diet of weak poisons, a home i22

n insipid surroundings, a circle of acquaintances who are not quiteour enemies, the noise of motors with just enough relief to prevent insanity? Who would want to live in a world which is just not quite fatal?’

Yet such a world is pressed upon us. The crusade to create a chemically sterile, insect-free world seems to have engendered a fanatic zeal on the part of many specialists and most of the so-called

control agencies. On every hand there is evidence that those engaged in spraying operations exercise a ruthless power. ‘The regulatory entomologists

(n.昆虫学者) function as prosecutor (n. 检察官；公诉人；[法] 起诉人；实行者), judge and jury, tax assessor and collector and sheriff to enforce their own orders,’ said Connecticut entomologist Neely Turner. The most flagrant (declared公然的；notorious) abuses go unchecked in both state and federal agencies.

It is not my contention that chemical insecticides must never be used. I

do contend that we have put poisonous and biologically potent

chemicals indiscriminately into the hands of persons largely or wholly

ignorant of their potentials for harm. We have subjected enormous

numbers of people to contact with these poisons, without their

consent and often without their knowledge. If the Bill of Rights contains

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no guarantee that a citizen shall be secure against lethal poisons

distributed either by private individuals or by public officials, it is surely

only because our forefathers, despite their considerable wisdom and

foresight, could conceive of no such problem.

I contend, furthermore, that we have allowed these chemicals to be

used with little or no advance investigation of their effect on soil, water,

wildlife, and man himself. Future generations are unlikely to condone

(forgive) our lack of prudent concern for the integrity of the natural

world that supports all life.

There is still very limited awareness of the nature of the threat. This is

an era of specialists, each of whom sees his own problem and is

unaware of or intolerant of the larger frame into which it fits. It is also

an era dominated by industry, in which the right to make a dollar at

whatever cost is seldom challenged. When the public protests,

confronted with some obvious evidence of damaging results of pesticide

applications, it is fed little tranquilizing pills of half truth. We urgently

need an end to these false assurances, to the sugar coating of

unpalatable facts. It is the public that is being asked to assume the risks

that the insect controllers calculate. The public must decide whether it

wishes to continue on the present road, and it can do so only when in

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full possession of the facts. In the words of Jean Rostand, ‘The

obligation to endure gives us the right to know.’

3. Elixirs (特效药)of Death

FOR THE FIRST TIME in the history of the world, every human being is

now subjected to contact with dangerous chemicals, from the moment

of conception (pregnancy) until death. In the less than two decades of

their use, the synthetic pesticides have been so thoroughly distributed

throughout the animate and inanimate world that they occur virtually

everywhere.

They have been recovered from most of the major river systems and

even from streams of groundwater flowing unseen through the earth.

Residues of these chemicals linger in soil to which they may have been

applied a dozen years before. They have entered and lodged in the

bodies of fish, birds, reptiles, and domestic and wild animals so

universally that scientists carrying on animal experiments find it almost

impossible to locate subjects free from such contamination. They have

been found in fish in remote mountain lakes, in earthworms burrowing

in soil, in the eggs of birds—and in man himself. For these chemicals are

now stored in the bodies of the vast majority of human beings,

regardless of age. They occur in the mother’s milk, and probably in the

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tissues of the unborn child.

All this has come about because of the sudden rise and prodigious growth of an industry for the production of man-made or synthetic chemicals with insecticidal

(adj.杀虫的；杀虫剂的)

properties. This industry is a child of the Second World War. In the course of developing agents of chemical warfare, some of the chemicals created in the laboratory were found to be lethal to insects. The discovery did not come by chance: insects were widely used to test chemicals as agents of death for man.

The result has been a seemingly endless stream of synthetic insecticides. In being man-made—by ingenious laboratory manipulation of the molecules, substituting atoms, altering their arrangement—they differ sharply from the simpler insecticides of prewar days. These were derived from naturally occurring minerals and plant products—compounds of arsenic (n. 砷；砒霜；三氧化二砷adj. 砷的；含砷的), copper, manganese (锰), zinc, and other minerals, pyrethrum (n. [农药] 除虫菊；除虫菊杀虫剂) from the dried flowers of chrysanthemums (n. 菊花), nicotine (尼古丁) sulphate from some of the relatives of tobacco, and rotenone (n. [农药] 鱼藤酮) from leguminous

( adj.豆科的) plants of the East Indies.

26

What sets the new synthetic insecticides apart is their enormous

biological potency. They have immense power not merely to poison but

to enter into the most vital processes of the body and change them in

sinister and often deadly ways. Thus, as we shall see, they destroy the

very enzymes (n. 酶) whose function is to protect the body from harm,

they block the oxidation (氧化）processes from which the body receives its

energy, they prevent the normal functioning of various organs, and they

may initiate in certain cells the slow and irreversible change that leads to

malignancy (恶性肿瘤或疾病).

Yet new and more deadly chemicals are added to the list each year and

new uses are devised so that contact with these materials has become

practically worldwide. The production of synthetic pesticides in the

United States soared from 124,259,000 pounds in 1947 to 637,666,000

pounds in 1960—more than a fivefold increase. The wholesale value of

these products was well over a quarter of a billion dollars. But in the

plans and hopes of the industry this enormous production is only a

beginning.

A Who’s Who of pesticides is therefore of concern to us all. If we are

going to live so intimately with these chemicals—eating and drinking

27

them, taking them into the very marrow of our bones—we had better

know something about their nature and their power.

Although the Second World War marked a turning away from inorganic

chemicals as pesticides into the wonder world of the carbon molecule, a

few of the old materials persist. Chief among these is arsenic (砷，砒霜),

which is still the basic ingredient in a variety of weed and insect killers.

Arsenic is a highly toxic mineral occurring widely in association with the

ores of various metals (五金矿), and in very small amounts in volcanoes, in

the sea, and in spring water. Its relations to man are varied and historic.

Since many of its compounds are tasteless, it has been a favorite agent of

homicide (murder) from long before the time of the Borgias to the

present. Arsenic is present in English chimney soot (烟囱的烟灰) and along

with certain aromatic hydrocarbons (芳香族碳氢化合物)

is considered

responsible for the carcinogenic (or cancer-causing) action of the soot,

which was recognized nearly two centuries ago by an English physician.

Epidemics of chronic arsenical poisoning

(慢性砷中毒流行病) involving whole

populations over long periods are on record. Arsenic-contaminated

environments have also caused sickness and death among horses, cows,

goats, pigs, deer, fishes, and bees; despite this record arsenical sprays

and dusts are widely used. In the arsenic-sprayed cotton country of

southern United States beekeeping as an industry has nearly died out.

28

Farmers using arsenic dusts over long periods have been afflicted with

chronic arsenic poisoning, livestock (家畜) have been poisoned by crop

sprays or weed killers containing arsenic. Drifting arsenic dusts from

blueberry lands have spread over neighboring farms, contaminating

streams, fatally poisoning bees and cows, and causing human illness. ‘It

is handle arsenicals with more utter disregard of

the general health than that which has been practiced in our country in

recent years,’ said Dr. W. C. Hueper, of the National Cancer Institute, an

authority on environmental cancer. ‘Anyone who has watched the

dusters and sprayers of arsenical insecticides at work must have been

impressed by the almost supreme carelessness with which the

poisonous substances are dispensed.’

Modern insecticides are still more deadly. The vast majority fall into one

of two large groups of chemicals. One, represented by DDT, is known as

the ‘chlorinated hydrocarbons (氯化烃). The other group consists of the

organic phosphorus insecticides (有机磷杀虫剂), and is represented by the

reasonably familiar malathion (马拉硫磷)

and parathion (对硫磷). All have one

thing in common. As mentioned above, they are built on a basis of

carbon atoms, which are also the indispensable building blocks of the

living world, and thus classed as ‘organic’. To understand them, we must

see of what they are made, and how, although linked with the basic

29

chemistry of all life, they lend themselves to the modifications which

make them agents of death.

The basic element, carbon, is one whose atoms have an almost infinite

capacity for uniting with each other in chains and rings and various other

configurations(配置), and for becoming linked with atoms of other

substances. Indeed, the incredible diversity of living creatures from

bacteria to the great blue whale is largely due to this capacity of carbon.

The complex protein molecule has the carbon atom as its basis, as have

molecules of fat, carbohydrates, enzymes, and vitamins. So, too, have

enormous numbers of nonliving things, for carbon is not necessarily a

symbol of life.

Some organic compounds are simply combinations of carbon and hydrogen. The simplest of these is methane (n. [有化] 甲烷；[能源] 沼气), or

marsh gas, formed in nature by the bacterial decomposition of organic matter under water. Mixed with air in proper proportions, methane becomes the dreaded ‘fire damp’ of coal mines. Its structure is beautifully simple, consisting of one carbon atom to which four hydrogen atoms have become attached: Chemists have discovered that it is possible to detach one or all of the hydrogen atoms and substitute other elements. For example, by substituting one a30

tom of chlorine(氯)

for one of hydrogen we produce methyl chloride(氯代甲烷):

Take away three hydrogen atoms and substitute chlorine and we have the anesthetic chloroform(麻醉剂氯仿(三氯甲烷）): Substitute chlorine atoms for all of the hydrogen atoms and the result is carbon tetrachloride(四氯化碳), the familiar cleaning fluid:

In the simplest possible terms, these changes rung upon the basic

molecule of methane illustrate what a chlorinated hydrocarbon is. But

this illustration gives little hint of the true complexity of the chemical

world of the hydrocarbons, or of the manipulations by which the organic

chemist creates his infinitely varied materials. For instead of the simple

methane molecule with its single carbon atom, he may work with

hydrocarbon molecules consisting of many carbon atoms, arranged in

rings or chains, with side chains or branches, holding to themselves with

chemical bonds not merely simple atoms of hydrogen or chlorine but

also a wide variety of chemical groups. By seemingly slight changes the

whole character of the substance is changed; for example, not only what

is attached but the place of attachment to the carbon atom is highly

important. Such ingenious manipulations have produced a battery of

poisons of truly extraordinary power.

31

DDT (short for dichloro-diphenyl-trichloro-ethane) was first synthesized

by a German chemist in 1874, but its properties as an insecticide were

not discovered until 1939. Almost immediately DDT was hailed as a

means of stamping out insect-borne disease and winning the farmers’

war against crop destroyers overnight. The discoverer, Paul Müller of

Switzerland, won the Nobel Prize.

DDT is now so universally used that in most minds the product takes on

the harmless aspect of the familiar. Perhaps the myth of the

harmlessness of DDT rests on the fact that one of its first uses was the

wartime dusting of many thousands of soldiers, refugees, and prisoners,

to combat lice(虱子). It is widely believed that since so many people came

into extremely intimate contact with DDT and suffered no immediate ill

effects the chemical must certainly be innocent of harm. This

understandable misconception arises from the fact that—unlike other

chlorinated hydrocarbons—DDT in powder form is not readily absorbed

through the skin. Dissolved in oil, as it usually is, DDT is definitely toxic. If

swallowed, it is absorbed slowly through the digestive tract; it may also

be absorbed through the lungs. Once it has entered the body it is stored

largely in organs rich in fatty substances (because DDT itself is fat-soluble

adj. 脂溶性的，可溶于油脂的) such as the adrenals肾上腺, testes睾丸, or thyroid甲状腺. Relatively large amounts are deposited in the liver, kidneys, and the

32

fat of the large, protective mesenteries

肠系膜that enfold the intestines脏.

内

This storage of DDT begins with the smallest conceivable intake of the

chemical (which is present as residues on most foodstuffs) and continues

until quite high levels are reached. The fatty storage depots act as

biological magnifiers放大镜, so that an intake of as little as of 1 part per

million in the diet results in storage of about 10 to 15 parts per million,

an increase of one hundredfold or more. These terms of reference, so

commonplace to the chemist or the pharmacologist药理学家, are

unfamiliar to most of us. One part in a million sounds like a very small

amount—and so it is. But such substances are so potent that a minute

quantity can bring about vast changes in the body. In animal experiments,

3 parts per million has been found to inhibit an essential enzyme in heart

muscle; only 5 parts per million has brought about necrosis

坏死；坏疽；骨疽or disintegration of liver cells; only 2.5 parts per million of the closely

related chemicals dieldrin and chlordane did the same.

This is really not surprising. In the normal chemistry

化学过程of the human

body there is just such a disparity between cause and effect. For example,

a quantity of iodine

碘；碘酒as small as two ten-thousandths of a gram

spells the difference between health and disease. Because these small

33

amounts of pesticides are cumulatively stored and only slowly excreted

(vt. 排泄；分泌), the threat of chronic poisoning and degenerative changes of

the liver and other organs is very real.

Scientists do not agree upon how much DDT can be stored in the human

body. Dr. Arnold Lehman, who is the chief pharmacologist of the Food

and Drug Administration, says there is neither a floor below which DDT is

not absorbed nor a ceiling beyond which absorption and storage ceases.

On the other hand, Dr. Wayland Hayes of the United States Public Health

Service contends that in every individual a point of equilibrium (balance)

is reached, and that DDT in excess of this amount is excreted. For

practical purposes it is not particularly important which of these men is

right. Storage in human beings has been well investigated, and we know

that the average person is storing potentially harmful amounts.

According to various studies, individuals with no known exposure (except

the inevitable dietary one) store an average of 5.3 parts per million to

7.4 parts per million; agricultural workers 17.1 parts per million; and

workers in insecticide plants as high as 648 parts per million! So the

range of proven storage is quite wide and, what is even more to the

point, the minimum figures are above the level at which damage to the

liver and other organs or tissues may begin.

34

One of the most sinister features of DDT and related chemicals is the

way they are passed on from one organism to another through all the

links of the food chains. For example, fields of alfalfa

苜蓿 are dusted

with DDT; meal is later prepared from the alfalfa and fed to hens; the

hens lay eggs which contain DDT. Or the hay, containing residues of 7 to

8 parts per million, may be fed to cows. The DDT will turn up in the milk

in the amount of about 3 parts per million, but in butter made from this

milk the concentration may run to 65 parts per million. Through such a

process of transfer, what started out as a very small amount of DDT may

end as a heavy concentration. Farmers nowadays find it difficult to

obtain uncontaminated fodder for their milk cows, though the Food and

Drug Administration forbids the presence of insecticide residues in milk

shipped in interstate commerce.

The poison may also be passed on from mother to offspring. Insecticide

residues have been recovered from human milk in samples tested by

Food and Drug Administration scientists. This means that the breast-fed

human infant is receiving small but regular additions to the load of toxic

chemicals building up in his body. It is by no means his first exposure,

however: there is good reason to believe this begins while he is still in

the womb. In experimental animals the chlorinated hydrocarbon

insecticides freely cross the barrier of the placenta胎盘, the traditional

35

protective shield between the embryo

胚胎；胚芽and harmful substances in

the mother’s body. While the quantities so received by human infants

would normally be small, they are not unimportant because children are

more susceptible (fragile / vulnerable) to poisoning than adults. This

situation also means that today the average individual almost certainly

starts life with the first deposit of the growing load of chemicals his body

will be required to carry thenceforth.

All these facts—storage at even low levels, subsequent accumulation,

and occurrence of liver damage at levels that may easily occur in normal

diets, caused Food and Drug Administration scientists to declare as early

as 1950 that it is ‘extremely likely the potential hazard of DDT has been

underestimated.’ There has been no such parallel situation in medical

history. No one yet knows what the ultimate consequences may be.

Chlordane[农药] 氯丹（一种强力杀虫剂）, another chlorinated hydrocarbon, has

all these unpleasant attributes of DDT plus a few that are peculiarly its

own. Its residues are long persistent in soil, on foodstuffs, or on surfaces

to which it may be applied. Chlordane makes use of all available portals

to enter the body. It may be absorbed through the skin, may be breathed

in as a spray or dust, and of course is absorbed from the digestive tract if

residues are swallowed. Like all other chlorinated hydrocarbons, its

36

deposits build up in the body in cumulative fashion. A diet containing

such a small amount of chlordane as 2.5 parts per million may eventually

lead to storage of 75 parts per million in the fat of experimental animals.

So experienced a pharmacologist as Dr. Lehman has described chlordane

in 1950 as ‘one of the most toxic of insecticides—anyone handling it

could be poisoned.’ Judging by the carefree liberality with which dusts

for lawn treatments by suburbanites are laced with chlordane, this

warning has not been taken to heart. The fact that the suburbanite

郊区居民is not instantly stricken has little meaning, for the toxins may sleep long

in his body, to become manifest months or years later in an obscure

disorder almost impossible to trace to its origins. On the other hand,

death may strike quickly. One victim who accidentally spilled a 25 per

cent industrial solution on the skin developed symptoms of poisoning

within 40 minutes and died before medical help could be obtained. No

reliance can be placed on receiving advance warning which might allow

treatment to be had in time.

Heptachlor七氯

, one of the constituents of chlordane, is marketed as a

separate formulation. It has a particularly high capacity for storage in fat.

If the diet contains as little as of 1 part per million there will be

measurable amounts of heptachlor in the body. It also has the curious

37

ability to undergo change into a chemically distinct substance known as

heptachlor epoxide环氧七氯. It does this in soil and in the tissues of both

plants and animals. Tests on birds indicate that the epoxide that results

from this change is more toxic than the original chemical, which in turn is

four times as toxic as chlordane.

As long ago as the mid-1930s a special group of hydrocarbons, the

chlorinated naphthalenes氯化萘, was found to cause hepatitis肝炎, and

also a rare and almost invariably fatal liver disease in persons subjected

to occupational exposure. They have led to illness and death of workers

in electrical industries; and more recently, in agriculture, they have been

considered a cause of a mysterious and usually fatal disease of cattle. In

view of these antecedents, it is not surprising that three of the

insecticides that are related to this group are among the most violently

poisonous of all the hydrocarbons. These are dieldrin[农药] 狄氏剂；氧桥氯甲桥萘, aldrin[农药] 艾氏剂；阿耳德林, and endrin异狄氏剂.

Dieldrin, named for a German chemist, Diels, is about 5 times as toxic as

DDT when swallowed but 40 times as toxic when absorbed through the

skin in solution. It is notorious for striking quickly and with terrible effect

at the nervous system, sending the victims into convulsions抽搐. Persons

thus poisoned recover so slowly as to indicate chronic effects. As with

38

other chlorinated hydrocarbons, these long-term effects include severe

damage to the liver. The long duration of its residues and the effective

insecticidal action make dieldrin one of the most used insecticides today,

despite the appalling destruction of wildlife that has followed its use. As

tested on quail

鹌鹑and pheasantstimes as toxic as DDT.

There are vast gaps in our knowledge of how dieldrin is stored or

distributed in the body, or excreted, for the chemists’ ingenuity in

devising insecticides has long ago outrun biological knowledge of the

way these poisons affect the living organism. However, there is every

indication of long storage in the human body, where deposits may lie

dormant

休眠的；静止的；睡眠状态的；隐匿的like a slumbering volcano, only to flare

up in periods of physiological

生理的stress when the body draws upon its

fat reserves. Much of what we do know has been learned through hard

experience in the antimalarial

抗疟疾的野鸡, it has proved to be about 40 to 50

campaigns carried out by the

World Health Organization. As soon as dieldrin was substituted for DDT

in malaria疟疾；瘴气-control work (because the malaria mosquitoes had

become resistant to DDT), cases of poisoning among the spray men

began to occur. The seizures

癫痫，痉挛；发作were severe—from half to all

(varying in the different programs) of the men affected went into

convulsions and several died. Some had convulsions as long as four

39

months after the last exposure.

Aldrin is a somewhat mysterious substance, for although it exists as a

separate entity it bears the relation of alter ego to dieldrin. When

carrots are taken from a bed treated with aldrin they are found to

contain residues of dieldrin. This change occurs in living tissues and also

in soil. Such alchemistic transformations have led to many erroneous

reports, for if a chemist, knowing aldrin has been applied, tests for it he

will be deceived into thinking all residues have been dissipated. The

residues are there, but they are dieldrin and this requires a different test.

Like dieldrin, aldrin is extremely toxic. It produces degenerative changes

in the liver and kidneys. A quantity the size of an aspirin tablet is enough

to kill more than 400 quail鹌鹑. Many cases of human poisonings are on

record, most of them in connection with industrial handling.

Aldrin, like most of this group of insecticides, projects a menacing

shadow into the future, the shadow of sterility. Pheasants fed

quantities too small to kill them nevertheless laid few eggs, and the

chicks that hatched soon died. The effect is not confined to birds. Rats

exposed to aldrin had fewer pregnancies and their young were sickly and

short-lived. Puppies born of treated mothers died within three days. By

40

one means or another, the new generations suffer for the poisoning of

their parents. No one knows whether the same effect will be seen in

human beings, yet this chemical has been sprayed from airplanes over

suburban areas and farmlands.

Endrin is the most toxic of all the chlorinated hydrocarbons. Although

chemically rather closely related to dieldrin, a little twist in its molecular

structure makes it 5 times as poisonous. It makes the progenitor

祖先；原著；起源of all this group of insecticides, DDT, seem by comparison almost

harmless. It is 15 times as poisonous as DDT to mammals, 30 times as

poisonous to fish, and about 300 times as poisonous to some birds.

In the decade of its use, endrin has killed enormous numbers of fish, has

fatally poisoned cattle that have wandered into sprayed orchards, has

poisoned wells, and has drawn a sharp warning from at least one state

health department that its careless use is endangering human lives.

41

In one of the most tragic cases of endrin poisoning there was no

apparent carelessness; efforts had been made to take precautions

apparently considered adequate. A year-old child had been taken by his

American parents to live in Venezuela. There were cockroaches in the

house to which they moved, and after a few days a spray containing

endrin was used. The baby and the small family dog were taken out of

the house before the spraying was done about nine o’clock one morning.

After the spraying the floors were washed. The baby and dog were

returned to the house in midafternoon. An hour or so later the dog

vomited, went into convulsions, and died. At on the evening of

the same day the baby also vomited, went into convulsions, and lost

consciousness. After that fateful contact with endrin this normal, healthy

child became little more than a vegetable—unable to see or hear,

subject to frequent muscular spasms肌痉挛, apparently completely cut off

from contact with his surroundings. Several months of treatment in a

New York hospital failed to change his condition or bring hope of change.

‘It is extremely doubtful,’ reported the attending physicians, ‘that any

useful degree of recovery will occur.’

The second major group of insecticides, the alkyl or organic phosphates,

烷基和有机磷酸盐are among the most poisonous chemicals in the world.

The chief and most obvious hazard attending their use is that of acute

42

poisoning of people applying the sprays or accidentally coming in contact

with drifting spray, with vegetation coated by it, or with a discarded

container. In Florida, two children found an empty bag and used it to

repair a swing. Shortly thereafter both of them died and three of their

playmates became ill. The bag had once contained an insecticide called

parathion, one of the organic phosphates磷酸盐; Tests established death

by parathion

对硫磷poisoning. On another occasion two small boys in

Wisconsin, cousins, died on the same night. One had been playing in his

yard when spray drifted in from an adjoining field where his father was

spraying potatoes with parathion; the other had run playfully into the

barn after his father and had put his hand on the nozzle

喷嘴；管口；鼻of the

spray equipment.

The origin of these insecticides has a certain ironic significance. Although

some of the chemicals themselves—organic estersacid磷酸的有机酯—had

酯类 of phosphoric

been known for many years, their insecticidal

properties remained to be discovered by a German chemist, Gerhard

Schrader, in the late 1930s. Almost immediately the German government

recognized the value of these same chemicals as new and devastating

weapons in man’s war against his own kind, and the work on them was

declared secret. Some became the deadly nerve gasesOthers, of closely allied structure, became insecticides.

43

神经错乱性毒气.

The organic phosphorus insecticides act on the living organism in a

peculiar way. They have the ability to destroy enzymes—enzymes that

perform necessary functions in the body. Their target is the nervous

system, whether the victim is an insect or a warm-blooded animal.

Under normal conditions, an impulse passes from nerve to nerve with

the aid of a ‘chemical transmitter’ called acetylcholine乙酰胆碱, a

substance that performs an essential function and then disappears.

Indeed, its existence is so ephemeral (temporary) that medical

researchers are unable, without special procedures, to sample it before

the body has destroyed it. This transient nature of the transmitting

chemical is necessary to the normal functioning of the body. If the

acetylcholine is not destroyed as soon as a nerve impulse has passed,

impulses continue to flash across the bridge from nerve to nerve, as the

chemical exerts its effects in an ever more intensified manner. The

movements of the whole body become uncoordinated: tremorsmuscular spasms, convulsions, and death quickly result.

This contingency

偶然性, 可能性震颤；颤动,

has been provided for by the body. A

protective enzyme called cholinesterase

胆碱酯酶is at hand to destroy the

transmitting chemical once it is no longer needed. By this means a

precise balance is struck and the body never builds up a dangerous

amount of acetylcholine. But on contact with the organic phosphorus

44

insecticides, the protective enzyme is destroyed, and as the quantity of

the enzyme is reduced that of the transmitting chemical builds up. In this

effect, the organic phosphorus compounds resemble the alkaloid

生物碱poison muscarine蕈毒碱；腐鱼毒, found in a poisonous mushroom, the fly

amanita.

Repeated exposures may lower the cholinesterase

胆碱酯酶level until an

individual reaches the brink of acute poisoning, a brink over which he

may be pushed by a very small additional exposure. For this reason it is

considered important to make periodic examinations of the blood of

spray operators and others regularly exposed.

Parathion对硫磷 is one of the most widely used of the organic

phosphates磷酸盐. It is also one of the most powerful and dangerous.

Honeybees become ‘wildly agitated and bellicose (aggressive)’ on

contact with it, perform frantic cleaning movements, and are near death

within half an hour. A chemist, thinking to learn by the most direct

possible means the dose acutely toxic to human beings, swallowed a

minute amount, equivalent to about .00424 ounce. Paralysis followed so

instantaneously that he could not reach the antidotes he had prepared

at hand, and so he died. Parathion is now said to be a favorite instrument

of suicide in Finland. In recent years the State of California has reported

45

an average of more than 200 cases of accidental parathion poisoning

annually. In many parts of the world the fatality rate from parathion is

startling: 100 fatal cases in India and 67 in Syria in 1958, and an average

of 336 deaths per year in Japan.

Yet some 7,000,000 pounds of parathion are now applied to fields and

orchards of the United States—by hand sprayers, motorized blowers and

dusters, and by airplane. The amount used on California farms alone

could, according to one medical authority, ‘provide a lethal dose for 5 to

10 times the whole world’s population.’

One of the few circumstances that save us from extinction by this

means is the fact that parathion and other chemicals of this group are

decomposed rather rapidly. Their residues on the crops to which they

are applied are therefore relatively short-lived compared with the

chlorinated hydrocarbons. However, they last long enough to create

hazards and produce consequences that range from the merely serious

to the fatal. In Riverside, California, eleven out of thirty men picking

oranges became violently ill and all but one had to be hospitalized. Their

symptoms were typical of parathion poisoning. The grove had been

sprayed with parathion some two and a half weeks earlier; the residues

that reduced them to retching

v. 干呕；恶心, half-blind, semiconscious

46

misery were sixteen to nineteen days old. And this is not by any means a

record for persistence. Similar mishaps (disasters) have occurred in

groves sprayed a month earlier, and residues have been found in the peel

of oranges six months after treatment with standard dosages

The danger to all workers applying the organic phosphorus insecticides in

fields, orchards, and vineyards, is so extreme that some states using

these chemicals have established laboratories where physicians may

obtain aid in diagnosis and treatment. Even the physicians themselves

may be in some danger, unless they wear rubber gloves in handling the

victims of poisoning. So may a laundress washing the clothing of such

victims, which may have absorbed enough parathion to affect her.

Malathion, another of the organic phosphates, is almost as familiar to

the public as DDT, being widely used by gardeners, in household

insecticides, in mosquito spraying, and in such blanket attacks on insects

as the spraying of nearly a million acres of Florida communities for the

Mediterranean fruit fly. It is considered the least toxic of this group of

chemicals and many people assume they may use it freely and without

fear of harm. Commercial advertising encourages this comfortable

attitude.

47

剂量；用量.

The alleged ‘safety’ of malathion rests on rather precarious (uncertain,

dangerous) ground, although—as often happens—this was not

discovered until the chemical had been in use for several years.

Malathion is ‘safe’ only because the mammalian

哺乳类动物的liver, an organ

with extraordinary protective powers, renders it relatively harmless. The

detoxification is accomplished by one of the enzymes of the liver. If,

however, something destroys this enzyme or interferes with its action,

the person exposed to malathion receives the full force of the poison.

Unfortunately for all of us, opportunities for this sort of thing to happen

are legion (numerous). A few years ago a team of Food and Drug

Administration scientists discovered that when malathion and certain

other organic phosphates are administered simultaneously a massive

poisoning results—up to 50 times as severe as would be predicted on

the basis of adding together the toxicities of the two. In other words, of

the lethal dose of each compound may be fatal when the two are

combined.

This discovery led to the testing of other combinations. It is now known

that many pairs of organic phosphate insecticides are highly dangerous,

the toxicity being stepped up or ‘potentiated’ through the combined

action. Potentiation seems to take place when one compound destroys

48

the liver enzyme responsible for detoxifying the other. The two need not

be given simultaneously. The hazard exists not only for the man who may

spray this week with one insecticide and next week with another; it

exists also for the consumer of sprayed products. The common salad

bowl may easily present a combination of organic phosphate insecticides.

Residues well within the legally permissible limits may interact.

The full scope of the dangerous interaction of chemicals is as yet

little known, but disturbing findings now come regularly from scientific laboratories. Among these is the discovery that the toxicity of an organic phosphate can be increased by a second agent that

is not necessarily an insecticide. For example, one of the plasticizing agents

塑化剂

may act even more strongly than another insecticide to make malathion more dangerous. Again, this is because it inhibits the liver enzyme that normally would ‘draw the teeth’ of the poisonous insecticide.

What of other chemicals in the normal human environment? What, in

particular, of drugs? A bare beginning has been made on this subject, but

already it is known that some organic phosphates (parathion and

malathion) increase the toxicity of some drugs used as muscle relaxants肌肉松驰剂, and that several others (again including malathion) markedly

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