Pesticide Impacts on
Human Health

Theo Colborn Receives the Rachel Carson Leadership Award

Acceptance Speech by Theo Colborn
Chatham College, Pittsburgh, PA
June 19, 1997

I would not be receiving this award tonight if it were not for a handful of field biologists whom I met in 1987 from the US and Canada who knew long before I did that something was wrong within the Great Lakes ecosystem .. For over 15 years these "silent heroes" -- who had been energized by what they had read in "Silent Spring" -- had been observing widespread evidence of damage in birds, fish, and other wildlife throughout the region and warned that something was wrong with the Lakes. They had persevered over the years to bring this message to the attention of regulators and decision makers, with little success. For their effort they were given lateral transfers, loss of pay increases, and reprimands, and their scientific findings were placed in the back of the bottom drawer of their supervisors' desks to await approval for publication. Their message was ignored. Their constant support for me and my coworkers since 1987 has grown to include a much larger number of scientists from many disciplines and geographic regions. Their patient instruction and willingness to share their results with me, made this award possible tonite. I did none of the original research that I and my coworkers have written about over the years. Instead we have taken their work, analysed it, repackaged it, and presented it from a global perspective. I accept this award for them tonight.

And then there have been years of constant support from the Charles Stewart Mott Foundation and the Joyce Foundation. And the exceptional support from the W. Alton Jones Foundation, encouraged by my co-author Dr. Pete Myers, that afforded me the opportunity to focus for three years on the hypothesis that man-made chemicals could be interfering with the development of wildlife and human offspring and undermining their birthright to reach their fullest potential as they mature. And of course there is Dianne Dumanoski who transformed this complex technical message into a salable book for all the world to read. Through her exceptional prose, thousands of non-scientists now are aware of the role of environmental contaminants that mimic or interfere with the natural chemical messengers that tell an embryo how to develop from the moment of conception to birth, from infancy to puberty, and through adulthood -- chemicals that have become known as endocrine disruptors, because they upset the endocrine system -- the physiological system that assures intellectual and sexual development, the ability to reproduce, and the integrity and perpetuation of a species.

Scientists now realize that although effects have been reported in adults who were directly exposed to some of these chemicals, the most sensitive period to exposure occurs prenatally and shortly after birth. The damage is insidious and irreversible and expressed in offspring as inconspicuous loss of function. These are population-wide effects, unlike cancer, acute toxicity, and obvious birth defects. Your children, their children, and all future children are at risk.

Many of the chemicals that are now known as endocrine disruptors are the same ones that Rachel Carson so vividly described in Silent Spring. She sensed that something like this was going to happen ... Early in "Silent Spring" when she was discussing DDT, she wrote:

"The poison may also be passed on from mother to offspring. Insecticide residues have been recovered from human milk [...] 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." She went on to point out that the chemicals can cross the placental barrier and although the quantities are small, they are not unimportant. She predicted what we now know is a certainty -- she wrote that "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."

She went on to write: "There has been no such parallel situation in medical history. No one yet knows what the ultimate consequences may be."

Thanks to the tenacity and curiosity of wildlife biologists, laboratory scientists, and researchers studying human health we are beginning to learn what the consequences are. They are spelled out -- article by article -- in the world's most reputable, well-respected, scientific and medical journals, such as Science, Nature, The New England Journal of Medicine, and The British Medical Journal ... to mention only a few ...

We now know that government's policy to protect us from chemicals of this nature has failed and industry's science has let us down. As Rachel Carson predicted, everyone of you has over 500 measurable man-made chemicals in your body that were never in anyone's body before the 1920s. If traditional risk assessment had worked, these chemicals would not be in your bodies or in the products you use everyday. These chemicals are found around the world. They are the legacy of the industrial chemistry of the past 70 years ... the burgeoning development of new generations of pesticides, plastics, construction material, components in automobiles, sporting goods, toys, compact discs, and other common products from the lining in food containers to dental sealants. Uncannily, Rachel Carson wrote that "what the public is asked to accept as "safe" today (remember, she wrote this in 1962)... may turn out tomorrow to be extremely dangerous." She was so right. The chemicals in your bodies were introduced into commerce because they were considered benign.

And now as we face the realization that not only pesticides but plastics and plastic components, the foundation of our econonmy and modern society, may be threatening our future, we can no longer ignore the problem.

A well coordinated entity must be establish immediately that is dedicated to long-term research and is solely devoid of political and economic control. And because the chemicals of concern are not limited to one nation or a group of nations this must be an international effort.

With hindsight we know we must address the fact that persistent organic pollutants (POPS) such as PCBS, DDT, and other pesticides are moving northward on oceanic and atmospheric currents and accumulating in wildlife and human tissue in the Arctic.

And with foresight we must take into consideration those nations in dire need to control insect-borne diseases such as malaria and dengue fever. We need a crash research program to develop alternatives for DDT and other persistent insecticides in order to reduce this source of global contamination.

A research agenda such as this will require cooperation among industry, governments, national institutes, and academia in a true spirit of addressing the many questions that have been raised about the role of prenatal exposure to synthetic contaminants on reductions in, and regional differences in, semen quality, for instance; and in the development of our children's brains and behavior; and whether the contaminants are, indeed, inducing cancers of the breast, ovaries, testicles, and prostate.

Corporations will have to take the lead and come forth with the money first. Governments will have to follow and contribute to the effort with the wealthier governments providing larger shares. Success of this ad hoc, cooperative effort will hinge solely on the ability to separate the industry and government monies from all facets of the work -- from the research design stage to the communication of the results.

In light of the weight of evidence concerning the ultimate threat to human health and survival, and biodiversity, it is imperative to establish this international entity as soon as possible. For if the hypothesis holds, the research costs will seem infinitesimally small compared with what the costs might be if society does not heed the messages from the scientific community.

I am optimistic about the future, however, for a number of reasons. First and most important, the effects caused by these man-made chemicals are not mutations. Instead the man-made chemicals interfere with the natural chemicals that tell cells, tissues, and organs how to develop and function. If exposure can be avoided, future generations can develop once again according to the blue print in the genes they inherited from their ancestors.

Over the past decade scientists from around the world have directed their research toward this problem. In so doing they have crossed a threshold of discovery that allows no turning back. Let me remind you of what Rachel Carson wrote about scientists: "There is one quality that characterizes all of us who deal with the sciences of the earth and life ... we are never bored. We can't be. There is always something new to be investigated. Every mystery solved brings us to the threshold of a greater one." In essence she was talking about discovery. Discovery is an elixir for scientists who care, it drives them forward ... and prevents burn out. Granted, there will always be skeptics. But they don't thrive on discovery, they thrive on special interest money, which is not as lasting as human endurance when seeking truth.

I am certain that this time around the world is going to listen. Mankind is now into the third generation of individuals, who, as Rachel Carson pointed out, from conception, have been exposed to these chemicals. The evidence is unfolding before multidisciplinary teams of scientists who are not going to let this new field of research die.

Because of this, paradigms are being challenged on how chemicals should be tested for their safety and how we measure risk. Terms like weight of evidence, reverse onus, and the precautionary principle are becoming the vogue in Washington, DC.

Industrialists are rethinking how products should be designed.

More than 100 nations have called for negotiations in an international convention to reduce or eliminate Persistent Organic Pollutants (POPs), all of which are endocrine disrupting chemicals.

The US Congress, in its 1996 session, passed several federal mandates acknowledging the problem of endocrine disruptors.

If we take advantage of this momentum and focus our attention on protecting the most vulnerable -- those in the womb -- I am certain that we will reaffirm our children's birthright to reach their fullest potential.

In closing: I could not have accepted this award tonight without also accepting the responsibility to press for the end of the great human experiment that Rachel Carson exposed over 35 year ago. I promise you that I will not quit now that I have this award. I intend to take advantage of every opportunity to raise consciousness about this issue ...

Thank you for this very special award and for giving me this opportunity to raise your consciousness.