Everyone’s Backyard, Summer 2000
Title: Understanding “Low Level” Chemical Exposures
Author: Stephen Lester
In These Times, August 21, 2000
Title: What’s In Your Green Tea?
Author: Frances Cerra Whittelsey
Faculty evaluator: Suzanne Toczyski, Ph.D., Lynn Cominsky, Ph.D.
Student researchers: Stephen Hayth, Stephanie Garber, Adam Sullens, Nathalie Manneville
Corporate media coverage: Chicago Tribune, 12/26/00 Section 1p.10
For years the public has been told that a low level of chemical exposure holds no significant risk to humans. The results of recent studies, however, show that even small amounts of chemicals (in drinking water, in foods) may in fact be very damaging.
One of the most important areas of research is the field of endocrine disrupters. New research in this area has shown that chemicals like dioxin, PCBs, and DDT act at very low levels to interfere with normal hormone functions of the body. Very low levels of these chemicals have been linked to a wide variety of health problems such as neurological and developmental problems, immune system disruption, learning disabilities, birth defects, and other reproductive anomalies.
The truth is that scientists know very little about how the body responds to small amounts of numerous chemicals. In the recent endocrine studies, health effects are being reported at levels of exposure not anticipated by our current understanding of how chemicals operate in the human body. The implication is that the standard methods for assessing chemical risks may not work for many low-level chemical exposures.
One proponent of the new thinking about how chemicals impact the human body is Dr. Pete Myers, one of the co-authors of Our Stolen Future. This book explores the threat contamination poses to fetal development, and the potentially wide-ranging impacts of chemicals on human potential. According to Myers, chemical attacks against fetal development work because some chemicals act as imposters, insinuating themselves in the body’s natural hormone system that normally directs fetal development. These natural hormone signals work at very low concentrations. When traditional methods for measuring toxic effects and assessing risks are relied on solely, the impacts of low levels of chemicals that disrupt hormone signals will not be understood. As a result, risk factors for these low-level chemical exposures will be underestimated and established improperly.
Frances Cerra Whittelsey reports that seven out of ten green tea samples tested from New York store shelves showed DDT or Dursban contamination. Both are cancer-causing chemicals banned by the EPA in food products for the United States. Dangerous pesticides are still being used in countries all over the world and U.S. consumers have no assurance that green tea is free of pesticide contamination.
What is becoming apparent is that important low-level effects, such as disruption of a hormone signaling system, may be hidden by higher levels of chemical exposure, which cause more obvious impacts that are easier to measure. The full impact of low-level exposure may not be visible for years, perhaps decades, until the infant has grown into an adult. This time lag means that evidence linking cause and effect may no longer be available when the effect becomes apparent. In fact, the timing of the exposure may be more important than the amount. Exposure at a certain step of fetal development may have a dramatic effect, while the same exposure perhaps only a day or two later may have no effect or very little effect.
Lastly, hormone disrupters occur in complex mixtures in the human body. Each of us has several hundred synthetic chemicals in our blood. Every baby born throughout the world has been exposed in the womb to complex mixtures. Exactly how these chemicals will act together to interfere with normal biological functions over time is the question we have yet to answer.
Update by Frances Cerra Whittelsey
The importance of this story is that it shows the connection between the purity of the American food supply and conditions in poverty-stricken regions of the world. Even though DDT has been banned in America for nearly three decades, this persistent organic pollutant still contaminates our food supply through imports from countries still using the pesticide. It was particularly shocking for a breast cancer survivor to find DDT in the organic green tea she had been drinking to try to prevent the reoccurrence of her cancer. If Americans wish to have a food supply that its free of DDT, then we must give priority-for selfish reasons, if not humanitarian-to helping the impoverished people of Asia, Africa and India fight malaria by means other than DDT.
Since publication of my article, diplomats from 122 countries finalized the text of a global treaty that will eliminate or minimize the use of persistent organic pollutants. Because of DDT’s still-essential role in malaria prevention, the proposed treaty allows a health exemption for the chemical in malaria-prone countries. The treaty will be signed at a diplomatic conference in Stockholm on May 22 or 23, 2001, but it must then be ratified by 50 governments before it takes effect.
I am not aware of any mainstream press response to my story. There have been significant stories about the suffering and economic depression caused by malaria, and about the proposed global treaty, but none have connected the situation to the American food supply.
Sources of information:
Physicians for Social Responsibility, Karen Perry: 202-898-0150
World Wildlife Fund, Rich Liroff: 202-778-9644
Frances Cerra Whittelsey: [email protected]