They are investigating the decline of sperm counts; the reproductive failures of species ranging from Florida alligators to bald eagles; deformities in frogs, fish, and birds; and the rise in childhood cancers and cancers in human reproductive systems. A number of these scientists have concluded there is a link between impaired intellectual and behavioral development in children and several of the thousands of human-made chemicals that form the foundation of modern industry.
In this issue, we focus primarily on those chemicals found in plastics, household and yard products, food, water, toys, and even baby bottles that may be disrupting our hormone systems. Virtually all of us already carry these persistent substances in our bodies. Those born since the early 1950s were probably exposed before birth - a time when these chemicals can affect the delicate hormonal balances that signal each developmental stage - and in the crucial first months of life through mothers' milk or formula.
There are over 70,000 synthetic chemicals dispersed in the environment. Some will be around for many years, concentrating as they move up the food chain. Many have never been tested for their effects on human and animal health, much less tested in the combinations that can increase their potency by 10 or 20 times. We and all life on Earth have become unwitting participants in an uncontrolled experiment on the effects of these human-made chemicals.
We can't recapture all the chemicals that have already been released into the biosphere. But we can minimize and phase out the manufacturing and use of these substances through smart design; we can reduce or eliminate further releases of these substances; and we can make our own homes and yards far less toxic.
Perhaps most basic to facing the dilemmas posed by these findings is to begin to take seriously the precautionary principle. As Barry Commoner suggests, we may need to avoid the introduction of any substances that were not part of the evolutionary soup in which we evolved - at least until their safety has been established.