Backgrounder: Endocrine 101

The endocrine system is a set of glands, and the hormones they produce help guide and regulate the development, growth, reproduction and behavior of most living things.

"Endocrine disrupting compounds" (EDC) found in synthetic chemicals like phthalates mimic estrogen in the body and have the ability to interfere with hormonal systems. They can seriously impair development in the brain, pituitary, gonads, thyroid, and other components of the endocrine system. They have also shown to interfere with fertility and reproduction in hundreds of laboratory studies involving fish and animal species.

The fear is that they may also be playing havoc with the basic building blocks of human sexual development.

Our children are more susceptible to the adverse effects of chemicals.

These effects have been well documented for decades. DDT, DES, dioxins, and PCB's are all endocrine disrupting compounds, and all were banned after it become evident that they were harmful to both animal species and humans. In the years since these earlier chemicals were outlawed there has been a massive increase in our exposure to a whole new spectrum of EDC's that are every bit as deadly in laboratory studies as the earlier examples. Read more about the chemicals.

In May of 2007, 200 of the world's leading environmental scientists gathered in Norway. They issued a strongly worded declaration that warned that exposure to common chemicals makes babies more likely to develop an array of health problems later in life, including diabetes, attention deficit disorders, prostate cancer, fertility problems, thyroid disorders and even obesity.

"There's no question that when you show that the mother's milk has contaminants, and then you actually look at babies and show that those contaminants are not only in that child, but they stay in that child. It is revolutionary."Dr. Louis Giullette

Children are at greater risk from chemicals because of their greater biological sensitivity and greater exposure to environmental pollution relative to bodyweight. They have very immature systems for excreting toxicants, a highly permeable gastrointestinal tract and highly permeable skin. Infants also consume eight times more food per kilogram of body weight than adults, making this a more significant exposure pathway. This means that a five year old child is likely to have 10 times the amount of certain toxins in its body than his or her parents. And for reasons we are only just beginning to understand - boys seem to be at a far greater risk.

Exposure in the Womb

The womb itself is certainly no safe haven. It is now known that many environmental contaminants cross the placenta and reach the fetus. In the past five years, "body burden" tests have shown that amniotic blood contains hundred of toxic chemicals that the mother has in her body. It is now known that at certain critical windows of vulnerability, maternal exposure to toxicants is enough to permanently harm the growing fetus, causing disease and disability in childhood and across the entire span of human life.

"There are more and more studies showing that before birth, between fertilization and birth, something's happening to boys. Basically, they die before they are born."Dr. Theo Colborn

Proponents of what is called 'fetal programming' have shown that babies are born not just with traits dictated by their parents' genes, such as brown eyes and olive skin. They may also be born with a tendency to develop all sort of illnesses and health problems based on what their mothers ate and were exposed to during pregnancy. And this damage to the child may not appear for many years, sometimes not until adulthood.

Parental Effects

A native community near Sarnia, a highly industrialized city, has seen an alarming drop in the birth of boys.

It is now known that fathers are as important as mothers in the period before conception. It has been known since the mid-1970s that occupational exposures to pesticides can diminish or destroy the fertility of workers. As well, certain occupations - rubber worker, petroleum worker, agricultural chemical worker, painter, welder, and janitor - have been particularly implicated as detrimental to the health of their offspring.

Paternal exposure to solvents, pesticides, and metals has now been associated in animals and humans with the occurrence of spontaneous abortion, low birth weight, birth defects, childhood leukemia, brain cancer, change in the male to female sex ratio of offspring.

And, as with mothers, some of the most damaging exposures are the most unexpected. Many golf courses use four times as many toxic pesticides per acre as the average farm, and men who play golf during the spring are exposing themselves to massive amount of pesticide vapors.

Exposure at Home

In the past few decades the profound threat of poisonous chemicals has come home. Literally. Its an astonishing fact - the latest chemical hot spot is not a oozing swamp of toxic effluent: its our bathrooms, kitchens, living and bedrooms.

Recent studies by scientists working in the new field of "exposure analysis" have concluded that our homes expose us to more severe pollution than we get from landfills, hazardous waste sites or smokestacks. In fact, our homes are now so chemically saturated that the health risks from these indoor pollutants are far greater than the risks in the outdoor world.

"Pollution isn't something that's coming out of a smokestack. It's in us. It's become part of the background chemistry in our bodies. And it's accumulating. And it's accumulating quickly."Dr. John Peterson

We clean with them. We build them into our walls and cabinets. We spray them on bugs, weeds and gardens. We drag them into the house on our shoes and we stir them up when we walk on our carpets. They're in our toys, our shower curtains, our clothes, the water bottles we use for hiking and the baby bottles we use for breast milk and formula. They're in the televisions we watch and some of the computers that entertain us.

The net result is that the environment of the family home has become a rich soup of contaminants all swirling together inside our tightly built personal spaces. Visit The Toxic House to find out more.