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Endocrine Disruptors: A World on Drugs

Are hormone disruptors to blame for deformed animals and humans?



Endocrine disruptors like BPA have been linked to birth defects in frogs, fish and humans alike.


Fish on drugs. It sounds like a horror movie, or a satirical headline from The Onion. But a growing number of scientists are deeply concerned about the effects that chemicals known as endocrine disruptors are having on wildlife -- and on people.

What Are Endocrine-Disrupting Chemicals?

Your body's hormones -- testosterone, estrogen, insulin, adrenaline and others -- are controlled by your endocrine system. Hormones start affecting human growth while a fetus is still developing, and continue to influence our health and development through adolescence into old age.

It's the same with most animals. The endocrine systems of birds, fish, frogs, reptiles and other animals profoundly influence the development of the males and females of each species. Only in the presence of testosterone, for example, will a male fetus properly develop a scrotum and a penis.

A class of chemicals called endocrine disruptors throw this delicately balanced system out of whack. Also called hormone disruptors, these chemicals can mimic hormones like estrogen; their presence can disrupt the normal development of a male fetus, causing significant birth defects including hypospadia (when the opening of the penis is misplaced, sometimes by several inches).

A wide range of chemicals -- most of which were developed after World War II -- are now recognized as endocrine disruptors. The pesticide DDT is a potent hormone disruptor that wreaks havoc on the female reproductive system. Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and pesticides including organochlorine insecticides are also widely believed to be endocrine-disrupting chemicals.

While most of the chemicals listed above are subject to strict restrictions or outright bans, two of the most troubling are still in wide use. Bisphenol-A, or BPA, is a plastic additive that makes plastics hard. Phthalates, on the other hand, are used to make plastic soft and squishy. Both of these are suspected of being potent endocrine disruptors, and are regulated only in certain cases, like in baby products.

The Rise of the Mutants

Several years ago, scientists starting seeing strange changes in wild fish, frogs, birds and other aquatic animals. It all started when raptors like eagles began laying eggs with shells so weak the eggs broke before they hatched. Soon, populations of birds like bald eagles, ospreys and other birds that live on aquatic animals like fish started plummeting.

As America's national bird, the bald eagle, began to disappear from the United States, scientists also started seeing some odd changes in the fish, frogs and other animals these birds eat. Birth defects like missing limbs, extra limbs and intersex animals -- individuals with both male and female characteristics -- began appearing worldwide.

Banning DDT helped restore America's national symbol to her skies, but reports from the field were far from encouraging. In 2003, scientists reported populations of trout in Lake Ontario were being decimated, and the cause was isolated: organochlorine pesticides, which caused blue sac disease, marked by a bluish fluid forming in the egg yolks. Many of the fish were either never born or died soon after birth.

In recent years, reports of aquatic animals with freakish mutations have come flooding in: An alarming 2010 study found a whopping 80 percent of the male bass fish in the Potomac River had intersex characteristics like carrying eggs in their testes. An earlier report found that of 111 test sites across the United States, one-third had intersex fish.

In 2013, the perch in three rivers in Maryland were found to have problems with their testes or ovaries. And in England, male river otters were found to have shrunken penis bones, undescended testicles and cysts on sperm-carrying organs.

In all of these cases, the culprit is believed to be the same: endocrine disruptors from plastics, pharmaceuticals and pesticides.

What About the Humans?

The CDC has reported that rates of the birth defect known as hypospadia, where the urethra is not at the tip of the penis but somewhere farther down the shaft, have almost doubled since 1968.

Dozens of reports have come in from around the world noting the sperm counts of otherwise healthy young men are a fraction of what they were just a few decades ago. In France, sperm counts are only two-thirds of what they were in 1989.

All of these studies, from fish to frogs to birds to humans, point to once common problem: The prevalence of endocrine-disrupting chemicals in our environment is wreaking havoc on the reproductive development of both animals and humans.

Stopping the Rise in Hormone Disruptors

Fortunately, scientists worldwide are now sounding the alarm over the dramatic rise in birth defects and reproductive deficiencies linked to endocrine disruptors. But there is much, much work to be done to safeguard human and animal health.

While Canada, Europe and other regions have taken steps to regulate or ban endocrine-disrupting compounds, the stranglehold that corporate lobbyists and campaign donors have over the U.S. Congress has stymied U.S. efforts to regulate many chemicals including hormone disruptors.

"For several well-studied endocrine disruptors, I think it is fair to say that we have enough data to conclude that these chemicals are not safe for human populations," Laura Vandenberg, a Tufts University developmental biologist, told the New York Times.

Many people, including scientists, aren't waiting for the government to act. John Peterson Myers, chief scientist at Environmental Health Sciences, no longer buys canned food because cans are usually lined with BPA.

"We don't microwave in plastic," he told the Times. "We don't use pesticides in our house. I refuse receipts whenever I can. My default request at the A.T.M. ... is 'no receipt.' I never ask for a receipt from a gas station."

Why? Because receipts often have a film of BPA on them. The endocrine-disrupting chemical is so pervasive, and so troubling, that even scientists won't touch it. Will you?

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