Dear EarthTalk: Can you explain what "hormone disrupting" chemicals are, how they affect our health and what they have to do with environmental problems? —Tom Rose, Oakland, CA
Many of the human body's process, including reproduction, mental processing and metabolism, are controlled and regulated by hormones, chemical "messengers" produced by the endocrine glands. In the embryo and fetus, hormones guide the development of the brain, the nervous and immune systems, the sexual organs, and the liver, blood and kidneys, among other organs and tissue.
Hormones work by attaching to "receptors," molecules on cell surfaces that carry information into the cells, triggering certain actions. In recent years, scientists have found that certain man-made chemicals disrupt this process by blocking it altogether, throwing off the timing—or by actually mimicking natural hormones and binding with the cells themselves. Such chemicals have been dubbed "hormone disruptors."
Since the 1940s thousands of chemicals have been released into our air, water and food. Chemicals now contaminate virtually every corner of the globe, and the average person has over 100 chemicals in his or her body. In one study of pregnant women, the average woman had 286 chemicals in her fetal blood.
Many of the worst chemicals have been banned or phased out, but they continue to linger in the environment and will no doubt do so for centuries to come. Among the worst culprits in hormone disruption are: PCBs, used heavily in the electrical industries until banned in 1978; phthalates, still widely used in the plastics industry; and dioxin, one of the most hazardous of all chemicals, a byproduct of paper-bleaching, waste incineration and coal-burning, among other industrial activities.
The effects of this growing "chemical soup" were first noticed in wildlife. Alligators in Florida's Lake Apopka, for example, have been unable to reproduce in recent years due to underdevelopment in young males. North Sea seals exposed to synthetic chemicals have also developed reproductive problems as well as suppressed immune systems. And gull colonies in California and elsewhere suffered significant population losses after exposure to chemicals interfered with their reproductive capabilities.
According to Our Stolen Future, co-authored by Dr. Theo Colburn of the World Wildlife Fund, former Boston Globe reporter Dianne Dumanoski and Dr. J.P. Myers, now Senior Advisor to the United Nations Foundation, numerous human health problems also owe their origin to hormone disrupting chemicals. They include low sperm count and increased testicular and prostate cancers among men, and increased rates of breast cancer, endometriosis and tubal pregnancies in women. "What we're talking about is an overall low-dose exposure and a cumulative effect," says Holly Lucille, author of Creating and Maintaining Balance: A Woman's Guide to Safe, Natural Hormone Health.
With so many chemicals permeating our environment, it is almost impossible to attribute specific health problems to specific substances. Individuals can hedge their bets by eating organic and choosing personal care and household products that avoid chemicals. They can also pressure their elected representatives as well as business leaders to work to reduce the amount of pervasive chemicals in the environment.
CONTACT: Our Stolen Future, www.ourstolenfuture.org.
Dear EarthTalk: Is bamboo really an environmentally friendly alternative to wood for making paper? If so, why are we still cutting down trees to keep our copiers and printers humming?—Ali Forte, via e-mail
Bamboo is a fast-growing and renewable resource, and it has long been used throughout Asia as a raw material for many goods, including paper. With North America's supply of forests now dwindling, bamboo is starting to look like a viable alternative to wood pulp to make paper for Western consumption. It has a similar consistency to wood pulp, and most existing paper mills can adapt to it with existing infrastructure.
On the other hand, clearing forests to establish bamboo plantations across the globe hardly makes environmental sense. Aaron Lehmer of ReThink Paper, a project of Earth Island Institute, calls the rapid expansion of bamboo plantations in Southeast Asia "alarming," and says that it is "setting up a status quo whereby natural forests are increasingly being developed" for bamboo cultivation for paper.
Most of this bamboo is feeding paper mills in China and India, says Lehmer, but increasing demand from North America and Europe could deplete existing supplies and force Southeast Asian producers to push deeper into the forests. This would deplete primary habitat for hundreds of threatened species of birds, pandas, reptiles and amphibians. "Since there are no international standards or certification mechanisms in place for bamboo, neither paper producers nor consumers have any way of knowing whether the bamboo they purchase is coming from endangered ecosystems," he adds.
According to the World Bamboo Organization, a trade group, 12 million acres of bamboo reserves exist across Asia today. If demand for bamboo were to increase, Lehmer says, surely the environment in these areas would suffer. Indeed, environmentalists in India are already crying foul over government-subsidized bamboo extraction from that country's supposedly protected forests, including the world-renowned Nagarjunasagar Tiger Reserve, one of the last suitable habitats in the world for the big endangered cats.
ReThink Paper would rather see North American paper producers convert existing mills to process locally generated agricultural waste, such as wheat or rice straw. These are usually plentiful and inexpensive, and paper companies could reap significant financial benefit getting raw material from local farmers eager to offload otherwise unmarketable "biomass" waste. This makes eminent environmental sense, too, says Lehmer, compared to importing bamboo chips from far away on planes, trains, ships and trucks that emit tons of climate-altering carbon dioxide en route.
The debate over papermaking reminds us that modern society has yet to go "paperless" as many predicted we would. But our inability to achieve that goal as yet doesn't make efforts to cut back worthless. Everyone can do their part at home, school and office to reduce paper usage, even if only one sheet at a time.