Plastics: What’s Dangerous, What’s Not

Enlarge Image Image Gallery Some water bottles can leach BPA into their contents when left out in the sun or otherwise heated. STEPHEN HUTCHINGS

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You’ve been out — working, exercising, shopping. You open the car door and slip into the ovenlike interior. Throat dry, you reach for the water bottle that’s been sitting in the cup holder all day. It’s warm. But at least it’s water, right? Water, yes, albeit water potentially spiked with chemicals that migrated out of the plastic — chemicals that aren’t good for your health.

The latest scientific research has given us a lot of good reasons to think carefully about how we use plastics. The main concern with several types of plastic is that they contain endocrine disruptors — substances that, when taken into our bodies, alter normal hormonal function. Over the past several years, scientists and the media have struggled to find answers to mysteries such as precocious puberty, declining fertility rates in otherwise healthy adults, hyperactivity in kids, the fattening of America, and the persistent scourges of prostate cancer and breast cancer. Although multiple factors play a role in all of these conditions, one recurrent theme is the brew of endocrine disruptors infiltrating our lives.

Effects of Endocrine Disruptors

Endocrine disruptors (which are now widespread in food, water, soil and even the air we breathe) include a long list of chemicals such as dioxins, cadmium, parabens, bisphenol A, phthalates, polychlorinated biphenyls (PCBs), agricultural chemicals, polybrominated flame retardants, and some of the active ingredients in sunscreens.

Many of these chemicals cause problems because they can mimic the action of natural estrogen. These foreign estrogens (also known as xenoestrogens) can upset normal hormonal balance, stimulate the growth and development of reproductive tumors (breast, uterine, prostate), impair fertility, and disrupt pregnancy. Worse, many can cross the placenta to affect the fetus and get into breast milk. Chemicals such as phthalates have an antiandrogenic effect, meaning they interfere with testosterone and other hormones responsible for male sex characteristics. Exposure to these agents during fetal life and early childhood can derail normal sexual development and heighten the risk for diseases that don’t become apparent until adulthood, such as cancer.

Problems with BPA

One of the most troubling endocrine disruptors is a common ingredient in plastic called bisphenol A (commonly called BPA). According to Laura N. Vandenberg, who holds a doctorate in cell, molecular and developmental biology and works at the Center for Developmental and Regenerative Biology at Tufts University, “BPA is one of the highest volume chemicals produced worldwide, with over 6 billion pounds produced each year.”

Used to produce polycarbonate plastics and epoxy resins, BPA is found in many drinking containers, the lining of most food and beverage cans (including soda cans), bottle caps, plastic cutlery, plastic food storage containers, toys, dental sealants, some dental composites, water pipes, eyeglass lenses, and more. Polycarbonate is often blended with other plastics to create products such as mobile phone cases, car parts, electronic equipment, medical equipment and household items. Because BPA is in printer ink, newspapers and carbonless receipts, most recycled paper contains it, including paper towels and paper used to contain food.

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