Pthalates in Blood
Air Date: Week of September 15, 2000
Janet Raloff, senior editor of Science News, speaks with host Steve Curwood about the latest research on phthalates. These chemicals found in plastics and solvents are being blamed for a number of hormonal disorders in women and children.
CURWOOD: It's Living on Earth. I'm Steve Curwood. We've heard that phthalates, the chemicals used to soften plastic and things like plastic bags, shower curtains, even toys, are bad for us. They've been linked to cancer, and most recently, a study found phthalates in medical tubes and bags that could be linked to problems in reproductive development for baby boys. But until recently, there have been no tests to accurately determine the levels of phthalates that actually make it into our bloodstream. Now, a researcher with the Centers for Disease Control and Prevention has formulated a test that checks levels of the chemical in urine that show whether or not the phthalates have been absorbed, and the results of his study will be published this October. Janet Raloff, Senior Editor at Science News and Living on Earth's Science Commentator, speaks with us from Washington. Hi, Janet.
RALOFF: Hello, Steve.
CURWOOD: Now tell us: What are phthalates, exactly?
RALOFF: Well, they're a whole, big, huge family, actually, of commercial chemicals. They're oily substances, and for the most part they're used to make rigid materials plastic. However, there are some that are also used as solvents, or just to dilute things. To make things mix up that didn't ordinarily want to mix and stay that way.
CURWOOD: What does this new study tell us about how much of these phthalates, these chemicals, are getting into our blood?
RALOFF: Well, first of all, it confirms conclusively that they are getting into the body. Second thing is that they're getting in, sometimes in very high levels, and one of the most interesting things is that the highest levels are showing up in the urine of women of reproductive age.
CURWOOD: Why higher for women, do you think?
RALOFF: Well, the supposition is that because of the type of phthalates that they're finding, they may be coming from cosmetics. Fragrances, deodorants, fingernail polish, that sort of thing.
CURWOOD: How concerned should we be about these phthalates that are showing up in women's bodies?
RALOFF: Again, nobody knows. The one that's showing up in the highest concentration is one that, for the most part, scientists had written off. First of all, it's not used in commerce very widely, so they hadn't expected it to show up in detectable levels in the body at all. It, however, may not be terribly toxic. One of the second-tier levels of compounds that are showing up is, however, a reproductive toxicant. At least in animal studies, it greatly perturbs, in fact, probably poisons the reproductive development of male animals. And this was showing up at levels ten to 100 times higher than estimates had predicted would occur in people.
CURWOOD: Are all phthalates the same? Do the ones in solvents have the same biological action as the ones in plastics?
RALOFF: Well, some will act like hormones. Others seem to cause cancer. And not necessarily through the same mechanism. You really have to look at each one on a case-by-case basis, and that hasn't been done to date.
CURWOOD: Recently there was a study linking phthalates with early onset of puberty, and I guess that's sort of misspeaking. If you're talking about breasts developing in a six-month-old baby, that's much more than puberty. What is this study all about?
RALOFF: Well, Puerto Rico currently has, for the last 20 years, been undergoing an epidemic of early breast development. This is very small children, six months to 24 months old. And nobody has been able to figure out why. They have been probing everything they can think of, from growth hormones in food, soy, infant formula to pesticides that might be getting in through water or other things. None of them panned out. Suddenly they do this test looking for pesticides in the blood, and they find no difference between kids developing normally and those with this premature breast development. The only thing that stands out, and it stands out big time, was a high level of phthalates in many of the children with the premature breast development.
CURWOOD: What alternatives are there to phthalates in the manufacturing and solvent business?
RALOFF: Well, there are a number. I don't think industry would like to switch over because they work so well, and they've been used for more than 50 years. And apparently, with little or no harm. Now, one of the concerns is that maybe as our society becomes more and more plastic, we're getting higher and higher exposures. Or, if they're not disposed properly, maybe we're getting exposures in ways we hadn't before. But, in many cases, you can make plastics without phthalates. They just may not function as well. They may not be as pliable. They may be more expensive. They clearly work very well, and industry doesn't want to let go of them.
CURWOOD: For people listening to us right now who would like to take steps to protect or limit their exposure to phthalates, what are some of the things they could do?
RALOFF: If you are a woman of childbearing age and you wanted to think about getting pregnant, you may lay off cosmetics that have fragrances. These are perfumes or, you know, talcum powders with lots of scents in them. Anything that is highly scented. In addition, some things like nail polish. Things that have solvents, that have a real chemical smell, you might want to avoid those. You might also want to avoid heating things up in the microwave in plastic containers. Use glass or ceramic instead. And not use plastic wrap in the microwave. Because, again, studies have shown that phthalates can leach from some of these materials into foods.
CURWOOD: Janet Raloff is Senior Editor at Science News and Living on Earth's Science Commentator. Thanks, Janet.
RALOFF: Thank you, Steve.
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