Dear EarthTalk: What is "BPA" used in plastics, and why should I worry about it? Are there certain household items or food containers to avoid because of BPA?
—Tina Sillers, via e-mail
According to the U.S. Department of Health and Human Services (HHS), Bisphenol A (also known as BPA) is a chemical that has been in use for upwards of four decades in the manufacture of many hard plastic food containers, including baby bottles and reusable cups and the lining of metal food and beverage cans (including canned liquid infant formula). The agency further reports that "trace amounts of BPA can be found in some foods packaged in these containers."
The non-profit Natural Resources Defense Council (NRDC) reports that "growing amount of scientific research has linked BPA exposure to altered development of the brain and behavioral changes, a predisposition to prostate and breast cancer, reproductive harm, diabetes, obesity and cardiovascular disease." The group adds that more than 93 percent of Americans have some BPA in their bodies, primarily from exposure through food contamination and other preventable contact.
The U.S. Food and Drug Administration was initially dismissive of worries about BPA, but increased public pressure and new research on the potential effects of BPA on the brain and the prostate gland in fetuses, infants and young children have forced the agency to revisit its last survey on the topic from 2008. "While we learn more, the Food and Drug Administration is supporting current efforts by industry to stop the manufacture of infant bottles and feeding cups made with BPA
," reports HHS.
In the meantime, consumers can be vigilant. The plastic items most likely to contain are made of either polyvinyl chloride (PVC, or plastic #3) or from mixed plastic sources, otherwise known in the recycling industry as "other" or plastic #7. PVC plastics—also notorious for leaching toxic phthalates that have been linked to human reproductive and developmental problems—are found in a wide range of products, from shampoo and salad dressing containers to shower curtains and kids" toys. Those once-ubiquitous polycarbonate unbreakable baby and water bottles reputed to leach BPA are also a #7 plastic, though #7 is a catch-all for otherwise unidentified or mixed plastics; as such, not all #7 plastic will contain BPA.
As for other disposable and non-disposable household items, if you can locate a recycling number and you find a #1 (polyethylene, PET or PETE), #2 (high density polyethylene), #4 (low density polyethylene) or #5 (polypropylene) or #6 (polystyrene), the item should be free of BPA. (Note: #6 polystyrene, often used for disposable cups, plates and cutlery, doesn't contain BPA but can leach the toxic carcinogen styrene into the foods and beverages it touches, and should also be avoided.)
If there's no recycling number on the item, you can find out if an item contains BPA yourself with a BPA Test Kit from Home-Health-Chemistry.com. A kit with two swabs, all needed testing solutions and instructions is $4.99; a 10-swab set costs $14.99. Otherwise, you can replace the questionable item with one that you know is BPA-free (many companies now use this as a selling point) and vow to make more informed purchasing choices in the future.
Dear EarthTalk: A friend of mine working on the Gulf Coast oil cleanup says that at least 50 percent of the loose oil is laying on the sea floor. What's the long-term prognosis of this?
—Chris H., Darien, CT
It's true that oil from BPs Deepwater Horizon fiasco is still sticking to and covering parts of the sea floor for some 80 miles or more around the site of the now-capped well. In early September, researchers from the University of Georgia found oil some two inches thick on the sea floor as far as 80 miles away from the source of the leak, with a layer of dead shrimp and other small animals under it.
“I expected to find oil on the sea floor,” Samantha Joye, lead researcher for the University of Georgia's team of scientists studying the effects of the Deepwater Horizon spill, told reporters. "I didn't expect to find layers two inches thick. It's kind of like having a blizzard where the snow comes in and covers everything," Joye said.
But as recently as three months ago the National Oceanic and Atmospheric Administration (NOAA) reported finding no evidence of oil accumulating on the sea floor in the Gulf. NOAA Administrator Jane Lubchenco told reporters then that the oil from the massive spill that never made it to the surface was dispersed naturally or chemically. She added that only about a quarter of the 200 million gallons of spilled oil remained in the Gulf, the rest having "disappeared" or been contained or cleaned up.
But some researchers say NOAA misled the public by saying that much of the oil simply disappeared. Ian MacDonald, an oceanographer at Florida State University, says that initial reports from NOAA about how much oil remains in the Gulf were too optimistic. The oil "did not disappear," he says. "It sank."
One of the reasons why so much oil may have sunk was because it was broken up into tiny droplets by chemical dispersants, making the oil so small that it wasn't buoyant enough to rise as would otherwise be expected. Also, as oil still in the water column ages it becomes more tar-like in a process called weathering, and as such becomes more likely to sink. And to make matters worse, oil on the sea floor takes longer to degrade than it would on the surface because of the colder temperatures down deep.
The new findings are particularly troubling because of the potential ripple effects the remaining oil could have on the wider ecosystem and industries that rely on a healthy marine environment. Marine biologists and environmentalists worry that the oil is doing significant harm to populations of tube worms, tiny crustaceans and mollusks, single-cell organisms and other underwater life forms that shape the building blocks of the marine food chain.
"Deep-sea animals, in general, tend to produce fewer offspring than shallower water animals, so if they are going to have a population impact, it may be more sensitive in deep water," reports Louisiana State University oceanographer Robert Carney. "There is also some evidence that deep-sea animals live longer than shallower water species, so the impact may stay around longer."
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