A study published this week in the journal Pediatrics found a link between levels of bisphenol-A in pregnant moms and behavioral problems such as anxiety and hyperactivity in their daughters at age 3. No such effects were seen in boys. BPA has estrogen-like activity and can lead to developmental and behavioral problems in animals—but whether or not it does the same in humans, and at what dosages, is a subject of considerable debate. This study won’t settle the debate but highlights the need to answer some basic questions about BPA that remain surprisingly unclear.
What’s the News: Most poisonous snakes don’t inject their prey with venom; instead, they bite the prey and venom insidiously trickles down a groove on their fangs into the wound. A new study in Physical Review Letters investigated the physics behind how venom travels down the grooves: It turns out that snake venom has unusual viscosity properties that keep it cohering together until it’s time to flow down the fangs and into the snake’s soon-to-be-snack—the same properties that account for how ketchup seems stuck in the bottle, then flows freely onto your fries.
A report (pdf) by the Washington Toxics Coalition found that the potentially harmful plastic chemical Bisphenol A is present in low levels on most money and about half of thermal paper receipts tested in a small study. As many researchers are concerned about the possible health effects of the hormone-disrupting chemical, this new evidence of BPA’s ubiquity in our modern lives is setting off new alarms. But are the levels found on money and receipts significant?
While most customers worry about ingesting BPA due to its presence in plastic bottles, canned foods linings, and other plastic containers, it can also be absorbed through the skin, says the coalition. Thermal paper (frequently used in receipts) is often made with a coating of BPA powder, which could be an unexplored exposure route to the chemical–especially for cashiers.
The coalition tested 22 thermal paper receipts and 22 dollar bills collected from around the country. Eleven of the receipts were positive for BPA (comprising up to 2.2 percent of the total receipt weight) and 21 of the dollar bills were, though at much lower levels. The researchers suggest that BPA may be tranferred from receipts to money when people handle them together or stuff them together into a wallet.
“Our findings demonstrate that BPA cannot be avoided, even by the most conscious consumer,” said Erika Schreder, Staff Scientist at the Washington Toxics Coalition and lead author of the report. “This unregulated use of large amounts of BPA is having unintended consequences, including exposure to people when we touch receipts.” [press release]
It’s no surprise that a chemical as potent as methylmercury harms wildlife when it enters an ecosystem in high concentration. In the case of wetland birds, researchers have found, it can even change sexual orientation, causing males to pair off with other males.
“We knew mercury could depress their testosterone (male sex hormone) levels,” explained Dr Peter Frederick from the University of Florida, who led the study. “But we didn’t expect this.” [BBC News]
Frederick and Nilmini Jayasena examined white ibises from South Florida for their study in the Proceedings of the Royal Society B. They gathered 160 of the birds and broke them up into four groups that ate food laced with different concentrations of methylmercury. Some ate 0.3 parts per million of mercury, some 0.1, some 0.05, and some none at all.
Birds exposed to any mercury displayed courtship behaviour less often than controls and were also less likely to be approached by females when they did. As the level of mercury exposure increased, so did the degree and persistence of homosexual pairing. Males that engaged in homosexual parings were also less likely to switch partners from year to year, which Frederick says ibises tend to do if they have been unsuccessful in mating during their first breeding season. [Nature]
The Story of Electronics has made its debut today (teaser above), following the form of the original Story of Stuff video in 2007. The Story of Stuff, written and narrated by Annie Leonard, created waves of discussion about the environment and consumption in classrooms, homes, and workplaces around the country.
She [created the movie], she said, after tiring of traveling often to present her views at philanthropic and environmental conferences. She attributes the response to the video’s simplicity. “A lot of what’s in the film was already out there,” Ms. Leonard said, “but the style of the animation makes it easy to watch. It is a nice counterbalance to the starkness of the facts.” [New York Times]
The new electronics chapter takes a step beyond the original video’s take on the manufacturing process and consumerism to explain the concept of planned obsolescence, the idea that our electronics are being “designed for the dump”–that is, to be cheaply replaceable as quickly as possible. The video makes a point that these cheap electronics come with hidden costs–to factory workers, people in unsafe electronics recycling facilities, and to the environment.
A new study of 218 Chinese men found that even low levels of the controversial plastics chemical bisphenol A (BPA) can lower sperm quality and count.
For the study, which was published in the journal Fertility and Sterility, researchers noted the participants’ sperm quality and urine BPA levels over five years. When compared to participants without detectable levels of the chemical, men with BPA in their urine were three times more likely to have low quality sperm.
“This adds additional human evidence that BPA is bad,” said [the study's first author] De-Kun Li…. “The general public should probably try to avoid exposure to BPA as much as they can.” [Washington Post]
That’s a tough order, because BPA is all over the place. It’s found in everything from sports equipment to medical devices to the plastic lining in canned foods.
Li’s previous studies have shown sexual effects of high levels of BPA, including inducing impotence in male factory workers exposed to it. Those studies were done with men exposed to about 50 times as much BPA as the average U.S. man, so the results might not apply to your average Joe.
The Canadian government today declared bisphenol A, a chemical in plastics also known as BPA, to be toxic.
A scientific assessment of the impact of human and environmental exposure to bisphenol A has determined that this substance constitutes or may constitute a danger to human health and the environment [Official notice]
The chemical has been linked to heart disease, impotence, and diabetes, while animal and cell culture experiments have shown that it can mimic the female hormone estrogen. It is found in some plastic containers, and some food cans are lined with it.
While Canada is forging ahead, most other governments are dithering about whether or not the chemical poses a health threat.
How much exposure is too much, though? There is no clear answer. Two weeks ago, the European Food Safety Authority declared that BPA did not pose sufficient risk to stop using it in food containers. While tiny amounts can leach out into food, they cannot raise human exposure to unacceptably risky levels, the authority concluded after an assessment of existing scientific studies. [Nature]
California sea otters, furry frolickers of the saltwater seas, are in trouble. And the root cause is… a freshwater toxin? That’s the surprising truth, according to a study in the journal PLoS One led by Melissa Miller, a state wildlife veterinarian.
For the last several years, the otters on California’s coast have been dying in droves, and their population diminishing. No one could quite put a finger on why. Disease and starvation floated as explanations, and sharks seem to be devouring more sea otters lately. But none of these were the root cause, Miller finally found.
An EPA report published Tuesday told residents near Pavillion, Wyoming to avoid drinking and cooking with well water after tests revealed petroleum hydrocarbons and other contaminants in 17 out of 19 wells near the town. Many residents worry that local drilling for natural gas is to blame. The EPA is still investigating.
“EPA has not reached any conclusions about how constituents of concern are occurring in domestic wells,” the report said. [Reuters]
As the agency continues its investigation, it along with other government organizations and the natural gas company EnCana, will provide alternative drinking water sources for affected residents. EnCana volunteered to provide the water, though a company representative told the AP that company’s tie to the contaminated the wells is unclear–since the chemicals appeared in earlier EPA tests, before EnCana’s drilling started in 2005.
If I could offer you only one tip for the future, sunscreen would be it. The long-term benefits of sunscreen have been proved by scientists, whereas the rest of my advice has no basis more reliable than my own meandering experience.
But is even this sage advice subject to the “it’ll cause cancer, no wait, it’ll cure cancer” back-and-forth that plagues medical studies? Reading some headlines today, you might think so. Don’t toss out your tube of Banana Boat just yet, though.
The non-profit Environmental Working Group released another of its reports on the sunscreen industry, coming down hard on the chemicals it uses and the claims it makes in its advertising. Some stories about the report drew headlines like “Sunscreen May Hurt, Not Help;” “Your Sunscreen May Give You Cancer: Study;” and “Study: Many Sunscreens May Be Accelerating Cancer.”
EWG’s report claims that a Vitamin A compound called retinyl palmitate, used in some 40 percent of sunscreens, breaks down and causes skin damage under exposure to sunlight. The report cites research done under the Food and Drug Administration. But, according to dermatologist Henry W. Lim of Henry Ford Hospital:
These claims, says Lim, are based on a study in mice, which are far more susceptible to skin cancer than humans. “It’s dangerous to apply a finding in mice to humans, and I’ve spoken with a number of my colleagues about this and we all agree that it’s very premature to even cast doubt about the safety of this chemical.” The EWG also flagged products with oxybenzone, which it calls a “hormone-disrupting” compound. This, too, is based on mice data, says Lim; the animals were fed significantly greater amounts of the chemical than what’s commonly applied in sunscreen. Other research found no significant changes in blood hormone levels in human volunteers who were told to apply sunscreens containing oxybenzone every day for two weeks [U.S. News & World Report].