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.

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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]

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Earlier today we reported on scientists at the Woods Hole Oceanographic Institution trying to answer the question, “Where’d all the oil in the Gulf go?” (At least some of it is floating around in giant plumes.) In the same issue of the journal Science released this afternoon, another team from Woods Hole tried to answer another pressing ocean question: “Where’d all the plastic in the Atlantic go?”

We’re referring to the great patch of plastic in the North Atlantic Gyre. You might have read the stories in DISCOVER and elsewhere about the more famous Great Pacific Garbage Patch, a Texas-sized soup of tiny plastic pieces in the middle of that ocean. Circulating ocean currents create these gyres in several places around the world, and ocean-borne plastic gets trapped. The Woods Hole paper is the result of a two-decade study of the Atlantic patch that produced a surprising result: The amount in total plastic appears to have leveled off—at least according to the data.

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After floating on plastic for more than 9,000 miles, the crew of the Plastiki arrived in Sydney, Australia today, more than four months after the ship set sail from San Francisco.

The boat of 12,500 bottles was the brainchild of David de Rothschild, who sought a way to bring more of the world’s attention to the problem of discarded plastic bottles and their tendency to wind up in the ocean.

He figured a good way to prove that trash can be effectively reused was to use some of it to build a boat. The Plastiki … is fully recyclable and gets its power from solar panels and windmills. The boat is almost entirely made up of bottles, which are held together with an organic glue made of sugar cane and cashews, but includes other materials too. The mast, for instance, is recycled aluminum irrigation pipe [AP].

The crew of six spent their four-month voyage cramped together in the catamaran’s cabin, taking showers in salt water, and eating dehydrated food. But they didn’t leave all the comforts at home behind. The team’s filmmaker managed to get a Skype connection at sea, which he used to witness the birth of his first child.

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Hasta luego, plastic bags? This week the California State Assembly approved a measure to ban single-use plastic bags, and if the state’s Senate approves it too, California will likely become the first of these United States to ban the bags. California governor Arnold Schwarzenegger has indicated that he supports the bill, and will sign it if it lands on his desk.

Shoppers who don’t bring their own totes to a store would have to purchase paper bags made of at least 40 percent recycled material for a minimum of 5 cents or buy reusable bags under the proposal, which would take effect Jan. 1, 2012 [San Francisco Chronicle].

Convenience and drug stores, as well as small businesses, would get a little longer to switch over. The law wouldn’t go into force for them until July 2013.

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Yesterday, a government entity called the President’s Cancer Panel released an alarming report declaring that environmental toxins are causing “grievous harm” to Americans. The authors of the report (pdf) went on to say that while much more research needs to be done to determine the long-term effects of exposure, they believe that the “true burden of environmentally induced cancer has been grossly underestimated.”

But no sooner had they released the report than other cancer experts came forward to say that it wasn’t alarming, but rather alarmist.

First, the panel’s findings. In the 240-page report, the advisory panel noted that Americans are exposed to chemicals whose safety hasn’t yet been definitively established–like the chemical BPA that’s found in some everyday plastics, pesticides, and the substances found in industrial pollution. They write:

“With nearly 80,000 chemicals on the market in the United States, many of which are used by millions of Americans in their daily lives and are un- or understudied and largely unregulated, exposure to potential environmental carcinogens is widespread” [TIME].

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In summer 2008, DISCOVER set sail for the Great Pacific Garbage Patch, that Texas-sized soup of tiny plastic bits that might now be an intractable mess in the middle of the ocean. With appearances in newspapers, magazines, and even “Good Morning America,” the Pacific patch became the newest target for environmental hand-wringing, and raised questions over whether it would even be possible to clean up. However, the ocean currents that cause the Pacific gyre don’t just happen in the North Pacific. Scientists at the Sea Education Association just finished a two-decade-long study of the North Atlantic and found similarly sad results.

The team dragged nets half-in and half-out of the water to take a trash census. The researchers carried out 6,100 tows in areas of the Caribbean and the North Atlantic — off the coast of the U.S. More than half of these expeditions revealed floating pieces of plastic on the water surface [BBC News]. Like the Pacific gyre, the Atlantic one—located mostly between 22 and 38 degrees north latitude—contains a dizzying number of small plastic pieces that used to be bags, bottles, and other consumer products. Lead researcher Kara Lavendar Law says it’s difficult to compare the two, but researchers in both places collected more than 1,000 pieces during a single tow of a net [The New York Times].

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There’s a new addition to the parade of studies investigating potential health problems connected to the ubiquitous plastics ingredient bisphenol A (BPA). But while the new data backs up the connection between BPA and heart disease that appeared in previous studies, the nature of the link still isn’t conclusive, and other links are not clear.

The study in PLoS One analyzed data gathered between 2003 and 2006. The association with diabetes is a bit weaker [than shown in earlier studies], but the one with heart disease remains robust. In fact, the authors are able to show a linear relationship between BPA exposure and cardiovascular disease in both data sets [Ars Technica]. While the authors confirmed that BPA-heart disease link from their 2008 study, they said they still could not sufficiently tell correlation versus causation and called for more study.

They did find another interesting tidbit, though, this one being on the good side. BPA levels in the urine of test participants plunged by 28 percent from the 2003/04 period to the 2005/06 period. That’s odd because it predates the wave of public concern over BPA, though perhaps changed industry practices are responsible, study author David Melzer says. “BPA in baby’s bottles has been very controversial and we speculate that manufacturers may be switching to other plastics for use involving food and beverages” [Scientific American].

Related Content:
80beats: Study: The Chemical BPA, in High Doses, Causes Impotence
80beats: More Bad News on BPA: Linked to Heart Disease and Diabetes in Humans
80beats: BPA Won’t Leave Public-Health Conversation—or Your Body
80beats: Plastic Is More Biodegradable Than We Thought. (That’s Bad.)
80beats: FDA Declares Chemical in Baby Bottles Safe, But Doubts Remain
DISCOVER: The Dirty Truth About Plastic

Image: iStockphoto

It’s been a bad month for chemicals and masculinity. Last week 80beats covered the discomforting link found between the chemical bisphenol A (BPA), which is found in any number of consumer products, and erectile dysfunction. Now the villains are phthalates, chemicals used to make plastics softer and more flexible. A new study in the International Journal of Andrology has raised a storm of concern that prenatal exposure to these chemicals could make boys less masculine in their play preferences.

Phthalates, which block the activity of male hormones such as androgens, could be altering masculine brain development, according to Shanna H. Swan, a professor of obstetrics and gynecology at the University of Rochester Medical Center and lead author of the new report [Los Angeles Times]. To test whether that link extended into behavior, Swan’s team tested women for phthalate levels midway through their pregnancy and then checked back in on the children four to seven years later.

The researchers asked parents to report their children’s patterns of play, but they knew they also had to separate any potential phthalate effect from the “nuture ” side of question. To determine how parental views might sway behavior, parents completed a survey that included questions such as, “What would you do if you had a boy who preferred toys that girls usually play with?” They were asked to respond with whether they would support or discourage such behavior, and how strongly [TIME].

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A chemical commonly found in plastics that has recently fallen under intense scrutiny by public health officials has now been linked to impotence. During a five year study, scientists followed 634 male Chinese factory workers who were exposed to high levels of the chemical bisphenol A (BPA) on the job and compared their sexual health with that of similar Chinese factory workers not exposed to BPA. The men handling BPA were four times as likely to suffer from erectile dysfunction and seven times as likely to have difficulty with ejaculation [Washington Post]. The study (PDF), published in the journal Human Reproduction, marks the first time sexual dysfunction has been linked to BPA exposure.

To be fair, the workers were exposed to BPA levels that are 50 times greater than the average U.S. man faces, so scientists can’t say how smaller amounts of the chemical will affect sexual health. However, the chemical resembles the hormone estrogen and that’s fueled worries that even very small amounts of BPA can cause harm [NPR News]. The feds are determined to get to the bottom of the issue and have pledged $30 million to researchers over the next two years in an effort to finally settle the question of whether BPA is safe.

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Here’s the good news: Plastic may break down in the ocean in as little as a year, not 500 to 1,000 years as scientists previously thought. Now, the bad news: This degradation could be releasing harmful compounds such as bisphenol A (BPA) into the ocean, according to research presented at the American Chemical Society meeting on Wednesday.

Ocean-borne plastic, such as that in the vast Great Pacific Garbage Patch, has traditionally been viewed as an environmental hazard due to the danger it can pose to sea life and birds. But to find out more about how plastic behaves when in the ocean, researchers acquired water samples from Japan, India, Europe, the United States, and other locations. The results? All the water samples were found to contain derivatives of polystyrene, a common plastic used in disposable cutlery, Styrofoam, and DVD cases, among other things [National Geographic News].

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Scientists will venture this summer to the Eastern Pacific Garbage Patch–a blob of discarded plastic twice the size of Texas that’s floating in the Pacific Ocean–in an extensive effort to assess just how detrimental the patch is to the marine ecosystem.

Two boats push off this month to examine and analyze the patch of plastic; one left from San Diego yesterday, the other is set to leave from San Francisco tomorrow. The expeditions will last four weeks and will cost $1.1 million. Researchers from the Scripps Institution of Oceanography in San Diego will conduct a wide range of experiments on the debris’ impact on phytoplankton, zooplankton, fish, whales, birds, salts and fouling communities – groups of organisms that live on the debris. They will spend 10 days traveling to and from the remote region [San Diego Union-Tribune]. Once the researchers are back on dry land, it will take months to fully analyze the samples collected during the voyage.

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Wouldn’t it be useful if an aging, weakening bridge started to turn red as a warning to structural engineers? That’s the potential inherent in a new invention from a team of chemists and materials scientists, who created a plastic that turns red when it’s exposed to stress. Ultimately, such color-changing polymers could be used as coatings on everything from bridges to airplane wings, alerting engineers when vital structures are near failure [ScienceNOW Daily News].

To make the red-alert plastics, researchers placed small ring-shaped molecules that they call “mechanophores” in the center of polymer chains. In response to mechanical force, these rings break, changing the color of the polymer [ScienceNOW Daily News].

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A new study has found higher than expected levels of a controversial plastics chemical in people who had fasted for 24 hours. This surprised researchers because the chemical, bisphenol A (BPA), was thought to be ingested when trace amounts leaked from plastic food containers and bottles, and researchers thought it quickly passed through the system.

The finding suggests that exposure to BPA may come from many different sources, not just food products, or that the body doesn’t metabolize the chemical as fast as has been thought, the researchers said…. “What this study shows is that either we are getting exposed to a lot more BPA than we thought, or it’s hanging around longer than we thought, or both,” said lead researcher Dr. Richard W. Stahlhut [HealthDay News].

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To truly assess the risks posed by a ubiquitous group of chemicals found in everything from vinyl shower curtains to bug spray, researchers need to study their cumulative impact on human health, declares a new report from the National Research Council, a group that advises the government on science and health policy. The chemicals, called phthalates, are used to make plastic products soft and flexible, and are also found in cosmetics, personal-care products, and even pharmaceuticals. In rodent studies exposure to phthalates has been shown to interfere with the development of the male reproductive system, causing infertility, reduced sperm production, undescended testes, penile birth defects and other reproductive-tract malformations [Science News].

Traditionally, health agencies have studied the risk of each chemical individually, but experts say such a process doesn’t accurately reflect human exposure. “It is extremely important to conduct cumulative risk assessments to protect public health,” said [phthalate researcher] Dr. Sheela Sathyanarayana…. “Unlike in scientific experiments, humans are exposed to multiple chemicals everyday,” she said, so combining the chemicals “can help identify how these multiple exposures could be leading to health outcomes in the general population” [Scientific American].

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