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Water Filtration System in a Straw

LifeStraw makes previously contaminated water drinkable by removing bacteria and viruses

LIFESTRAW: is a mobile personal filtration system containing filters that make water teaming with typhoid-, cholera- and diarrhea-causing microorganisms drinkable.
Courtesy of The Vestergaard Frandsen Group

Sometimes, it's the simplest technologies that have the greatest potential impact on people's lives. Take the Vestergaard Frandsen Group's mobile personal filtration system, otherwise known as LifeStraw. It is a powder-blue plastic tube—much thicker than an ordinary straw—containing filters that make water teeming with typhoid-, cholera- and diarrhea-causing microorganisms drinkable.

The filters, made up of a halogenated resin, kill nearly 100 percent of bacteria and nearly 99 percent of the viruses that pass through LifeStraw. A University of North Carolina at Chapel Hill evaluation tested the device's performance in water containing Escherichia coli B and Enterococcus faecalis bacteria and the MS2 coliphage virus as well as iodine and silver. The results indicated that LifeStraw filtered out all contaminants to levels where they don't pose a health risk to someone drinking the water.

But the device does not filter heavy metals such as iron or fluoride nor does it remove parasites like cryptosporidium or giardia, although the Switzerland-based company's CEO, Mikkel Vestergaard Frandsen, says there is a version of LifeStraw available to relief groups in Bangladesh and India that can filter arsenic.

At less than 10 inches (25 centimeters) long, the device can filter up to 185 gallons (700 liters) of water, estimated to be about a year's supply for one person. The device is no longer usable when its filters become too clogged to pass water through, typically after a year of hard use.

The success of the personal filtration system led Vestergaard Frandsen to introduce earlier this month its LifeStraw Family device, an instant microbiological purifier that provides about 2.6 gallons (10 liters) of safe drinking water in an hour and about 4,000 gallons (15,000 liters) over its life span for a family of six. LifeStraw Family is designed to sieve dirt, parasites, bacteria and viruses, and will be available starting in May.

The next step is promoting LifeStraw technology so that nongovernmental organizations (NGOs) and aid groups will buy and distribute them. This is no small task, given that the need for clean water is not promoted as heavily as AIDS prevention or literacy training in some developing countries, Frandsen says, adding, "No one is stepping forward to be the rock star of diarrhea [eradication]."

But LifeStraw was recognized by Saatchi & Saatchi's public relations arm as the top "world-changing idea" in a recent competition of technologies impacting medicine, education and aid work. Vestergaard Frandsen Group received $50,000 from Saatchi, plus another $50,000 worth of the PR firm's marketing services.

Saatchi, which is owned by France's Publicis Groupe, SA, chose LifeStraw over a field of competitors that included a reusable controller to improve the distribution of IV fluids, a collapsible wheel that can be folded down for easier storage when not in use on bicycles or wheelchairs, an energy-efficient laptop designed for children in developing countries, a 3-D display that uses special optics and software to project a hologramlike image of patient anatomy for cancer treatment, an inkjet printing system for fabricating tissue scaffolds on which cells can be grown, a visual prosthesis for bypassing a diseased or damaged eye and sending signals directly to the brain, books with embedded sound tracks to help educate illiterate adults on health issues, a phone that provides telecommunications coverage to poor rural populations in developing countries, and a brain-computer interface designed to help paralyzed people communicate via neural signals.

Energy storage nears its day in the sun

Solar panels in a file photo. Energy storage is an unglamorous pillar of an expected revolution to clean up the world's energy supply but will soon vie for investors attention with more alluring sources of energy like solar panels, manufacturers say.

Energy storage is an unglamorous pillar of an expected revolution to clean up the world's energy supply but will soon vie for investors attention with more alluring sources of energy like solar panels, manufacturers say.

"It's been in the background until now. It's not sexy. It's the enabler, not a source of energy," said Tim Hennessy, chief executive of Canadian battery makers VRB Power, speaking on the sidelines of a "CleanEquity" technologies conference in Monaco.

VRB will start mass production this year of a longer-lasting rival to the lead acid battery currently used to store energy for example produced by solar panel, Hennessy said.

Low carbon-emitting renewable energy is in vogue, driven by fears over climate change, spiraling oil prices and fears over energy supply and security.

While the supply of the wind and sun far exceeds humanity's needs it doesn't necessarily match the time when people need it: the sun may not be shining nor the wind blowing when we need to cook dinner or have a shower.

Soaring production of solar panel and wind turbines is now spurring a race to develop the winning energy storage technologies which will drive the electric cars and appliances of the future.

The race is heating up as manufacturers with entirely different solutions near the moment of commercial production.

For example, UK-based ITM Power sees the future of energy storage in the explosive gas hydrogen. The company is developing a piece of kit called an electrolyzer which uses solar or wind power to split water into hydrogen and oxygen.

The hydrogen is then stored in a pressurized container until it is needed, whether to drive a car, produce electricity or for cooking.

"With batteries you're taking enormous quantities of basic raw materials," said Chief Executive Jim Heathcote, referring to cadmium in nickel cadmium varieties. His company won an award for research at the Monaco conference, organized by corporate finance advisers Innovator Capital.

"Two things we're confident of is the supply of renewable energy and water," he said.

ITM Power aims to start production later this year of electrolyzers and next year of hydrogen fuel cells which generate electricity.

"The one problem everyone's had is how to store. The ability to take (surplus) renewable energy and make useful fuel out of it is almost priceless," Heathcote said.

RICH

The economic opportunities are highlighted by a third company, U.S.-based EnerDel, which aims to supply batteries for the "Th!nk City" electric vehicle, manufactured by Norway's Think Global.

In the case of electric cars, cheap, lightweight batteries are needed to power motors, and will eliminate carbon emissions if the batteries are charged using renewable power sources.

EnerDel has patented a lithium-ion battery which it says is lighter and cheaper than the nickel metal hydride batteries currently used in hybrid electric cars such as the Toyota Prius.

"I think energy storage is the next frontier," said Charles Gassenheimer, chairman of EnerDel's owners Ener1 Inc.

The "Th!nk" car could be the world's first mass production electric vehicle, starting in earnest in 2009. It will go from 0 to 60 miles an hour in about 8 seconds and have a range of up to 100 miles, said Gassenheimer.

Investors have given their thumbs up to Ener1, which now has a market capitalization of around $700 million, a ten-fold increase over two years ago.

Scientists Tuning Very Large Array Radio Telescope for Deeper Exploration

The NSF's Very Large Array radio telescope is getting a digital makeover that will give it the sensitivity to pick up a cell phone signal on Jupiter, and to probe deeper into outer space

SILENT VIGIL: The NSF's Very Large Array (VLA) radio telescope has become the Expanded VLA and will be 10 times more powerful when work is completed in 2012.

EYES TO THE SKIES: The NSA is upgrading each antenna so it can collect eight simultaneous data streams at about two GHz, up from the previous capability of four data streams at about 50 MHz.

AWESOME ARRAY: Construction on the EVLA began in 2001, at an estimated cost of about $93.8 million.

MAKEOVER: The VLA's field of 28, 230-ton dish antennas--each 82 feet (25 meters) in diameter--are being converted to use state-of-the-art digital electronics, including a fiber-optic system replacing the older waveguide system.

HIGH AND DRY IN THE ANDES: The Atacama Large Millimeter / submillimeter Array (ALMA) will be installed by 2012 in northern Chile's Atacama Desert, at an altitude of 16,500 feet (5,000 meters).

SUPERNOVA: A VLA image of the region surrounding the W30 supernova remnant located in the Milky Way. The image was created to look for new supernova remnants through their nonthermal radio emission.

THE SUN: This VLA image shows the full disk of the Sun at a frequency of 4.6 GHz. The brightest features (red) have a temperature of one million degrees and show where very strong magnetic fields exist in the sun's atmosphere.

The National Science Foundation (NSF) is in the process of transforming its Very Large Array radio telescope into the—wait for it—Expanded Very Large Array, thanks to digital technology that will boost the Socorro, N.M., facility's already impressive ability to tune in on black holes, supernovae and the rest of the deep space menagerie.

Half of the Very Large Array's (VLA) 28 dish antennas—each weighing 230 tons—have already been upgraded so it can collect eight simultaneous data streams at about two giga- (billion) hertz, up from the previous capability of four data streams at about 50 mega- (million) hertz. The rest of the 28 antennas—which made their debut on the silver screen in the 1997 movie Contact, starring Jodie Foster and based on the eponymous Carl Sagan sci-fi novel—will go digital by 2012, increasing the facility's power 10-fold. The makeover will also replace original components that had been in operation since it was built in the 1970s.

"Certain objects radiate over a wide range of frequency," says Mark McKinnon, project manager for the Expanded VLA. "Improving the sensitivity of the telescope boils down to its bandwidth."

Completed in 1980 but operational before then, the VLA was behind the discoveries of water ice on Mercury; the complex region surrounding Sagittarius A*, the black hole at the core of the Milky Way galaxy; and it helped astronomers identify a distant galaxy already pumping out stars less than a billion years after the big bang.

The increased sensitivity and improved resolution of the EVLA will let scientists peer deep into star-forming clouds and spy on protoplanetary disks of dense gas surrounding young stars as well as track supernovae, fast-moving neutron stars and black holes, McKinnon says. The EVLA's receiving system will be sensitive enough to detect the weak radio transmission from a cell phone at the distance of Jupiter—half a billion miles away—at a projected cost of $94 million.

Data gathered by all 28 of the 82-foot- (25-meter-) diameter dish antennas are brought to a correlator—a central, special-purpose computer—which merges the input into a form that allows scientists to produce detailed, high-quality images of the astronomical objects under investigation. A new fiber-optic system replaces the older waveguide system for taking data collected by the receivers to the central control building and increases the amount of data that can be delivered from the antenna to the new $17-million correlator being built by Canadian scientists and engineers to handle the increased data flow.

In addition to its work for the NSF, the VLA site is also playing an important role in the development of another radio telescope, the Atacama Large Millimeter / submillimeter Array (ALMA). Started in 2003 and scheduled to be completed by 2012 in northern Chile's Atacama Desert at 16,500 feet (5,000 meters) above sea level, the facility employs more than 64 40-foot (12-meter) antennas. Scientists have been using the VLA site to test the performance of the dishes before they are installed at ALMA.

"The observations we make with the EVLA will be complementary with what they do at ALMA and at other radio telescopes," McKinnon adds. "Trying to understand astrophysical phenomena requires a multiwavelength approach."

Is China's Great Wall Visible from Space?

Though it stretches for some 4,500 miles, the ancient Chinese fortification is not as visible from orbit as modern desert roads

Choose a legend: The Great Wall of China is the one of the few man-made structures visible from orbit. Or, more remarkably, it's the only human artifact on Earth visible from the moon. Both are false, say astronauts and remote-sensing specialists. Although the Great Wall spans some 4,500 miles (7,200 kilometers), it's constructed from materials that make it difficult to discern from space.

The unglamorous truth is that the wall is only visible from low orbit under a specific set of weather and lighting conditions. And many other structures that are less spectacular from an earthly vantage point—desert roads, for example—appear more prominent from an orbital perspective.

Misinformation about the barrier's visibility dates back decades. A 1932 Ripley's Believe It or Not! cartoon claimed that the wall is "the mightiest work of man, the only one that would be visible to the human eye from the moon." The belief persisted into the Space Age. Since Neil Armstrong returned from the moon in 1969, he has been repeatedly asked whether he could see it.

His answer was relayed in a recent NASA Johnson Space Center oral history: He saw continents, lakes and splotches of white on blue. But he could not make out any man-made structures from the lunar surface, which averages a distance of 230,000 miles (370,000 kilometers) from Earth.

So just how visible is the Great Wall from low Earth orbit, at an altitude that begins around 100 miles (160 kilometers) up? Not very. Although sections near Beijing, China's capital, have been restored for tourists, in many areas the structure is crumbling. Where it still stands, the wall's mixture of stone and clay blends into the surrounding land.

"I have spent a lot of time looking at the Earth from space, including numerous flights over China, and I never saw the wall," asserts former NASA astronaut Jeffrey Hoffman, who flew on five space shuttle missions from 1985 to 1996. "The problem is that the human eye is most sensitive to contrast, and the color of the wall is not that different from the ground on either side of it."

Hoffman, now an aerospace engineering professor at the Massachusetts Institute of Technology, failed to make out the Egyptian pyramids for the same reason. But he could identify roads, airport runways and irrigation ditches simply because they stood out in their environments.

Some U.S. astronauts, notably Eugene Cernan and Ed Lu, have said they've seen the wall from low orbit. But it tends to show up only in certain lighting conditions. When the sun is low on the horizon, for example, the wall casts extended shadows that make it possible to discern its silhouette.

In 2004 American astronaut Leroy Chiao snapped a photo from the International Space Station of a swath of Inner Mongolia, around 200 miles (320 kilometers) north of Beijing, while the sun's angle was favorable. NASA experts later confirmed that the photo appears to show the wall. But Chiao admitted that he wasn't sure what he was seeing from space.

Machines can do a better job. Low-orbit satellites have sensors that can penetrate through haze and clouds, making it easier for them to produce clear images. But, as with the naked eye, identifying the wall is hardly a guarantee.

Moderate-resolution satellites, like the U.S. Geological Survey's (USGS) two operating Landsat land observation satellites that orbit 438 miles (705 kilometers) above Earth's surface, can typically only pick up the structure under specific weather conditions, says Ronald Beck, program information specialist with the USGS's Land Remote Sensing Program. "We have satellite images where snow covers the fields near the wall and snow has been cleared on the wall, and that allows us to see the wall," Beck says. "The key is contrast."

Often, identifying the rampart in satellite images requires a degree of sleuth work. In populated areas, Beck says, USGS scientists pinpoint sections of the wall by looking for parking lots and pathways. In more remote areas, they may scan for breaks in the vegetation surrounding the structure. But those techniques are hardly foolproof; at many points, the vegetation grows up and over the wall.

For the Chinese, the wall's visibility from space has long been a point of pride. When "taikonaut" Yang Liwei, China's first man in space, returned from the 14-orbit Shenzhou 5 mission in 2003 and admitted to reporters that he had not seen the Great Wall, online forums exploded with disappointment. The Ministry of Education even moved to revise its elementary school textbooks, which had long claimed the ancient barricade was visible.

Since then, a debate has raged in China, with scholars grasping at evidence that might settle the question of how great the wall really is. Chinese Academy of the Sciences Institute of Remote Sensing Application professor Wei Chengjie, who appeared on a national television special devoted to the issue in 2006, says more research is needed. "We need to carry out more tests and improve astronaut training. Some astronauts have said that they didn't see it, but that doesn't mean it isn't there. A shuttle passes by so quickly."

In the meantime, however, China's search for clarity is coming up against a modern complication. As the country industrializes and its factories belch out noxious gases, the wall further fades from view. "The biggest problem nowadays is the pall of pollution which exists over much of China," Hoffman says. "It effectively makes it impossible to see almost anything."

Dark Side of Solar Cells Brightens

A life cycle analysis proves that solar cells are cleaner than conventional fossil fuel power generation

SUNNY DAY: Even accounting for all the energy--and pollution--involved in the manufacture of photovoltaic cells, they still produce less pollution over their lifecycle than other alternatives.

It takes power to make power—even with a solar grand plan. From the mining of quartz sand to the coating with ethylene-vinyl acetate, manufacturing a photovoltaic (PV) solar cell requires energy—most often derived from the burning of fossil fuels. But a new analysis finds that even accounting for all the energy and waste involved, PV power would cut air pollution—including the greenhouse gases that cause climate change—by nearly 90 percent if it replaced fossil fuels.

Environmental engineer Vasilis Fthenakis, a senior scientist at Brookhaven National Laboratory in Upton, N.Y., and his colleagues examined the four most common types of PV cells: multicrystalline silicon, monocrystalline silicon, ribbon silicon and thin-film. (Other contenders, such as amorphous silicon or superefficient multijunction cells were excluded for lack of data or lack of widespread application to date.) Even taking into account the low efficiency of thin-film solar cells or the energy needed to purify silicon for the other types of PV, all proved to entail significantly fewer emissions in their entire life cycle than the fossil fuels needed to produce an equivalent amount of electricity.

In fact, most of their dirty side derived from the indirect emissions of the coal-burning power plants or other fossil fuels used to generate the electricity for PV manufacturing facilities.

These four types of solar cells pay back the energy involved in their manufacture in one to three years, according to an earlier analysis by the same team. And even the most energy-intensive to produce—monocrystalline silicate cells with the highest energy conversion efficiency of 14 percent—emit just 55 grams (1.9 ounces) of globe warming pollution per kilowatt-hour—a fraction of the near one kilogram (2.2 pounds) of greenhouse gases emitted by a coal-fired power plant per kilowatt-hour.

Even though thin-film solar PVs employ heavy metals such as cadmium recovered from mining slimes, the overall toxic emissions are "90 to 300 times lower than those from coal power plants," the researchers write in Environmental Science & Technology.

The energy benefits of solar photovoltaics will only improve as the technology continues to boost its efficiency at converting sunlight to electricity or proves to last longer than the 30 years anticipated by manufacturers. "There is no reason for this not to last a lot more than 30 years," Fthenakis says.

If solar energy begins to power its own production—a so-called PV breeder cycle, in which PV-generated electricity goes to produce more PV cells—the outlook is even sunnier. "I think 30 percent of the energy consumption in the [manufacturing] facilities is easily met from the land they have available [on] the roof and in the parking lot," Fthenakis says.

And, as Fthenakis and colleagues argued in a recent article in Scientific American, if storage technologies such as compressed air improve, then PV could provide the majority of electricity needs in the U.S. "With storage," Fthenakis says, "it is feasible to go to 100 percent."

Climate Change after Bali

Do the math: affordable new technologies can prevent global warming while fostering growth

Last December’s agreement in Bali to launch a two-year negotiation on climate change was good news, a rare example of international cooperation in a world seemingly stuck in a spiral of conflict. Cynics might note that the only accomplishment was an agreement to talk some more, and their cynicism may yet be confirmed. Nevertheless, the growing understanding that serious climate-control measures are feasible at modest cost is welcome.

The arithmetic is becoming clearer. If the rich nations continue to grow in income and the poor ones systematically narrow the income gap with successful development, by 2050 the global economy might increase sixfold and global energy use roughly fourfold. Today’s anthropogenic carbon dioxide (CO2) emissions are around 36 billion tons annually, of which 29 billion are the result of fossil-fuel combustion and industrial processes, and another seven billion or so are the result of tropical deforestation.

Roughly speaking, every 30 billion tons of emissions raises CO2 levels by around two parts per million (ppm). The current atmospheric concentration of CO2 is around 380 ppm, up from 280 ppm at the start of the industrial era in 1800. Thus, to arrive at 440 ppm by midcentury—a plausibly achievable “safe” level in terms of its likely climate change consequences but only 60 ppm more than the current one—cumulative emissions should be kept to roughly 900 billion tons, or roughly 21 billion tons a year on average until 2050. This goal can be achieved by ending deforestation (on a net basis) and by cutting our current fossil-fuel-based emissions by one third.

So here is the challenge. Can the world economy use four times more primary energy while lowering emissions by one third?

A promising core strategy seems to be the following: Electricity needs to be made virtually emission-free, through the mass mobilization of solar and nuclear power and the capture and sequestration of carbon dioxide from coal-burning power plants. With a clean power grid, most of the other emissions can also be controlled. In less than a decade, plug-in hybrid automobiles recharged on the grid will probably get 100 miles per gallon. Clean electricity could produce hydrogen for fuel-cell-powered vehicles and replace on-site boilers and furnaces for residential heating. The major industrial emitters could be required (or induced through taxation for tradable permits) to capture their CO2 emissions or to convert part of their processes to run on power cells and clean electricity.

Carbon capture and sequestration at coal-fired power plants might raise costs for electricity as little as one to three cents per kilowatt-hour, according to a special report of the Intergovernmental Panel on Climate Change. The mass conversion of the U.S. to solar power might involve an incremental cost of roughly four cents per kilowatt-hour, with overall electricity costs on the order of eight to nine cents per kilowatt-hour. These incremental costs imply far less than 1 percent of the world’s annual income to convert to a clean power grid. The costs in the other sectors will also be small. The fuel savings of low-emissions cars could easily pay for batteries or fuel cells. Residential heating by electricity (or co-generated heat) rather than by home boilers will generally yield a net savings, especially when combined with improved insulation.

The Bali negotiations will succeed if the world keeps its eye on supporting the speedy adoption of low-emissions technologies. Issues of blame, allocation of costs, and choice of control mechanisms are less important than rapid technological development and deployment, backed by a control mechanism chosen by each country.

If the less polluting technologies pan out at low cost, as seems possible, the rich countries will be able to afford to clean up their own energy systems while also bearing part of the costs to enable the poor to make the needed conversions. Climate control is not a morality play. It is mainly a practical and solvable technological challenge, which, if met correctly, can be combined with the needs and aspirations for a growing global economy.

Gene studies confirm "out of Africa" theories

A compass lies on a map of Africa in London August 1, 2002. Two big genetic studies confirm theories that modern humans evolved in Africa and then migrated through Europe and Asia to reach the Pacific and Americas.

Two big genetic studies confirm theories that modern humans evolved in Africa and then migrated through Europe and Asia to reach the Pacific and Americas.

The two studies also show that Africans have the most diverse DNA, and the fewest potentially harmful genetic mutations.

One of the studies shows European-Americans have more small mutations, while the others show Native Americans, Polynesians and others who populated Australia and Oceania have more big genetic changes.

The studies, published in the journal Nature on Wednesday, paint a picture of a population of humans migrating off the African continent, and then shrinking at some point because of unknown adversity.

Later populations grew and spread from this smaller genetic pool of founder ancestors -- a phenomenon known as a bottleneck.

Populations that remained in Africa kept their genetic diversity -- something seen in many other studies.

"The one thing that I think we cannot say from this study is that any one person's genome is any healthier or evolutionarily fit than another person's genome," said Carlos Bustamante of Cornell University in New York, who worked on one study.

"You have to think of this at the population level," Bustamante said in a telephone interview.

Bustamante's team has been looking at the DNA sequences of 15 African-Americans and 20 European-Americans, examining tiny one-letter changes in the DNA code called single-nucleotide polymorphisms or SNPs (pronounced "snips").

FIT OR EXTINCT

They tested these changes to qualify them as benign, or potentially affecting genes, amino acids and eventually proteins in a way that could damage health or make people less "fit" -- in evolutionary terms, less likely to survive and reproduce.

"Like every other study ... the African-American panel as a whole showed more variation than the European-American panel," Bustamante said.

Then his team did a computer simulation of a bottleneck, and found it predicted this pattern.

Bustamante said it is possible some of the SNPs are beneficial, and he said his team and others should compare the genetic changes they found to known genetic changes linked with diseases.

"I wish we had done that (already)," he admitted.

In the other study, Noah Rosenberg and colleagues at the University of Michigan and the National Institute on Aging analyzed DNA from 485 people around the world.

They looked for three types of genetic variation, including SNPs and larger changes that involve duplications, deletions and repetitions of large segments of DNA.

The patterns they found produced what they call the highest-resolution map yet of human genetic variation.

They also reinforce the idea that humans originated in Africa, then spread into the Middle East, followed by Europe and Asia, the Pacific Islands and finally to the Americas.

"Diversity has been eroded through the migration process," Rosenberg said in a statement.

People of African descent are the most genetically diverse, followed by people from the Middle East, and then Asians and Europeans. Native Americans resemble one another the most on a DNA level.

The study also found it is sometimes possible to trace a person's ancestry to a small group within a geographic region.

Plastic (Not) Fantastic: Food Containers Leach a Potentially Harmful Chemical

Is bisphenol A, a major ingredient in many plastics, healthy for children and other living things?

CHEMICAL LEACHING: When exposed to hot water, plastic bottles--including baby bottles--leach a chemical that is known to mimic estrogens in the body.

Bisphenol A (BPA) is a ubiquitous compound in plastics. First synthesized in 1891, the chemical has become a key building block of plastics from polycarbonate to polyester; in the U.S. alone more than 2.3 billion pounds (1.04 million metric tons) of the stuff is manufactured annually.

Since at least 1936 it has been known that BPA mimics estrogens, binding to the same receptors throughout the human body as natural female hormones. And tests have shown that the chemical can promote human breast cancer cell growth as well as decrease sperm count in rats, among other effects. These findings have raised questions about the potential health risks of BPA, especially in the wake of hosts of studies showing that it leaches from plastics and resins when they are exposed to hard use or high temperatures (as in microwaves or dishwashers).

The U.S. Centers for Disease Control (CDC) found traces of BPA in nearly all of the urine samples it collected in 2004 as part of an effort to gauge the prevalence of various chemicals in the human body. It appeared at levels ranging from 33 to 80 nanograms (a nanogram is one billionth of a gram) per kilogram of body weight in any given day, levels 1,000 times lower than the 50 micrograms (one millionth of a gram) per kilogram of bodyweight per day considered safe by the U.S. Environmental Protection Agency (EPA) and the European Union's (E.U.) European Food Safety Authority (EFSA).

Studies suggest that BPA does not linger in the body for more than a few days because, once ingested, it is broken down into glucuronide, a waste product that is easily excreted. Yet, the CDC found glucuronide in most urine samples, suggesting constant exposure to it. "There is low-level exposure but regular low-level exposure," says chemist Steven Hentges, executive director of the polycarbonate / BPA global group of the American Chemistry Council. "It presumably is in our diet."

BPA is routinely used to line cans to prevent corrosion and food contamination; it also makes plastic cups and baby and other bottles transparent and shatterproof. When the polycarbonate plastics and epoxy resins made from the chemical are exposed to hot liquids, BPA leaches out 55 times faster than it does under normal conditions, according to a new study by Scott Belcher, an endocrine biologist at the University of Cincinnati. "When we added boiling water [to bottles made from polycarbonate] and allowed it to cool, the rate [of leakage] was greatly increased," he says, to a level as high as 32 nanograms per hour.

A recent report in the journal Reproductive Toxicology found that humans must be exposed to levels of BPA at least 10 times what the EPA has deemed safe because of the amount of the chemical detected in tissue and blood samples. "If, as some evidence indicates, humans metabolize BPA more rapidly than rodents," wrote study author Laura Vandenberg, a developmental biologist at Tufts University in Boston, "then human daily exposure would have to be even higher to be sufficient to produce the levels observed in human serum."

The CDC data shows that 93 percent of 2,157 people between the ages of six and 85 tested had detectable levels of BPA's by-product in their urine. "Children had higher levels than adolescents and adolescents had higher levels than adults," says endocrinologist Retha Newbold of the U.S. National Institute of Environmental Health Sciences, who found that BPA impairs fertility in female mice. "In animals, BPA can cause permanent effects after very short periods of exposure. It doesn't have to remain in the body to have an effect."

But experts are split on the potential health hazards to humans. The Food and Drug Administration has approved its use and the EPA does not consider it cause for concern. One U.S. National Institutes of Health (NIH) panel agreed, but another team of government scientists last year found that the amount of BPA present in humans exceeds levels that have caused ill effects in animals. They also found that adults' ability to tolerate it does not preclude damaging effects in infants and children.

"It is the unborn baby and children that investigators are most worried about," Newbold says, noting that BPA was linked to increased breast and prostate cancer occurrences, altered menstrual cycles and diabetes in lab mice that were still developing.

Fred vom Saal, a reproductive biologist at the University of Missouri–Columbia, warns that babies likely face the "highest exposure" in human populations, because both baby bottles and infant formula cans likely leach BPA. "In animal studies, the levels that cause harm happen at 10 times below what is common in the U.S." says vom Saal, who also headed the NIH panel that concluded the chemical may pose risks to humans.

Amid growing concern, Rep. John Dingell (D–Mich.) chairman of the House Committee on Energy and Commerce, has launched an investigation into BPA, sending letters last month to the FDA and seven manufacturers of infant products sold in the U.S. requesting information on any BPA safety tests as well as specific levels in the baby goods. The companies that make Similac, Earth's Best and Good Start have already responded, confirming that they coat the inside of their cans with BPA but that analyses did not detect it in the contents. They also emphasize that FDA has approved BPA for such use.

"Based on the studies reviewed by FDA, adverse effects occur in animals only at levels of BPA that are far higher orders of magnitude than those to which infants or adults are exposed," says FDA spokeswoman Stephanie Kwisnek. "Therefore, FDA sees no reason to ban or otherwise restrict the uses now authorized at this time."

FDA first approved BPA as a food container in 1963 because no ill effects from its use had been shown. When Congress passed a law—the Toxic Substances Control Act of 1976—mandating that the EPA conduct or review safety studies on new chemicals before giving them the nod, compounds like BPA were already on the market. Therefore, they were not subject to the new rules nor required to undergo additional testing unless specific concerns had been raised (such as in the case of PCBs). "The science that exists today supports the safety of BPA," ACC's Hentges says, based largely on research his organization has funded.

But other studies since 1976 have shown that small doses (less than one part per billion) of estrogenlike chemicals, such as BPA, may be damaging. "In fetal mouse prostate you can stimulate receptors with estradiol at about two tenths of a part per trillion, and with BPA at a thousand times higher," vom Saal says. "That's still 10 times lower than what a six-year-old has." In other words, children six years of age were found to have higher levels of BPA's by-product glucuronide in their urine than did mice dosed with the chemical that later developed cancer and other health issues.

Further complicating the issue is the stew of other estrogen-mimicking chemicals to which humans are routinely exposed, from soy to antibacterial ingredients in some soaps. The effects of such chemical mixtures are not known but scientists say they may serve to enhance the ill effects of one another. "The assumption that natural estrogens are somehow immediately good for you and these chemicals are immediately bad," Belcher says, "is probably not a reasonable assumption to make."

The chemical industry argues that unless BPA is proved to have ill effects it should continue to be manufactured and used, because it is cheap, lightweight, shatterproof and offers other features that are hard to match. "There is no alternative for either of those materials [polycarbonate plastics and epoxy resins] that would simply drop in where those materials are used," Hentges says.

Not so, says vom Saal, who notes that there are plenty of other materials, such as polyethylene and polypropylene plastics, that would be fine substitutes in at least some applications. "There are a whole variety of different kinds of plastic materials and glass," he says. "They are all more stable than polycarbonate."

Concern over BPA is not confined only to the U.S. Japanese manufacturers began to use natural resin instead of BPA to line cans in 1997 after Japanese scientists showed that it was leaching out of baby bottles. A subsequent study there that measured levels in urine in 1999 found that they had dropped significantly.

A new E.U. law (Registration, Evaluation, Authorization and Restriction of Chemical Substances, or REACH), which took effect last year, requires that chemicals, such as BPA, be proved safe. Currently, though, it continues to be used in Europe; the EFSA last year found no reason for alarm based on rodent studies. European scientists cited multigenerational rat studies as reassuring and noted that mouse studies may be flawed because the tiny rodent is more susceptible to estrogens.

For now, U.S. scientists with concerns about BPA recommend that anyone sharing those worries avoid using products made from it: Polycarbonate plastic is clear or colored and typically marked with a number 7 on the bottom, and canned foods such as soups can be purchased in cardboard cartons instead.

If canned goods or clear plastic bottles are a must, such containers should never be microwaved, used to store heated liquids or foods, or washed in hot water (either by hand or in much hotter dishwashers). "These are fantastic products and they work well … [but] based on my knowledge of the scientific data, there is reason for caution," Belcher says. "I have made a decision for myself not to use them."

U.S. Medical Schools Still Vulnerable to Financial Conflicts of Interest

Research centers are uneven in monitoring ties that might harm study volunteers

Many U.S. medical schools lack procedures to deal with the full range of financial conflicts of interests.

According to a new survey, fewer than half of the U.S. medical schools queried have policies in place to safeguard against improper financial links with drug companies. And it is not clear whether those with such safeguards actually enforce them. The findings come from the first national survey to examine the potential for what are called institutional conflicts of interest (ICOI) between pharmaceutical manufacturers or other for-profit groups and academic medical research centers that oversee drug testing on human subjects.

There is no data on whether the lack of oversight is damaging research, but "it's another potential source of at least apparent conflict, if not real," says study co-author Susan Ehringhaus, assistant general counsel for the Association of American Medical Colleges (AAMC) in Washington, D.C. "The protection of the integrity of research, the protection of human subjects—these are fundamental values. Anything that would call them into question suggests the need for systematic and serious response."

Ehringhaus, working with colleagues from the AAMC as well as Massachusetts General Hospital and the University of Michigan at Ann Arbor, sent surveys to the deans of 125 medical schools, both public and private, questioning them about the scope and nature of their ICOI policies.

Of the 86 schools (69 percent) that responded, 30 (38 percent) said they had procedures for evaluating sources of income such as royalties on patents, stocks and large contributions that fill their schools' coffers. Some said they also kept tabs on officials involved in drug testing: 55 schools (70 percent) reported monitoring senior and mid-level officials responsible for hiring and firing, and 62 of them (81 percent) said they kept an eye on members of so-called institutional review boards, who approve human research proposals.

Congress in 1980 passed a law called the Bayh–Dole Act, designed to speed commercialization of publicly funded research by making it easier for universities to patent and license their research as well as partner with for-profit companies.

The AAMC in 2001 recommended a set of specific guidelines to prevent ICOI, including separating the staffs that supervise human research from those that manage investments and license technology. Nearly all the 77 schools (74, or 94 percent) reported that they were following this guideline by assuring no single individual was responsible for both supervising research and approving financial investments.

U.S. Set to Destroy Crippled Satellite Before It Contaminates the Atmosphere

The Pentagon says rocket fuel from plummeting rogue satellite poses a health threat

MERCY MISSION: NASA administrator Michael Griffin (right) comments on a proposed attempt to destroy an unresponsive U.S. reconnaissance satellite just as it enters the Earth's atmosphere, during a news briefing at the Pentagon, Feb. 14, 2008. Griffin was joined by Marine Gen. James Cartwright (center), vice chairman of the Joint Chiefs of Staff, and Ambassador James Jeffrey, assistant to the president and deputy national security advisor.

NO ENTRY: Satellites tend to rotate in space just above the Earth's atmosphere and don't usually return with as much highly toxic hydrazine fuel as the troubled National Reconnaissance Office satellite.

THE WRONG STUFF: The largest uncontrolled re-entry by a US space agency (NASA) craft was the abandoned 91-metric ton (200,600-pound) Skylab space station in 1979.

The U.S. military plans to try to blast a malfunctioning satellite out of the sky by the end of the month to prevent the bus-size hunk of metal from leaking highly hazardous fuel into the atmosphere as it falls to Earth. The U.S. Department of Defense says the Navy will use surface-to-air missiles to knock it out sometime after February 20, when the space shuttle Atlantis is scheduled to return from its mission to the International Space Station.

The satellite, launched by the National Reconnaissance Office in December 2006 is not expected to hit a populated area, James Jeffery, deputy national security advisor, said yesterday during a press conference. But he added that President Bush decided to it should be destroyed to prevent leakage of highly toxic hydrazine fuel on its return. (For a transcript of the press conference, click here.)

In late January the U.S. government notified other nations that the satellite was unresponsive and would make an uncontrolled reentry later this month or in early March. Now the Navy is planning to intercept it prior to reentry at about 150 miles (240 kilometers) altitude, so that the unused hydrazine will be dispersed before it reaches the atmosphere. The weapon of choice: three modified Standard Missile (SM) 3 surface-to-air missiles launched from Aegis ships located somewhere in the North Pacific (the military would not be more specific). The window for shooting down the satellite opens in the next three or four days and will remain open for as many as eight days, according to Marine Gen. James Cartwright, vice chairman of the Joint Chiefs of Staff.

The Defense Department estimates that if the satellite is not intercepted, a sizable 2,800-pound (1,270-kilogram) chunk (about half its total weight) will survive reentry. The vehicle's 20-inch (50-centimeter) round fuel tank holds about 1,000 pounds (450 kilograms) of hydrazine that would have been spent during a successful mission; it was not, however, because ground control lost contact with it soon after launch. The Washington Post reported today that the shuttle Columbia contained a canister of hydrazine when it ripped apart during reentry over Texas in 2003, but that most of the toxic fuel had already burned because the doomed shuttle had nearly completed its mission.

Cartwright said that if the satellite is not shot down, its hydrazine could disperse over an area roughly the size of two football fields. He noted that anyone who inhaled the chemical, which can severely damage lung tissue, would need medical attention.

Military officials refused to release certain details—insisting that information such as the manufacturer, mission and price tag of the failed satellite is "classified." But they insist that the strike against the vehicle is not an effort to keep debris that survives the impact from falling into the wrong hands and divulging military secrets.

Cartwright positioned the situation by saying, "the worst that could happen is that we miss" (although this doesn't take into account the impact that failure could have on the environment). "If we hit the hydrazine tank, then we've improved the potential to mitigate that threat," he added. "The regret factor of not acting clearly outweighed the regret factor of acting."

The largest uncontrolled reentry by a U.S. spacecraft was NASA's abandoned 91-metric ton (200,600-pound) Skylab space station in 1979. China sparked international outrage last year when it was discovered that it had used a ground-based ballistic missile to destroy a target satellite about 600 miles (375 kilometers) above Earth. The U.S., Japan and Australia expressed concerns that China was demonstrating its ability to shoot down spy satellites and the destroyed vehicle's debris is hazardous to other orbiting spacecraft. The U.S. is hoping its concern over its errant satellite's fuel will obviate international criticism.