NO MATTER WHAT FLAME RETARDANT IS USED, IT SHOWS UP IN THE ENVIRONMENT
Another chapter has been added to the troubled history of flame retardants. The latest compounds used to reduce the risk of fire have been found in household dust for the first time.
First, there were polychlorinated biphenyls, which were banned in the 1970s when it became clear that they were highly toxic and were accumulating in people and wildlife.
PCBs were replaced by PBDEs (polybrominated diphenyl ethers), which were used in a wide array of consumer products, including televisions and baby clothing. But then those also showed up in wildlife, including whales in the Arctic.
Canadians carry one of the highest levels of PBDEs (second only to Americans) and the levels are rising every year. Laboratory work indicates that PBDEs interfere with thyroid hormones, damage the brain and cause “ADHD-like symptoms” in mice. The handful of studies in humans have linked them to reproductive defects such as poor sperm quality.
While the European Union and some U.S. states have banned deca-BDEs, the only form of PBDE still being used, Canada decided last month to permit their use while banning their manufacture. Industry contends that deca is safe and doesn’t break down into the banned penta and octa forms, though recent studies indicate that it does.
Now, brominated phthalates, which were brought in to replace the penta form, have been identified in household dust. “We know very little about the toxicity of these chemicals,” says Heather Stapleton, a chemist at Duke University, lead author of the study on brominated phthalates published in an upcoming issue of Environmental Science and Technology.
So, will brominated phthalates also become a problem? We can’t know yet, Prof. Stapleton says. But “is it really necessary to have your TV withstand an open flame for 10 minutes?” she asks.
FUEL FOR HYDROGEN ECONOMY
Scientists and politicians have long dreamed of a “hydrogen economy” – one run on fuel cells that use metal electrodes to combine hydrogen and oxygen to create electricity (with only water as exhaust). But pragmatists point out that the hydrogen economy has proved elusive: Existing fuel cells are inefficient and expensive.
Now, researchers at the Massachusetts Institute of Technology, publishing their work July 31 in the journal Science, say they may have brought us one step closer with a simple solution – replacing a costly platinum electrode with a cheaper material made from indium tin oxide that is immersed in a cobalt and potassium phosphate solution.
When voltage is applied to the electrode, water is oxidized to form oxygen gas and free hydrogen ions. At another electrode, coated with platinum, the hydrogen ions form hydrogen gas. In a fuel cell, the oxygen and hydrogen would be recombined to provide electricity.
GENDER BENDER
Climate change is nudging many species, including polar bears, songbirds and trees, toward extinction by, for example, causing their prey to move. And some animals are experiencing another consequence: Climate change may be skewing their gender ratios.
A study published in the journal PLoS Biology shows that the gender of at least 40 fish species are determined by temperature. Warmer water always mean more male fish and even small temperature rises could drive large shifts. A 1.5-degree Celsius rise (considered “very likely” by the Intergovernmental Panel on Climate Change) will shift the fish to 62 per cent males, on average, from 50 per cent. But some species are more sensitive than others. Atlantic silversides, important commercially in South America, see males rise to 73 per cent with a 1.5-degree rise – and up to 98 per cent with an increase of four degrees.
Even in fish with genetically determined gender, warmer water can produce more males by inhibiting the enzymes that produce estrogen.
“Remember that there are 30,000 species of fish in total worldwide and the sex-determination mechanism is only known for a few of them,” says Francesc Piferrer, of the Institute of Marine Sciences in Barcelona, lead author of the study. “This could be bad news.”