A roundup of some of the week's science headlines:
Don't ditch that water bottle yet: 150 scientific studies show that bisphenol A (BPA), a controversial component of plastic bottles and canned food linings, may be present in quantities too small to negatively affect human health. The analysis, presented at the American Association for the Advancement of Science's annual meeting in Boston , shows that BPA in the blood of the general population is many times lower than levels that consistently cause toxicity in animals. The result suggests that animal studies might not reflect the human BPA experience appropriately, the study says. – Agence France-Presse
Fish with the munchies? Not as funny as it seems: What happens to fish that swim in waters tainted by traces of drugs that people take? When it's an anti-anxiety drug, they become hyper, anti-social and aggressive, a Swedish study found. It may sound funny, but it could threaten the fish population and upset the delicate dynamics of the marine environment, scientists say. The findings, published online Thursday in the journal Science, add to the mounting evidence that minuscule amounts of medicines in rivers and streams can alter the biology and behaviour of fish and other marine animals. Calling their results alarming, the researchers who conducted the study suspect the perch, exposed to the sedative Oxazepam, could become easier targets for bigger fish because they are more likely to venture alone into unfamiliar places. Plus, the drugged perch ate faster, a change that could also impact the ecological balance, researchers said in a release. You can read more here and here .– The Associated Press/Aleysha Haniff
And in other space rock news: A strike from a big asteroid more than 300 million years ago left a huge impact zone buried in Australia and changed the face of the earth, researchers said on Friday.
"The dust and greenhouse gases released from the crater, the seismic shock and the initial fireball would have incinerated large parts of the earth," said Andrew Glikson, a visiting fellow at the Australian National University. The asteroid was bigger than 10 kilometres in diameter, while the impact zone itself was larger than 200 kilometres – the third largest impact zone in the world. The strike may have been part of an asteroid impact cluster that caused an era of mass extinction, wiping out primitive coral reefs and other species, added Glikson, co-author of a study published in the journal Tectonophysics. – Reuters