A common chemical found in plastic makes male mice act like females, a new study reports, adding more fuel to the ongoing debate about whether the chemical is safe for humans. Known as bisphenol A, or BPA, it mimics the female hormone estrogen and has long been blamed on a variety of health problems, including asthma, cancer, accelerated puberty and heart disease. And now, according to research published in the Proceedings of the National Academy of Sciences, BPA not only appears to emasculate male deer mice, but also hurts their chances of finding a mate.
"The BPA-exposed deer mice in our study look normal; there is nothing obviously wrong with them. Yet they are clearly different," says study co-author Cheryl Rosenfeld, a biomedical scientist at the University of Missouri. "Females do not want to mate with BPA-exposed male deer mice, and BPA-exposed males perform worse on spatial navigation tasks that assess their ability to find female partners in the wild." The male test subjects, exposed to BPA while in the womb, grew up to be anxious or indifferent about navigating through mazes — behavior that's rare among male deer mice but typical in females, the researchers say. That didn't elicit much sympathy from the females, though, who still rejected the BPA-exposed males as breeding partners by a rate of 2 to 1. This led the researchers to conclude BPA exposure in males "could impact behavioral cues, pheromone signaling, or both."
BPA is used in a wide range of plastics, and has been linked to negative outcomes in many animal studies. Fewer human studies have been conducted, however, and there's no evidence BPA affects boys or men similarly to how it affects male deer mice. Yet experts say the new study does reveal a need for subtler ways to study BPA in humans — for example, the BPA-exposed male deer mice showed normal levels of testosterone, suggesting BPA can affect behavior without changing adult hormone levels. "In a human study, we often depend on an outcome like hormone levels," the University of Michigan's John Meeker tells CNN. "It's possible that BPA could be impacting reproduction in a way that wouldn't be picked up in our typical way of studying things. [This study] may inform how we go about studying those things in the future."
Three U.S. nuclear facilities are being encroached upon by rising floodwaters and a spreading wildfire, raising fears of a catastrophe akin to Japan's Fukushima Daiichi crisis. Officials say none of the three facilities is in immediate danger, although the specter of a meltdown on U.S. soil has still sparked plenty of anxiety, especially in a year when so many disasters have already struck the country's midsection.
Two nuclear power plants in Nebraska are threatened by the surging Missouri River: the Fort Calhoun Station and the Cooper Nuclear Station. The Nuclear Regulatory Commission has set up an incident response center to monitor the situation at Fort Calhoun, the Huffington Post's Tom Zeller Jr. reports, while NRC Chairman Gregory Jaczko visited both sites in recent days. Floodwaters around Fort Calhoun rose to 1,006 feet above sea level Monday, but the site is equipped to withstand up to 1,014 feet and the river isn't likely to surpass 1,008 feet. Officials at the Cooper facility also say they expect to avoid serious flooding, but Zeller notes that similar assurances at both plants in the past have proved overly optimistic. After plant officials downplayed a flood at the Cooper site in 1993, for example, an NRC inquiry found water had invaded areas where electrical equipment could be at risk. Fort Calhoun also reportedly has ongoing problems with leaks even below its designed flood limit of 1,014 feet. Still, Jackzo insists all U.S. plants are safe. "[A]ll the plants in the U.S. have been designed to deal with historically the largest possible [skipwords]floods[/skipwords]," he tells ABC News.
Meanwhile, a wildfire is raging in New Mexico within about a mile of the Los Alamos National Laboratory, forcing the federal research facility to close Monday and Tuesday as a precaution. As Zeller reports, Los Alamos is home to several metric tons of plutonium as well as other hazardous and volatile materials that could spark a major disaster if ignited. But officials say all such substances are safe, and no combustible trees, brush or grasses are close enough to sensitive buildings to fuel the fire. "No other fires are currently burning on Lab property, no facilities face immediate threat, and all nuclear and hazardous materials are accounted for and protected," the lab said in a statement.
More Americans are investing in small, residential wind turbines to generate their own electricity at home, USA Today reports, even as economic woes continue to plague many of the country's homeowners. And advocates of wind energy say new technological and manufacturing advances are poised to make such personal power plants even more affordable and popular in coming years.
"We do envision the day when we will have houses that are super-efficient, that are generating renewable energy through [skipwords]solar[/skipwords] and building-integrated wind, and they are producing more energy than they consume and exporting energy into the grid," says James Hunt, chief of environmental and energy services in Boston, where officials have passed ordinances to encourage more small-scale wind development. Nationwide, almost 10,000 residential wind turbines were sold in 2009, the latest year for which data are available, USA Today reports. That's up from just 2,100 units sold in 2001 — or an increase of roughly 376 percent in 10 years.
Still, there are significant hurdles for this trend, not the least of which is price. A 10-kilowatt wind turbine, which is needed to power an average home, can cost anywhere from $35,000 to $50,000 upfront, according to data from the nonprofit Windustry. It should eventually pay for itself via reduced electricity bills, but that will take varying amounts of time depending on local energy costs and wind strength. Another hurdle is local zoning codes, USA Today points out — home wind turbines are still so new that many municipal governments have no laws governing their use. "Zoning and permitting is a big issue in small wind," says Larry Flowers of the American Wind Energy Association. "There's progress being made in some places and struggles in others."
(Source: USA Today)
An invasive pest from Asia has become an increasing nuisance in vegetable fields, orchards, vineyards and home gardens across the U.S., the AFP reports, leaving farmers and gardeners with little recourse to deal with it. Pesticides, traps and even parasites have been introduced to fight off the brown marmorated stink bug, but to no avail. Introduced to the U.S. from Asia in 1996, the insect has now spread to 33 states.
"I smash 'em, I am so mad at 'em," Maryland farmer Bob Black tells the AFP, explaining how he uses his bare hands to battle the bugs. "The thing stinks, it's terrible ... they emit this defensive odor system and that is why nothing will eat them." Black's fruit orchards sustained heavy damage from the stink bugs last year, and now he's letting scientists research the bugs on his land — and spraying them with pesticides, too. The brown marmorated stink bug can survive on any of 300 different host plants, the AFP reports, including apples, corn, grapes, peppers and tomatoes. Certain [skipwords]birds[/skipwords], bats, spiders and other predators will eat them, but the bugs reproduce so quickly they usually outbreed their enemies. "A single female can lay on average about 200 to 250 eggs in her lifetime," says Tracy Leskey, a research entomologist at the U.S. Department of Agriculture. "Some females can lay up to 400 eggs."
The invasive insects are such a big problem, in fact, the EPA is now considering legalizing the use of more pesticides in some areas to fend them off. This highlights just how unusually destructive the brown marmorated stink bug has become, says Doug Pfeiffer, an entomologist at Virginia Tech University. "It is so seldom that we get a pest of this magnitude that affects so many things, that it has really shifted a lot of our research activity," he says. "It is really a megapest compared to our native stink bugs."
(Source: Agence France-Presse)
U.N. warns of desertification, U.S. removes bald eagles from the endangered species list, and more.
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Photo (deer mouse): U.S. National Science Foundation
Photo (Jemez Fire in New Mexico, June 26): John Fowler/Flickr
Photo (rooftop residential wind turbines): ZUMA Press
Photo (brown marmorated stink bugs): U.S. Department of Agriculture