Earth Talk:

Dear EarthTalk: Are there any flea and tick products out there that don’t contain toxic chemicals? –Ewan Locke, Madison, WIHarmful pesticides in mainstream flea and tick products are indeed hazardous to more than insects. The active substance in most of these products is likely one of seven common organophosphate insecticides (OPs), which work by interfering with the transmission of nerve signals in the brains and nervous systems of not just insects—most of whom die on the spot—but to a lesser degree in pets and humans as well. While it would certainly take an awful lot of exposure to OPs to affect a full-grown healthy human adult, no one is sure how the chemicals might affect children or those with pre-existing nerve disorders.The non-profit Natural Resources Defense Council (NRDC), which authored the 2000 report “Poisons on Pets” (results are online at the group’s GreenPaws.org website), reports that “studies with lab animals have raised concerns among scientists that children exposed to certain of the pesticides in pet products—even at levels believed to be safe for adults—face much higher risks, not only for acute poisoning, but also for longer-term problems with brain function and other serious disease.” The group adds that children’s behavior—notably toddlers’ hand-to-mouth tendencies and the fact that kids play where such toxins often accumulate—makes them more vulnerable to ingesting OPs than adults in the same household.The magnitude of the potential risk to public health is what makes the inclusion of such chemicals in pet products so troubling: Surveys show that as many as 50 percent of American families report using some kind of flea and tick control product on pets, subjecting untold millions of children to toxic chemicals on a daily basis. Initial research also shows that thousands of pets may be sickened or die each year as a result of chronic low-dose exposure to OPs through their flea and tick collars.Fortunately, several non-toxic alternatives to OP-laden flea and tick control products are now available. NRDC tested upwards of 125 pet-oriented flea and tick control products for its Poisons on Pets report and found less than two dozen that don’t contain harmful chemical compounds. Stripe-On formulations from Adams, Breakthru, Demize and Scratchex get high marks from NRDC for low-toxicity, while tabs (pills) from Comfortis, Program and Sentinel also make the safety grade. Hartz, which uses OPs in most of its product line, also offers some safer formulations (Spot-On, Advanced Care and Ultra Guard) for cats and kittens. These products rely on insect growth regulators, which arrest the growth and development of young fleas, rather than pesticides to simply kill them. NRDC notes, however, that even these safer formulations contain chemicals, and that all such products should be used with caution.One way to treat your pet but avoid chemicals altogether is to go the essential oil route. Oils from cedarwood, lemongrass, peppermint, rosemary or thyme have all been shown to be effective, when used sparingly, to keep fleas and ticks away from pets and their favorite haunts. Of course, a little conscientious legwork can obviate the need for any kind of topical or pill-based flea and tick control products, toxic or otherwise. According to NRDC, frequent washing and combing of pets and vacuuming carpets and furniture can bring mild flea infestations under control and help avoid outbreaks altogether.* * * *Dear EarthTalk: Some say that polar bears are going to disappear in 50 years, but Alaskan officials insist their populations are recovering. What’s the real story? — Harper Howe, San Francisco, CA There is no doubt that polar bears are in serious trouble. Already on the ropes due to other human threats, their numbers are falling faster than ever as a result of retreating ice due to global warming. The nonprofit International Union for the Conservation of Nature, which added the polar bear to its “Red List” of the world’s most imperiled wildlife back in 2006, predicts a 30 percent decline in population for the great white rulers of the Arctic within three generations (about 45 years). The nonprofit Center for Biological Diversity presents an even more pessimistic forecast. If current warming trends continue, they say, two-thirds of all polar bears—including all of Alaska’s polar bears—will be extinct by 2050. Both organizations agree that the species as a whole will likely be wiped out completely within 100 years unless humans can get global warming in check. The erroneous notion that Alaska wildlife officials don’t believe the polar bear is in trouble was put forth by Alaska governor Sarah Palin when she initiated a suit against the federal government in hopes of overturning its decision to include the polar bear under the umbrella of endangered species protection. “I strongly believe that adding them to the list is the wrong move at this time,” Palin wrote in a January 2008 New York Times Op Ed piece. “My decision is based on a comprehensive review by state wildlife officials of scientific information from a broad range of climate, ice and polar bear experts.” The real story is that affording the polar bear endangered species protection would bring further regulations capping greenhouse gas emissions, a threat to Alaska’s main economic driver: oil revenues. Alaska professor Rick Steiner uncovered the misinformation in Palin’s claims when he found evidence that the state’s top wildlife officials agreed with federal findings that polar bears are headed toward extinction: “So, here you have the state’s marine mammal experts, three or four of them, very reputable scientists, agreeing with the federal proposed rule to list polar bears and with the USGS [United States Geological Survey] studies showing that polar bears are in serious trouble,” said Steiner. A solid link between global warming and polar bear mortality emerged in 2004 when researchers were surprised to find four drowned bears in the Beaufort Sea off Alaska’s North Slope. The meltdown of sea ice—the polar ice cap had retreated a record 160 miles to the north—forced the bears to swim unusually long distances to find solid ice, which they depend on as hunting and fishing platforms and for rest and recuperation. And more recently, USGS researcher Steven Amstrup published findings that polar bears are “stalking, killing and eating other polar bears” as competition for scarcer food heats up. Beyond global warming, other risks to polar bear populations include toxic contaminants in the surrounding environment as well as in the fatty tissue of the prey they rely on, conflicts with shipping, stresses from recreational polar-bear watching, oil and gas exploration and development, and overharvesting through legal and illegal hunting.