Thursday, August 20, 2009

The trouble with DEET

New research on DEET health risks

DEET, the active ingredient in many insect repellents used by some 200 million people every year, appears to affect proteins in mammals as well as mosquitoes and other target insects. Some previous studies have implicated DEET in seizures among children. A new study (PDF) by an international group of scientists, supported by Agence Nationale pour la Recherche in France, published August 5 at (BMCBiology), reports that DEET "is not simply a behaviour-modifying chemical but that it also inhibits cholinesterase activity, in both insect and mammalian neuronal preparations." Symptoms of lowered levels of cholinesterase, an enzyme essential to proper nervous system function, can include nausea, headaches, convulsions and, in extreme cases, death. Health risks increase when DEET and other pesticides are used together. The researchers concluded that "DEET is commonly used in combination with insecticides and we show that deet has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase." The new findings are "consistent with previous studies, says Bahie Abou-Donia of the Duke University Medical Center in Durham, NC," speaking to Science News. Abou-Donia's research found increased toxicity when DEET and chlorpyrifos, an organophosphate insecticide hazardous by itself, were used together. "These effects should be clearly labeled on products containing DEET, or N,N-diethyl-3-methylbenzamide," says Abou-Donia. In Canada, he noted, "insect repellents can contain no more than 30 percent DEET. The United States - where 100 percent DEET repellents are available - should consider such restrictions."

- Pesticide Action Network of North America

  • Mosquito Repellants and Deterrents
  • Some Insects of British Columbia
  • Monday, August 03, 2009

    Nuk Tessli Update

    Just received from Chris Czajkowski:

    August 3, 8:55 a.m.

    "When the helicopter flew over Knot Lake yesterday the fire was still on the far side of Knot Lake which is very good news. There was little wind yesterday and none last night. Tomorrow the temperature is supposed to cool dramatically, which will help, and a chance of showers is forecast. It is supposed to rain in a few days. "

    Chris drew this map at the time of the 2004 fire.

    Sunday, August 02, 2009

    Fire threatens Nuk Tessli. Chris Czajkowski has to fly out.

    Five years later and once again, Chris Czajkowski has had to evacuate Nuk Tessli. In an e-mail sent a couple of hours ago, she reports:

    "Even if the fire did not reach us, the smoke would probably be very unpleasant. Been there, done that. 11 clients and a wwoofer/guide had flown out that morning and 4 clients had flown in. These were a couple my age, their 80+ mother, and their 9-year-old grand-daughter. The fire would likely stay away for a couple of days but the smoke would be distressing: at least now the visibility was good enough to fly out."