The methodology used by the EPA to approve pesticides has been proven to be flawed.
Their assumption has always been that if an organism can cope with an amount of a substance, then smaller amounts will also be fine. It's just common sense - if you can survive a gram of a toxin then a microgram will be even easier to survive - right?
Well if the substance is a hormone imitator then the answer is no - a large amount triggers the organisms defence system and is neutralised, while a smaller amount can sneak past the defences and cause havoc.
Tyrone Hayes has found that 0.1 parts per
billion of herbicide atrazinean causes tadpoles' sexual development to go awry. Tyrone used to work for the EPA, but they didn't like his research so he is now at the University of California.
Other hormone imitators (some such as BPA are used in plastics) have similar results, where tiny amounts are far more harmful than moderate amounts!
http://www.pesticide.org/the-buzz/mixture-of-corn-pesticides-harms-frogs-1
