Pesticides and frogs – it's worse than we thought

  The article on frogs and pesticides is useful, but incomplete (HCN, 5/26/03: Agriculture exacts a price in the High Sierra). At a recent Rachel Carson Council seminar in Baltimore, Md., two researchers presented their findings. Tyrone Hayes of Berkeley, Calif., found, in both laboratory and field tests, that very low levels of atrazine, a pesticide component, produce lowered immune response and a disruption of reproductive capacity in leopard frogs. Though the Environmental Protection Agency sets the risk level for aquatic organisms at 10 to 20 micrograms/liter, Hayes finds risks for frogs at 0.1 micrograms/liter.

Joseph Kriesecker found the following atrazine effects on leopard frogs: enhanced susceptibility to trematode parasites, cysts and limb abnormalities. The Rachel Carson Council tracks and disseminates scientific data on pesticides (

Martin Murie
North Bangor, New York