PERMETHRIN
The insecticide permethrin (in the synthetic pyrethroid family) is
widely used on cotton, wheat, corn, alfalfa, and other crops. In
addition, over 100 million applications are made annually in and
around U.S. homes.
Permethrin, like all synthetic pyrethroids, is a neurotoxin.
Symptoms include tremors, incoordination, elevated body
temperature, increased aggressive behavior, and disruption of
learning. Laboratory tests suggest that permethrin is more acutely
toxic to children than to adults.
The U.S. Environmental Protection Agency has classified permethrin
as a carcinogen because it causes lung tumors in female mice and
liver tumors in mice of both sexes. Permethrin inhibits the
activity of the immune system in laboratory tests, and also binds
to the receptors for a male sex hormone. It causes chromosome
aberrations in human and hamster cells.
Permethrin is toxic to honey bees and other beneficial insects,
fish, aquatic insects, crayfish, and shrimp. For many species,
concentrations of less than one part per billion are lethal.
Permethrin causes deformities and other developmental problems in
tadpoles, and reduces the number of oxygen-carrying cells in the
blood of birds.
Permethrin has been found in streams and rivers throughout the
United States. It is also routinely found on produce, particularly
spinach, tomatoes, celery, lettuce, and peaches.
A wide variety of insects have developed resistance to permethrin.
High levels of resistance have been documented in cockroaches, head
lice, and tobacco budworm.
BY CAROLINE COX
Caroline Cox is JPRs editor.
