18 June 2003
lower sperm levels, study finds
By Rita Rubin
for the first time have shown a link between levels of widely used
agricultural pesticides in men's bodies and the number and quality
of their sperm.
a study out Wednesday, researchers found that men with higher levels
of three pesticides widely used in the Midwest were more likely
to have below-average semen quality and sperm counts than men with
lower levels of the chemicals.
scientists studied 50 men in rural Missouri and 36 men in Minneapolis.
Their wives were patients at prenatal care clinics, so they were
fertile. Based on semen samples, the men were divided into two groups:
those with low sperm counts and quality and those with better semen
interesting that even within fertile men, there's a huge range,"
says lead author Shanna Swan, a family and community medicine professor
at the University of Missouri-Columbia.
Centers for Disease Control and Prevention lab measured levels of
the byproducts of 15 different pesticides in urine samples from
the men. Men with higher levels of alachlor, atrazine and diazinon
were significantly more likely to have poorer sperm quality, the
researchers report in the journal Environmental Health Perspectives.
All three pesticides were more likely to be found in high levels
in the Missouri men than in the Minneapolis men.
two of the Missouri men were farmers. Swan and her coauthors speculate
that the men were exposed to the pesticides through drinking water.
According to the authors, usual water treatment methods cannot remove
Gordon, a spokesman for Syngenta, which makes atrazine, says there
have been more than 800 studies of its health effects. "An
overwhelming body of research supports the safety of atrazine for
humans and the environment," Gordon says.
Hess, a reproductive toxicologist at the University of Illinois-Urbana,
praised the design and execution of Swan's study. The logical next
step would be to test drinking water in Missouri for the pesticides,
biologist Sally Perreault of the Environmental Protection Agency
says rodent studies suggest that even the highest pesticide levels
found in Swan's subjects would have been too low to affect sperm
quality. Still, Perreault says, the new study "really does
raise a flag."