Science

Diesel fumes lower sperm counts in rats

TOKYO, Nov 13 (Reuters Health) - Exposure to
diesel fumes lowers sperm count in rats,
according to Dr. Ken Takeda of Science University
of Tokyo.

Dr. Takeda and colleagues at his institution, at
Teikyo University and at the National Institute for
Environmental Studies exposed animals to three
different levels of fumes for 12 hours a day over
six months.

The low-exposure group received 0.3 mg
particles/cubic meter of air, the middle-exposure
group received 1 mg/cubic meter of air and the
high-exposure group received 3 gm/cubic meter of
air. The lowest level of exposure corresponded to
double the amount of diesel fumes recently
detected in a highly polluted area of Tokyo, Dr.
Takeda said.

Sperm counts in the low-exposure group averaged
21% lower than sperm counts in control animals,
36% lower in the middle-level group compared
with controls and 53% lower in the high-exposure
group than controls.

Dr. Takeda told Reuters Health that it is important
to determine the substance that causes lower
sperm count in experimental animals and to
examine the effect of exposure of diesel fumes on
primates.

Epidemiological studies of people who live in
areas that are highly contaminated with diesel
fumes or who are occupationally affected by
diesel fumes are also needed, he said.

He added that his findings do not necessarily
support epidemiological studies that have shown
lower sperm counts in men over recent years.

"We hope this study will help the development of
measures to reduce the amount of exhaust fumes
in the air," Dr. Takeda said. He presented his
findings at a symposium on environmental
science sponsored by Osaka University.

Copyright 1998 by Reuters Ltd.
Story by Sandra Katzman