Traffic pollution shown to damage sperm quality
After studying 85 attendants at tollgates on Italian motorways, researchers at the University of Naples in southern Italy discovered the men had poorer quality sperm than other young and middle-aged Italian workers in the same area.
"The sperm count did not differ significantly between our study group and the controls but, in general, the sperm of the study group was more feeble and less active so it has a lower fertility potential," said Dr Michele de Rosa, a researcher at the university.
Levels of testosterone and other hormones in the men, who were exposed to pollutants for about six hours a day, were normal, but sperm motility, or ability to swim, was lower which could affect its ability to fertilise a female egg.
"Our study demonstrates that continuous exposure to traffic pollutants impairs sperm quality in young and middle-aged men," De Rosa added in a statement.
About one third of all infertility cases are due to a male problem, which is usually related to the quality or quantity of sperm. Men normally produce at least 20 million sperm per millilitre of semen. Fewer sperm is considered to be impaired fertility.
Poor mobility and shape of sperm can also hamper a man's ability to father a child.
De Rosa and his colleagues, who reported their findings in the journal Human Reproduction, said the tollgate workers were interviewed and had a complete physical examination. Eighty-three percent of the men were married. Seven of the 71 married workers were childless.
The researchers said the toll workers had been exposed to higher levels of nitrogen oxides, sulphur oxides, carbon monoxide and lead than the other men in the area.
They identified nitrogen oxides and lead as the most likely causes of sperm damage.
Although more research is needed, De Rosa said he hopes the findings will prompt more studies of men who are exposed to similar levels of environmental pollution in other occupations.
"Meanwhile, given our findings, health authorities should be alert to the insidious health effects of environmental pollution," he added.