Study says benzene exposure can cause sperm abnormalities
Posted by Administrator (admin) on Mar 05 2010 at 12:27 PM
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According to a researchers report in the journal Environmental Health Perspectives, men exposed to benzene at levels near to the U.S. acceptable limit are more likely to have an abnormal number of chromosomes in their sperm.

The study says benzene exposure may result in some sperms to develop with either too many or too few chromosomes, a condition known as “aneuploidy”. Aneuploidy can have a negative impact on fertility and fetal development. It has been proved that Aneuploidy (in either the sperm or the egg) is the major cause of miscarriages in people.

The study conducted among male factory workers in China links benzene exposure to aneuploidy in the men’s sperm. 66 factory workers had been enrolled for the study, among which 33 men were recruited from factories that used benzene-containing adhesives to manufacture shoes, paper bags and sandpaper and the remaining 33 men were selected from a meat packing plant and an ice cream factory where there were no chance for benzene exposure.

Levels of benzene and benzene metabolites were measured in the men’s urine. To compare sperm aneuploidy, the men were then divided into three groups: 33 unexposed, 17 low-exposed and 16 high-exposed. A semen sample was collected from each man. After that the researchers applied colored fluorescent tags to chromosome 21 and to the X and Y chromosomes. The sperm were then observed under a microscope and the number of colored chromosomes were visually identified and counted. Ten thousand sperm were examined for each man to find out the number of sperm cells with aneuploidy.

The researchers discovered that the number of sperm a man produces with an extra sex chromosome increases as his benzene exposure becomes higher.

The study found men with low benzene exposure are twice as likely to have some sperm with two X chromosomes when compared to men with no benzene exposure, while men with high exposure are almost three times as likely. Men with high benzene exposure are also more likely to have sperm with two Y chromosomes.

The conclusion of the study is that men exposed to benzene have a two or three times higher risk for having abnormal numbers of chromosomes in their sperm than men who have not at all been exposed to the hazardous chemical.

Men exposed to benzene at work have a two or three times higher risk for having abnormal numbers of chromosomes in their sperm than men who have not been exposed to the chemical.

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