Objectives 

Organic solvents have been suspected to exert detrimental effects on human spermiogenesis.

Styrene, which is both mutagenic and neurotoxic, was selected as a suitable organic solvent for further assessment of a possible effect on semen quality and sperm DNA damage.

Subjects and methods 

Semen samples were collected from 23 reinforced plastics workers at the time of employment and after 6 months of styrene exposure and from 21 nonexposed farmers.

Intra-individual changes in conventional semen parameters and sperm-DNA denaturation patterns were related to the internal dose of styrene exposure as measured by postshift urinary mandelic acid.

Results 

A statistically significant decline in sperm density was seen during styrene exposure from 63.5 to 46.0 million sperm/ml, whereas no decline was seen in the nonexposed subjects.

The total sperm count was almost halved from an initial value of 175 million sperm/ejaculate.

However, no relationship was apparent when the sperm parameters were related to internal levels of exposure.

However, an exposure-response relationship was shown for DNA-denaturation patterns, but the numbers were small.

Conclusion 

A declining sperm count following styrene exposure is suggested. (...)