Chromosome aberrations and micronuclei in lymphocytes of workers exposed to low and medium levels of styrene.

In the present study we analysed 19 workers exposed to styrene in two factories where polyester resins were used. Because of the different sizes of the pieces undergoing resin processing, the environmental styrene concentrations and urinary mandelic acid (MA) levels of the analysed subjects were quite different in the two plants examined. Cytogenetic monitoring was performed by analysis of chromosome aberrations (CAs) and micronuclei (Mn) in peripheral blood lymphocytes. Cytogenetic analysis revealed a significant increase in the percentage of aberrant cells and total aberrations in the group with higher styrene exposure (group 2) and no increase in the group with lower exposure (group 1), as compared with matched controls. Mn frequencies were not significantly increased in the two exposed populations. No correlations between length of exposure and CA or Mn frequency were found, and a weak correlation was found between exposure levels, measured as urinary MA, and Mn frequencies. Only 5 of the 12 exposed workers examined in group 2 had urinary MA levels higher than the limit recommended by the ACGIH in 1990-91 [1]. Significant increases in DNA damage are therefore already found at urinary MA levels lower than the internationally suggested exposure limits.