[Cytogenetic effects of wide-range noise]

Noise at 40-12,000 hz frequency and 100 dBA with maximums in medium and high frequency ranges, maintained for 3 months and 4 hours per day did not change the number of chromosome aberration cells in the spinal marrow, but decreased by 1,3 the number of the aberrant hepatocytes in male rats. This was apparently caused by the mitotic activity of the liver parenchyma and related elimination of the damaged cells. The noise maintained for 4 months caused an increase by 1,7 in aberrant hepatocytes. This cytogenetic effect is regarded as potentially dangerous.