Effect of NOx on the somatic chromosomes of goldsmiths.

The genotoxic effect of NOx was investigated on somatic human chromosomes obtained from lymphocytes of 45 goldsmiths exposed to 1770.5 mg/m3 NOx in ambient air at normal temperature and pressure and compared to an equal number of matched controls breathing air containing 50 microgram/m3 NOx. Short-term lymphocyte cultures were set up from blood collected from both exposed and control individuals by venipuncture in heparinized sterile syringes. Mitotic index (MI), chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and satellite associations (SAs) were analyzed. All the parameters showed a significant increase (p<0.01 and p<0.05) in the exposed individuals as compared to the controls: MI (9.57 vs. 5.01), CAs (3. 48 vs. 0.711), SCEs (10.56 vs. 7.02), and SAs (25.97 vs. 12.84), respectively. Occurrence of DG-type SAs (one D-group chromosome and one G-group chromosome) was highest and 3 D-type (three D-group chromosomes) lowest. NOx was thus found to be genotoxic for humans.