Clastogenic chromosomal aberrations in 26 individuals accidentally exposed to ortho dichlorobenzene vapors in the National Medical Center in Mexico City.
Chromosome studies were done in 8 males and 18 females who were accidentally exposed for 4 work days (i.e., 8 hr/day) to vapors of ortho dichlorobenzene. The clinical symptoms in 10 individuals included headache, general malaise, dizziness, and nausea. All persons had variable degrees of mucosal irritations. Of the 1345 cells studied, 120 disclosed chromosomal aberrations (mean = 8.92%), whereas a control group of 11 healthy individuals revealed 19 cells with aberrations in 942 cells examined (mean = 2.02%). The main chromosomal alterations were 84 single breaks (6.25%) and 86 double breaks (6.39%). In the control group there were 2 single breaks (0.92%) and 10 double breaks (1.06%), with significant statistic values of P less than .001 for the exposed group. Other chromosomal aberrations were poliploidy and ring formation but these were not statistically significant. Chromosome studies conducted 6 months later in 15 persons of the exposed group disclosed a significant reduction of chromosomal aberrations, but these were still present as compared with the control group. Although definite chromosomal changes occurred, these alterations seemed to be reversible after several months, at least with an original 4-day exposure to the clastogen chemical.