CLASTOGENICITY OF FORMALDEHYDE FUMES AND X-RAYS EVALUATED BY THE TRADESCANTIA-MICRONUCLEUS ASSAY

The present study was designed to demonstrate the clastogenic effect o f formaldehyde fumes (FA) with the Tradescantia-micronucleus (Trad-MCN ) assay, which exhibits chromosome damage in the form of micronuclei i n the meiotic microspore mother cells. The clastogenic effect of X-ray s on the same germ cell system was also evaluated for comparison with that of FA to establish the relative effectiveness of FA. Tradescantia plant cuttings were exposed to FA for 3, 6, 12, 24 and 36 h at a dose rate of 72 ppm/min in a dynamic gas flow fumigation chamber. The MCN frequencies of 5.5, 8.2, 20, 26 and 37 MCN/100 tetrads were induced by each of the increasing dosages of FA, respectively. Linear regression analysis of the FA data yielded a correlation coefficient of 0.956, A parallel series of experiment using five increasing doses of X-rays a t 18.6, 27.9, 37.2, 46.5 and 55.8 cGy at a dose rate of 37.3 cGy/min w as conducted. The MCN frequencies of 7.7, 10.5; 17.2, 27.4, and 44.8 M CN/100 tetrads were observed from each of the increasing X-ray dosage groups, respectively. Linear regression analysis of the X-ray data MCN frequencies yielded a correlation coefficient of 0.997. The MCN frequ ency for the control groups yielded 4.3 MCN/100 tetrads for the FA and 3.2 MCN/100 tetrads for the X-ray experiments. By comparing thr resul ts of these two series of experiments, the relative clastogenic effect iveness of FA at the median dose of 2.7 x 10(-4) MCN/ppm for FA is equ ivalent to 5.08 x 10(-4) MCN/0.01 mGy for X-rays, or roughly the clast ogenic effect of 1 ppm of FA equals 5.3 mu Gy of X-rays. In other word s, the amount of damage from 1 ppm of FA could inflict as much as the damage done by the exposure to 0.57 mrad of ionizing: radiation. (C) 1 998 Elsevier Science B.V. All rights reserved.