REVERSION PROFILES OF COOLWHITE FLUORESCENT LIGHT COMPARED WITH FAR-ULTRAVIOLET LIGHT - HOMOLOGIES AND DIFFERENCES

General Electric and Sylvania 15 W coolwhite fluorescent lamps emit ro ughly 6% of their total irradiance as light in the UV spectrum. Illumi nation of sensitive Salmonella tester strains results in both lethal a nd mutagenic activities. In contrast, comparable Philips lamps emit lo wer levels of UV light, especially UVB, and exhibit no detectable leth al or mutagenic effects. The spectra of mutations induced by General E lectric coolwhite lamps in histidine-requiring base substitution mutan ts hisG46 and hisG428 (''reversion profiles'') resemble mutagenesis by far UV light (UVC) and differ quite markedly from the spectra of muta tions that occur spontaneously. Coolwhite and UVC reversion profiles a re not identical, however. The percentage of C to A transversion mutat ions induced in hisG46 are elevated over those found after UVC treatme nt, and a strong bias for one particular class of tandem base substitu tions (TAA --> TGT) prevails after treatment of hisG428 with coolwhite light, a bias not observed with UVC. Increased attention needs to be given to minimization of exposure to UV light from fluorescent lamps c ommonly used in homes and workplaces.