ACCUMULATION OF NICOTINE IN HUMAN HAIR DURING LONG-TERM CONTROLLED EXPOSURE TO A LOW CONCENTRATION OF NICOTINE VAPOR

Hair from 5 subjects were exposed in dynamic exposure chambers to air nicotine vapour for 72 hr or 12 months at concentrations of 200 or 5 m u g/m(3), respectively. Nicotine in the chamber air and human hair was determined by GC/MS. A linear accumulation of nicotine in hair was fo und with time for all hairs during the long-term, law concentration ex posure, with individual hair nicotine uptake rate constants ranging fr om 0.70 to 3.75 x 10(-3) m(3)/gxhr. The corresponding hair nicotine up take rate constants during short-term, high concentration exposure, we re re significantly higher, ranging from 1.35 to 15.11x10(-3) m(3)/gxh r, showing, however, a highly significant linear correlation dth the i ndividual long-term exposure rate constants, r(2)=0.9961. It is indica ted that long-term hair nicotine uptake rate constants calculated from controlled exposure experiments with pure nicotine vapour are adequat e for estimation of individual long-term hair accumulation of nicotine from environmental tobacco smoke even at variable and intermittent ex posure. Although higher than the long-term uptake rate constants, the short-term uptake rate constants seem well fitted for a differentiatio n between different types of hair in their ability to adsorb nicotine also during long-term exposures. The short-term uptake rate constants might also be useful parameters for establishing a reliable cut-off li mit in tile hair concentration of nicotine between smokers and non-smo kers which otherwise seems to be overlapping.