CYTOGENETIC STUDIES ON COMMERCIAL HEXANE SOLVENT

Commercial hexane is a solvent mixture of six-carbon isomers, consisti ng principally of n-hexane, 3-methylpentane, methylcydopentane and 2-m ethylpentane. The potential of commercial hexane to produce chromosome aberrations was evaluated in both an in vitro assay using Chinese ham ster ovary (CHO) cells and an in vivo cytogenetics assay using Sprague -Dawley rats. The CHO cells were exposed to media containing commercia l hexane at concentrations of 0.014-0.42 mu l ml(-1) in the presence a nd absence of an S-9 activation mixture. Cellular toxicity was observe d at the higher dose levels, but no increase in chromosome aberrations was observed in either the non-activated or S-9-activated systems. Fo r the in vivo cytogenetics assay, rats were exposed nose-only for 6 h per day for 5 consecutive days to commercial hexane vapor at target co ncentrations of 900, 3000 and 9000 ppm. Bone marrow cells were collect ed at 6 and 24 h after the midpoint of the last exposure. Metaphase ce lls were examined microscopically for chromosome aberrations. No stati stically significant increases in aberrant cells were observed in the commercial hexane-exposed animals of any dose group at either of the b one marrow harvest times. In conclusion, commercial hexane did not pro duce chromosomal mutations under the conditions of these studies.