| Abstract |
Carbaryl has been reported to cause point mutations in bacteria, Drosophila, and mammalian cells in vitro; unscheduled DNA synthesis in human cells in culture; and chromosome effects (including spindle effects) in plants, mammalian cells in vitro, and animals. Although there are inadequacies in these studies, the results when considered together are strongly suggestive that carbaryl may have the intrinsic ability to act as a mutagen. It should be noted that because carbaryl appears to act as a weak mutagen in the experimental test systems, it is likely to act as a weak mutagen in humans as well. To cause heritable effects in humans, however, carbaryl and/or an active metabolite(s) must reach the germinal tissue. Evidence that carbaryl reaches the mammalian gonad is considered suggestive. Adverse gonadal effects, e.g., abnormal sperm morphology (Degraeve et al. 1976), reduction in the number of spermatogonia and spermatozoa in the seminiferous tubules, (Kitagawa et al. 1977) reduced sperm motility (Shtenberg and Rybakova 1968), and decreased fertilization index (Collins et al. 1971) have been reported in rodents exposed to carbaryl. In addition, abnormal sperm head morphology has been reported in workers with known exposure to carbaryl (Wyrobek et al. 1980). Therefore, carbaryl may have the potential to act as a germ-cell mutagen. |
