Genotoxic potential of acephate technical: in vitro and in vivo effects

The genotoxic potential of acephate technical (AT) in vitro and in vivo has been studied in bioassays detecting primary DNA damage, chromosomal alterations, and gene mutation. Results from in vitro assays have ranged from negative to weakly positive; AT is apparently a direct-acting agent in these tests. However, expressed in terms of molar potency, AT has generally been at least 100-1000 times less potent than known positive mutagens tested in vitro. Following in vivo exposure at maximum tolerated doses, AT did not induce chromosomal aberrations, sister chromatid exchange, or micronuclei in mouse bone marrow cells; a dominant lethal study in mice was also negative. In a supplemental study, no induced chromosomal aberrations or sister chromatid exchange could be detected in lymphocytes from a pair of cynomolgus monkeys following exposure to AT at a low dose level for 20 days. At dose levels limited by toxicity, no positive results were observed for induction of sex-linked, recessive lethality in D. melanogaster. Acephate technical (ORTHENE) appears to present little or no genetic hazard to in vivo mammalian systems.