Cytogenetic, genetic, and embryotoxicity studies with dimethyl...

The hemiacetal (CH3O)2P(O)CHOCHOHCCl3)CCl3, a hypothetical contaminant in technical preparations of the organophosphorus pesticide trichlorfon, was tested for cytogenetic, mutagenic, and embryotoxic activity after ip administration to mice of different strains. A single dose of 81 mg/kg (0.2 mmol/kg) caused a significant enhancement in the percentage of chromosome aberrations in bone marrow cells of CFLP mice; a similar effect was induced by an equimolar single dose of chemically pure trichlorfon (51.5 mg/kg). At the same dosage level, the hemiacetal proved to be ineffective in the micronucleus test on fetal blood of DBA and AB Jena/Halle mice. In the dominant lethal mutation assay, a single dose of 81 mg/kg hemiacetal to males resulted in a slight increase in the fetal mortality of DBA mice, whereas AB Jena/Halle mice did not respond under these conditions. Four consecutive doses of 81 mg/kg hemiacetal to pregnant AB Jena/Halle mice at Days 2, 3, 4, and 5 of gestation caused only a very weak embryotoxic effect comparable to that of trichlorfon at equimolar dosage. On the basis of these results the hemiacetal tested may not be considered to represent a potential risk factor in technical grade trichlorfon.