Cytogeneticity of quinalphos and methyl parathion in human peripheral lymphocytes.

1. Four different concentrations of quinalphos and methyl parathion were tested on human peripheral lymphocytes over different time periods, for the analysis of chromosomal aberrations and sister chromatid exchanges (SCEs). 2. A significant increase in chromosomal aberrations was observed when cells were treated with quinalphos for 48 and 72 h and a significant increase in SCEs was observed at all the concentrations and over all the time periods. 3. Methyl-parathion did not induce chromosomal aberrations but it did induce SCEs significantly over all time periods.