To detect cellular DNA damage, comet assay was performed as described
by Singh and Stephens[30]with slight modification. Aliquots of HepG2 cells were suspended in 2 ml MEM and incubated with TCE (0, 0.5, 1, 2 and 4 mM) at 37 for 1 h. H2O2(20M) was used as a positive control.