Belma ImamoviÄ, Jasmin MušanoviÄ, Ervina BeÄiÄ, Miroslav Šober
Objective: The aim of this study was to investigate the genotoxic effects of chlorinated homosalate by-products occurred in the presence of free chlorine. Method: The genotoxic effects of chlorinated homosalate by-products were investigated using Allium test. Cytogenetic analysis included monitoring influence of various concentrations of the test filter (10, 30 and 50 ng/ml) at various concentrations of free chlorine (0.2, 0.4 and 0.6 mg/ml), on mitotic activity of meristem cells., as well as the types of genotoxic effects expressed during the cell cycle. The observed effects were quantitatively presented at 2000 analyzed cells. Results: Each tested homosalate concentration causes a reduction of the mitotic index (MI) comparing to the water as a control, after 24 and 48 hours exposure as well. Statistical analysis demonstrated highly significant difference (p<0.0001) between the MI of water and MI of investigated solution. Besides the water as the basic control, the comparison was also performed compared to the three controls represented the concentration of free chlorine (0.2, 0.4 and 0.6 mg/ml). Most of the investigated concentration had highly significant difference of MI if compared to MI of their control containing different concentration of free chlorine. The number of irregular phases caused by investigated homosalate solutions was determined by cytogenetic analysis. It was found that the investigated solutions in the applied concentration and at the length of treatment (24 and 48 hours), disturbed chromosomes kinetics at certain stages of cell division. Aberrations in cells of the onion root appeared in the form of chromosome kinetic disturbance, the appearance of cells with "chromosomal bridge", cells with agglutinated chromosomes and micronuclei. Conclusion: The results of this study have shown that chlorinated homosalate byproducts that occur in the presence of free chlorine, show genotoxic effects on the onion root and interfere with the normal division of meristem cells.