Chromosomes damage by sewage water studies in the Allium cepa L. and Zea mays L.

Abstract

The effect of sewage water sample of the three locations Khardah (22.7003° N, 88.3753° E), Titagarh (22.7383° N, 88.3737° E), Madhyamgram (22.6924° N, 88.4653° E), and Control (distilled H2O) in the district of North 24 Parganas (22.6168° N, 88.4029° E), West Bengal, India on the damage of chromosomes in the onion (Allium cepa L.) and maize plant (Zea mays L.) were investigated by employing mitotic chromosomal aberration assay. Physiochemical analysis of sewage water samples showed the pH is 5.10-5.30 in nature. Few heavy elements: Fe, Mn and Zn in the sample from Khardah (22.7003° N, 88.3753° E) sewage water exceeded the Indian Standard 10500:2012 and WHO’s (2006) permissible limits. Whereas Cl, Cu, Pb, Cr, and Cd are more or less within limit of the standard condition. The obtained data exhibited a decline in reproductive capacity of cells and the occurrence of deviation from the normal mitotic cell division. The mitotic index (MI) decreased significantly (p < 0.05) in both the cases and is given as Control (57.03 %) > Madhyamgram (41.70 %) > Titagarh (33.85 %) > Khardah (31.57 %) in Allium cepa L. and Control (49.33 %) > Titagarh (21.45 %) > Madhyamgram (26.47 %) > Khardah (24.05 %) in Zea mays L. The chromosomal aberrations (CAs): Karyorrhexis, Karyolysis, Fragments, Lagging chromosome, Anaphase bridges are present in significant amount in the crops treated with sewage water sample than the one with control condition. Heavy metals act as pollutants in the sewage water sample which has cytotoxic effect on cells, threat to water ecosystem and human health.