Cytotoxic Effect of Sewage Effluent on Root Tip Cells of <I>Allium cepa</I> L.

Abstract

Screening for mutagens in complex environmental mixtures, such as surface water or industrial wastewater, is gradually being accepted as a routine method in environmental monitoring programs. In the present work, the simplified Allium cepa root assay was utilized to evaluate the possible cytotoxic effect of sewage effluent on root tip cells of A. cepa L. Sewage effluents were collected from Kunnamkulam market. Treatements were done in five different time durations such as 3, 6, 12, 24, and 48 hours. Allium cepa exposed to sewage effluents resulted to cells with chromosomal aberration. The Mitotic index was decreased when the time durations were increased. The mitotic index of the control was 49.65±3.35. The mitotic index of the sewage effluent in 3 hr was 42.28±3.37. From this a gradual decrease in the mitotic index when the duration of time increased. The mitotic index 42.15±3.17, 32.27±3.04, 31.65±3.19 and 28.19±2.87 are 6 h, 12 hr, 24 h and 48 h respectively chromosomal abnormalities such as bridges, fragments, vagrant chromosomes, sticky chromosomes, C‐mitosis, spindle abnormalities and disoriented chromosomes were observed. The impacts of using sewage effluent as fertilizer on the environment are difficult to predict. So they may be treated to remove its toxic particles prior to its release into the environment. Toxicity or genotoxicity bioassays should be an integral tool in the evaluation of waste water toxicity.