Evaluation of Cytotoxic and Phytotoxic Potentials of “Chi Limited” Industrial Effluent on Allium Cepa and Vignaunguiculata

Cytotoxicity and phytotoxicity of Chi limited industrial effluent were investigated using Allium cepa and Vigna unguiculata. Physicochemical properties, heavy metals and pH of the industrial effluent were determined in accordance with standard method. Onions root growth inhibition test was used to assess the cytotoxicity of the effluent. Onion bulbs were exposed to 0%(control), 4%, 8%, 12% and 16% concentrations of the effluent samples in the dark for 72 hours before measuring the root lengths of the onion bulbs. Also, the seeds of Vigna unguiculata were planted in Petri dishes in the laboratory at concentrations of 0%(control), 5%, 10%, 15% and 20% for more than six days before measuring the root length, shoot length and determining the number of germinating seeds in each concentration of the effluent. A. cepa root tips exposed to effluent concentrations ranging from 4% to 16% v/v showed a significant reduction in mitotic index (MI) from 39% to 33% compared to control which is 77%, indicating effluent induced cytotoxicity. Statistical analysis using analysis of variance (ANOVA) showed that there was significant difference (P < 0.05) in the mean root lengths of A. cepa exposed to different concentrations of Chi limited industrial effluent at both day six and twelve. Also, the effects of concentrations and varieties on the shoot lengths of Vigna unguiculata are statistically different compared to root lengths which are not significantly different at P< 0.05.