Kassaye Balkew Workagegn

Department of Biology, College of Natural and Computational Sciences, Hawassa University, P.O. Box 5, Hawassa, Ethiopia
Author    Correspondence author
International Journal of Aquaculture, 2013, Vol. 3, No. 10   doi: 10.5376/ija.2013.03.0010
Received: 24 Apr., 2013    Accepted: 28 Apr., 2013    Published: 08 May, 2013

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Workagegn, 2013, Toxicity Evaluation of Waste Treatment Plant of Textile Effluent Using Fish: Nile tilapia, Oreochromis niloticus, International Journal of Aquaculture, Vol.3, No.10 43-48 (doi: 10.5376/ija.2013.03.0010)

The experiment was conducted to evaluate the acute toxicity level of effluents from inlet and outlet of the biological lagoons of Hawassa Textile waste treatment plant using Nile tilapia, Oreochromis niloticus as test organism. Data for 24hrs, 48hrs, 72hrs and 96hrs were recorded, and were analysed to determine the effects of toxicants of the effluent on behavioural responses and survival rate of Oreochromis niloticus. The results revealed that normal swimming behaviours were observed on the fish stocked at lower effluent concentration, while erratic swimming, gasping and frequent surfacing behavioural responses were observed on the fish stocked at higher effluent concentration. There was no fish mortality in control and 10% (v/v) outlet effluent concentration. The highest percentage mortality was observed at 100% (v/v) inlet effluent concentration followed by 100% (v/v) outlet and 40% (v/v) inlet effluent concentrations. The 96hrs fifty present lethal concentration (LC50) and acute toxicity unit (ATU) values for inlet and outlet wastewater were 30.5% (v/v), 3.279, 71.5% (v/v) and 1.399, respectively. The safe effluent concentration for both inlet and outlet wastewater is set to be 3.05% and 7.15%, respectively. As a whole the present results revealed that the total efficiency level of the treatment plant to remove toxicants was 57.33% (v/v). However, efficiency of the treatment plant should be improved to use the water for irrigation and other domestic purposes; otherwise, the use of the wastewater at present condition is unsafe.

Oreochromis niloticus; Percentage mortality; Textile effluent; Toxicity test