Acute Toxicity of Industrial Effluents Acting Singly or Jointly on Clarias gariepinus
Ona River, Nigeria is a major part of a dense network of inland water courses emptying into Lagos lagoon and receives industrial effluents as a point source. A series of static short term tests were conducted for 96hrs to evaluate the effect of single and joint bioassays of effluents from food (100%) and beverage (100%) industries and their mixtures 50:50% (food: beverage); 75:25% (Food:beverage) and 25:75% (food:beverage) discharged into Ona River on fingerlings of Clarias gariepinus. Test organisms were exposed to concentrations of 0.00% (Control), 10.00%, 20.00%, 30.00%, 40.00% in two replicates using standard methods. Effluent samples and exposure concentrations were analyzed for temperature, pH and dissolved oxygen (DO) levels while effluent samples were further analysed for electrical conductivity, total solids (TS), total suspended solids (TSS), Sulphate, Chloride, Phosphate, and heavy metals (Pb, Cu, Cd, Mn Cr, and Ni). Mean values of the 96hr LC50 were 33.50% (100% (food)); 31.00% (50:50% (food:beverage)); and 23.00% (75:25% (food beverage) while no LC50 values could be derived for the other concentrations (25:75% (food:beverage) and 100% (beverage). Toxicity evaluation of effluent mixtures revealed decreasing toxicity in the order 75:25% (food:beverage); 50:50% (food:beverage); and (100% (food) when acting singly thus indicating synergistic interaction. The computed synergistic ratios based on 96hr LC50 were 1.08 and 1.46 for various mixtures. It can be inferred tha the various mixtures were more toxic than the two effluents acting singly. Effluent samples and exposure concentrations were characterised by acidic pH and low DO (except for control exposures) while other effluent physico-chemical analysis revealed that Pb, Cr and Fe exceeded NESREAs permissible limit for food and beverage industries effluent discharged into surface waters. The pollution implications of these effluents from industrial operations located within residential areas may result in poor water quality and reduction in species diversity for resident organisms. Thus the institution of stringent measures in monitoring the quality of effluent discharge into this river in view of its importance to domestic use and aquatic life.
ADEOGUN Aina O. CHUKWUKA Azubike V.
Department of Zoology, University of Ibadan, Ibadan, Nigeria
国际会议
2011 International Symposium on Environmental Science and Technology(2011 环境科学与技术国际会议 2011 ISEST)
广东东莞
英文
75-82
2011-06-01（万方平台首次上网日期，不代表论文的发表时间）