Studies on the Physicochemical Properties and Genotoxicity of Effluents from a Dairy Industry

Abstract

In this study, the physicochemical analysis of raw and treated effluents obtained from a dairy industry was carried out and it revealed the presence of zinc, iron, manganese, nitrates and sulphates at levels higher than Standards Organisation of Nigeria (SON) permissible limits. The pH of the effluents was acidic (pH 4.7 and 6.43 respectively). Results obtained from the macroscopic evaluation of Allium cepa after 96 hours of cultivation in both effluents showed a significant (p<0.05) concentration-dependent root growth inhibition. Root tip cells of A. cepa processed for cytological studies by the aceto-orcein squash technique after exposure to the effluents for 48 hours at concentrations of 0.5%, 1.0%, 2.5%, 5.0%, and 10% (v/v) showed chromosomal aberrations at all concentrations. Sticky chromosomes with bridges and laggards were the most observed, however, the frequency of these aberrant chromosomes was more in the raw compared with those in the treated effluent. Statistical analysis of microscopic results showed significant (p<0.05) reduction of mitotic index in a concentration-dependent relationship. The findings of this study have shown that a combination of physicochemical analysis and genotoxicity assay is effective in assessing the mutagenic components of industrial effluents for environmental monitoring of pollutants. The treated wastewater from the dairy industry, if discharged into water bodies without further treatment, could pollute the receiving water bodies and impair biolife.

Keywords: Dairy effluent, genotoxicity, Allium cepa, physicochemical analysis