Remediaton of pesticide-polluted River using Anabaena and Nostoc spp.

Abstract

Cyanobacteria are phototrophic aquatic microbes that are found in various environments and can reproduce rapidly either heterotrophically or chemoheterotrophically. Pesticide-pollutants are released into water bodies as a method of disposal. Bioremediation is considered an efficient and environmentally safe technology for inexpensive decontamination of such environments. Cyanobacteria species investigated in this study were highly beneficial in the remediation of the pesticide-polluted River. The Cyanobacteria isolated were identified as Anabaena and Nostoc species using Abattoir effluent and Aquaculture water from Ogoniland. Temperature, pH, phosphate and nitrate enhanced the growth of these organisms in the polluted environments with varying concentrations of pesticide {Nostoc(N14%, N240%, N380%), Anabaena (A14%, A240%, A380%), Anabaena and Nostoc (AN14%, AN240%, AN380%). The microbiological analysis showed that 80% mixed culture (AN3) had higher microbial counts especially on day 7, which could be due to the presence of a mixed consortium of organisms and nutrients (Nitrogen and Phosphorus). The effectiveness of the Cyanobacteria used in the analysis was in the following descending order: 80%AN3> 40%AN2> 4%AN1> 80%N3> 80%A3> 40%N2> 40%A2> 4%N1> 4%A1. From the student T test table, AN3 (80% mixed culture) was more effective and capable of remediating the pesticide-polluted environment. The analysis of variance (ANOVA) showed that at 95% confident level the significant differences among the samples varied in their ability to remediate the environment. Pollutant was removed by all the species, either as individuals or in a mixed consortium at all concentrations. Results established high removal efficiencies of the investigated species for the removal of the target contaminant which were species and contaminant-dependent. The contaminants removal efficiency (RE) percentage of cyanobacterial species ranged between 76.3 and 100% for 4% pesticide concentration, 83.9% and 99.9% for 40% concentration. Mixed culture ( Anabaena and Nostoc (AN)) RE percentages ranged between 99.5 and 100% at 4% while at 40%, the RE percentage ranged between 95.9 and 99.9% and at 80% pesticide concentration, it ranged between 91.7 and 100%. Results obtained stipulate the potential of natural resources as proficient mediators for pollution control.