An assessment of pollution in aquatic environment using bioindicators: a review

This review highlights the importance of biological indicators in monitoring presence of pollution in aquatic environment. This assessment involves the use of living organisms (macro or microorganisms and plants or animals) as bioindicators of pollution in water bodies. These organisms are believed to show higher sensitivity to pollution than the best chemical indicators. Bioindicators or test of relevance to water study includes: test based on Chlorella vulgaris, Daphnia magna straus, test Spirotox, Microtox, using macroinvertebrates, algae and vertebrates (such as fishes). Variety of biotic indices based on macroinvertebrates community as indicators have been highlighted which includes: Microinvertebrate Biotic Index (MBI), Extended Trend Biotic index (ETBi), Belgian Biotic index (BBi), Rapid Bioassessment Protocols (RBPs), Biological Monitoring Water Quality (BMWQ) and Family level Biotic Index (FBI). Based on Microinvertebrate Biotic Index (MBI), grading of water quality alone with the taxonomic group of macroinvertebrate was divided into grade I, II, III, IV and V representing clean water, mildly, moderately, highly and severely polluted water with the tolerance rating of 2, 4, 6, 8 and 10 respectively. The review emphasized the need for the use of bioindicators in detecting water pollution, because bioindicators are much more sensitive than the best chemical indicators.Keywords: aquatic environment, bioassessment, bioindicators, pollutant, tolerance rating