Application of Some Biometric Indices in the Assessment of the Water Quality of the Benin River, Niger Delta, Nigeria

Abstract

Rapid Bioassessment Protocols (RBP) using some biometric indices including taxa richness, Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa richness, EPT to total ratio, Hilsenhoff’s Biotic Index (HBI) and Percent Model Affinity Score (PMAS) were employed in assessment of the water quality of the Benin River. The results showed that the water quality varied from non-impacted to severely impacted. HBI and PMAS showed similar results among the designated stations along the river. Shannon (H’) and Margalef (d’) diversity indices were highest at stations 4 and 3 respectively. The biometric and diversity indices adopted in this study are better for assessing organic pollution and eutrophication but inadequate for assessing toxic inorganic pollution. More assessments using various biometric indices are needed for investigation in order to fully ascertain their consistency with the physico-chemical parameters. The merits of the different biometrics are reported.

Keywords: Water quality, biometric indices, diversity, assessment, Benin River