Assessing the ecological health of River Ringim, Northwestern, Nigeria using macroinvertebrate-based Chanchaga Multimetric Index

Abstract

ABSTRACT The ecological health of River Ringim, Jigawa State, northwestern Nigeria was assessed between November 2018 and March 2019. Key physico-chemical variables alongside macroinvertebrates assemblage were used to achieve the aim of the study. The result of the physico-chemical variables showed that the four stations sampled were relatively perturbed judging from the high values of turbidity, nitrate, phosphate, BOD, TDS, and EC. Twelve (12) taxa and 365 individuals of macroinvertebrates were recorded in the entire study period of five months, confirming the deteriorating state of the river system. Hemiptera which was represented by 126 individuals was the most preponderant macroinvertebrate Order, followed by Coleoptera with 100 individuals. The least represented Order was Crustacea with only five individuals. The result of the diversity indices conducted showed that the Margalef index (1.32), Simpson diversity (0.76), and Shannon-Weiner index (1.59) were highest in Station 1. The results were used to check the implementation of the Chanchaga multimetric index and it showed that that the four stations of River Ringim were of poor water quality with a corresponding D ecological category. This further, confirmed the deteriorating state of the four stations sampled. We recommend that macroinvertebrate-based multimetric index (MMI) be developed for the river using a macroinvertebrates particular to the river instead of using the results in this study in checking the implementation of MMI developed for another river. This will ascertain the actual level of degradation River Ringim is undergoing due to the numerous human disturbances within the river catchments.