Phyisco-Chemical Characteristics and Macro Invertebrates of River Benue at Makirdi, Benue State, Nigeria

Abstract

Indiscriminate dumping of wastes into rivers without control measures is widely practiced in the developing nations of the World as it is observed in River Benue at Makurdi. To ascertain the health status and integrity of River Benue at Makurdi, water samples and sediments were collected monthly from five different locations on the shoreline of River Benue at Makurdi for a period of two years (July 2011-June 2013). The physico-chemical quality of the water samples were examined using standard methods (APHA, 1999). The sediments were examined for the presence and absence of macro benthic fauna. The results of the physico-chemical parameters indicate the river water samples with the following characteristics: Conductivity (92.97±118.15µS/cm), pH (6.63±0.84), TDS (46.90±60.50mg/L),TSS (62.42±61.57mg/L), Colour (276.50±163.42TCU), Turbidity (63.08±53.01NTU), Temperature (28.74±1.89⁰C), Bicarbonate (147.89±111.37mg/L), Chloride (148.79±84.27), Nitrate (3.23±4.21mg/L), Sulphate (13.51±14.72mg/L), Phosphate (1.27±1.77mg/L) and Copper (0.19±0.27mg/L). The mean values were generally within the WHO and the Nigerian Standard for Drinking Water Quality accepted maximum limit except for colour and turbidity. The result of ANOVA for all the parameters was significant (PË‚0.05), except temperature, bicarbonate, nitrate, sulphate, phosphate and copper that were not significant (ANOVA, P˃0.05). The result of the sediments showed that a total of 4,451 macro benthic fauna individuals comprising of 4 phyla and 21 taxa were obtained. Athropoda(90.16%) had the highest population of individuals as compared to the other phyla: Annelida (4.74%), Mollusca (3.39%) and Platyhelminthes (1.71%). There was generally low biodiversity of benthic fauna community which indicate the perturbed nature of the study area. A significant relationship at some instances was noticed between benthic fauna group and some physico-chemical parameters indicating association between benthos and hydrochemistry of River Benue. It is recommended that the discharged of effluents and other waste into the River Benue should be controlled and enforced.