A Novel Timomam Model for the Assessment of Water Quality of Four Rivers in Lafia-Nigeria, Using Selected Physicochemical Parameters
T. M. Akpomie
*
Department of Chemistry, Federal University of Lafia, P.M.B. 146, Lafia, Nasarawa State, Nigeria.
G. O. Ikuyun
Department of Chemistry, Federal University of Lafia, P.M.B. 146, Lafia, Nasarawa State, Nigeria.
A. I. Ambo
Departments of Chemistry and Science Laboratory Technology, Federal University of Lafia, P.M.B. 146, Lafia, Nasarawa State, Nigeria.
J. O. Akpomie
Department of Chemistry, Federal University of Lafia, P.M.B. 146, Lafia, Nasarawa State, Nigeria.
S. E. Anwani
Department of Chemistry, Federal University of Petroleum Resources Effurun, Delta State, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Water samples were collected from Gandu, Tundu-Amba, Ombi-Anzaku and Shabu communities in Lafia Local Government Area of Nasarawa State, north-central Nigeria, to assess water quality and develop a model based on selected physico-chemical parameters. Samples from four rivers were obtained during the dry and wet seasons and analysed for pH, temperature, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and electrical conductivity (EC) using standard procedures. The mean pH values ranged from 6.4 to 7.2 in the dry season and from 5.9 to 7.6 in the wet season, while the mean temperatures were 27.10 °C and 26.3 °C, respectively. The corresponding dry- and wet-season mean values were 4.3 and 4.35 mg/L for DO, 2.6 and 2.0 mg/L for BOD, 2.8 and 2.7 mg/L for COD, and 100 and 86 µS/cm for EC. The measured values were below or within the maximum permissible limits for domestic water recommended by the United States Environmental Protection Agency and the World Health Organization. Using Minitab 18, a multivariate water quality index model, designated the TIMOMAM model, was developed from the measured parameters. The model was statistically significant (P0.10), and 98.08% of the variation in the water quality index was explained by pH, temperature, DO and BOD; COD and EC were not retained in the model. The model was applied to Shabu River and compared with the weighted arithmetic and Oregon water quality models. The respective WQI values were 19.32, 19.43 and 4.95, indicating excellent water quality status on the 0-25 scale.
Keywords: TIMOMAM model, water quality index, physico-chemical parameters, river water, Lafia, Nasarawa State, dissolved oxygen, biochemical oxygen demand, electrical conductivity, seasonal variation