Assessment of Water Quality Parameters in the Lower Benue River, Makurdi: Implications for Ecological Health

Abstract

Assessment of water quality indicators in the lower Benue River, Makurdi with emphasis on ecological health was studied for a year. Water samples collected monthly using plastic bottles were analysed for physicochemical variables and heavy metals following standard methods. The data obtained were subjected to statistical tools for descriptive and inferential analysis using Statistical Packages for Social Sciences (SPSS) version 25.0. The mean values were used to ascertain the pollution status of the area. Some variables ranged as pH, 5.60-8.00, Dissolved oxygen (DO), 3.20mg/l-5.80mg/l, Electrical conductivity (EC), 210-1890µs/cm, Temperature, 25.00 - 30.50⁰C. Total dissolved solute (TDS), 122-867. Nitrate, phosphate and sulphate ranged as, 30-70mg/l, 0.010-0.90mg/l and 20-34mg/l respectively. Heavy metals ranged as, Cd, 0.0050-0.550mg/l, Cr, 0.150-0.580mg/l, Fe, 0.005-2.880mg/l, Pb,0.010-0.950 mg/l) and Ni, 0.068-0.40 (0.219±0.10mg/l). Only EC, and TDS exhibited both spatial and seasonal variation significantly at P<0.05. Single factor pollution index (SFI) ranged from 0.055-256 (non-pollution-severe pollution). Some parameters in the stations met acceptable limits but Station 3 exhibited significant pollution, particularly in heavy metals and nitrates. Comprehensive pollution index (CPI) ranged between 143.36 (Station 2) and 280.32. Contamination factor (CF) ranged between 2.03-104.33(station 1 and station 3) but highest in wet season. Pollution load index (PLI) ranged from 4.45-9.25 (ST3 and ST2), heavy metal evaluation index (HEI), 58.02-180.03 (ST1 and ST3) while heavy metal pollution index (HPI) was 11.60-360.01. It was concluded that the Lower Benue River was slightly to severely polluted. Adequate measures should be put in place to monitor the levels of anthropogenic activities in the area.