Correlation study of the spatio-temporal and seasonal variations of physicochemical parameters in Kazaure Reservoir, Jigawa State, Nigeria

Abstract

The aim of the study was to assess the pollution status of Kazaure Reservoir in terms of Spatio- temporal and seasonal variations of physicochemical parameters and established statistical relationship between them. Water samples were collected in triplicates from four selected sites (A, B, C and D) between January to December. Twelve parameters were analyzed following the standard procedures of APHA (2010). The results revealed the pollution status of the reservoir to be lower in Site D and higher in site C as indicated in the mean spatial ranges of water temperature (24.7 ± 1.9 to 34.3 ± 1.6 °C), transparency (11.2 ± 1.87cm to 32.0 ± 6.0cm), total suspended solids (114.6 ± 14.5 mg/l and 218.0 ± 17.4 mg/l), total dissolved solids (68.0 ± 5.26 mg/l to 187.3 ± 3.25 mg/l ), conductivity (119.0 ± 14.5μS/cm and 202.0 ± 19.5 μS/cm ), salinity ( 51.5 ± 6.51 mg/l and 80.9 ± 7.92 mg/l), BOD ( 10.80 ± 1.77 mg/l and 17.7 ± 1.53 mg/l), nitrate (11.3 ± 0.57 mg/l to 19.7 ± 2.08 mg/l) and phosphate (8.7 ± 1.47 to 18.0 ± 1.00 mg/l). Higher pollution level in dry than wet season is evident in the study. While TDS, pH, salinity, conductivity differed significantly between wet and dry seasons (P<0.05), no significant seasonal variation was recorded in the remaining parameters (P>0.05). Pearson Correlation Coefficient showed strong positive correlation between Temperature with BOD (r=0.883) and Nitrate (r=0.908), TDS with salinity (r=0.953), pH with TSS (r=0.868) and alkalinity (r= 0. 894), Conductivity with alkalinity (r= 0.845), BOD (r=0.831), TSS (r=0.838) and TDS (r=0. 987). Strong negative correlation existed between Transparency with TDS (r=− 0.855) and pH (r=−0. 837), Salinity and pH (r = -0.801) DO and BOD (r=−0.893). The elevated mean values of BOD, Nitrate and Phosphate in all the sampling sites exceeding standard limits of WHO (2018) throughout the study period indicated pollution loading traced back to detergents and soaps used for laundry, agricultural runoff, human and animal wastes and increased concentration of wastes by decreased water volume. It is therefore recommended that washing off of waste and excessive use of phosphate fertilizers should be prevented. Kazaure Reservoir should be revisited by relevant authourities to prevent its collapse and reduce the impact of pollution aggravated by reduced water volume from source.