Effect of Sunlight on the Different Strata of Lake Water

Aneke Nwabueze Peter, Prof. Ademiluyi Joel Ojo

Lake water, Stratification, Disinfection, Multiple Regression Analysis

Lake Water samples were collected from Nike Lake which is located in Enugu East Local Government Area of Enugu state, Nigeria. The lake water sample was poured into the experimental set-up. The samples were analysed for 13 physicochemical parameters and two microbial parameters according to standard procedures. Samples were tested at different time intervals for exposure to sunlight (day 1, day 7 and day 14). Turbidity, iron and dissolved oxygen exceeded the acceptable limits for surface water guidelines (NER, AUS-NZ and EQSSW). The results of the Water Quality Index (WQI) show an average value of 209.64, indicating that the water in the lake is excessively polluted and unsuitable for drinking. Correlation analysis was carried out to investigate the strength of relationship between the physicochemical and microbiological parameters of lake water. Multiple regression analysis was done to investigate the effect of sunlight on the different strata of lake water. The results indicates that the days of exposure of lake water sample to sunlight and the depth of lake water column influences the concentrations of iron and total hardness. Principal component analysis (PCA) and cluster analysis (CA) were carried out to investigate the sources of contaminant of the lake water samples. The results shows that the lake water is influenced by impact from faecal contamination (principal component 1, 53.288%), water hardness from rainwater which dissolves mineral matter and flows through the ground to the lake (principal component 2, 18.101%), impact from agricultural activity (principal component 3, 13.066%) and impact from domestic and industrial wastewater disposal (principal component 4, 8.640%).

https://doi.org/10.31871/IJNTR.7.1.29