The Distribution and Load Duration Curves of Selected Pollutants in River Ekulu Enugu urban, Nigeria

Abstract

The study investigated the seasonal distribution and load duration curves of selected pollutants in River Ekulu, Enugu urban,  Nigeria. Selected water quality parameters such as turbidity, total suspended solid, iron, magnesium, phosphate, and total coliform were analyzed using standard methods. Data were collected between October 2015 and September, 2016. Stream flow measurement was undertaken for 12 calendar months using the Velocity-Area Method. The result shows very high concentration of the selected pollutants in River Ekulu when compared with the WHO maximum permissible Limit. Turbidity recorded mean value of 84.6NTU. Average concentration of 143.6mg/l, 1.2mg/l, 4.2mg/l, 3.1mg/l and 142.2CFU/100ml were recorded for TSS, Fe, Mg, PO₄^3-and TCC respectively. Results of load duration curve show that the actual load of these pollutants exceeds their permissible limits. Deterministic relationship between flow and pollutant distributions at 0.05 level of significance shows high level of correlation. Turbidity, TSS, Fe, Mg, PO₄^3- and TCC yielded coefficient of determination values of 0.92, 0.93, 0.90, 0.97, 0.98 and 0.77 respectively.  High values of Turbidity, TSS, iron, magnesium, phosphate and TCC observed from the study especially at flow peak are indications of expanding/unplanned residential and commercial land uses. The high concentration of these pollutants could be deleterious to human health if the water from the River is continuously consumed without proper treatment. The study, therefore, recommends proper waste management practices. There is also need to enact and enforce laws on effluent treatments at slaughter houses before discharge into water bodies.

Keywords: Flow duration curve, pollutant load, urbanization, water, quality

DOI: 10.7176/JRDM/64-05

Publication date: April 30^th 2020