Assessing the impacts of municipal solid wastes disposal on Ayap stream water quality:

Abstract

Uncontrolled disposal of municipal solid wastes from different sources into Ayap stream pollutes its water and can be detrimental to the urban population who use this water source. Gradual accumulations of contaminants in the water sources can result into high loads of pollutants which are potentially toxic to the users. In lira City Ayap stream that drain through the city is the sources of water for some residents. The major aim of the study was to determine the impact of municipal solid waste disposal on Ayap stream water quality. Specific objectives were; to determine the physiochemical characteristics of water in Ayap stream at selected points; to evaluate the impacts of municipal solid wastes on the quality of water in Ayap stream using water quality index; to predict the concentrations of pollutants in the Ayap stream using WASP model and provide some mitigation measures for municipal solid wastes management. The stream water samples were collected at three sampling points from the stream at depth of ≤ 30cm. All samples were analyzed for physiochemical pollution indicators. The physicochemical parameters investigated included: Temperature, pH, Electrical conductivity, Nitrates, Biochemical Oxygen Demand (BOD), Dissolved Oxygen (DO), Fecal Coliforms (FC), Total Dissolved Solids (TDS), Total Suspended Solids (TSS) and Turbidity which were determined used using the standard analytical methods. From the tests carried out in the lab for NWSC Manafwa area, Turbidity ranged from 53.9- 61.3 NTU, Fecal Coliforms ranged from 1650– 1700 mg/l, PH ranged from 5.87– 7.45, EC ranged from 236 - 625μs/cm, TSS ranged from 40 - 71 mg/l, Nitrates ranged from 9–13.2 mg/l, Temperature ranged from 21.6 – 24.8OC, DO ranged from 1.3 –3.2 mg/l, BOD ranged from 22.3 – 28 mg/l and TDS ranged from 5402 - 6170 mg/l. The results were compared with the WHO standards for surface water quality and almost of them were found to be high. Based on the average concentrations of both physical and chemical parameters of all the three sampling points of Ayap stream and the WASP Model predicted values, it was concluded that the stream is highly polluted due to the high concentrations of the various pollutants in municipal solid wastes discharged into the stream. The results depict need for periodic assessment of the water quality and enactment of law on solid wastes handling from the source. Keywords: Ayap stream; Municipal Solid Wastes; Water pollution; WQI; Lira City.