Assessment of the Impact of Industrial Wastewater on the Water Quality of Rivers around the Bole Lemi Industrial Park (BLIP), Ethiopia

The discharge of industrial waste into water bodies without significant treatment can be a source of water pollution. This study was conducted to assess the impact of industrial wastewater on the water quality in rivers around the Bole Lemi Industrial Park (BLIP). Data were collected from six sampling stations in midstream, downstream, and upstream locations between May and June 2021. In situ (pH, electrical conductivity [EC], total suspended solids [TSS], and temperature) and ex situ (chemical oxygen demand [COD], total nitrogen [TN], total dissolved solids [TDS], total phosphorus [TP], and biological oxygen demand [BOD]) determinations of water quality were conducted. The quality of the water samples was examined using the weighted arithmetic water quality index (WQI) method. A statistical analysis showed that there are significant differences in the water quality parameters among the sampling stations along the river. The results showed different levels of temperature, EC, pH, TSS, TDS, COD, BOD, TN, and TP. The pH values were higher than the pH ranges (6.5-8.5) of USEPA, EU, CES, and WHO at two sampling stations. The results of the WQI showed that the analyzed water samples were in the "unsuitable for consumption" water quality category. These results will be useful for the city administration of Addis Ababa in crafting strategies for the protection and sustainable management of the Bole Lemi River.