Assessing enrichment and contamination of sediments in the effluent canal of the ore processing industry and Naviundu River in Lubumbashi, Democratic Republic of Congo

The Naviundu River is exposed to heavy metal pollution from a mineral processing industry that discharges its effluents into the river. Heavy metals can accumulate in sediments and affect the aquatic ecosystem. The study collected surface sediment samples from the effluent pipe and along the Naviundu River, upstream and downstream of the industry. The samples were analyzed for the concentration of As, Co, Cd, Cr, Cu, Pb, Zn using ICP-OES. The study used various methods and indices to assess the level and source of contamination and the potential ecological risk of the heavy metals in the sediments. The results showed that the mean concentrations of As, Cr, Cu, Pb, and Zn were above the sediment quality guideline values for protection of aquatic life and the probable biological effect level. The enrichment factor and geo accumulation index results indicated sediment contamination in the pipe and downstream by As, Cu, Co, Cd, Pb and Zn. The association of these elements with Cr generated a very high ecological risk for the biocenosis. The study concluded that the sediments of the Naviundu river are highly contaminated with heavy metals. The origin of the heavy metals in the sediments is the effluent from the mineral processing plant