Trace Metal Contamination of Water in Naviundu River Basin, Luano and Ruashi Rivers and Luwowoshi Spring in Lubumbashi City, Democratic Republic of Congo

Abstract

Aluminum (Al), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Strontium (Sr), Molybdenum (Mo), Silver (Ag), Cadmium (Cd), Tin (Sn), Caesium (Cs), Barium (Ba), Lead (Pb), Bismuth (Bi) and Uranium (U) concentrations were investigated in water samples from fifteen sampling locations in Naviundu river basin, Luano and Ruashi rivers and Luwowoshi spring in Lubumbashi city during February, March and April 2016. Chemical analyses of the samples were carried out using Inductively Coupled Plasma-Mass Spectrometer. Water pH was determined using a pH-meter and mean pH values ranged from 4.2 to 5.8. The highest mean levels of Al (5,961.954 µg?L-1), Pb (472.287 µg?L-1), V (21.014 µg?L-1), Cr (8.185 µg?L-1), U (4.163 µg?L-1) and Bi (0.012 µg?L-1) were recorded in Chemaf (Chemicals of Africa) hydrometallurgical plant effluent, those of Mn (29,714.593 µg?L-1), Sr (374.377 µg?L-1), Cd (11.358 µg?L-1) and Cs (0.107 µg?L-1) in Naviundu river at Cimenkat (Katanga’s Cement Factory) exit, those of Fe (14,258.9 µg?L-1) and Ba (307.641 µg?L-1) in Luano river and those of Ag (2.669 µg?L-1), Mo (0.559 µg?L-1) and Sn (0.325 µg?L-1) were respectively noted in Foire channel, Naviundu river under bridge on Kasenga road and Kalulako river. The concentrations of Cd in Naviundu river at Cimenkat exit (11.358 µg?L-1), Chemaf hydrometallurgical plant effluent (9.697 µg?L-1), Naviundu river under bridge on De Plaines Avenue (6.95 µg?L-1) and Kalulako river (3.229 µg?L-1), Pb concentrations in Chemaf hydrometallurgical plant effluent (472.287 µg?L-1) as well as the Al, Fe and Mn concentrations recorded in most waters in this study exceeded the WHO (World Health Organization) maximum permissible limits for drinking water. The metal contamination of waters of the studied rivers, channel and spring might be partially attributed to natural processes, unplanned urbanization and poor waste management, and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city