As (Arsenic), Ba (Barium), Cr (Chromium), Cu (Copper), Fe (Iron), Mne (Manganese), Pb (Lead) and Zn (Zinc) concentrations were investigated in sediments collected from fifteen sampling locations in Naviundu river basin, Luano and Ruashi rivers and Luwowoshi spring in Lubumbashi city from February to April 2016. Chemical analyses of the samples were carried out using a portable X-ray fluorescence spectrometer. Mean pH values ranged from 4.2 to 5.8. The sediment highest mean levels of As (40 mgkg-1 dw) and Cu (3,723 mgkg-1 dw) were noted in Chemaf (Chemicals of Africa) hydrometallurgical plant effluent, those of Pb (51.5 mgkg-1 dw) and Zn (335 mgkg-1 dw) were recorded in Kabecha river and those of Ba (657.5 mgkg-1 dw), Cr (75 mgkg-1 dw), Mn (591 mgkg-1 dw) and Fe (88,450 mgkg-1 dw) were respectively found in Naviundu river at Cimenkat (Katanga's Cement factory) exit, Naviundu river under bridge on De Plaines avenue, Mukulu river and Foire channel. Mean As, Cu and Zn levels of sediments exceeded the corresponding SQGs (Sediment Quality Guidelines), PELs (Probable Effect Levels) in some of the studied rivers. They could have adverse effects on aquatic organisms in those rivers and on the health of people who depend on the rivers for water supply, irrigation and/or recreation.

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Concentrations of fifteen trace metals including 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) were investigated in water samples collected from sixteen sampling locations in the Lubumbashi river basin and five locations in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Chemical analyses of the samples were carried out using ICP-MS (Inductively Coupled Plasma-Mass Spectrometer). Water pH was determined using a pH-meter and pH values ranged from 4.2 to 7.8. The highest mean trace metal levels of water were 5,515. Trace metal contamination of water of the studied rivers, channel and springs might be partially attributed to natural processes, unplanned urbanization, poor waste management and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.

Arsenic (As), Barium (Ba), Cadmium (Cd), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Manganese (Mn), Lead (Pb) and Zinc (Zn) concentrations were investigated in sediments collected from sixteen sampling sites in the Lubumbashi river basin and five sites in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Analyses of the samples were carried out using a portable X-RFS (X-Ray Fluorescence Spectrometer). Water pH and OM (Organic Matter) content of the sediments were also determined. Trace metal toxicity risk to aquatic organisms was assessed using SQGs (Sediment Quality Guidelines)TELs (Threshold Effect Levels) and PELs (Probable Effect Levels)for freshwater sediments. Mean values of pH and OM ranged from 4.2 to 7.8 and from 1.27% to 6.22%, respectively. The highest mean levels of trace metals in sediments were 5,438 mgkg -1 dw and 902.5 mgkg -1 dw for Cu and Co, respectively in Lubumbashi river 1.45 kilometer downward the Lubumbashi Slag heap, 1,534.5 mgkg -1 dw and 342 mgkg -1 dw for Zn and Pb, respectively at the confluence of Lubumbashi and Kafubu rivers, 108,900 mgkg -1 dw, 547 mgkg -1 dw and 174.5 mgkg -1 dw for Fe, Ba and Cr, respectively in Kinkalabwamba river, 531 mgkg -1 dw and 22 mgkg -1 dw for Mn and Cd, respectively in Kimilolo river, and 37 mgkg -1 dw for As at the confluence of Tshondo and Lubumbashi rivers. The mean concentrations of As, Cd, Cr, Cu, Pb and Zn in the sediments exceeded the corresponding SQGs' PELvalues and could have adverse effects on aquatic organisms of those rivers. Trace metal contamination of the studied sediments 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.

(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.