title: Accumulation of toxic metals and organic micro-pollutants in sediments from tropical urban rivers, Kinshasa, Democratic Republic of the Congo.
abstract: The increasing contamination of fresh water resource by toxic metals and Persistence Organic Pollutants (POPs) is a major environmental concern globally. In the present investigation, surface sediments collected from three main rivers named, Makelele, Kalamu and Nsanga, draining through the city of Kinshasa, Democratic Republic of the Congo, were characterized for grain size, organic matter, toxic metals, POPs (including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs)), and polycyclic aromatic hydrocarbons (PAHs). Furthermore, enrichment factor (EF) and geoaccumulation index (Igeo) were performed to determine metal source and pollution status. The results highlighted high concentration of toxic metals in all sediment samples, reaching the values (mg kg-1) of 325 (Cu), 549 (Zn), 165 (Pb) and 1.5 (Cd). High values of PCBs and OCPs were detected in sediment samples, e.g. in Makelele river, PCB values ranged from 0.9 to 10.9 with total PCBs (∑7 PCBs × 4.3): 169.3 μg kg-1; OCPs from 21.6 to 146.8 with ∑OCPs: 270.6 μg kg-1. The PBDEs concentrations were higher in investigated rivers comparatively with values detected in many rivers from Sub-Saharan Africa. The ΣPAHs value ranged from 22.6 to 1011.9 μg kg-1. River contamination may be explained by local intense domestic activities, urban and agricultural runoff, industrial and hospital wastewaters discharge into the rivers without prior treatment. This research provides not only a first baseline information on the extent of contamination in this tropical ecosystem but also represents useful tools incorporated to evaluate sediment quality in the river receiving systems which can be applied to similar aquatic environments.
authors.affiliation: University of Kinshasa (UNIKIN), Faculty of Science, Department of Chemistry, B.P. 190, Kinshasa XI, Democratic Republic of the Congo.
authors.forename: Pitchouna I
authors.initials: PI
authors.lastname: Kilunga
authors.affiliation: University of Geneva, Faculty of Science, Department F.-A. Forel for Environmental and Aquatic Sciences, and Institute of Environmental Sciences, 66, Boulevard Carl-Vogt, CH-1205, Geneva, Switzerland.
authors.forename: Periyasamy
authors.initials: P
authors.lastname: Sivalingam
authors.affiliation: University of Geneva, Faculty of Science, Department F.-A. Forel for Environmental and Aquatic Sciences, and Institute of Environmental Sciences, 66, Boulevard Carl-Vogt, CH-1205, Geneva, Switzerland.
authors.forename: Amandine
authors.initials: A
authors.lastname: Laffite
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Central Environmental Laboratory (GR-CEL), CH-1015, Lausanne, Switzerland.
authors.forename: Dominique
authors.initials: D
authors.lastname: Grandjean
authors.affiliation: University of Kinshasa (UNIKIN), Faculty of Science, Department of Chemistry, B.P. 190, Kinshasa XI, Democratic Republic of the Congo.
authors.forename: Crispin K
authors.initials: CK
authors.lastname: Mulaji
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), Central Environmental Laboratory (GR-CEL), CH-1015, Lausanne, Switzerland.
authors.forename: Luiz Felippe
authors.initials: LF
authors.lastname: de Alencastro
authors.affiliation: University of Kinshasa (UNIKIN), Faculty of Science, Department of Chemistry, B.P. 190, Kinshasa XI, Democratic Republic of the Congo.
authors.forename: Pius T
authors.initials: PT
authors.lastname: Mpiana
authors.affiliation: University of Kinshasa (UNIKIN), Faculty of Science, Department of Chemistry, B.P. 190, Kinshasa XI, Democratic Republic of the Congo; University of Geneva, Faculty of Science, Department F.-A. Forel for Environmental and Aquatic Sciences, and Institute of Environmental Sciences, 66, Boulevard Carl-Vogt, CH-1205, Geneva, Switzerland. Electronic address: john.pote@unige.ch.
authors.forename: John
authors.initials: J
authors.lastname: Poté
mesh_terms: D002947:Cities; D015023:Democratic Republic of the Congo; D004784:Environmental Monitoring / Q000379:methods; D019015:Geologic Sediments / Q000737:chemistry*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis; D000075322:Heavy Metal Poisoning; D006843:Hydrocarbons, Chlorinated / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis; D010575:Pesticides / Q000032:analysis; D011041:Poisoning; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D055768:Halogenated Diphenyl Ethers; D006843:Hydrocarbons, Chlorinated; D019216:Metals, Heavy; D010575:Pesticides; D011078:Polychlorinated Biphenyls; D011084:Polycyclic Aromatic Hydrocarbons; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: PAHs; POPs; Sediments; Toxic metals; Tropical conditions; Urban rivers