Trace metal pollution in aquatic sediments and some fish species from the Kwilu-Ngongo River, Democratic Republic of Congo (Bas-Congo)

Abstract

In this study, the concentrations of some metals in sediments and consumable fish from the Kwilu Ngongo River, province of Bas-Congo, Democratic Republic of Congo, are investigated. The digested muscle tissue, whole fish, and river sediment samples were subjected to trace element analysis by inductively coupled plasma mass spectroscopy and by using an automatic mercury analyzer. The highest values of trace metals in fish muscle tissue were found for Cr, Cu, Pb and Hg, with maximum values of 8.6 (Cr), 15.7 (Cu), 6.0 (Pb) and 3.3 (Hg) mg kg _1. These values are higher than maximum tolerable limits recommended by the European Commission Regulation for Food. The highest metal concentrations in sediments were 81 (Cr), 86 (Cu), 21 (Sb), 41 (Pb), and 0.8 (Hg) mg kg _1. Sediment toxicity tests using benthic crustaceans (ostracods) revealed mortality rates of up to 30% after six days of exposure to the sediments near the sugarcane industry outlet pipe discharge. The contamination of the sediments and fishes by the elements and the bio-accumulation of mercury in fish most likely arise from the adjacent agricultural fields where intensive sugarcane cultivation since 1925 has probably contaminated the soils through the long-term use of fertilizers and pesticides

Hospital and urban effluent waters as a source of accumulation of toxic metals in the sediment receiving system of the Cauvery River, Tiruchirappalli, Tamil Nadu, India

“…2) than the PELs (probable effect levels) (CCME EPC-98E 1999). According to previous studies by the authors (Pote et al 2008;Haller et al 2011;Thevenon et al 2011a, b;Thevenon and Pote 2012;Mubedi et al 2013;Ngelinkoto et al 2013;Mwanamoki et al 2014a, c), and compared to the results of this study, the sediment receiving systems from HOP and CRB (especially in site E1) can be considered to be heavily contaminated by toxic metals, especially Cr, Cu, Zn, Cd, Pb, and Hg, which are frequently associated with adverse biological effects.…”

Hospital Effluents Are One of Several Sources of Metal, Antibiotic Resistance Genes, and Bacterial Markers Disseminated in Sub-Saharan Urban Rivers

“…Lastly, these results indicate that river receiving systems could depend on hospital practices but also that river sediments are already significantly contaminated by unknown sources. As the rivers flow through the City of Kinshasa, additional pollutant sources such as domestic sewage, uncontrolled landfill and artisanal activities located in the banks of rivers can probably explain the presence of contaminants accumulation in sediment (Mubedi et al, 2013 ; Ngelinkoto et al, 2014 ; Mwanamoki et al, 2015 ).…”

Trace metal distributions in the sediments from river-reservoir systems: case of the Congo River and Lake Ma Vallée, Kinshasa (Democratic Republic of Congo)

“…Therefore, the measurement of pollutants in the overlying waters is not conclusive due to fluctuations of water discharge, changing concentration in suspended matter and low resident time, whereas the analysis of river sediments is a useful method to assess metal pollution (Förstner and Wittmann 1979;Schwarzenbach et al 2006;Varol 2011). Moreover, polluted sediments represent a potential source of contamination for freshwater organisms (Kang et al 2000;Ngelinkoto et al 2014). Therefore, in the context of anthropogenic-triggered aquatic environmental changes, sedimentary archives provide an excellent opportunity to reconstruct the level, evolution with time and patterns of pollutants, namely, toxic metals, organic nutrients, pesticides and persistent organic pollutants (POPs) emitted to aquatic systems over the last decades or even centuries (Thevenon et al 2013).…”