Assessment of Heavy-Metal Pollution in Sediments and Tilapia Fish Species in Kafue River of Zambia

Abstract

We report results from an evaluation of the levels of heavy metals, i.e., copper (Cu), cadmium (Cd), lead (Pb), nickel (Ni), manganese (Mn), chromium (Cr), and iron (Fe) in sediment and tilapia fish samples from a wide stretch of the Kafue river of Zambia. In sediment samples, the highest Pb and Fe concentrations were recorded at Hippo Dam, i.e., 36.2 ± 0.1 mg/kg dw and 733 ± 37 mg/kg dw at Kafue Town, respectively. Other notably high metal concentrations in sediment were Cr at Kafue Bridge (42.5 ± 0.1 mg/kg dw [dw]), Cu at Mpongwe (233 ± 5 mg/kg dw), and Mn at Kafue Town (133 ± 1 mg/kg dw); it was highest at Ithezi Tezhi Dam at 166 ± 1 mg/kg d. Three fish species, i.e., three-spot bream Tilapia andersonii, red-breasted bream T. rendalli, and nile tilapia Oreochromis niloticus were evaluated for levels of the seven metals. The concentrations of the metals in these fish species afforded estimation of the biota sediment-accumulation factor, which is the ratio of the concentration of the metal in liver to that in the sediment. The coefficients of condition (K) values, which give an indication of the health of the fish, were also estimated. The K values ranged from 2.5 ± 0.5 to 5.1 ± 0.6 in all of the three fish species. Partial least squares analysis showed that heavy metals are generally sequestered evenly in all of the parts of all of the three fish species except for elevated levels of Mn, Cd, and Pb in the liver samples.

Aquatic Ecological Risk of Heavy-Metal Pollution Associated with Degraded Mining Landscapes of the Southern Africa River Basins: A Review

“…HM bioaccumulation in the endocrine system of fish in Kafue River, Zambia, has potentially negative effects on reproduction by depressing sex hormones [197]. Further, the sequestration of HM in fish tissues and organs is emerging as a human and aquatic ecological health concern [198][199][200].…”

Integrated Use of Nanomechanical, Histological, and Biochemical Biomarkers of Oreochromis niloticus as a Signature of Metal Stress

“…When Co enters the body, it is transferred through the blood into all organs, especially the liver and bones (Javed and Usmani, 2013;Otludİl et al, 2017). When Pb enters the fish body, it is transferred to red blood cells and attacks hemoglobin and membranes (Jaishankar et al, 2014;Mbewe et al, 2016).…”

Chronic exposure to low doses of Pb induces hepatotoxicity at the physiological, biochemical, and transcriptomic levels of mice

“…Liu et al (2013) reported that the doses of Pb ranged from 10.1 to 184.2 mg/kg in farmland soils in China . In addition, high concentrations of Pb have also been observed in fish and vegetables in recent years, the maximum Pb concentrations were accumulated in mint roots (44 μg/g dw) as compared to coriander and fenugreek, and Pb was highest in O. niloticus at 38.5 ± 0.1 mg/kg dw, O. andersonii and T. rendalli had 26.9 ± 0.1 and 27.5 ± 0.1 mg/kg dw Pb, respectively . According to the Centers for Disease Control and Prevention (CDC), the safety threshold for blood Pb is currently 10 mg/dL for adults.…”