Distribution, Concentration, and Ecological Risk Assessment of Trace Metals in Surface Sediment of a Tropical Bangladeshi Urban River

Abstract

Trace metal contamination in sediments is a global concern. This study aimed to assess the contamination level of trace metals, their sources, and ecological risk in surface sediments of Karnaphuli River—a tropical urban river in Bangladesh. Forty-five sediment samples were analyzed by atomic absorption spectrophotometry (AAS) for Cu, Fe, Zn, Pb, Cr, Cd, and Ni metals along with physicochemical parameters like pH and organic matter (OM). The pollution status and potential ecological risk were assessed by using the geo-accumulation index (Igeo), contamination factor (CF), and potential ecological risk index (PERI). Source identification of trace metals was performed by correlation analysis, cluster analysis, and principal component analysis (PCA). The results show that the range of Cu, Fe, Zn, Pb, Cr, Cd, and Ni concentrations were 0.62–1.61 mg/kg, 23.95–85.70%, 0.52–1.89 mg/kg, 7.99–12.90 mg/kg, 33.91–65.47 mg/kg, 0.77–1.17 mg/kg, and 2.73–5.36 mg/kg, respectively. The concentrations of Fe, Cd, and Cr were above the permissible limits while the contamination factor (CF) and geo-accumulation index (Igeo) values revealed that Fe and Cd were the most dominant pollutants. Cluster analysis and PERI exhibited significant anthropogenic intrusions of trace metals. A significant positive correlation between Fe-Cr, Cr-Ni, Fe-Ni, and Pb-Cd shows their common anthropogenic source and influences. PERI also revealed that Cr, Fe, and Cd have a significant contribution with a moderate to considerable potential threat.

Physicochemical Quality and Health Risks Associated with Use of Water from Nyamwamba River, Kasese, Western Uganda

“…Secondly, it has accelerated the introduction and transport of legacy contaminants, threatening the existence of humans, the environment and other organisms [5]. Common examples of anthropogenic environmental contaminants include active pharmaceutical ingredients, heavy metals (HMs), macro-, micro-and nanoplastics, endocrine disrupting chemicals, current use pesticides, preservatives and personal care products [6][7][8]. Within this frame of reference, HMs have been the most ubiquitous in the environment.…”

“…6 for Pb ingested by adults to 7.815 × 10 −1 for As ingested by children. Thus, the cancer risks were above the safety level (1 × 10…”

Heavy Metal Contamination of Sediments from an Exoreic African Great Lakes’ Shores (Port Bell, Lake Victoria), Uganda

“…The pH of the samples was determined at a sediment-to-water ratio of 1:2.5 using a precalibrated Hanna 211 digital microprocessor-based bench top pH/mV/ • C meter (Hanna instruments, Italy) [7]. A measurement of 20 g of the sample was transferred into a 100 mL beaker and 50 mL of distilled water was added to it.…”

“…These are fueled by the ever-increasing human population which has in turn caused great pressure on the pristine environment with their need for habitats, resources and waste assimilation [6]. Consequently, the direct and indirect introduction of contaminants such as heavy metals (HMs), plastics, agrochemicals (such as fertilizers and pesticides), preservatives, endocrine-disrupting compounds, personal care products and pharmaceuticals into the environment has raised concerns [7]. This is arguably because they pose threats to the pursuit and realization of some Sustainable Development Goals and thus, need to be continuously monitored [8].…”

“…Upon entry into aquatic ecosystems, HMs equilibrate between aqueous and solid phases, and can bioaccumulate depending on their solubility and the toxicokinetics in the organism. Due to the ability of HMs to exist in two forms i.e., dissolved and accumulated, a large proportion of HMs tend to accumulate in sediments [7,12,13]. Thus, sediments and biota form a useful portion of the passive samples that can be used to reflect the exposures and developments of the detection of compounds that are otherwise undetectable in the aqueous phase [14][15][16][17].…”