Potentially toxic elemental contamination in Wainivesi River, Fiji impacted by gold-mining activities using chemometric tools and SOM analysis

Abstract

Potentially toxic elements (PTEs) contamination in Wainivesi River, Fiji triggered by gold-mining activities is a major public health concern deserving attention. However, chemometric approaches and pattern recognition of PTEs in surface water and sediment are yet hardly studied in Paci c Island countries like Fijin urban River. In our study, twenty-four sediment and eight water sampling sites from the Wainivesi River, Fiji were explored to evaluate the spatial pattern, eco-environmental pollution, and source apportionment of PTEs. This analysis was done using an integrated approach of self-organizing map (SOM), principle component analysis (PCA), hierarchical cluster analysis (HCA), and indexical approaches. The PTEs average concentration is decreasing order of Fe > Pb > Zn > Ni > Cr > Cu > Mn > Co > Cd for water and Fe > Zn > Pb > Mn > Cr > Ni > Cu > Co > Cd for sediment, respectively. Outcomes of eco-environmental indices including contamination and enrichment factors, and geo-accumulation index differed spatially indicated that majority of the sediment sites were highly polluted by Zn, Cd, and Ni. Cd and Ni contents can cause both ecological and human health risks. According to PCA, two sources such as point and geogenic sources for sediment and also two sources including weathering of rock-water and anthropogenic sources of PTEs for water were identi ed in the study area. The SOM analysis identi ed three spatial patterns e.g., Cr-Co-Zn-Mn, Fe-Cd and Ni-Pb-Cu in water and Zn-Cd-Cu-Mn, Cr-Ni and Fe, Co-Pb in sediment. Spatial distribution of entropy water quality index values depicted that northern and northwestern areas possess 'poor' to 'extremely-poor' quality water. The entropy weights indicated Zn, Cd and Cu as the major pollutants in deteriorating the water quality. Our nding provides a baseline database with eco-environmental and health risk measures for the Wainivesi river contamination.

Indexical and statistical approaches to investigate the integrated origins of elements in the sediment of Teesta River, Bangladesh: sediment quality and ecological risk assessment

“…Cluster analysis was applied to experimental data that had been normalized using z -scale transformation to minimize misclassification due to large variances in data dimensionality. 9 The outcome is shown in a 2D HCA plot known as a dendrogram. Ward's approach using squared Euclidean distances is employed in the research.…”

“…Non-crustal or anthropogenic sources of contamination, such as road constructions, settlement expansion, garbage disposal, discharging municipal effluents, mining actions, and the brick kiln industry in the riverine area, are suggested by high positive loading values of Cr, Zn, and As. 9,22,[73][74][75] In contrast, As concentration is naturally high in the clay fraction; 76 additionally, shallow rivers in South-East Asia are frequently responsible for the reductive dissolution of As-carrying rocks via metal-reducing bacteria and unstable organic compounds. 77,78 Furthermore, Zn possesses non-point pollution sources, such as signicant agricultural expansion near the river catchment region.…”

“…[5][6][7][8] Sediment, in contrast, has the capacity to accumulate toxins existing in the environmental system (soil and water) at a faster rate. 7,[9][10][11] Hence, enrichment a Industrial Ecology in Energy Research Center, Faculty of Environmental Management, Prince of Songkla University, Songkhla 90112, Thailand. E-mail: khamphe.p@psu.ac.…”

“…5–8 Sediment, in contrast, has the capacity to accumulate toxins existing in the environmental system (soil and water) at a faster rate. 7,9–11 Hence, enrichment of potentially toxic elements in sediments having geogenic and/or anthropogenic origin can cause ecological risks.…”

Element-based ecological and human health risk assessment in a lagoon system in a densely populated basin

“…One of the main causes of ecological degradation is toxic element contamination (Di Beneditto et al 2019, Fural et al 2020, Islam et al 2021, Kowalska et al 2020, Wu et al 2022. Elements with high toxicity can remain intact in the ecosystem for a long time and cannot be purified by treatment systems (Al-Solaimani et al 2022, Kumar et al 2022, Ustaoğlu et al 2020. Element contamination can spread far in aquatic ecosystems.…”