The Effect of Meanders on Contributions to Changes in the Magnetic Susceptibility and Potentially Toxic Elements in Volcanic and Tropical River Sediments

The upstream Citarum River is one of the volcanic and tropical rivers used by local inhabitants for their daily needs and potentially influences the magnetic mineral traits of the sediments, including in meanders as part of the river system. This study aims to investigate the impact of meanders in the upstream Citarum River on the physicochemical properties of the sediments. The magnetic properties of the sediments in the river were characterized through measurements of magnetic susceptibility, hysteresis parameters, magnetic morphology and mineralogy. These results were then cross-referenced with physical and chemical attributes, as well as other pollution indices. In addition to direct comparison, Principal Component Analysis (PCA) was performed to identify strong and significant correlations that reflect the environmental conditions recorded in the sediment samples. The results indicate that although the point bar exhibited relatively higher magnetic susceptibility values, the straight flow samples showed greater concentrations of Potentially Toxic Elements (PTEs) and higher values of the associated indices (e.g., Pollution Load Index = 1.95 – 4.04) compared to those from the point bar and cut bank. The elevated magnetic susceptibility and pollution indices suggest a dominant influence of anthropogenic activities on the sediment composition. The spatial heterogeneity of sediment physicochemical parameters is driven by differences in hydrodynamic conditions, geomorphological settings, and topographic gradients along the river continuum, from upstream to downstream. Furthermore, sediment transport dynamics, contaminant redistribution, and adsorption–desorption interactions of PTEs with magnetic particles play significant roles in governing the observed spatial variations in physicochemical characteristics of sediments.