Magnetic characterization and heavy metals pollutions of sediments in Citarum River, Indonesia

Abstract

Magnetic methods have been successfully used for pollution detection and mapping in riverine environment. These methods are considered faster and easier compared to conventional analytical methods. In this study, sediment samples from Citarum River, the largest river system in West Java Province and main water supply for more than 10 million people, were measured for their magnetic characteristics and heavy metals content to test the effectiveness of magnetic methods in detecting heavy metals pollution. Magnetic measurements include measurements of magnetic susceptibility (MS), isothermal remanent magnetization (IRM) saturation, and anhysteretic remanent magnetization (ARM) decay. The results show that mass-specific MS values tend to decrease from upstream to downstream, from 1127.3 to 393.2× 10-8m3kg-1. In all samples, the dominant magnetic mineral is found to be magnetite based on the IRM saturation field. The magnetic grains are predominantly multi domain (MD). Geochemical analyses showed that all water and sediment samples contain Fe, Cd, Co, Ni, Pb, Zn, As, Hg, and Mn. The heavy metals content varies irregularly in sediment samples although a negative correlation is found between heavy metals contents and magnetic parameters.