Magnetic susceptibility of river sediment in polluted area of traditional gold mining in Kuris Sumbawa Indonesia

Abstract

The traditional gold mining carried out by the Labuan Kuris village community traditionally, with processing facilities located in the vicinity of the River Basion, Sumbawa Indonesia, allows the river flow to be contaminated with heavy metal processing gold waste. One effort to understand the environmental conditions was through a study of the magnetic properties of river sediments to study how pollution conditions can be responded to by the magnetic properties of the sediment. River sediment collection from upstream to downstream was carried out at 10 points. This study aims to compare the magnetic properties of river sediments before and after exposure to gold processing waste through magnetic susceptibility analysis of low frequency (χlf) and high frequency (χhf) measured using Bartington MS2B Susceptibility meter. The results showed that the average value of low-frequency magnetic susceptibility (χlf) river sediment samples before exposure to waste was 1763.50 × (10-8m3kg-1), whereas for low-frequency magnetic susceptibility values (χlf) river sediment samples after exposure to waste of 1907.33 × (10-8m3kg-1). Analysis of χlf shows that an increase in the magnetic susceptibility of river sediments from upstream to downstream after exposure to community mining waste. Through the measurement of frequency-dependent susceptibility (χfd), river sediment samples contain Multydomain (MD) and Pseudo Single Domain (PSD / SSD) grains and indicate that magnetic minerals in the environment are derived from lithogenic and anthropogenic minerals.