La Ode Safiuddin

Magnetic susceptibility properties of pesticide contaminated volcanic soil

Pesticides, unfortunately, are still widely used in many countries as way to eradicate agricultural pests. As they are being used continuously over a long period of time, they accumulate as residues in soils posing serious threats to the environment. In this study, we study the changes in magnetite-rich volcanic soils that were deliberately contaminated by pesticide. Such changes, in any, would be useful in the detection of pesticide residue in contaminated soils. Two different types of magnetically strong volcanic soil from the area near Lembang, West Java, Indonesia were used in this study where they were contaminated with varying concentrations of pesticide. The samples were then measured for magnetic susceptibility at two different frequencies. The measurements were then repeated after a period of three months. We found a reduction of magnetic susceptibility as well as a reduction in SP (superparamagnetic) grains proportion in contaminated soil. These might be caused by pesticide-induced magnetic diss...

The effectiveness of magnetic methods in delineating soil horizons: A case study of volcanic soil from Lembang, West Java

Rock magnetic methods are used widely in many studies ranging from environmental studies to exploration geophysics. The main advantages of these methods are their simplicity and non-destructiveness as well as their low cost. In this study, we test the effectiveness of rock magnetic methods in delineating soil horizons in highly magnetic volcanic soil. A soil outcrop in Lembang, West Java is used as a test bed. Samples were taken in duplicate at an interval of about 10 cm from the 3 meters outcrop. At the site, soil horizons are clearly defined based on their colorations and textures. A series of magnetic methods, in the form of bulk magnetic and frequency-dependent susceptibility measurements as well as measurement of anhysteretic remanent magnetization, were conducted on all samples. The results show that magnetic properties, especially bulk magnetic susceptibility correlate well with soil horizons. The three visually distinct horizons possess distinctive magnetic properties. The magnetic properties coul...