Analyses of Magnetic Properties and Mineralogy on Pesticide Contaminated Soils.

Pesticides have been used for years to increase farm production by reducing and exterminating pests and plant diseases. Once they are poured into soil, physical, chemical and biological processes occur controlling the level of their persistence in the soil. This study focuses on the application of rock magnetism to study the properties of pesticide residues on soil. We investigate the effects on soil caused by dichlorodiphenyltrichloroethane (DDT) known as organochlorine (OC), a type of pesticide that is widely used by farmers. Results from the analysis of low frequency magnetic susceptibility show that addition of OC causes change in mineral type for diamagnetic and paramagnetic minerals, whereas for ferromagnetic mineral, addition of OC affects the magnetic susceptibility insignificantly. Results from the magnetic viscosity analysis indicate that addition of OC will reduce the magnetic susceptibility of soil. Based on SEM measurement, the amount of oxygen increases due to oxidation whereas Fe decreases. After OC addition the porous spaces decrease and the grain size reduces one grade from ferromagnetic to ferromagnetic and from ferromagnetic to diamagnetic. [ABSTRACT FROM AUTHOR]