Elemental profiling and identification of eco-toxic elements in agricultural soil by laser-induced breakdown spectroscopy

Abstract

Laser induced breakdown spectroscopy (LIBS) was used to determine the elemental content and to detect probable eco-toxic elements in agricultural soil in Gazipur, Bangladesh (latitude: 24.0958° N, longitude: 90.4125° E). Soil samples were collected from three experimental plots of Bangladesh Rice Research Institute (BRRI), Gazipur and from a fallow land in the same area where no crop has been produced for a long time. This land is believed to be contaminated by the affluent discharged from nearby industries. Rice and husk samples were also collected from one of the experimental plots. Several elements such as Ni, Cu, Zn, Fe, Ca, Al, Si, Sn, Na, K, Ti, Mn, Li, Mo, Co were identified in the soil samples of the three experimental plots. Rice and husk samples also have the same elements including Sr, P, C and Mg. The LIBS study of the soil of the fallow land confirms the presence of the toxic element Cd along with all the elements found in the soil samples of the experimental plots. The sample from the fallow land from Gazipur was also analyzed for Cd by atomic absorption spectroscopy (AAS). The presence of 6.5 ppm of Cd in this fallow land above the tolerance limit (3 ppm) is supposedly the main reason for barrenness of the fallow land in the present case.