Assessment of heavy metals and thermal properties of soil-rice-husk system collected from three districts of Bangladesh

Abstract

This study was conducted to evaluate the contamination of heavy
metals and their thermogravimetric properties in the soil-rice-husk system.
Heavy metals concentration was determined by Atomic Absorption
Spectroscopy (AAS) and thermal property was also analyzed by using Thermo
Gravimetric Analyzer (TGA). Metals uptake in rice crop grown in soils of three
different areas (Savar, Chapainawabganj and Gazipur) in Bangladesh was
studied. Soil, rice husk and rice samples were analyzed after microwave acid
digestion. Heavy metals concentration detected in rice samples decreases in the
following order as Fe > Mn > Zn > Cu > Ni > Co > Cd > Pb. The metal content in
husk was higher than in corresponding rice. Fe concentration was higher than
other metals in soil, husk and grain samples. The concentrations of Cd and Pb in
the soil were found to be below the detection limit and the order of the other
heavy metals as Fe > Mn > Zn > Cu > Ni. The thermal properties of the soil-ricehusk
system did not show any significant visible variation during this
experiment except for the soil of the Gazipur areas. The residual mass obtained
from the TG thermogram helps to make a relation between the quality of soil and
the rate of uptake of heavy metals by rice or its husk.