Document Type : Research Paper
Authors
1
Department of Soil Science, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan, Iran
2
Department of Soil Science, Faculty of Agriculture, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Khuzestan
3
Department of Soil Science, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran
4
Department of Soil Science, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran.
Abstract
Heavy metals exist in soil in various chemical forms, and this distribution of chemical forms affects their reactivity, dynamics, and bioavailability. To investigate the effect of carbon black on the chemical distribution of lead and some physical properties of soil in contaminated soil, an experiment was conducted as a factorial in a completely randomized design with 3 contamination levels (0, 50, and 100 mg/kg) and 4 carbon black levels (0, 1, 2, and 4 % W/W) in 4 replications. Chemical fractions of lead was determined by Tessier method. Some physical properties of the soil, including the mean weight diameter (MWD) of soil aggregates and soil moisture at suctions of 0.1, 0.3, 0.5, 5, and 15 bars, were measured in different treatments. The application of carbon black significantly reduced lead in the exchangeable fraction by 4.49% and significantly increased other forms of lead in the soil (carbonates, bound to iron-manganese oxides, bound to organic matter, and residual). The highest soil aggregate stability was related to the 4% carbon black treatment, which increased aggregate stability by 21.05% compared to the control. It also significantly increased soil moisture at different suctions, except for the 15 bar suction. In general, it can be concluded that adding carbon black to the soil causes the transformation of elements from an unstable form (exchangeable form) to stable forms (forms bound to oxides and organic matter and residual), resulting in reduced metal mobility in the soil.
Keywords
Main Subjects
)