Biochar Enhanced Chemical and Biological Properties of Contaminated Soils with Lead

Abstract

Soil pollution has become a global problem due to the significant increase in the concentration of heavy elements. Lead is one of the most dangerous heavy elements cause damages to soil microorganisms and soil chemical properties. In this study the effect of adding of biochar (EFBB and WSB) with different addition rates (0%, 1% and 3%) in two soil textures (sandy loam, clay loam) contaminated with lead (500 ppm) were studies to approve the role of biochars on some soil chemical properties of soils and microorganisms activity. The results showed the amount of released CO2 has increased up to (127.6 and 123.2 mg CO2 100 g-1 soil) with addition rate (3%) of WSB and EFBB compared to control treatments (45.4 mg CO2 100 g-1 soil). This result indicated that the microorganism’s activity was enhanced with incubation periods in contaminated soils. It was noted that biochars improved soil chemical properties such as OM, OC, CEC, cations of positive elements such as Ca2+, Mg2+, and K+ and improved electrical conductivity EC. A larger surface area and the negative charges content as well as micro pores are made biochars more effective to adsorbed heavy metals, which allows reducing toxicity of lead in contaminated soil and making its environment more suitable for microorganism’s life with enhancing some soil chemical properties. Therefore, it is recommended to add biochar to contaminated soils and it could be an alternative to other treatments due to its low-cost.