Soil remediation of Lebanese contaminated soils using organic sorbents

The studies on the influence of organic-based sorbents on the mobility of potentially toxic elements (PTE) in contaminated soils have been constantly growing in the last decades. However, given the variety of PTE and pollution status, as well as the diversity of factors governing the fate of PTE in soil, to date it is still hard to foresee the amendment effectiveness in a specific soil environment. The aim of this PhD thesis was therefore to assess the influence of biochar, compost and their combination on the mobility, (phyto)toxicity and bioavailability of several PTE (i.e. Sb, As, Ni, Cr and Zn) present in different polluted soils of Lebanon.The addition of compost, biochar and their combination generally reduced labile PTE pools (i.e. readily soluble) and increased their residual (non-extractable) fractions. The amendments also changed the C-source utilization potential of the soil microbial community as revealed by the Biolog community level physiological profile. At the same time, soil dehydrogenase, β-glucosidase and urease were significantly enhanced in amended soils while the growth of Capsicum annuum L. and Triticum aestivum L. (in a selected polluted soil) was significantly enhanced and PTE uptake significantly reduced.Overall, the results obtained indicated that biochar and compost could be useful to stabilise PTE in contaminated soils, to stimulate soil microbial activity and functionality and to improve plant growth.