Abstract:The use of vermicompost for remediating soil contaminated with the commercial formulation containing deltamethrin was proposed. Biotoxicity tests with the goal of evaluating the potential remediation degree of the vermicompost after its addition to contaminated soils were performed. The tests lasted 56 days and involved Eisenia foetida earthworms. Possible structural changes in humic acids from these soils were evaluated by means of FTIR spectroscopy. The soil contaminated with deltamethrin offers toxicity to the earthworms. However, the vermicompost addition caused great positive impact on soil contamination level, which became quite similar to the reference soil. The vermicompost remedial effect depends on the source material. In this study the vermicompost were from filter cake and orange peel. The results obtained by FTIR pointed out for a weak interaction such as van der Waals type between the pyretroid and humic acids.