Evaluation of Rapeseed Meal, Soybean Meal, and Fertilizer (NPK) Amendment on Improving Enzymatic Activities of Diesel-Contaminated Soil

Background and Aim : Introduction: Soil contamination with recalcitrant organic compounds like diesel created widespread environmental complications. So, clean-up strategies are required to remediate the contaminated site. Biostimulation, adding nutrients to a contaminated site to stimulate the growth of the indigenous soil microbial community, is known as effective bioremediation strategy to accelerate bioremediation processMethods : Material and Method: Soil sample was collected from an arable land of Pistachio farm, Damghan. The pristine soil was manually contaminated with the diesel. The effect of amending rapeseed meal (BS۱), soybean meal (BS۲), and fertilizer (NPK-BS۳) as biostimulants was studied on pH, catalase and dehydrogenase activities of diesel-contaminated soil. Uncontaminated soil and diesel-contaminated soil without amendment were used as controls. Results : Results: The pH of uncontaminated soil at first week was ۸.۳ and diesel contamination reduced pH to ۷.۸. The final pH value of BS۱ (۶.۴) and BS۲ (۶.۷۷) groups was near neutral. pH values of treatment groups were ۸-۶.۳ in BS۱, ۸.۴-۶.۴ in BS۲, and ۹.۱۵-۷ in BS۳ groups. The results showed that amending BS۱, BS۲, and BS۳ was resulted in ۹.۹۶, ۷.۷, and ۶.۷۵-fold increase in dehydrogenase and ۲.۵۲, ۲.۴ and ۲.۵۲-fold enhancement in catalase activity of diesel-contaminated soil in comparison with natural attenuation group. Conclusion : Conclusion: it is obvious that amending organic compounds to the contaminated soil is an effective, cost effective and environmentally friendly approach to improve bioremediation rate of diesel contaminated sites.

Keywords:

Biostimulation , Bioremediation , organic and inorganic amendment