Effect of organic amendment on chronically hydrocarbon contaminated soil after chemical remediation

ROSSO J. A.; MEDINA R.; MORA V. C.; DEL PANNO M.T.; DI CLEMENTE N

Leipzig

Simposio; 17th International Symposium on Microbial Ecology; 2018

Polycyclic aromatic hydrocarbons (PAHs) are hydrophobicorganic pollutants persistent in soil. The remediation using chemical oxidantscould overcome the limitations of bioremediation in the PAHs elimination,although it could also damage the community and the soil structure.The aim of this work was to evaluate the early effectof a combined strategy applied to chronically PAHs-contaminated soil.Chronically contaminated soil, S0 (214 ppmof PAHs), was treated with 3.3 g of ammonium persulfate, OxS0. Bioremediationtreatments, BS and BOxS, were carried out in microcosms containing 500 g of S0or OxS0 respectively, keeping constant the humidity and temperature.The stimulation treatments in SS and SOxS microcosms were done adding maturecompost in S0 and OxS0 respectively. All microcosms wereincubated 1 month at 25°C.The oxidative treatment produced anelimination of 29% of the total PAHs, and an additional PAHs elimination were detectedfrom SOxS microcosms. The amendmentallowed the microbial population recover and the dehydrogenase increase in SOxSmicrocosms in comparison with S0, after the first week. However, theincrease was minor than that detected in SS microcosms. Both, the persulfatetreatment and compostaddition increased the toxicity of the aqueous extracts.The combined treatment in SOxS allowed thediversity indexes of the bacterial community were recovered after a month. Members of Sphingomonadales, Actinomycetales, AcidobacteriaGp6 and Rizobiales orders were predominant,suggesting the active metabolism of organic matter, nutrients mobilization andhydrocarbons degradation.A longer term treatment could define the potentiality of the combined strategyfor the elimination of PAH.