Remediation of a soil chronically contaminated with hydrocarbons through persulfate oxidation and bioremediation

MEDINA, ROCÍO; DAVID GARA, PEDRO MAXIMILIANO; FERNÁNDEZ-GONZÁLEZ, ANTONIO JOSÉ; ROSSO, JANINA ALEJANDRA; DEL PANNO, MARÍA TERESA

THE SCIENCE OF TOTAL ENVIRONMENT

elsevier

Año: 2018 vol. 618 p. 518 - 530

0048-9697

The impact of remediation combining chemical oxidation followed by biological treatment on soil matrixand microbial community was studied, of a chronically hydrocarbon contaminated soil sourced from alandfarming treatment. Oxidation by ammonium persulfate produced a significant elimination of polycyclicaromatic hydrocarbons (PAHs) and an increase in PAH bioavailability. Organic-matter oxidation mobilizednutrients from the soil matrix. The bacterial populations were affected negatively, with a marked diminutionin the diversity indices. In this combined treatment with oxidation and bioremediation working in tandem,the aliphatic-hydrocarbon fractions were largely eliminated along with additional PAHs. The chemicaland spectroscopic analyses indicated a change in soil nutrients. In spite of the high residual-sulfate concentration,a rapid recovery of the cultivable bacterial population and the establishment of a diverse and equitablemicrobial community were obtained. Pyrosequencing analysis demonstrated a marked successionthroughout this twofold intervention in accordance with the chemical and biologic shifts observed. Theseremediation steps produced different effects on the soil physiology. Spectroscopic analysis became a usefultool for following and comparing those treatments, which involved acute changes in amatrix of such chronicallyhydrocarbon-contaminated soil. The combined treatment increased the elimination efficiency of boththe aliphatic hydrocarbons and the PAHs at the expense of themobilized organicmatter, thus sustaining the recovery of the resilient populations throughout the treatment. The high-throughput?DNA-sequencingtechniques enabled the identification of the predominant populations that were associated with the changesobserved during the treatments.