nZVI-assisted rhizoremediation of mixed contaminated soil

The expansion of human activity in the last decades has resulted in an increase of seriously contaminated scenarios with both organic and inorganic pollutants. The mixed nature of these pollutants makes soil remediation difficult, but biological remediation techniques have shown promising results in the recovery of mixed contaminated soils. The aim of this study was to assess the effect of nZVI and organic amendments (composted sewage sludge and horse manure) for the rhizoremediation of a soil simultaneously contaminated with lindane (100 mg kg-1) and zinc (2500 mg kg-1) using Brassica napus plants. A factorial design was used to assess the expected beneficial effects of the combination of the three treatments on (i) the reduction of Zn bioavailability, (ii) the degradation of lindane and (iii) the recovery of soil health measured through a variety of microbial parameters. The addition of nZVI was the most effective treatment for the reduction of lindane concentration, with an average reduction of 58%. Likewise, the most significant reduction of Zn bioavailability was observed in organically amended soils plus nZVI and/or B. napus, where the greatest increase in soil microbial parameters was also observed. We concluded that the combination of the three studied treatments is highly promising for the remediation of soils simultaneously contaminated with trace elements and organic compounds