USE OF NANOMATERIALS FOR ENHANCING SUNFLOWER ASSISTED BIOREMEDIATION OF A PCB AND HEAVY METAL POLLUTED SOIL

Soil pollution is an important threat of environment and human health. Recently, green remediation technologies are gaining popularity due to their numerous advantages in term of high sustainability and economic costs. Among these strategies, Plant Assisted BioRemediation (PABR), based on the synergistic action established between root system and soil rhizosphere microorganisms, has been proved to be efficient in restoring soil quality of contaminated soils (Ancona et al, 2017, 2020). In recent years, the use of nanomaterials (particles of 1-100 nm size) in assisting phytoremediation of polluted soil has been tested (Song et al., 2019; Srivastav et al., 2018). Among these, titanium dioxide (TiO 2 ) nanoparticles have been studied in several experimental tests to favour phytoremediation of heavy metals (HMs) contaminated soil (Zand et al., 2020; Gul et al., 2020). In this work, the use of TiO 2 nanoparticles for enhancing the efficiency of PABR technology for recovering a soil multi-contaminated from polychlorinated biphenyls (PCBs) and HMs, was assessed in greenhouse microcosms. Sunflower (Argentario var) seeds were employed as plant species for promoting soil restoration. To set up microcosms, soil was collected from a multi-contaminated area of Southern Italy, located close to Taranto city (Ancona et al. 2017). Then, it was spiked with TiO 2 nanoparticles, synthetized in accordance with Dell'Edera et al., (2020). A series of soil microcosms (without sunflower/TiO 2 ) were also set up as Control samples. Soil chemico-physical parameters (pH, EC, Available P, Organic C), contaminant analyses and microbiological investigations (microbial abundance and dehydrogenase activity) were performed at different sampling times (0, 45, 90 days). Moreover, the structure of the main microbiological groups was evaluated by qPCR assays. Pollutants analyses were also carried out on biomass (roots, leaves and stems) samples.