In situ cultivation of aromatic plant species for the phytomanagement of an aged-trace element polluted soil: Plant biomass improvement options and techno-economic assessment of the essential oil production channel

Due to the presence of trace element (TE) in agricultural soils, wide areas are unproper for food production and the clean-up of soil is not a feasible option. Considering the potential remediation options, the use of aromatic plants producing a high quantity of biomass and developing high-added value sectors such as essential oil (EO) production could be valuable regarding one of the phytomanagement objectives, i.e. the restoration of an economic activity. The purpose of this study was hence to evaluate in situ the suitability of two aromatic crops, clary sage and coriander, for the phytomanagement of aged TE-polluted soils, taking into account plants' growth, development and biomass production, essential oil (EO) content and quality as well as a techno-economic feasibility analysis of the channel. In situ experiments have been carried out on two agricultural plots of 1.5 ha, a TEpolluted one (Pb: 394 ppm -Zn: 443 ppm -Cd: 7.2 ppm) and an unpolluted one (Pb: 22 ppm -Zn: 48 ppm -Cd: 0.4 ppm). Our findings have shown the ability of coriander and sage to grow similarly on both unpolluted and TEpolluted soil and to produce significant amounts of biomass. The pesticide residue and TE analyses have demonstrated that the EO only contained trace amounts of the contaminants, below or close to the limit of quantification of the method used and similar to marketed products. Mycorrhizal inoculation has also shown promising results by increasing the colonization rates of both aromatic plants, but did not result in higher biomass or EO amounts. Our study brings new evidence towards the potential of clary sage to be used for the phytomanagement of TEpolluted areas, given its perennial vegetation cover, tolerance to TE and obtained EO yields. (c) 2021 Elsevier B.V. All rights reserved.