Phytoremediation & Valorization of Cu-contaminated Soils Through Cannabis sativa (L.) Cultivation: A Smart Way to Produce Cannabidiol (CBD) in Mediterranean Soils

Abstract

PurposeThe potential of industrial hemp (Cannabis sativa L.) for phytoremediation of copper-contaminated Mediterranean soils was investigated. The accumulation of copper in hemp’s parts and the effect of contaminated soil on the production of cannabidiol (CBD) were, also, of primary concern.MethodsTwo soil types, a Clay Loam & a Sandy Clay Loam, were exposed to two levels of Cu contamination, with low & high Cu concentrations. The soils’ total and available Cu content, along with Cu in plant tissues, were determined. Height, fresh aboveground biomass and leaf chlorophyll content were further evaluated. Furthermore, the amount of cannabidiol (CBD) in the hemp flowers was determined.ResultsHemp appeared to be highly resistant, as can successfully grow in both soil types having low or high Cu levels. The maximum Cu content was detected in the highest part of the plant roots, with a progressive decline towards the upper parts of the plant (CuRoots > CuShoots > CuLeaf), in both soil types. It has been observed that more than 50% of the plant’s copper concentration is accumulated in the roots. Furthermore, the hemp plants cultivated in high Cu-contaminated soils produced greater amounts of cannabidiol (CBD).ConclusionΗemp proved to be a promising plant for phytostabilization in Cu-contaminated soils, as its above-ground biomass is almost free of metals and can be used further for fiber production. The presence of Cu in soils did not appear to disrupt the production of the important secondary metabolite CBD, but rather increased following increasing soil Cu content.Graphical