New approaches concerning the utilization of natural amendments in cadmium phytoremediation

Different vegetal biomass resources such as Picea abies bark, Castanea sativa chestnuts shell and Asclepias syriaca plant were considered to provide a source of natural bioactive compounds, which can be properly used in several directions such as: plant growth regulators and amendments in bioremediation. Having in mind a complex processing biomass technology, these raw materials are used in a first step to separate bioactive compounds by an aqueous extraction. The obtained extracts containing polyphenols were tested in germination tests to evaluate their influence on cadmium bioaccumulation in oat plant (Avena sativa). It was observed that the mentioned extracts modulated cadmium bioaccumulation, photosynthesizing pigments biosynthesis, plant growth and its development depending on metal ion concentration (5, 12.5, 25 mg/L), and extracts composition determined by vegetal raw material and their total polyphenols content (130, 122, 114 mg/L related to gallic acid). FTIR spectra and histo-anatomical cross section of the roots certify that P. abies bark and A. syriaca plant extracts amendments stimulated cadmium bioaccumulation, promoting the translocation of heavy metals to the aerial part of the plant, meanwhile chestnuts shell extract reduced the mobility of cadmium determining in situ inactivation of heavy metal ions.

► This study analyzed the influence of naturally bioactive compounds in cadmium phytoremediation.
► The changes were analyzed through morpho-physiological and anatomical cross-sections analysis, FTIR and AAS techniques.
► Polyphenolic aqueous extracts could properly be used in bioremediation, depending on metal contamination level.
► P. abies bark and A. syriaca plant extracts stimulated cadmium bioaccumulation, promoting the Cd2+ translocation.
► C. sativa extract act as a chelator of cadmium ions, reducing their mobility, decreasing thus translocation and determining in situ inactivation of heavy metal ions being suitable in phytostabilisation.