Potential of the submerged plant Myriophyllum spicatum for treatment of aquatic environments contaminated with stable or radioactive cobalt and cesium

Modern technological routes of decontamination of polluted environments are expected to outperform traditional strategies. Such routes have been perceived as more efficient and/or less expensive, and, most of all, as environmentally friendly. In this context, submerged plants without any agricultural use are considered new and intriguing alternatives in the current search for more sustainable remediation of toxic and radioactive wastewater. Myriophyllum spicatum (Eurasian watermilfoil), a submerged aquatic plant present in fresh water streams, is considered a threat for aquatic environment. In present research, this plant was utilized for decontamination of simulated wastewater spiked with both radioactive and non-radioactive cobalt and cesium isotopes. Several parameters were evaluated to optimize the phytoremediation of these elements, such as the pH-value of the contaminated medium, illumination, contact time, ion competition, concentration of dissolved elements, mass of plant, and content of radioactive material. More than 90% and 60% of stable cobalt and cesium, respectively, were eliminated at optimal conditions of contact time with higher pH-value, light, and optimum mass of applied biomass. The same elimination values were achieved also in case of using radioisotopes of the same elements. The study demonstrates that Myriophyllum spicatum can be used as a promising candidate for phytoremediation of cobalt and cesium even if present as radioisotopes from contaminated aqueous media, thus being a green alternative for traditional remediation technologies.