Exploring a library of water-soluble polymers as abiotic phytoremediation agents for treating (Pseudo)metal...

Herein, we investigate the effect of eleven water-soluble polymers on the growth of Sedum alfredii and its uptake of As, Cd, or Pb in polluted soil in a pot experiment. The polymers selected are generally non-toxic, metal-chelating, and hygroscopic. They also range from acidic (carboxylate-containing polymers) to neutral (e.g. polyacrylamide, polyvinyl alcohol) and to basic (polyethylene imine). It has been found that sodium alginate exhibits a significant growth-promoting effect (as much as ∼8-fold) as determined by plant total dry weight, while all other tested polymers exert either minor growth promotion or a negative effect. To examine the absorption of heavy (pseudo)metals, the pollutant content in above- and below-ground portions of the plant were separately studied by inductively coupled plasma mass spectrometry. Among the tested polymers, sodium alginate emerges as the strongest absorption accelerator for all three metal pollutants in the above-ground part of the plant (∼3-4-fold increase over blank), mainly due to promotion of plant growth. On the other hand, polyethylene imine is the most potent inhibitor of metal absorption (10%-51% of blank) due to a combination of plant growth inhibition and absorption deactivation. Polymers with such effects may be used to reduce the contamination of (pseudo)metals in crops.