Potential interferences of microplastics in the phytoremediation of Cd and Cu by the salt marsh plant Phragmites australis

Abstract

The negative impacts of microplastics (MPs) in aquatic organisms have been stressed out, but investigation on MPs impacts in plants is scarce. This study aimed to investigate possible interferences of polyethylene microbeads (mPE) (intentionally produced MPs) in the phytoremediation of metals. For that, the plant Phragmites australis, a salt marsh plant with known capability for metals phytoremediation, was exposed for seven days to media contaminated with Cu or Cd and mPE. Elutriate solution, with or without sediment, was used to simulate interactions between estuarine water, plants and sediments. Metal contents on plants tissues and media were measured afterwards. Results showed that plants accumulated significant amounts (up to 70 times more than in non-exposed plants) of both metals in their belowground tissues (reaching ca. 1 mg/g of Cu and ca. 70 μg/g of Cd in roots). Metal accumulation occurred either in absence or in presence of sediments, denoting plants capability to phytoremediate Cu and Cd. No significant metal translocation to the upper ground tissues was observed, metals levels being identical to those of non-exposed plants. The accumulation of both metals in plants belowground tissues was identical in the presence and absence of mPE, indicating that mPE did not interfered with plants capacity to phytoremediate Cu or Cd contaminated medium. This study further our scientific understanding of MPs impacts in saltmarsh plants and on their phytoremediation potential.