Response of two salt marsh plants to short- and long-term contamination of sediment with cadmium

Purpose: This work evaluated the response of two saltmarsh plants, Juncus maritimus and Phragmites australis, to short- and long-term exposure to sediment contaminated with Cd. Materials and methods: Plants (including roots and associated sediment) were placed in vessels in a greenhouse with tidal simulation. Vessels were spiked with Cd, with Cd solution in contact with the sediment/root plant system for 6 h. Half of the vessels were then dismantled whereas the other set was maintained for 2 months. Short-term Cd exposure (6 h) simulated a flood situation with metal in a more bioavailable form. Long-term exposure simulated what normally happens in the field after contamination, the metal being progressively incorporated into the sediment and therefore less available. Results and discussion: Both plants were able to take up considerable amounts of Cd in their belowground tissues in a short-time period; this accumulation increasing after 2 months. P. australis displayed short-term Cd translocation, but, for J. maritimus metal, translocation was only observed in the long-term. Both J. maritimus and P. australis have the ability to promptly respond to Cd contamination, being able to cope with Cd contamination in the long-term. Conclusions: Results indicate these plants can contribute to the remediation of sediment contaminated with Cd in estuarine environments, retaining metal in their belowground structures, which contributes to the recovery of moderately impacted environments.