Assessing the use of two halophytes species and seaweed composting in Cu-pollution remediation strategies

In order to evaluate suitable remediation strategies for Cu-polluted soils, the growth, tolerance, and Cu accumulation of Sarcocornia perennis and Limonium brasiliense were studied in hydroponic culture using different Cu concentrations, with and without Undaria pinnatifida compost. Most measured variables (e.g., water content, aboveground dry weight, malondialdehyde, pigments concentrations, tolerance index) showed a negative effect of high Cu levels in plants without compost but not in plants with compost. Plants accumulated high Cu levels in belowground tissues (bioaccumulation factor > 1) showing low translocation to aboveground parts. Based on the results, we suggest two remediation strategies: a short-term strategy: root absorption of Cu by halophytes, and a long-term strategy: using halophytes and U. pinnatifida compost, involving absorption of Cu by the plants together with metal immobilization in the substrate. This last strategy offers an additional advantage: it provides a use for seaweed waste, considered a problem for several coastal cities. [Display omitted] •Seaweed compost improved the growth of S. perennis and L. brasiliense.•High Cu levels affected the growth and tolerance responses in studied halophytes.•Plants of Cu-added treatments accumulated Cu in their tissues, mainly in roots.•Seaweed waste compost and/or halophytes could be used in remediation strategies.