Evaluating the potential of remediated dredged sediments as a growth medium for landscape plants: Effects of soil amendments and heavy metal uptake

This study investigated the potential application of dredged sediments as a medium for cultivating landscape plants, assessing plant performance in contaminated dredged sediment (CDS) and remediated dredged sediment (RDS), using commercial horticultural soil as a control. Three ornamental plant species, Korean lawn grass (KLG), Aster arenarius Nemoto, and English poppy, were grown under distinct soil conditions both with and without the addition of organic and biochar-based amendments. Soil quality indices and responses in plant growth were measured to determine the influence of sediment remediation and amendment application. The findings demonstrated that RDS created a more suitable substrate for plant development compared to CDS, with KLG exhibiting the most pronounced growth improvement, especially when supplemented with wood-derived biochar and soil conditioner (SC). Incorporating SC into CDS markedly improved KLG biomass, with dry weight increases of 7.4 % and 136.9 % at 2 % and 5 % SC, respectively. Significant correlations (p < 0.05) were observed between soil and leaf Ni concentrations. Additionally, the study analyzed how soil properties impacted heavy metal(loid) accumulation in KLG, showing that soil pH, electrical conductivity, and cation exchange capacity exerted significant effects on Pb and Zn levels in plant tissues. Overall, these results indicate that adequately remediated and amended RDS has the potential to be utilized as a sustainable medium for landscape plant production and may play a role in environmental restoration initiatives.