Metal(oid)s accumulation (Hg and As) and their biochemical effects in Halimione portulacoides (Ria de Aveiro, Portugal)

• Published in: Marine pollution bulletin 2022-07, Vol.180, p.113804-113804, Article 113804
• Main Authors: Oliveira, Vitor H., Coelho, J.P., Borgogni, R., Pereira, M.E., Figueira, E.
• Format: Article
• Language: English
• Subjects: Antioxidant enzymes; Arsenic; Bioaccumulation; Mercury; Oxidative stress; Saltmarsh recovery; Toxicity
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2022.113804

For decades, mercury (Hg) and arsenic (As) were discharged into the Aveiro Lagoon. This study was designed to assess the natural attenuation process evolution by: (1) evaluating Hg and As concentration in sediments and in Halimione portulacoides, and assess the long-term evolution of a historically contaminated salt-marsh system; (2) evaluating the stress levels imposed by Hg and As, and the mechanisms triggered to squash oxidative damage. Concentrations of Hg and As in sediments varied considerably between sampling locations. H. portulacoides did not bioconcentrate Hg and As, restricted translocation to aerial biomass and immobilized contaminants in cell walls. The ions that reached the cytosol induced oxidative stress, restrained by antioxidant mechanisms, especially SOD and CAT activity. Results show that after 25 years of natural attenuation, contamination decreased in the sediment, but remains above non-contaminated systems and continues to induce toxicity in the saltmarsh halophyte community, evidencing the persistent effect of Hg and As contamination. •H. portulacoides (H.P.) roots act as barriers against the translocation of metals•H.P. has mechanisms to prevent Hg and As from reaching the upper tissues•H.P. can act as a phytostabilizer of Hg and As and accumulate in the root system•SOD, CAT, chlorophylls and carotenoids used to combat oxidative stress in H.P.