Influence of a salt marsh plant (Halimione portulacoides) on the concentrations and potential mobility of metals in sediments

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Marisa M R Almeida (Author) Other; Mucha, AP (Author) Other; Adriano Bordalo (Author) ICBAS; Vasconcelos, MTSD (Author) Other

Journal

Title: Science of the Total Environment

Vol. 403

Pages: 188-195

ISSN: 0048-9697

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 30 Citations

Scopus - 34 Citations

Other information

Authenticus ID: P-003-W78

DOI: 10.1016/j.scitotenv.2008.05.044

Abstract (EN): influence of Halimione portulacoides, commonly found in temperate salt marshes, an sediment metal contents, speciation and potential mobility in case of sediment re-suspension was evaluated. Both colonized and non-colonized sediments were studied for total Cd, Cu, Pb and Zn contents and metal fraction exchangeable to water collected in situ. Sediment elutriates, prepared with water collected from each site, were used to simulate a sediment re-suspension phenomenon. As the characteristics and degree of contamination of sediments may influence system behaviour, salt marshes of two Portuguese estuaries, Cavado (NW coast) and Sado (SW coast), were studied. Cu, Pb and Zn contents higher than ERL (quality guideline, effect range-low) were observed, indicating potential risks for living organisms. Strong Cu-complexing organic ligands, also determined in both water and elutriates, were higher in rhizosediment elutriates, at concentrations similar, or even higher, to those of Cu. Such ligands condition metals speciation in the water column and probably also metal bioavailability. From rhizosediment significant amounts of Cu and Zn were transferred to the aqueous phase, concentrations 2-8 times higher than concentrations present in water. In contrast, elutriates of non-colonized sediment removed metals from water, Cu and Zn levels in elutriates being 2-6 times lower than initial ones. Cd and Pb levels in water and elutriates were not measurable in most cases. Results clearly indicate that metals potential solubility in the rhizosphere of plants was markedly higher than that in the surrounding sediment. The obtained results indicated that H. portulacoides presence (and probably other salt marsh plants) may cause a marked increase in metals concentrations in dissolved phase (pore water or even water column if rhizosediment is re-suspended). As salt marsh plants may be abundant in temperate and subtropical estuaries and costal lagoons, this phenomenon should not be disregard in future studies towards the sustainable management of such environments.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8