Mercury uptake by halophytes in response to a long-term contamination in coastal wetland salt marshes (northern Adriatic Sea)

• Published in: Environmental geochemistry and health 2017-12, Vol.39 (6), p.1273-1289
• Main Authors: Pellegrini, E., Petranich, E., Acquavita, A., Canário, J., Emili, A., Covelli, S.
• Format: Article
• Language: English
• Subjects: Contamination; Dimethylmercury; Earth and Environmental Science; Environment; Environmental Chemistry; Environmental Health; Geochemistry; Geologic Sediments - chemistry; Halophytes; Italy; Lagoons; Mercury; Mercury (metal); Mercury - metabolism; Mercury - toxicity; Metal concentrations; Metals; Methyl mercury; Methylmercury; Original Paper; Physical properties; Plant Structures - chemistry; Plant tissues; Public Health; Reference Standards; Saline Waters - chemistry; Salt marshes; Salt-Tolerant Plants - classification; Salt-Tolerant Plants - drug effects; Salt-Tolerant Plants - metabolism; Saltmarshes; Sediment; Sediments; Soil Science & Conservation; Species Specificity; Spectrometry, Fluorescence; Terrestrial Pollution; Tissue; Toxicity; Translocation; Uptake; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Wetlands
• ISSN: 0269-4042; 1573-2983
• DOI: 10.1007/s10653-017-9981-y

Mercury (Hg) distribution in saltmarsh sediments and in three selected halophytes ( Limonium narbonense , Sarcocornia fruticosa and Atriplex portulacoides ) of a wetland system (Marano and Grado Lagoon, Italy) following a contamination gradient in sediments was investigated. The Hg uptake was evaluated at the root system level by calculating the enrichment factor (EF) and in the aboveground tissues by means of the translocation factor (TF). The related methylmercury (MeHg) concentrations in the halophytes were also investigated with regard to the location of the sites and their degree of contamination. Hg concentration in halophytes seemed poorly correlated both with the total Hg in rhizo-sediments and with the specific plant considered, supporting the evidence that the chemico-physical parameters of sediments could significantly affect metal availability for plants. Hg concentrations in roots increased with depth and were 20-fold higher than content measured in related rhizo-sediments (high EF). A low content of Hg is translocated in aboveground tissues (very low TF values), thus highlighting a kind of avoidance strategy of these halophytes against Hg toxicity. MeHg values were comparable between the two sites and among species, but the translocation from below- to aboveground plant tissues was more active.