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Mercury in sediments and vegetation in a moderately contaminated salt marsh (Tagus Estuary, Portugal)
- Source :
- Journal of Environmental Sciences. 22:1151-1157
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- Depth variations of total mercury (Hg) and methylmercury (MeHg) concentrations were studied in cores from non-colonized sediments, sediments colonized by Halimione portulacoides, Sarcocornia fruticosa and Spartina maritima and belowground biomass, in a moderately contaminated salt marsh (Tagus Estuary, Portugal). Concentrations in belowground biomass exceeded up to 3 (Hg) and 15 (MeHg) times the levels in sediments, and up to 198 (Hg) and 308 (MeHg) times those found in aboveground parts. Methylmercury in colonized sediments reached 3% of the total Hg, 50 times above the maximum values found in non-colonized sediments. The absence of correlations between total Hg concentrations in sediments and the corresponding MeHg levels suggested that methylation was only dependent on the environmental and microbiological factors. The analysis of belowground biomass at high-depth resolution (2 cm) provided evidence that Hg and MeHg were actively absorbed from sediments, with higher enrichment factors at layers where higher microbial activity was probably occurring. The results obtained in this study indicated that the biotransformation of Hg to the toxic MeHg could increase the toxicity of plant-colonized sediments.
- Subjects :
- Geologic Sediments
Environmental Engineering
chemistry.chemical_element
Wetland
chemistry.chemical_compound
Rivers
Environmental Chemistry
Water pollution
Atlantic Ocean
Methylmercury
Ecosystem
General Environmental Science
geography
geography.geographical_feature_category
Portugal
biology
Chemistry
Ecology
Water
Estuary
Mercury
General Medicine
Methylmercury Compounds
Plants
biology.organism_classification
Mercury (element)
Halimione portulacoides
Environmental chemistry
Salt marsh
Spartina maritima
Water Pollutants, Chemical
Environmental Monitoring
Subjects
Details
- ISSN :
- 10010742
- Volume :
- 22
- Database :
- OpenAIRE
- Journal :
- Journal of Environmental Sciences
- Accession number :
- edsair.doi.dedup.....96f9cd17e18c136337b6255f6fea4cae
- Full Text :
- https://doi.org/10.1016/s1001-0742(09)60231-x