Adsorption of mercury species on river sediments — effects of selected abiotic parameters

Pelcová, Pavlína; Margetínová, Jana; Vaculovič, Tomáš; Komárek, Josef; Kubáň, Vlastimil

doi:10.2478/s11532-009-0128-6

Cited by 7 publications

(3 citation statements)

References 21 publications

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“…Sorption of Hg 2+ on sediments is a complex process controlled by a number of parameters, such as pH, temperature, mercury concentration, composition of sediment and aqueous media, presence of other cations (e.g. Fe 3+ , Al 3+ , Mn 2+ , Ca 2+ ) and anions (such as S 2− , SO 4 2− ) (Pelcová et al, 2010). Vegetated Ria de Aveiro sediments contain about 20-40% organic matter and have iron oxide contents that range between 0.50 and 2.6% (Table 1).…”

Section: Sediment Samplesmentioning

confidence: 99%

Thermo-desorption: A valid tool for mercury speciation in soils and sediments?

et al. 2015

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Mercury (Hg) speciation by thermo-desorption is considered an alternative to laborious sequential chemical procedures; hence its popularity has increased in the last years. In this work, steps were taken to improve the information obtained by Hg speciation through thermo-desorption, specifically to improve peak resolution and increase the number of species that can be identified. The thermo-desorption behavior of Hg bound to iron oxides was characterized, as well as a new Hg-humic acid synthetic standard material. In contrast to previous studies, the peak corresponding to the Hg fraction associated with humic acids was clearly separated from the mineral fraction, and identified in some natural samples. With increasing temperature, Hg species are released in the following order: HgCl 2 = Hg associated with Fe 2 O 3 b Hg associated with humic acids b HgS b HgO, with an overlap of HgCl 2 and Hg associated with iron oxides. An evaluation of the effects of sample pre-treatment and storage on Hg speciation was also performed. It was found that sieving to b2 mm improved the sample homogeneity. The importance of fast sample analysis was highlighted, given that after 10 days of storage at room temperature, volatile Hg 0 could no longer be identified in the sample. The suitability of thermo-desorption for mercury speciation in soils and sediments is discussed.

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Section: Sediment Samplesmentioning

confidence: 99%

Thermo-desorption: A valid tool for mercury speciation in soils and sediments?

et al. 2015

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“…In the case of the hotspot samples, the concentrations are high and incomplete removal of organically bound Hg or resorption of Hg during the F3 step causing a later extraction in step F4 cannot be completely ruled out. Even though the sediment composition has a large effect on Hg adsorption (Pelcová et al, 2010), the general sediment characterization (elemental and mineralogical composition) did not indicate clear shifts in the sediment composition between the sampling locations. Differences in organic matter content can also not explain the shift towards a higher proportion of organically bound Hg.…”

Section: Hg Concentrations and Binding Formsmentioning

confidence: 77%

Large extent of mercury stable isotope fractionation in contaminated stream sediments induced by changes of mercury binding forms

Schwab¹,

Rothe²,

McLagan³

et al. 2022

Front. Environ. Chem.

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Mercury (Hg) release from contaminated legacy sites is a large contributor to riverine ecosystems and can represent a significant local and regional environmental issue even long after the initial site contamination. Understanding processes of in-stream species transformation is therefore important to assess the fate and bioavailability of the released Hg. In this study, we investigated in-stream Hg transformation processes with analyses of Hg binding forms and Hg stable isotopes. Stream sediments were collected downstream of a former kyanization facility (Black Forest, SW Germany), where highly soluble Hg(II)-chloride (HgCl2) was used as an anti-fouling agent to treat timber. Exfiltration of partly anoxic, contaminated groundwater with Hg concentrations of up to 700 μg L−1 into the adjacent Gutach stream is the main source of Hg to sediments. Total Hg concentrations in the stream bottom sediments (<2 mm) ranged from background values of 6.3 µg kg−1 upstream of the contaminated site to 77 mg kg−1 near the location of exfiltration of contaminated groundwater. A five-step sequential extraction procedure and Hg pyrolytic thermal desorption (PTD) analyses indicated changes in Hg binding forms in the sediments along the flow path towards a higher proportion of organically bound Hg. A large shift towards negative δ202Hg values was observed downstream of the contaminated site (change of ≈2‰) along with a minor offset in mass-independent fractionation. Binary mixing models based on Hg isotope ratios using one industrial and different natural background endmembers were tested to estimate their respective contribution of Hg to the sediments but failed to produce plausible allocations. Based on the observed changes in isotopic composition, total Hg concentrations and Hg binding forms, we propose that the large extent of fractionation observed in downstream sediments is the result of a combination of kinetic isotope effects during sorption, redistribution of Hg within the sediment and the preferential transport of Hg associated with the sediment fine fraction. These results highlight the importance of transformation processes when assessing the sources and fate of Hg in environmental systems and show limitations of using simple mixing models based on Hg stable isotopes.

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“…Specific physicochemical properties, such as pH, oxidation-reduction potential, dissolved oxygen, and suspended solids in solution, are important factors in mercury's availability and mobilization in freshwater ecosystems [17], since they control mercury's speciation and transport between the water column, sediment, and biological communities [18]. Sediments play a major role in the dynamics of natural aquatic systems [19] and are key to evaluating the contamination of a given water body [20]. Sediments can act as an important Hg sink and harbor micro-organisms that convert inorganic Hg into one of its organic forms, methylmercury (MeHg) [21], which is easily absorbed by the biota, therefore entering the aquatic trophic chain [22,23].…”

Section: Introductionmentioning

confidence: 99%

Sediment Mercury, Geomorphology and Land Use in the Middle Araguaia River Floodplain (Savanna Biome, Brazil)

Moraes,

Bernardi,

de Souza

et al. 2023

Soil Systems

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In order to assess the influencing factors of the presence of mercury in a river within the Savanna biome (Cerrado), we surveyed total mercury (THg) in bottom sediment from 50 lakes along 750 km of the Middle Araguaia floodplain. The sampling sites included non-urban and urban surroundings over three distinct geomorphologies. We measured water physicochemical parameters at each site and tested statistically if land use nested within the geological formation influenced the THg concentration in bottom sediments and related water parameters. Multivariate results indicate that the interaction between geological groups and land use is statistically significant (p < 0.05). Nested ANOVA and Tukey HSD tests confirmed that the geological formation with its nested land use influences the THg, pH, DO, conductivity, and TDS (p < 0.05). THg was significantly lower in Quaternary terrains (p < 0.05) and differed significantly between non-urban and urban areas in Neoproterozoic terrains (p = 0.02). The spatial projections of the THg eigenvector on the main axes with the scoring factors of the Neoproterozoic/Paleoproterozoic terrains, and urban/non-urban, confirmed the spatial correlations. These results indicate that the association of land use and geology could be the main driver of THg in the bottom sediments of lakes from the Middle Araguaia floodplain.

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Adsorption of mercury species on river sediments — effects of selected abiotic parameters

Cited by 7 publications

References 21 publications

Thermo-desorption: A valid tool for mercury speciation in soils and sediments?

Thermo-desorption: A valid tool for mercury speciation in soils and sediments?

Large extent of mercury stable isotope fractionation in contaminated stream sediments induced by changes of mercury binding forms

Sediment Mercury, Geomorphology and Land Use in the Middle Araguaia River Floodplain (Savanna Biome, Brazil)

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