Hg methylation in sediments and floating meadows of a tropical lake in the Pantanal floodplain, Brazil

Guimarães, Jean Rémy Davée; Meili, Markus; Malm, Olaf; Brito, Elcia Margareth Souza

doi:10.1016/s0048-9697(98)00089-8

Cited by 93 publications

(57 citation statements)

References 8 publications

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“…A number of authors have reported that the submerged/ emerged Hg accumulation ratio increased with an increasing external Hg concentration (Soltan and Rashed, 2003;Göthberg et al, 2004). In our study this proportion showed no significant difference between HgCl 2 treatments of 2.5 and 5 mg L , which may occur in water or in the roots of the water hyacinth (Guimarães et al, 1998). When Hg evaporates from the nutritive solution it can be absorbed by the leaf surfaces of control plants nearby (Göthberg et al, 2004) with little transport to roots.…”

Section: Discussioncontrasting

confidence: 47%

Physiological responses of Eichhornia crassipes [Mart.] Solms to the combined exposure to excess nutrients and Hg

Caldelas

Iglesia-Turiño

Araus

et al. 2009

Braz. J. Plant Physiol.

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. The accumulation of P and S was reduced by the addition of HgCl 2 , and also the P and K concentrations in emerged and submerged parts respectively decreased. In contrast, the addition of HgCl 2 increased Ca and Mg concentrations in submerged parts. Furthermore, the concentration ratios of submerged/ emerged parts for Ca, Mg and P were also reduced by the addition of HgCl 2 . The interaction of HgCl 2 and KNO 3 was synergistic and decreased F v /F m , total chlorophyll content and P and Mn concentrations in emerged parts. In submerged plant parts Ca concentration increased and K content stabilized as a result of the above interaction. However, the total accumulation of Hg per plant was not reduced, thereby confirming the water hyacinth as a promising candidate for the heavy metal phytoremediation of eutrophic waters.

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Section: Discussioncontrasting

confidence: 47%

Physiological responses of Eichhornia crassipes [Mart.] Solms to the combined exposure to excess nutrients and Hg

Caldelas

Iglesia-Turiño

Araus

et al. 2009

Braz. J. Plant Physiol.

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“…In addition to water and bottom sediments, suspended sediments may be (Guimarães et al, 1998). Moreover, the general trend of lower Hg contents in the rooted S. montividenses and E. densa species than in the free-floating P. stratiotes, E. crassipes and S. auriculata may be influenced by the lower Hg concentrations in both water and sediments in Santana reservoir than in Vigário reservoir (Table 2).…”

Section: Resultsmentioning

confidence: 99%

“…The capacity of aquatic macrophytes to accumulate Hg can enable these plants to play at least three important roles in aquatic environments: as biomonitors of environmental Hg concentrations (Jackson et al, 1991); as conveyors of Hg to food chains Simon & Boudou (2001); and as important sites for Hg methylation (Guimarães et al, 1998). Regarding the capacity for responding to environmental concentrations, the relationship between metal concentrations in the environment (water and substrate) and in the macrophytes showed that, at the very least, E. densa and P. stratiotes can be considered good monitors of Hg contents, the former in bottom sediments and the latter in the water column of the reservoirs studied here.…”

Section: Resultsmentioning

confidence: 99%

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Mercury contents in aquatic macrophytes from two reservoirs in the Paraíba do Sul: Guandú river system, SE Brazil

et al. 2006

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This paper reports on a study to determine the Hg content in the five most abundant aquatic macrophyte species (Elodea densa, Sagittaria montevidensis, Salvinia auriculata, Pistia stratiotes and Eichhornia crassipes) in two artificial reservoirs flooded by water diverted from the Paraíba do Sul river, SE Brazil. The potential of these species for Hg accumulation and their role in Hg transport along the river system due to macrophyte management were evaluated. Mercury concentrations were higher in free-floating than in rooted species. Roots were also richer in Hg than were leaves. Dry weight Hg concentrations in leaves and roots from all species varied from 46-246 ng.g -1 to 37-314 ng.g -1 , respectively. These values are higher than those reported for uncontaminated lakes in Brazil and in other tropical areas and similar to those reported for moderately contaminated sites. Mercury concentrations can be attributed to fluvial transport from the heavily industrialized Paraíba do Sul river basin. Intensive sampling of Pistia stratiotes from two sites in the Vigário reservoir was performed to evaluate the capacity of Hg incorporation in short periods of time. The results showed a significant negative correlation between Hg content and size class of individual plants, demonstrating the importance of juveniles, fast growing plants in absorbing Hg. The foremost impact related to Hg contents in the studied area concerns the periodic removal of macrophytes for reservoir management, followed by disposal in nearby areas. This results in the mobilization of 0.52 to 1.3 Kg of Hg per year, a significant fraction of the Hg burden present in reservoir waters. Disposal of such material may result in Hg leaching to river systems, affecting the Hg transfer throughout the basin.Keywords: mercury, aquatic macrophytes, artificial reservoirs. RESUMO

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“…5 Several studies have been carried out in order to determine the environmental conditions that favor or suppress the formation of organic mercury from Hg 2+ in the aquatic environment. [6][7][8] Considering that the literature about the fate of metallic mercury in the environmental system (and more specifically tropical waters and sediments) is scarce, evaluating the real impact of the release of metallic mercury is very important for understanding of the metal cycle, 9 especially in tropical areas.…”

Section: Introductionmentioning

confidence: 99%

Production of organic mercury from Hg0: experiments using microcosms

Bisinoti

Jardim

2003

J. Braz. Chem. Soc.

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A produção de Hg orgânico em água e sedimento a partir de Hg 2+ é um processo conhecido, embora pouco se saiba sobre a produção de Hg orgânico a partir do substrato Hg 0 em ambientes tropicais. Neste trabalho, usando microcosmos contendo água:sedimento seco na proporção de 6:1 e contaminado com 0,1% (m/m) de Hg 0 , acompanhou-se a produção de Hg orgânico na água e no sedimento, sob condições aeróbias e anaeróbias. Constatou-se que esta é dependente da concentração de matéria orgânica presente no sedimento. A taxa de produção de Hg orgânico no sedimento foi maior no meio anaeróbio (617 µg kg -1 dia -1 ) do que no aeróbio (280 µg kg -1 dia -1 ). A avaliação abiótica da produção de Hg orgânico não foi possível devido às alterações nas características do microcosmo quando comparado ao experimento conduzido sob condições aeróbias. Conclui-se que o Hg 0 lançado no ambiente, principalmente através da atividade de garimpo, sofre uma dissolução reativa em água podendo ser um bom substrato para a produção de Hg orgânico em ambientes tropicais.Transformation of inorganic to organic mercury is a process known to occur in the water column as well as in sediment. However, little is known about the fate of metallic mercury in tropical environments. In this work the production of organic mercury in water and sediment under aerobic and anaerobic conditions was demonstrated in a microcosm setup using a 6:1 water: dry sediment ratio, after a spike of 0.1% (w/w) of Hg 0 . The rate of production of organic mercury in sediment was higher under anaerobic conditions (617 µg kg -1 day -1 ) than that obtained under aerobic conditions (280 µg kg -1 day -1 ). An attempt to evaluate the production of organic mercury in abiotic conditions was not possible due to drastic changes in the microcosm during sterilization when compared to the experimental conditions maintained under biotic conditions. It was concluded that metallic mercury, which enters the environment mainly due to gold-mining activities, undergoes a reactive dissolution in the aquatic medium, thus becoming a suitable substrate for the production of organic mercury in tropical environments.

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Hg methylation in sediments and floating meadows of a tropical lake in the Pantanal floodplain, Brazil

Cited by 93 publications

References 8 publications

Physiological responses of Eichhornia crassipes [Mart.] Solms to the combined exposure to excess nutrients and Hg

Physiological responses of Eichhornia crassipes [Mart.] Solms to the combined exposure to excess nutrients and Hg

Mercury contents in aquatic macrophytes from two reservoirs in the Paraíba do Sul: Guandú river system, SE Brazil

Production of organic mercury from Hg0: experiments using microcosms

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