Methylation of mercury by humic substances in an aquatic environment

Nagase, Hisamitsu; Ose, Youki; Sato, Takahiko; Ishikawa, Tetsuya

doi:10.1016/0048-9697(82)90082-1

Cited by 93 publications

(34 citation statements)

References 6 publications

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“…Humic substances have been found to methylate mercury abio tically (Rogers 1977, Nagase et al 1982, Nagase et al 1984. Furthermore, it has recently been reported that in polyhumic waters up to more than 90% of the total carbon in zooplankton may be allochthonous (Salonen and Hammar 1984).…”

Section: The Effect Of the Soil And Humic Materials On Mercury Concentmentioning

confidence: 99%

Organic and inorganic mercury in the food chain of some lakes and reservoirs in Finland

et al. 1986

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Section: The Effect Of the Soil And Humic Materials On Mercury Concentmentioning

confidence: 99%

Organic and inorganic mercury in the food chain of some lakes and reservoirs in Finland

et al. 1986

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“…Abiotic methylation may occur if sufficient methyl donors are present; conditions that may be afforded by an environment rich in organic material (Nagase et al 1982). However, abiotic methylation is generally thought to be of little importance in most aquatic systems (Ullrich et al 2001).…”

Section: Why Is Net Methylmercury Production Important and How It Is mentioning

confidence: 99%

Recent advances in the study of mercury methylation in aquatic systems

Paranjape

Hall

2017

FACETS

119

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With increasing input of neurotoxic mercury to environments as a result of anthropogenic activity, it has become imperative to examine how mercury may enter biotic systems through its methylation to bioavailable forms in aquatic environments. Recent development of stable isotope-based methods in methylation studies has enabled a better understanding of the factors controlling methylation in aquatic systems. In addition, the identification and tracking of the hgcAB gene cluster, which is necessary for methylation, has broadened the range of known methylators and methylation-conducive environments. Study of abiotic factors in methylation with new molecular methods (the use of stable isotopes and genomic methods) has helped elucidate the confounding influences of many environmental factors, as these methods enable the examination of their direct effects instead of merely correlative observations. Such developments will be helpful in the finer characterization of mercury biogeochemical cycles, which will enable better predictions of the potential effects of climate change on mercury methylation in aquatic systems and, by extension, the threat this may pose to biota.

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“…Mercury in the aquatic environment is predominated by 2 major chemical forms, inorganic (Hg(II)) and methylated mercury (MeHg). Inorganic mercury can be transformed either biologically or chemically into highly toxic methylmercury (Wood et al 1968, Jensen & Jernelov 1969, Nagase et al 1982. Differences between Hg(II) and MeHg bioaccumulation in many aquatic species has been documented (Riisgard & Famme 1986, Watras & Bloom 1992, Rouleau et al 1993, Laporte et al 2002.…”

Section: Introductionmentioning

confidence: 99%

Uptake of Hg(II) and methylmercury by the green mussel Perna viridis under different organic carbon conditions

Pan¹,

Wang²

2004

Mar. Ecol. Prog. Ser.

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The bioavailability and toxicity of mercury to aquatic organisms are greatly dependent on its chemical species, such as inorganic and methylated mercury. We examined the influences of various physico-chemical parameters [metal concentration, salinity, dissolved organic carbon (DOC) and colloidal organic carbon (COC) on the bioavailability of inorganic mercury (Hg(II)] and monomethylmercury (MeHg) to the green mussel Perna viridis. The uptake rate constant of MeHg was about 8.5x higher than that of Hg(II). The uptake increased by 75% for Hg(II) and 117% for MeHg with decreasing salinity from 30 psu to 15 psu. Biogenic DOC derived from diatom decomposition decreased the uptake of Hg(II), consistent with the results of DOC originating from natural seawater. In contrast, the uptake of Hg(II) was enhanced considerably in the presence of humic acid. The bioavailability of MeHg was only weakly influenced by differences in DOC quality or quantity, but it was significantly decreased by estuarine DOC. The influence of COC on Hg bioavailability was also dependent on the colloidal structural properties and the colloid-metal complexation. Binding with colloidal nanoparticles increased the uptake of Hg(II) by 3.3 to 7.3 times compared to low molecular weight-complexed Hg, but decreased the uptake of MeHg by 42 to 73%. For both Hg(II) and MeHg, the uptake of the 9 d aged radiolabeled metals was lower than the uptake of the 2 d aged radiolabeled forms. Our study suggests that various mechanisms, such as facilitated transport and direct colloidal ingestion, are involved in the uptake of Hg(II) and MeHg under different dissolved and colloidal organic carbon conditions. COC and DOC need to be separately considered, given their different influences on mercury uptake. KEY WORDS: Mercury · Methylmercury · Dissolved organic carbon · Colloidal organic carbon · InfluxResale or republication not permitted without written consent of the publisher

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Methylation of mercury by humic substances in an aquatic environment

Cited by 93 publications

References 6 publications

Organic and inorganic mercury in the food chain of some lakes and reservoirs in Finland

Organic and inorganic mercury in the food chain of some lakes and reservoirs in Finland

Recent advances in the study of mercury methylation in aquatic systems

Uptake of Hg(II) and methylmercury by the green mussel Perna viridis under different organic carbon conditions

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