Decline of Acid Rain Enhances Mercury Concentrations in Fish

Hongve, Dag; Haaland, Ståle; Riise, Gunnhild; Blakar, Inggard Arne; Norton, Stephen A.

doi:10.1021/es3002629

Cited by 18 publications

(21 citation statements)

References 3 publications

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“…In a more global perspective, the present study could be part of the explanation for many environmental hazards, among others the observed connection between lake acidity and increased (methyl) mercury levels in fish (Mailman et al 2006;Hongve et al 2012) and the effects of primary physical-chemical factors on the harmful Hg uptake and methylation in the food webs.…”

Section: Hill Plot Of Mercury Uptakementioning

confidence: 69%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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Mercury adsorption on the cell surface and intracellular uptake by bacteria represent the key first step in the production and accumulation of highly toxic mercury in living organisms. In this work, the biophysical characteristics of the mercury bioaccumulation are studied in intact cells of photosynthetic bacteria by use of analytical (dithizone) assay and physiological photosynthetic markers (pigment content, fluorescence induction and membrane potential) to determine the amount of mercury ions bound to the cell surface and taken up by the cell. It is shown that the Hg(II) uptake mechanism 1) has two kinetically distinguishable components, 2) includes co-opted influx through heavy metal transporters since the slow component is inhibited by Ca 2+ channel blockers, 3) shows complex pH-dependence demonstrating the competition of ligand binding of Hg(II) ions with H + ions (low pH) and high tendency of complex formation of Hg(II) with hydroxyl ions (high pH) and 4) is not a passive but an energy-dependent process as evidenced by light-activation and inhibition by protonophore. Photosynthetic bacteria can accumulate Hg(II) in amounts much (about 10 5 ) greater than their own masses by well defined strong and weak binding sites with equilibrium binding constants in the range of 1 (μM) -1 and 1 (mM) -1 , respectively. The strong binding sites are attributed to sulfhydryl groups as the uptake is blocked by use of sulfhydryl modifying agents and their number is much (two orders of magnitude) smaller than the number of weak binding sites. Biofilms developed by some bacteria (e.g. Rvx. gelatinosus) increase the mercury binding capacity further by a factor of about five. Photosynthetic bacteria in the light act as sponge of Hg(II) and can be potentially used for biomonitoring and bioremediation of mercury contaminated aqueous cultures.2

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Section: Hill Plot Of Mercury Uptakementioning

confidence: 69%

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

2017

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“…Our results are consistent with the concept that the terrestrial OM, mobilized from the catchment by decreased ionic strength of soils as a result of reduced acid precipitation [ Haaland et al , ; Monteith et al , ], may serve as a vector of both OC and Hg from soils to surface waters [ Hongve et al , ] and may leave an imprint in the sediment record [ Teisserenc et al , ] (Figure ). If so, these results may carry further environmental implications because despite the decrease of Hg atmospheric emission, the mobilization of Hg by increased mobilization of terrestrial OM due to lake browning might lead to increased Hg concentrations in boreal lakes of similar characteristics and geographical location.…”

Section: Discussionmentioning

confidence: 99%

“…Hg binds strongly to sulfur species such as inorganic sulfides and organic thiols [Skyllberg, 2008]. The decrease in soil ionic strength, due to the decline of atmospheric acid deposition, can mobilize soil OC [Monteith et al, 2007] but might also enhance the transport of organically bound Hg to lakes [Hongve et al, 2012]. An enhanced terrestrial Hg load due to recent lake browning has been linked to increased Hg concentrations in fish [Hongve et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

“…The decrease in soil ionic strength, due to the decline of atmospheric acid deposition, can mobilize soil OC [Monteith et al, 2007] but might also enhance the transport of organically bound Hg to lakes [Hongve et al, 2012]. An enhanced terrestrial Hg load due to recent lake browning has been linked to increased Hg concentrations in fish [Hongve et al, 2012]. A fraction (0.1-15%) of inorganic Hg (IHg) can be transformed to MeHg under suboxic and anoxic conditions in stratified water columns and/or lake sediments during anaerobic respiration of OM by bacteria [Fleming et al, 2006;Gilmour et al, 2011;King et al, 2000].…”

Section: Introductionmentioning

confidence: 99%

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The effect of lake browning and respiration mode on the burial and fate of carbon and mercury in the sediment of two boreal lakes

et al. 2016

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In many northern temperate regions, the water color of lakes has increased over the past decades ("lake browning"), probably caused by an increased export of dissolved organic matter from soils. We investigated if the increase in water color in two lakes in Norway has resulted in increased burial of organic carbon (OC) and mercury (Hg) in the sediments and if the Hg was prone to methylation. Lake Solbergvann experienced a threefold water color increase, and OC burial increased approximately twofold concomitant to the water color increase. This lake had prolonged periods of anoxic bottom water, and anoxic OC mineralization rates were only about half of the oxic OC mineralization rates (7.7 and 17.5 g C m À2 yr À1 , respectively), contributing to an efficient OC burial. In Lake Elvåga, where water color increase was only approximately twofold and bottom water was oxygenated, no recent increase in OC burial could be observed. Hg burial increased strongly in both lakes (threefold and 1.6-fold in Lake Solbergvann and Lake Elvåga, respectively), again concomitant to the recent water color increase. The proportion of methylated Hg (MeHg) in surficial sediment was 1 order of magnitude higher in Lake Elvåga (up to 6% MeHg) than in Lake Solbergvann (0.2-0.6% MeHg), probably related to the different oxygenation regimes. We conclude that lake browning can result in increased OC and Hg burial in lake sediments, but the extent of browning and the dominating mode of sediment respiration (aerobic or anaerobic) strongly affect burial and fate of OC and Hg in sediments.

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“…171 In contrast, recent studies in Scandinavia report increases in fish Hg associated with increases in DOM resulting from watershed recovery from decreases in acid deposition. 176,177 These variable spatial and temporal patterns indicate that while controlling Hg inputs are essential to decrease Hg exposure, the response of biota will be highly variable in space and time due to the residence time of Hg associated with processing through detrital organic pools, and watershed processes/disturbances that affect Hg transport, net methylation and trophic transfer.…”

Section: Land and Freshwatersmentioning

confidence: 99%

Mercury as a Global Pollutant: Sources, Pathways, and Effects

Driscoll

Mason

Chan

et al. 2013

Environ. Sci. Technol.

2,003

1,176

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Mercury (Hg) is a global pollutant that affects human and ecosystem health. We synthesize understanding of sources, atmosphere-land-ocean Hg dynamics and health effects, and consider the implications of Hg-control policies. Primary anthropogenic Hg emissions greatly exceed natural geogenic sources, resulting in increases in Hg reservoirs and subsequent secondary Hg emissions that facilitate its global distribution. The ultimate fate of emitted Hg is primarily recalcitrant soil pools and deep ocean waters and sediments. Transfers of Hg emissions to largely unavailable reservoirs occur over the time scale of centuries, and are primarily mediated through atmospheric exchanges of wet/dry deposition and evasion from vegetation, soil organic matter and ocean surfaces. A key link between inorganic Hg inputs and exposure of humans and wildlife is the net production of methylmercury, which occurs mainly in reducing zones in freshwater, terrestrial, and coastal environments, and the subsurface ocean. Elevated human exposure to methylmercury primarily results from consumption of estuarine and marine fish. Developing fetuses are most at risk from this neurotoxin but health effects of highly exposed populations and wildlife are also a concern. Integration of Hg science with national and international policy efforts is needed to target efforts and evaluate efficacy.

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Decline of Acid Rain Enhances Mercury Concentrations in Fish

Cited by 18 publications

References 3 publications

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

Stoichiometry and kinetics of mercury uptake by photosynthetic bacteria

The effect of lake browning and respiration mode on the burial and fate of carbon and mercury in the sediment of two boreal lakes

Mercury as a Global Pollutant: Sources, Pathways, and Effects

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