Mercury isotope signatures in sediments and marine organisms as tracers of historical industrial pollution

Bonsignore, Maria R.; Manta, Daniela Salvagio; Barsanti, Mattia; Conte, Fabio; Delbono, Ivana; Horvat, Milena; Quinci, Enza María; Schirone, Antonio; Shlyapnikov, Yaroslav; Sprovieri, Mario

doi:10.1016/j.chemosphere.2020.127435

Cited by 19 publications

(8 citation statements)

References 81 publications

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“…The strong relationship observed between the Hg MIF and energy of incident radiation suggests that MIF signatures may be used as a tool for quantifying photochemical cycling of Hg. Indeed, MIF has been demonstrated in tracing the source and degradation of MeHg in marine biota, ,,,− and it is estimated that about 56–80% of MeHg could be photodegraded prior to entering the food web . MIF has also been used in studying the effects of DOM and its chemical-structural properties on photodemethylation of MeHg, but additional studies are warranted to understand the links between MIF and photoreduction and photodemethylation before this tool can be fully utilized.…”

Section: Abiotic Demethylationmentioning

confidence: 99%

Demethylation─The Other Side of the Mercury Methylation Coin: A Critical Review

Barkay

2021

ACS Environ. Au

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The public and environmental health consequences of mercury (Hg) methylation have drawn much attention and considerable research to Hg methylation processes and their dynamics in diverse environments and under a multitude of conditions. However, the net methylmercury (MeHg) concentration that accumulates in the environment is equally determined by the rate of MeHg degradation, a complex process mediated by a variety of biotic and abiotic mechanisms, about which our knowledge is limited. Here we review the current knowledge on MeHg degradation and its potential pathways and mechanisms. We describe detoxification by resistant microorganisms that employ the Hg resistance (mer) system to reductively break the carbon− mercury (C−Hg) bond producing methane (CH 4 ) and inorganic mercuric Hg(II), which is then reduced by the mercuric reductase to elemental Hg(0). Very recent research has begun to elucidate a mechanism for the longrecognized mer-independent oxidative demethylation, likely involving some strains of anaerobic bacteria as well as aerobic methane-oxidizing bacteria, i.e., methanotrophs. In addition, photochemical and chemical demethylation processes are described, including the roles of dissolved organic matter (DOM) and free radicals as well as dark abiotic demethylation in the natural environment about which little is currently known. We focus on mechanisms and processes of demethylation and highlight the uncertainties and known effects of environmental factors leading to MeHg degradation. Finally, we suggest future research directions to further elucidate the chemical and biochemical mechanisms of biotic and abiotic demethylation and their significance in controlling net MeHg production in natural ecosystems.

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Section: Abiotic Demethylationmentioning

confidence: 99%

Demethylation─The Other Side of the Mercury Methylation Coin: A Critical Review

Barkay

2021

ACS Environ. Au

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“…The Hg concentrations in the ECMS are comparable with those measured in sediments from the Gulf of Mexico (35.0 ± 15.0 μg kg −1 , n = 14; Ruiz‐Fernández et al., 2019), Greenland coastal regions (48.8 ± 36.5 μg kg −1 , n = 20; Asmund & Nielsen, 2000), and the Antarctica coastal regions (e.g., the Ross Sea, Hope Bay, and the Bransfield Strait; 32.2 ± 16.4 μg kg −1 , n = 28; Delhaye et al., 2023; Zheng et al., 2015), but they are lower than those of Atlantic coast of Northern Europe and North America, such as the Baltic Sea (130.0 ± 63.2 μg kg −1 , n = 7; Leipe et al., 2013) and the East Coast of USA (e.g., Penobscot River Estuary, Estuary and Gulf of St. Lawr, and Mississippi River Delta; 330.6 ± 259.6 μg kg −1 , n = 34; Santschi et al., 2001; J. N. Smith & Schafer, 1999; Yeager, Schwehr, Louchouarn, et al., 2018; Yeager, Schwehr, Schindler, & Santschi, 2018). Additionally, the maximum sedimentary Hg levels observed in the Sagua Estuary (ranges: 220–2,680 μg kg −1 ; Díaz‐Asencio et al., 2009), the Tagus River Estuary (ranges: 200–1,700 μg kg −1 ; Mil‐Homens et al., 2009), and the coastal areas of Rosignano Solvay (ranges: 250–6,870 μg kg −1 ; Bonsignore et al., 2020). These coastal ocean regions may have suffered from a strong impact of anthropogenic perturbations and input of local point sources.…”

Section: Resultsmentioning

confidence: 99%

Mercury Burial in Modern Sedimentary Systems of the East China Marginal Seas: The Role of Coastal Oceans in Global Mercury Cycling

Sun,

Hu,

Sun

et al. 2023

Global Biogeochemical Cycles

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Coastal oceans, the transition zones between terrestrial and oceanic systems, are susceptible to anthropogenic mercury (Hg) inputs and are regarded as critical dynamic interfaces of the global Hg cycle. However, the extent to which coastal oceans are accountable for sequestering Hg remains largely unknown owing to a lack of data on high‐resolution Hg accumulation in marine sediments. Synthesizing the results of this study (eight cores and 212 surface sediments) and the literature (three cores and 149 surface sediments), we provide a quantitative evaluation of the biogeochemical cycle of sedimentary Hg in the East China Marginal Seas (ECMS), including the response of the coastal marine sediments to anthropogenic disturbance as well as both human‐derived and natural Hg burial fluxes. We find a linear increase in Hg accumulation since the 1950s (2.0 ± 2.5% yr‐1) and a decline in Hg accumulation between 2010 and 2016. Modern burial fluxes of total and anthropogenic Hg in the ECMS (covering ∼4.8×105 km2 of sea surface) were estimated to be 89.1 ± 48.3 and 35.9 ± 33.1 Mg yr‐1, respectively. Using a compilation of 688 surface sediments and 131 sediment cores (819 samples in total) distributed globally in coastal oceans, we estimate that approximately 1,590 (range: 1,190–2,760) Mg yr‐1 (Method 1) and 540 (range: 310–960) Mg yr‐1 (Method 2) Hg are accumulated in coastal ocean regions. Our findings suggest that coastal oceans are likely the largest global marine sinks for Hg and play a dominant role in regulating the oceanic Hg cycle and budgets.

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“…[58][59][60][61] Metal isotope profiles of dated sediment cores are useful to verify anthropogenic contamination evolution across time (Fig. 2), [62][63][64][65][66][67] while surface sediments enable mapping the recent dispersion of metal contaminants. 59,68,69 Combining isotope ratios and geostatistical interpolation methods to model isotope variations across large space and time scales in the so-called "isoscapes" has been long used for non-metal stable isotopes (C, H, O, S) and radiogenic systems (Sr) for environmental, ecological, archeological and forensic purposes.…”

Section: Anthropogenic Source Apportionments and Metal Contamination ...mentioning

confidence: 99%

“Non-traditional” stable isotopes applied to the study of trace metal contaminants in anthropized marine environments

Araújo¹,

Knœry²,

Briant³

et al. 2022

Marine Pollution Bulletin

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Mercury isotope signatures in sediments and marine organisms as tracers of historical industrial pollution

Cited by 19 publications

References 81 publications

Demethylation─The Other Side of the Mercury Methylation Coin: A Critical Review

Demethylation─The Other Side of the Mercury Methylation Coin: A Critical Review

Mercury Burial in Modern Sedimentary Systems of the East China Marginal Seas: The Role of Coastal Oceans in Global Mercury Cycling

“Non-traditional” stable isotopes applied to the study of trace metal contaminants in anthropized marine environments

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