An empirical approach to modeling methylmercury concentrations in an Adirondack stream watershed

Burns, Douglas A.; Nystrom, Elizabeth A.; Wolock, David M.; Bradley, Paul M.; Riva-Murray, Karen

doi:10.1002/2013jg002481

Cited by 11 publications

(12 citation statements)

References 71 publications

(139 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The rapid increase in pore water MeHg as a result of soil flooding and elevated fraction of filter-passing Hg T as MeHg in O a horizon pore waters (≤ 9%) suggests that surface soils are a more important source of MeHg to adjacent surface waters than underlying soils. Our results corroborate watershed-scale studies of contaminated and uncontaminated sites that identify reduced riparian soils as important sources of MeHg to adjacent surface waters (Balogh et al, 2004;Shanley et al, 2008;Brigham et al, 2009;Regnell et al, 2009;Barringer et al, 2010;Southworth et al, 2010), and support models that use riparian zone hydrology (i.e., hydrologic flow path, water table depth) to predict MeHg concentrations in streams (Burns et al, 2014;Eklӧf et al, 2015). MeHg levels were greatest under iron-and sulfate-reducing conditions, which adds evidence that the flushing of reduced riparian soils is responsible for episodic fluxes of MeHg into streams that coincide with reduced stream water chemistry.…”

Section: Mercury Methylation In Riparian Soilssupporting

confidence: 82%

“…In-stream measurements of MeHg during high flow events have been observed to coincide with low concentrations of molecular oxygen and increased concentrations of manganese and iron (Balogh et al, 2004;Regnell et al, 2009;Barringer et al, 2010), which suggests that the hydrologic flushing of reduced riparian soils may be the source of MeHg. Furthermore, several models that describe MeHg concentrations in streams use parameters based on riparian zone hydrology (i.e., hydrologic flow path, water table depth) (Burns et al, 2014;Eklӧf et al, 2015). Under dark anoxic conditions, Hg(II) can also be reduced to Hg 0 (aq) through biotic (e.g., dissimilatory metal-reducing bacteria) (Wiatrowski et al, 2006;Hu et al, 2013a) and abiotic pathways (e.g., redox-active DOM groups, aqueous Fe(II), Fe(II)-bearing minerals) (Allard and Arsenie, 1991;Wiatrowski et al, 2009;Gu et al, 2011;Zheng et al, 2012;Bone et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mercury transformation and release differs with depth and time in a contaminated riparian soil during simulated flooding

Poulin

Aiken

Nagy

et al. 2016

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Riparian soils are an important environment in the transport of mercury in rivers and wetlands, but the biogeochemical factors controlling mercury dynamics under transient redox conditions in these soils are not well understood. Mercury release and transformations in the O a and underlying A horizons of a contaminated riparian soil were characterized in microcosms and an intact soil core under saturation conditions. Pore water dynamics of total mercury (Hg T), methylmercury (MeHg), and dissolved gaseous mercury (Hg 0 (aq)) along with selected anions, major elements, and trace metals were characterized across redox transitions during 36 d of flooding in microcosms. Next, Hg T dynamics were characterized over successive flooding (17 d), drying (28 d), and flooding (36 d) periods in the intact core. The observed mercury dynamics exhibit depth and temporal variability. At the onset of flooding in microcosms (1-3 d), mercury in the O a horizon soil, present as a combination of ionic mercury (Hg(II)) bound to thiol groups in the soil organic matter (SOM) and nanoparticulate metacinnabar (β-HgS), was mobilized with organic matter of high molecular weight. Subsequently, under anoxic conditions, pore water Hg T declined coincident with sulfate (3-11 d) and the proportion of nanoparticulate β-HgS in the O a horizon soil increased slightly. Redox oscillations in the intact O a horizon soil exhausted the mobile mercury pool associated with organic matter. In contrast, mercury in the A horizon soil, present predominantly as nanoparticulate β-HgS, was mobilized primarily as Hg 0 (aq) under strongly reducing conditions (5-18 d). The concentration of Hg 0 (aq) under dark reducing conditions correlated positively with byproducts of dissimilatory metal reduction (). Mercury dynamics in intact A horizon soil were consistent over two periods of flooding, indicating that nanoparticulate β-HgS was an accessible pool of mobile mercury over recurrent reducing conditions. The concentration of MeHg increased with flooding time in both the O a and A horizon pore waters. Temporal changes in pore water constituents (iron, manganese, sulfate, inorganic carbon, headspace methane) all implicate microbial control of redox transitions. The mobilization of mercury in multiple forms, including Hg T associated with organic matter, MeHg, and Hg 0 (aq) , to pore waters during periodic soil flooding may contribute to mercury releases to adjacent surface waters and the recycling of the legacy mercury to the atmosphere.

show abstract

Section: Mercury Methylation In Riparian Soilssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Mercury transformation and release differs with depth and time in a contaminated riparian soil during simulated flooding

Poulin

Aiken

Nagy

et al. 2016

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…The substantial heterogeneity in fish THg concentrations across the landscape is consistent with findings from other regions of North America; for example, large variation among individual water bodies was evident in the analyses of fish THg levels across the Great Lakes region (Sandheinrich et al, 2011), the northeastern US and eastern Canada (Kamman et al, 2005), and across Canada (Depew et al, 2013b). The variation in fish THg concentrations among water bodies elsewhere has been attributed to a number of catchment and lake-specific parameters, including wetland density (Burns et al, 2014;Burns et al, 2012), coniferous forest cover (Drenner et al, 2013;Eagles-Smith et al, 2016a), pH (Clayden et al, 2014;Jardine et al, 2013), dissolved organic carbon concentrations (Driscoll et al, 1995;French et al, 2014;Rolfhus et al, 2011), and primary productivity (Chen and Folt, 2005), that influence the production of MeHg or its concentration at the base of aquatic food webs.…”

Section: Figure 4 Here-captionsupporting

confidence: 79%

Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada

Eagles‐Smith

Ackerman

Willacker

et al. 2016

Science of The Total Environment

141

View full text Add to dashboard Cite

Methylmercury contamination of fish is a global threat to environmental health. Mercury (Hg) monitoring programs are valuable for generating data that can be compiled for spatially broad syntheses to identify emergent ecosystem properties that influence fish Hg bioaccumulation. Fish total Hg (THg) concentrations were evaluated across the Western United States (US) and Canada, a region defined by extreme gradients in habitat structure and water management. A database was compiled with THg concentrations in 96,310 fish that comprised 206 species from 4262 locations, and used to evaluate the spatial distribution of fish THg across the region and effects of species, foraging guilds, habitats, and ecoregions. Areas of elevated THg exposure were identified by developing a relativized estimate of fish mercury concentrations at a watershed scale that accounted for the variability associated with fish species, fish size, and site effects. THg concentrations in fish muscle ranged between 0.001 and 28.4 (μg/g wet weight (ww)) with a geometric mean of 0.17. Overall, 30% of individual fish samples and 17% of means by location exceeded the 0.30μg/g ww US EPA fish tissue criterion. Fish THg concentrations differed among habitat types, with riverine habitats consistently higher than lacustrine habitats. Importantly, fish THg concentrations were not correlated with sediment THg concentrations at a watershed scale, but were weakly correlated with sediment MeHg concentrations, suggesting that factors influencing MeHg production may be more important than inorganic Hg loading for determining fish MeHg exposure. There was large heterogeneity in fish THg concentrations across the landscape; THg concentrations were generally higher in semi-arid and arid regions such as the Great Basin and Desert Southwest, than in temperate forests. Results suggest that fish mercury exposure is widespread throughout Western US and Canada, and that species, habitat type, and region play an important role in influencing ecological risk of mercury in aquatic ecosystems.

show abstract

“…In total, 108 studies were excluded through that screening process. A total of 44 studies were kept from this search (Bergman & Bump, 2014;Berndt et al, 2016;Berndt & Bavin, 2012;Braaten et al, 2014;Bravo et al, 2017;Brazeau et al, 2013;Burns et al, 2012Burns et al, , 2013Burns et al, , 2014Burton et al, 2013;Chaves-Ulloa et al, 2016;de Wit et al, 2014;Demers et al, 2013;Denkenberger et al, 2014;Dranguet et al, 2017;Eckley et al, 2015;Eklöf et al, 2013;Ekstrom et al, 2016;Fagnani et al, 2012;Gerson & Driscoll, 2016;Girard et al, 2016;Guedron et al, 2014;Hamelin et al, 2015;Haverstock et al, 2012;Houben et al, 2016;Jeremiason et al, 2016;Leopold et al, 2012;Loftin et al, 2012;Luo et al, 2014;MacMillan et al, 2015;Moreno et al, 2016;Navratil et al, 2015;Noh et al, 2016;Oswald & Branfireun, 2014;Painter et al, 2015;Picado & Bengtsson, 2012;Poste et al, 2015;Pyhtila et al, 2012;Riscassi et al, 2016;Sherman & Blum, 2013;…”

Section: Data Acquisitionmentioning

confidence: 99%

Global Meta‐Analysis on the Relationship Between Mercury and Dissolved Organic Carbon in Freshwater Environments

2019

View full text Add to dashboard Cite

In freshwater ecosystems, several studies have shown a strong linear relationship between total mercury (THg) or methylmercury (MeHg) and dissolved organic carbon (DOC) concentrations. Variations in this linear relationship have been reported, but the magnitude and causes of this variation are not well known. The objective of this study was to conduct a meta‐analysis to quantify and understand the global variation of this mercury (Hg)–DOC association. This meta‐analysis included 54 studies in lentic and lotic ecosystems for a total of 85 THg–DOC and 59 MeHg–DOC relationships. There was an increase in Hg with DOC concentrations in water with a global average slope of 0.25 (confidence interval (CI): 0.20–0.35) ng/mg for THg and 0.029 (CI: 0.014–0.044) ng/mg for MeHg. Relationships were stronger for (1) North American studies, (2) natural environments compared to those disturbed by anthropogenic activities, (3) spatial studies compared to temporal studies, (4) filtered samples (THg only), and (5) the aromatic fraction of DOC compared to the bulk DOC. Coupling with DOC was stronger for THg than for MeHg. Ecosystem type (lentic vs. lotic), geographical coordinates, and publication year did not influence the strength of relationships. Overall, we show that there is a strong but variable coupling between carbon and mercury cycles in freshwater ecosystems globally and that this link is modulated regionally by geographic location, temporal scale, and human activity, with implications for understanding these rapidly changing biogeochemical processes in response to global change.

show abstract

An empirical approach to modeling methylmercury concentrations in an Adirondack stream watershed

Abstract: Inverse empirical models can inform and improve more complex process-based models by quantifying the principal factors that control water quality variation. Here we developed a multiple regression model that explains 81% of the variation in filtered methylmercury (

Cited by 11 publications

References 71 publications

Mercury transformation and release differs with depth and time in a contaminated riparian soil during simulated flooding

Mercury transformation and release differs with depth and time in a contaminated riparian soil during simulated flooding

Spatial and temporal patterns of mercury concentrations in freshwater fish across the Western United States and Canada

Global Meta‐Analysis on the Relationship Between Mercury and Dissolved Organic Carbon in Freshwater Environments

Contact Info

Product

Resources

About