Gaseous elemental mercury emissions and CO2 respiration rates in terrestrial soils under controlled aerobic and anaerobic laboratory conditions

Obrist, Daniel; Faïn, Xavier; Berger, Cory A.

doi:10.1016/j.scitotenv.2009.12.008

Cited by 38 publications

(36 citation statements)

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“…Previously, Rogers and McFarlane (1979) reported declines in Hg 0 emissions following soil sterilization, albeit without directly measuring CO 2 respiration rates. Obrist et al (2010) observed relationships between CO 2 and Hg 0 efflux rates in controlled laboratory studies and also showed that Hg/C ratios in surface emission only accounted for ∼3 % of the Hg/C ratio present in soils. They also showed that experimental treatments (such as implementation of anaerobic conditions) easily disrupted this CO 2 -Hg 0 flux relationship.…”

Section: Concentration and Mass Changes Of Hg Plus Stoichiometric Relmentioning

confidence: 72%

“…Organic C also is subject to mineralization, however, and a hypothesized fate of Hg contained in organic C includes release from the matrix as C decomposes (Grigal, 2003;Obrist, 2007). A few recent studies indicate correlations between CO 2 and Hg 0 emission fluxes from soils, indicative of some gaseous losses of Hg in volatile form upon C mineralization (Wickland et al, 2006;Fritsche et al, 2008a;Obrist et al, 2010), and it has been proposed that Hg losses from soils may be in the range of a few percent of total Hg originally bound to organic C fractions (Obrist et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

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Fate of mercury in tree litter during decomposition

Pokharel

Obrist

2011

Biogeosciences

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Abstract. We performed a controlled laboratory litter incubation study to assess changes in dry mass, carbon (C) mass and concentration, mercury (Hg) mass and concentration, and stoichiometric relations between elements during decomposition. Twenty-five surface litter samples each, collected from four forest stands, were placed in incubation jars open to the atmosphere, and were harvested sequentially at 0, 3, 6, 12, and 18 months. Using a mass balance approach, we observed significant mass losses of Hg during decomposition (5 to 23 % of initial mass after 18 months), which we attribute to gaseous losses of Hg to the atmosphere through a gas-permeable filter covering incubation jars. Percentage mass losses of Hg generally were less than observed dry mass and C mass losses (48 to 63 % Hg loss per unit dry mass loss), although one litter type showed similar losses. A field control study using the same litter types exposed at the original collection locations for one year showed that field litter samples were enriched in Hg concentrations by 8 to 64 % compared to samples incubated for the same time period in the laboratory, indicating strong additional sorption of Hg in the field likely from atmospheric deposition. Solubility of Hg, assessed by exposure of litter to water upon harvest, was very low (<0.22 ng Hg g −1 dry mass) and decreased with increasing stage of decomposition for all litter types. Our results indicate potentially large gaseous emissions, or re-emissions, of Hg originally associated with plant litter upon decomposition. Results also suggest that Hg accumulation in litter and surface layers in the field is driven mainly by additional sorption of Hg, with minor contributions from "internal" accumulation due to preferential loss of C over Hg. Litter types showed highly species-specific differences in Hg levels during decomposition suggesting that emissions, retention, and sorption of Hg are dependent on litter type.

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Section: Concentration and Mass Changes Of Hg Plus Stoichiometric Relmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Fate of mercury in tree litter during decomposition

Pokharel

Obrist

2011

Biogeosciences

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“…For example, linear responses between Hg and C changes might be expected upon complete loss of both Hg and organic C pools (e.g., that may occur in surface organic horizons during wildfires) where significant Hg losses have in fact been observed (Artaxo et al, 2000;Brunke et al, 2001;Friedli et al, 2001;Sigler et al, 2003;Turetsky et al, 2006;. In contrast, however, the few experimental studies that correspondingly measured the fate of Hg upon C mineralisation indicate that only a small fraction of Hg may be subject to volatilisation losses upon evasion of CO 2 (Fritsche et al, 2008;Obrist et al, 2010b), which would indicate a much smaller magnitude of soil Hg losses compared to that of C. The biogeochemistry of terrestrial Hg is very complex, including various deposition and emission pathways (Graydon , 2008b;Gustin et al, 2008), redox transformations between volatile and non-volatile Hg forms (Lalonde et al, 2001;Obrist et al, 2010a), and methylation and demethylation processes (Ullrich et al, 2001). The statistical approach used in this study does not allow simulating individual biogeochemical processes, and clearly the quantitative response of Hg upon changes in soil C will depend on these underlying processes and need to be addressed by further experimental studies.…”

Section: Sensitivity To Change In Air Temperaturementioning

confidence: 99%

“…Fate processes and potential changes in terrestrial Hg storage have important implications for global cycling of Hg, including implications for back-evasion of Hg to the atmosphere or runoff to aquatic systems (Obrist, 2007;Smith-Downey et al, 2010). For example, bi-directional flux behaviour that Hg shows between terrestrial components and the atmosphere (Ericksen et al, 2006;Fritsche et al, 2008) is of concern for atmospheric Hg loads... (Ericksen et al, 2005;Harris et al, 2007;Pokharel and Obrist, 2011;Obrist et al, 2010b). Re-emissions of Hg from terrestrial surfaces -also termed secondary emissions -have the potential to become increasingly important due to a cumulative effect of past and ongoing pollution loads accumulating in surface reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools

2013

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Substantial amounts of mercury (Hg) in the terrestrial environment reside in soils and are associated with soil organic carbon (C) pools, where they accumulated due to increased atmospheric deposition resulting from anthropogenic activities. The purpose of this study was to examine potential sensitivity of surface soil Hg pools to global change variables, particularly affected by predicted changes in soil C pools, in the contiguous US. To investigate, we included a soil Hg component in the Community Land Model based on empirical statistical relationships between soil Hg / C ratios and precipitation, latitude, and clay; and subsequently explored the sensitivity of soil C and soil Hg densities (i.e., areal-mass) to climate scenarios in which we altered annual precipitation, carbon dioxide (CO₂) concentrations and temperature.

Our model simulations showed that current sequestration of Hg in the contiguous US accounted for 15 230 metric tons of Hg in the top 0–40 cm of soils, or for over 300 000 metric tons when extrapolated globally. In the simulations, US soil Hg pools were most sensitive to changes in precipitation because of strong effects on soil C pools, plus a direct effect of precipitation on soil Hg / C ratios. Soil Hg pools were predicted to increase beyond present-day values following an increase in precipitation amounts and decrease following a reduction in precipitation. We found pronounced regional differences in sensitivity of soil Hg to precipitation, which were particularly high along high-precipitation areas along the West and East Coasts. Modelled increases in CO₂ concentrations to 700 ppm stimulated soil C and Hg accrual, while increased air temperatures had small negative effects on soil C and Hg densities. The combined effects of increased CO₂, increased temperature and increased or decreased precipitation were strongly governed by precipitation and CO₂ showing pronounced regional patterns. Based on these results, we conclude that the combination of precipitation and CO₂ should be emphasised when assessing how climate-induced changes in soil C may affect sequestration of Hg in soils

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“…Además, la naciente industria de explotación petrolera y minera en esta región ha generado preocupación en las comunidades que habitan en las cercanías de estos ríos, debido a las posibles contaminaciones, incluyendo contaminación por metales pesados, ya que estos no pueden ser considerados elementos inalterables, sino que presentan movilidad hacia el agua, transferencia a la atmósfera por volatilización [5], adsorción por plantas e incorporación a las cadenas tróficas [6,7].…”

Section: Introductionunclassified

Análisis de metales pesados en suelos irrigados con agua del río Guatiquía

Niño

Ramirez

2015

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Recepción: 05-ene-15 Aceptación: 22-abr-15 Resumen En este trabajo se analizaron muestras de suelos usados principalmente para el cultivo de arroz, en la vereda La Esperanza, del municipio de Villavicencio; estos suelos son irrigados con aguas del río Guatiquía, que atraviesa la ciudad de Villavicencio. Se tomó como base para la extracción y cuantificación de metales en suelos la metodología descrita en la Norma Técnica Colombiana 3388 y 3934, respectivamente. Dado que actualmente en Colombia no se tiene determinado el nivel de referencia para la concentración de metales en el suelo, se utilizó una norma internacional para poder determinar el grado de contaminación de los suelos. Los resultados obtenidos mostraron que las concentraciones de los metales analizados (cadmio, cobre, plomo, níquel y zinc) se encuentran por debajo de los parámetros internacionales permitidos. Este estudio es uno de los primeros avances en la determinación del nivel de referencia de estos metales en suelos de uso agrícola en la región de la Orinoquía.Palabras clave: contaminación de los suelos, metales en suelos, suelos. AbstractIn this study, soil samples mainly used for rice crops in the countryside La Esperanza, Villavicencio municipality, were analyzed. These soils are irrigated with water from the Guatiquía River, which runs through the city of Villavicencio. The extraction and quantification were based on the methods described in the Colombian technical standard 3388 and 3934 respectively. Since nowadays in Colombia the reference level for metal concentration in soil is undefined, an international standard norm was used to determine the degree of soil pollution. The results showed that concentrations of the tested metals (cadmium, copper, lead, nickel and zinc) are below the levels allowed by international standards. This study is one of the first advances in determining the reference level of these metals in agricultural soils.

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Gaseous elemental mercury emissions and CO2 respiration rates in terrestrial soils under controlled aerobic and anaerobic laboratory conditions

Cited by 38 publications

References 61 publications

Fate of mercury in tree litter during decomposition

Fate of mercury in tree litter during decomposition

Modelling the sensitivity of soil mercury storage to climate-induced changes in soil carbon pools

Análisis de metales pesados en suelos irrigados con agua del río Guatiquía

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