scholarly journals An Integrated Investigation of Atmospheric Gaseous Elemental Mercury Transport and Dispersion Around a Chlor-Alkali Plant in the Ossola Valley (Italian Central Alps)

Toxics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 172
Author(s):  
Laura Fantozzi ◽  
Nicoletta Guerrieri ◽  
Giovanni Manca ◽  
Arianna Orrù ◽  
Laura Marziali
Keyword(s):  
Elemental Mercury ◽  
Background Concentration ◽  
Dispersion Pattern ◽  
Central Alps ◽  
Gaseous Elemental Mercury ◽  
Mercury Transport ◽  
Close Proximity ◽  
Potential Impact ◽  
Hg Accumulation

We present the first assessment of atmospheric pollution by mercury (Hg) in an industrialized area located in the Ossola Valley (Italian Central Alps), in close proximity to the Toce River. The study area suffers from a level of Hg contamination due to a Hg cell chlor-alkali plant operating from 1915 to the end of 2017. We measured gaseous elemental Hg (GEM) levels by means of a portable Hg analyzer during car surveys between autumn 2018 and summer 2020. Moreover, we assessed the long-term dispersion pattern of atmospheric Hg by analyzing the total Hg concentration in samples of lichens collected in the Ossola Valley. High values of GEM concentrations (1112 ng m−3) up to three orders of magnitude higher than the typical terrestrial background concentration in the northern hemisphere were measured in the proximity of the chlor-alkali plant. Hg concentrations in lichens ranged from 142 ng g−1 at sampling sites located north of the chlor-alkali plant to 624 ng g−1 in lichens collected south of the chlor-alkali plant. A north-south gradient of Hg accumulation in lichens along the Ossola Valley channel was observed, highlighting that the area located south of the chlor-alkali plant is more exposed to the dispersion of Hg emitted into the atmosphere from the industrial site. Long-term studies on Hg emission and dispersion in the Ossola Valley are needed to better assess potential impact on ecosystems and human health.

scholarly journals Speciated Atmospheric Mercury during Haze and Non-haze Days in an Inland City in China

2016 ◽  
Author(s):  
Qianqian Hong ◽  
Zhouqing Xie ◽  
Cheng Liu ◽  
Feiyue Wang ◽  
Pinhua Xie ◽  
...  
Keyword(s):  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Central China ◽  
Mercury Emissions ◽  
Gaseous Elemental Mercury ◽  
Enhanced Production ◽  
Mercury Transport ◽  
Haze Pollution ◽  
The Mean ◽  
Haze Days

Abstract. Long-term continuous measurements of speciated atmospheric mercury were conducted at Hefei, a mid-latitude inland city in east central China, from July 2013 to June 2014. The mean concentrations (± standard deviation) of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) were 3.95 ± 1.93 ng m−3, 2.49 ± 2.41 pg m−3 and 23.3 ± 90.8 pg m−3, respectively, during non-haze days, and 4.74 ± 1.62 ng m−3, 4.32 ± 8.36 pg m−3 and 60.2 ± 131.4 pg m−3, respectively, during haze days. Potential source contribution function (PSCF) analysis suggested that the atmospheric mercury pollution during haze days was caused primarily by local mercury emissions, instead of via long-range mercury transport. In addition, the disadvantageous diffussion during haze days will also enhance the level of atmospheric mercury. Compared to the GEM and RGM, change in PBM was more sensitive to the haze pollution. The mean PBM concentration during haze days was 2.5 times that during non-haze days due to elevated concentrations of particulate matter. A remarkable seasonal trend in PBM was observed with concentration decreasing in the following order in response to the frequency of haze days: autumn, winter, spring, summer. A distinct diurnal relationship was found between GEM and RGM during haze days, with the peak values of RGM coinciding with the decline in GEM. Using HgOH as an intermediate product during GEM oxidation, our results suggest that NO2 aggregation with HgOH could explain the enhanced production of RGM during the daytime in haze days. Increasing level of NOx will potentially accelerate the oxidation of GEM despite the decrease of solar radiation.

scholarly journals A dual, single detector relaxed eddy accumulation system for long-term measurement of mercury flux

2015 ◽  
Vol 8 (8) ◽  
pp. 8113-8156
Author(s):  
S. Osterwalder ◽  
J. Fritsche ◽  
M. B. Nilsson ◽  
C. Alewell ◽  
J. Sommar ◽  
...  
Keyword(s):  
Trace Gases ◽  
Accurate Determination ◽  
Elemental Mercury ◽  
Urban Setting ◽  
Emission Rates ◽  
Sample Collection ◽  
Gaseous Elemental Mercury ◽  
Relaxed Eddy Accumulation ◽  
Single Detector

Abstract. The fate of anthropogenic emissions of mercury (Hg) to the atmosphere is influenced by the exchange of elemental Hg with the earth surface. This exchange which holds the key to a better understanding of Hg cycling from local to global scales has been difficult to quantify. To advance and facilitate research about land–atmosphere Hg interactions, we developed a dual-intake, single analyzer Relaxed Eddy Accumulation (REA) system. REA is an established technique for measuring turbulent fluxes of trace gases and aerosol particles in the atmospheric surface layer. Accurate determination of gaseous elemental mercury (GEM) fluxes has proven difficult to technical challenges presented by extremely small concentration differences (typically < 0.5 ng m−3) between updrafts and downdrafts. To address this we present an advanced REA design that uses two inlets and two pair of gold cartridges for semi-continuous monitoring of GEM fluxes. They are then analyzed sequentially on the same detector while another pair of gold cartridges takes over the sample collection. We also added a reference gas module for repeated quality-control measurements. To demonstrate the system performance, we present results from field campaigns in two contrasting environments: an urban setting with a heterogeneous fetch and a boreal mire during snow-melt. The observed emission rates were 15 and 3 ng m−2 h−1. We claim that this dual-inlet, single detector approach is a significant development of the REA system for ultra-trace gases and can help to advance our understanding of long-term land–atmosphere GEM exchange.

scholarly journals First eddy covariance flux measurements of gaseous elemental mercury (Hg<sup>0</sup>) over a grassland

2019 ◽  
Author(s):  
Stefan Osterwalder ◽  
Werner Eugster ◽  
Iris Feigenwinter ◽  
Martin Jiskra
Keyword(s):  
Detection Limit ◽  
Eddy Covariance ◽  
Net Ecosystem Exchange ◽  
Elemental Mercury ◽  
Terrestrial Ecosystems ◽  
Co2 Uptake ◽  
Gaseous Elemental Mercury ◽  
Flux Measurements ◽  
Net Co2 Uptake

Abstract. Direct measurements of the net ecosystem exchange (NEE) of gaseous elemental mercury (Hg0) are crucial to improve the understanding of global Hg cycling und ultimately human and wildlife Hg exposure. The lack of long-term, ecosystem-scale measurements causes large uncertainties in Hg0 flux estimates. Today it remains unclear whether terrestrial ecosystems are net sinks or sources of atmospheric Hg0. Here we show a detailed validation of the eddy covariance technique for direct Hg0 flux measurements (Eddy Mercury) based on a Lumex mercury monitor RA-915AM. The flux detection limit derived from a zero-flux experiment in the laboratory was 0.22 ng m−2 h−1 (maximum) with a 50 % cut-off at 0.074 ng m−2 h−1. The statistical estimate of the Hg0 flux detection limit under real-world outdoor conditions at the site was 5.9 ng m−2 h−1 (50 % cut-off). We present the first successful eddy covariance NEE measurements of Hg0 over a low-Hg level soil (41–75 ng Hg g−1 topsoil [0–10 cm]) in summer 2018 at a managed grassland at the Swiss FluxNet site in Chamau, Switzerland (CH-Cha). We measured a net summertime re-emission over a period of 34 days with a median Hg0 flux of 2.5 ng m−2 h−1 (−0.6 to 7.4 ng m−2 h−1, range between 25th and 75th percentiles). We observed a distinct diel cycle with higher median daytime fluxes (8.4 ng m−2 h−1) than nighttime fluxes (1.0 ng m−2 h−1). Drought stress during the measurement campaign in summer 2018 induced partial stomata closure of vegetation which led to a midday depression in CO2 uptake which did not recover during the afternoon. Thus, the cumulative net CO2 uptake was only 8 % of the net CO2 uptake during the same period in the previous year 2017. We suggest that partial stomata closure dampened Hg0 uptake by vegetation, resulting in a NEE of Hg0 dominated by soil re-emission. Finally, we give suggestions to further improve the precision and handling of the Eddy Mercury system in order to assure its suitability for long-term NEE measurements of Hg0 over natural background surfaces with low soil Hg concentrations (

scholarly journals Can the MerPAS Passive Air Sampler Discriminate Landscape, Seasonal, and Elevation Effects on Atmospheric Mercury? A Feasibility Study in Mississippi, USA

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 617 ◽  
Author(s):  
Byunggwon Jeon ◽  
James V. Cizdziel
Keyword(s):  
Temporal Trends ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Concentration Gradients ◽  
Gaseous Elemental Mercury ◽  
Passive Air Sampler ◽  
Air Sampler ◽  
Direct Mercury Analyzer ◽  
Close Proximity ◽  
Mercury Analyzer

Accurately measuring gaseous elemental mercury (GEM) concentrations in the atmosphere is important to understand its sources, cycling, distribution, and temporal trends. The MerPAS passive air sampler from Tekran Inc. (Toronto, ON, Canada) captures GEM on sulfur-impregnated activated carbon after it passes through a Radeillo diffusive barrier. Because they are small, relatively low in cost, and require no power, they can be deployed at multiple locations, yielding a much greater spatial resolution, albeit at coarser temporal resolution, compared to active sampling. In this study, we used the MerPAS to measure GEM concentration gradients at a mixed hardwood forest, wetland, pond, and a mowed (grass) field, all within close proximity (<500 m) to each other. Vertical profiles (0.5, 3.0, 5.5 m) were assessed during summer and winter. The sorbent was analyzed using a direct mercury analyzer. The samplers were captured between 0.90 to 2.2 ng over 2 weeks, well above the mean blank of 0.14 ng. We observed differences between the landscapes, elevation, and seasons. Nearest to the surface, GEM concentrations were lowest in the wetland (both seasons), where there was dense vegetation, and highest in the mowed field (both seasons). Generally, GEM levels increased with the elevation above the ground, except for the forest where the trend was slightly reversed. This suggests a possible net GEM deposition from the atmosphere to surfaces for three of the four landscapes. GEM concentrations were slightly higher in the winter than the summer at 5.5 m height where air masses were unimpeded by vegetation. Overall, we conclude that the MerPAS is indeed capable of measuring GEM gradients between landscapes, elevations, and seasons, if given sufficient collection time, good analytical precision, and low blank levels.

scholarly journals Eddy covariance flux measurements of gaseous elemental mercury over a grassland

2020 ◽  
Vol 13 (4) ◽  
pp. 2057-2074 ◽  
Author(s):  
Stefan Osterwalder ◽  
Werner Eugster ◽  
Iris Feigenwinter ◽  
Martin Jiskra
Keyword(s):  
Detection Limit ◽  
Eddy Covariance ◽  
Co2 Flux ◽  
Elemental Mercury ◽  
Terrestrial Ecosystems ◽  
Co2 Uptake ◽  
Global Networks ◽  
Gaseous Elemental Mercury ◽  
Flux Measurements

Abstract. Direct measurements of the net ecosystem exchange (NEE) of gaseous elemental mercury (Hg0) are important to improve our understanding of global Hg cycling and, ultimately, human and wildlife Hg exposure. The lack of long-term, ecosystem-scale measurements causes large uncertainties in Hg0 flux estimates. It currently remains unclear whether terrestrial ecosystems are net sinks or sources of atmospheric Hg0. Here, we show a detailed validation of direct Hg0 flux measurements based on the eddy covariance technique (Eddy Mercury) using a Lumex RA-915 AM mercury monitor. The flux detection limit derived from a zero-flux experiment in the laboratory was 0.22 ng m−2 h−1 (maximum) with a 50 % cutoff at 0.074 ng m−2 h−1. We present eddy covariance NEE measurements of Hg0 over a low-Hg soil (41–75 ng Hg g−1 in the topsoil, referring to a depth of 0–10 cm), conducted in summer 2018 at a managed grassland at the Swiss FluxNet site in Chamau, Switzerland (CH-Cha). The statistical estimate of the Hg0 flux detection limit under outdoor conditions at the site was 5.9 ng m−2 h−1 (50 % cutoff). We measured a net summertime emission over a period of 34 d with a median Hg0 flux of 2.5 ng m−2 h−1 (with a −0.6 to 7.4 ng m−2 h−1 range between the 25th and 75th percentiles). We observed a distinct diel cycle with higher median daytime fluxes (8.4 ng m−2 h−1) than nighttime fluxes (1.0 ng m−2 h−1). Drought stress during the measurement campaign in summer 2018 induced partial stomata closure of vegetation. Partial stomata closure led to a midday depression in CO2 uptake, which did not recover during the afternoon. The median CO2 flux was only 24 % of the median CO2 flux measured during the same period in the previous year (2017). We suggest that partial stomata closure also dampened Hg0 uptake by vegetation, resulting in a NEE of Hg0 that was dominated by soil emission. Finally, we provide suggestions to further improve the precision and handling of the “Eddy Mercury” system in order to assure its suitability for long-term NEE measurements of Hg0 over natural background surfaces with low soil Hg concentrations (< 100 ng g−1). With these improvements, Eddy Mercury has the potential to be integrated into global networks of micrometeorological tower sites (FluxNet) and to provide the long-term observations on terrestrial atmosphere Hg0 exchange necessary to validate regional and global mercury models.

scholarly journals The Human Microbiome in Multiple Sclerosis: Pathogenic or Protective Constituents?

2010 ◽  
Vol 37 (S2) ◽  
pp. S24-S33 ◽  
Author(s):  
Christopher Power ◽  
Joseph M. Antony ◽  
Kristofor K. Ellestad ◽  
André Deslauriers ◽  
Rakesh Bhat ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Human Microbiome ◽  
Pathogenic Microorganisms ◽  
Infectious Agents ◽  
Herpes Viruses ◽  
Immune Mediated ◽  
Close Proximity ◽  
Potential Impact ◽  
Pathogen Exposure

ABSTRACT:The human microbiome is comprised of commensal and pathogenic microorganisms, which exert diverse effects in close proximity to the site of intection as well as in remote tissues through immune-mediated mechanisms. Multiple infectious agents have been implicated in the pathogenesis of multiple sclerosis (MS) with variable findings depending on the agent, techniques, and disease phenotype. Herein, the contributions of individual infectious agents to MS and their effects on the immune and nervous systems are reviewed, focusing on herpes viruses, coronaviruses, retroviruses, and synchronic infections. While infectious agents are often assumed to be pathogenic, their effects might also be beneficial to the host in the long-term, depending on age and the type of immunogen/pathogen exposure, as proposed by the hygiene hypothesis. The human microbiome has potential impact on future diagnostic and therapeutic issues in MS.

A bottom up approach to quantify foliar uptake of gaseous elemental mercury by European forests during the 2018 growing season

2020 ◽  
Author(s):  
Lena Wohlgemuth ◽  
Stefan Osterwalder ◽  
Günter Hoch ◽  
Christine Alewell ◽  
Martin Jiskra
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Elemental Mercury ◽  
Growing Season ◽  
Accumulation Rates ◽  
Bottom Up ◽  
Deposition Fluxes ◽  
Gaseous Elemental Mercury ◽  
Species Specific ◽  
Hg Accumulation

&lt;p&gt;The deposition of gaseous elemental mercury, Hg(0), from the atmosphere to terrestrial surfaces remains poorly understood mainly due to difficulties in measuring net Hg(0) fluxes on the ecosystem scale. However, there is emerging evidence that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. We will present a novel bottom up approach to calculate Hg(0) deposition fluxes to aboveground foliage by combining foliar Hg accumulation rates on the basis of leaf area with species-specific leaf area indices. We analyzed Hg content in 583 foliage samples from major tree species at 10 European forested research sites along a latitudinal gradient from Switzerland to Northern Finland over the course of the 2018 growing season. Foliar Hg concentrations increased over time in all tree species at all sites. We found that foliar Hg accumulation rates normalized to leaf area increased with crown height and decreased with the age of multi-year old needles. We did not detect a clear latitudinal gradient in foliar Hg accumulation rates.&lt;/p&gt;&lt;p&gt;On an ecosystem scale we developed a simple bottom up approach for foliar Hg(0) uptake considering the systematic variations in crown height, needle age and tree species. We calculated species-specific average foliar Hg(0) dry deposition rates for the 2018 growing season of 22 &amp;#177; 4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for beech, 16 &amp;#177; 8 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for oak, 3 &amp;#177; 0.4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for birch, 18 &amp;#177; 10 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for spruce and 8 &amp;#177; 4 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt; for pine. For comparison, the average Hg wet deposition flux measured at 4 of our 10 research sites during the same time period was 2.5 &amp;#177; 0.2 &amp;#181;g Hg m&lt;sup&gt;-2&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;Scaling up site-specific deposition rates to the forested area of Europe (EU28) resulted in a total aboveground Hg(0) deposition to foliage of approximately 20 Mg during the 2018 growing season. Our results confirm that vegetation uptake of atmospheric Hg(0) represents a major deposition pathway to terrestrial surfaces. The bottom up approach we used is a promising method to quantify Hg(0) deposition fluxes based on easy-to-do Hg concentration measurements in foliage.&lt;/p&gt;

scholarly journals Analysis of the relationship between pineal hormone melatonin level and occupational mercury exposure in ex-miners with machine learning methods

2005 ◽  
Vol 2 (1) ◽  
Author(s):  
Joško Osredkar ◽  
Bernard Ženko ◽  
Darja Kobal Grum ◽  
Mladen Krsnik ◽  
Sašo Džeroski ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Scientific Literature ◽  
Elemental Mercury ◽  
Mercury Vapour ◽  
Melatonin Level ◽  
Antioxidative Effect ◽  
Machine Learning Methods ◽  
The Relationship ◽  
Hg Accumulation

The aim of this study was an analysis of the relationship between pineal hormone melatonin level and long-term occupational exposure to elemental mercury vapour (Hg°) of ex-mercury miners. Melatonin (MEL) is a hormonal product of the pineal gland. Hg accumulation in the pineal gland in ex-miners could modify the synthesis of melatonin and there are no data available in the scientific literature on the possible effects of Hg on melatonin excretion. Regression/model trees were used to perform the analyses and investigate the interactions between melatonin secretion and excretion on one hand, and various indicators of occupational Hg exposure and some other medical variables on the other. The results point us towards some previously unknown factors that influence the excretion of melatonin and support some assumptions that melatonin also has antioxidative effect. In the process of antioxidation activity melatonin decomposes and we assume this is the reason for decreased excretion of melatonin in mercury miners.

scholarly journals Trend of atmospheric mercury concentrations at Cape Point for 1995–2004 and since 2007

2017 ◽  
Vol 17 (3) ◽  
pp. 2393-2399 ◽  
Author(s):  
Lynwill G. Martin ◽  
Casper Labuschagne ◽  
Ernst-Günther Brunke ◽  
Andreas Weigelt ◽  
Ralf Ebinghaus ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Wet Deposition ◽  
Southern Oscillation ◽  
Elemental Mercury ◽  
Atmospheric Mercury ◽  
Austral Spring ◽  
Mercury Emissions ◽  
Gaseous Elemental Mercury ◽  
Regional Processes

Abstract. Long-term measurements of gaseous elemental mercury (GEM) concentrations at Cape Point, South Africa, reveal a downward trend between September 1995 and December 2005 and an upward one from March 2007 until June 2015, implying a change in trend sign between 2004 and 2007. The trend change is qualitatively consistent with the trend changes in GEM concentrations observed at Mace Head, Ireland, and in mercury wet deposition over North America, suggesting a change in worldwide mercury emissions. Seasonally resolved trends suggest a modulation of the overall trend by regional processes. The trends in absolute terms (downward in 1995–2004 and upward in 2007–2015) are highest in austral spring (SON), coinciding with the peak in emissions from biomass burning in South America and southern Africa. The influence of trends in biomass burning is further supported by a biennial variation in GEM concentration found here and an El Niño–Southern Oscillation (ENSO) signature in GEM concentrations reported recently.

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