Source Of Mercury Research Articles

Impact of intense rains and flooding on mercury riverine input to the coastal zone

The aim of the present research was to determine the impact of intense rains and flooding on mercury riverine input to the coastal zone. This study focused on four small rivers (Reda, Zagórska Struga, Płutnica, Gizdepka), typical of the Southern Baltic region, with no significant mercury sources. Samples were collected for 16months during average flow conditions and during selected meteorological events: floods, downpours, thaws and droughts. Results showed decreased retention of mercury during intense rainfalls, thus demonstrating mercury elution from the catchment. Floods and melting snow also have a tremendous impact on the outflow of mercury from the catchment. Development of urban infrastructure and farmlands increases the outflow of mercury from the catchment too, making such areas a significant source of mercury in the river. On the other hand, areas with natural character, predominated by forests, stimulate retention of mercury that reaches them through dry and wet atmospheric deposition.

MERCURY IN THE SANTA CRUZ CHANNEL, NE BRAZIL - A POTENTIAL RISK

This work evaluated the level of mercury contamination in a mangrove system (Santa Cruz Channel) a couple of years after Hg discharge into its main tributary (Botafogo River) ceased, as well as the role of mangrove sediments as sinks or secondary sources of mercury whiting the system and/or to coastal areas. Mangrove oysters, suspended matter and sediment cores representing different compartments of the Channel and seasonal and tidal stages were analyzed. Mercury concentrations was 0.27-2.21 ppm (dry mass DM) in mangrove oysters; 0.04-6.20 ppm in total sediment (DM) and 0.3-20.5 ppm in relation to the grain size fraction <63 μm. Mercury concentrations in suspended matter were between 0.43-5.56 ppm (DM), corresponding to 4-175 ngL-1 particulate mercury. Results corroborates the importance of fine and organic-rich matter for the accumulation of mercury but also indicated that mangrove sediments do not function as a long-term trap for Hg. Instead, mercury is remobilized from the sediments, presumably as bioavailable species. As the export to coastal areas is small, a large portion of the remobilized Hg probably cycles within the system or is released into the air. Both processes represent a considerable risk for aquatic organisms and humans exposed to the mercury.

Suspended particulate mercury associated with tidal fluxes in a lagoon environment impacted by cinnabar mining activity (northern Adriatic Sea)

The Isonzo River has been demonstrated to be a continuing point source of mercury (Hg) in the Gulf of Trieste although the Idrija mine was last active in 1996. The present study aims to investigate the role of the suspended particulate matter (SPM) associated with tidal fluxes to disperse particulate Hg (PHg) into the Grado coastal lagoon system. PHg concentrations (avg. 3.11±2.62μg/g, d.w.), notwithstanding the ebb or flood tides, were significantly higher than the local sediment background (0.13μg/g). The relative affinity of Hg for the particulate phase in surface waters was confirmed by higher average distribution coefficient (Kd) values (5.6–6.7). PHg contents showed the highest values in ebb tide conditions, thus suggesting their origin from the erosion of tidal flats and saltmarshes of the lagoon. When compared to river discharge, high PHg surface concentrations in flood tide are related to rainfall events occurring within the river basin. Results can be used to make an indicative assessment of the amount of Hg bound to SPM which is transported in and out of the lagoon basin following the action of tidal fluxes. A simple estimation provides a negative budget for the Grado lagoon sub-basin which loses between 0.14 and 1.16kg of PHg during a tidal semi-cycle. This conclusion is in agreement with the evidence of morphological deterioration which has emerged from recent studies on the lagoon environment, and which testifies to a current sedimentary loss from the lagoon into the northern Adriatic Sea.

Methylmercury Biogeochemistry in Freshwater Ecosystems: A Review Focusing on DOM and Photodemethylation.

Mercury contamination is a growing concern for freshwater food webs in ecosystems without point sources of mercury. Methylmercury (MeHg) is of particular concern, as this is the form of mercury that crosses the blood-brain barrier and is neurotoxic to organisms. Wetlands and benthic sediments have high organic content and low oxygen availability. Anaerobic bacteria drive the metabolic function in these ecosystems and subsequently can methylate mercury. The bioavailability of MeHg is controlled by physicochemical characteristics such as pH, binding affinities, and dissolved organic matter (DOM). Similarly, photodemethylation is influenced by similar characteristics and thereby the two processes should be studied in tandem. The degradation of MeHg through photochemistry is an effective destruction mechanism in freshwater lakes. This review will highlight the uncertainties and known effects of DOM on subsequent photoreactions that lead to the occurrence of mercury photodemethylation and reduction in mercury bioavailability in freshwater ecosystems.

ICP Analyses from the Cinnabar-Mercury Occurrence at Azogues (Loma Guashon), Ecuador: Ancient Industrial Uses and Human Health Implications

ICP (Inductively Coupled Plasma) analyses of the Cretaceous marine sandstones at the Azogues (Loma Guashon), Ecuador cinnabar-mercury occurrence gave 11 - 113 ppm Hg. However, the ancient Azogues mines have been well documented previously, for example: 1) a 1799 hand drawn map “Plan del Cerro Mineral de Azogue” shows numerous adits; 2) during Colonial time, Cuenca founder, Gil Ramirez Davalos was owner of the mercury mines; 3) in the late 1800s, Teodoro Wolf described well-worked adits at Guashon and samples with 0.5% Hg; and more recently, 4) the Metallogenic Map of Ecuador shows the mercury occurrence at Azogues. Mineral resource assessment of the Azogues occurrence is important to regional archaeological studies of resource availability and ancient use of cinnabar as a pigment and as a source of mercury for gold amalgamation before the arrival of the Europeans, and possibly later, for silver amalgamation, during Colonial time.

Spatial and Ontogenetic Variation in Mercury in Lake Superior Basin Sea Lamprey (Petromyzon marinus).

Mercury concentrations were measured in eggs, larvae, and adult spawning-phase sea lampreys (Petromyzon marinus) collected in tributaries of Lake Superior to investigate spatial and ontogenetic variation. There were significant differences in mercury concentrations between all three life stages, with levels highest in adults (mean = 3.01µg/g), followed by eggs (mean = 0.942µg/g), and lowest in larvae (mean = 0.455µg/g). There were no significant differences in mercury concentrations by location for any life stage or by sex in adults. Mercury was not correlated with adult or larval lamprey length or mass. Mercury levels in adult lampreys exceeded U.S. and Canadian federal guidelines for human consumption. Mercury concentrations in all life stages exceeded criteria for the protection of piscivorous wildlife, posing a threat to local fish, birds, and mammals. High mercury levels in adult lampreys combined with their semelparous life history make them a potential source of lake-derived mercury to spawning streams.

Natural stable isotopic compositions of mercury in aerosols and wet precipitations around a coal-fired power plant in Xiamen, southeast China

In this study, samples of 18 wet precipitations (WPs) and 38 aerosols were collected around a coal-fired power plant (CFPP) located in Xiamen, southeast China, which was equipped with a seawater flue gas desulfurization system. Total particulate mercury (TPM) in aerosol samples, and total mercury (WP-TM), dissolved mercury (WP-DM) and particulate mercury (WP-PM) in WP samples were analyzed for the natural isotopic compositions of mercury. For the first time, both mass dependent fractionation (MDF) and mass independent fractionation of odd (odd-MIF) and even (even-MIF) isotopes of WP-DM and WP-PM were reported and discussed. Both WP-TM and TPM displayed negative MDF and slightly positive even-MIF. Negative odd-MIF was observed in TPM and WP-PM, whereas positive odd-MIF was observed in WP-TM and WP-DM. It was found that the mercury budget in WP-PM samples was mainly controlled by atmospheric particles. Potential sources of mercury in samples were identified via analysis of mercury isotopic signatures and meteorological data with the NOAA HYSPLIT model. The results showed that TPM and WP-PM in solid samples were homologous and the isotopic compositions of WP-TM depended on those of WP-DM. The ratios of Δ199Hg/Δ201Hg resulting from photochemical reactions and positive Δ200Hg values (from -0.06‰ to 0.27‰) in all samples indicated that the mercury coming from local emission of the CFPP together with long-distance transportation were the two main contributing sources.

Usage Proposal of a common urban decorative tree (Salix alba L.) to monitor the dispersion of gaseous mercury: A case study from Turda (Romania)

Closure of chloralkali plants poses a risk of abandonment of important sources of gaseous mercury. In this work, an assessment has been made of the potential for pollution from one of these plants in the proximity of a densely populated town in central Romania.The work involved a comparison between two major types of monitoring survey: biomonitoring using leaves of a tree common in urban environments; and LUMEX-based gaseous mercury analysis. For biomonitoring, 21 samples from Salix alba L. trees were taken in Turda area. Atmospheric monitoring included two mobile surveys and one at a fixed location.The results from both monitoring systems show similarities in gaseous mercury dispersion patterns, with high mercury contents clearly related to the presence of the chloralkali plant. Particularly high levels were measured in the following situations: (i) in a ‘smog’ area related with thermal inversion and (ii) during dusk. Direct monitoring suffered from limitations in acquiring information, especially in a medium-long time range, but biomonitoring provided these data and is capable of covering studies on temporary trends or comparative assessments between European cities with contrasting gaseous mercury sources.The thermal speciation of mercury contents indicates that the whole fraction of mercury in leaves corresponds to organic mercury. This finding implies a non-reversible uptake process, which in turn ensures the applicability of this technique to biomonitor long-term exposure.As a conclusion, the assessment of gaseous mercury pollution based on biomonitoring using S. alba has proven to be a useful, reliable and cost-effective methodology.

Mercury flux from salt marsh sediments: Insights from a comparison between 224Ra/228Th disequilibrium and core incubation methods

In aquatic environments, sediments are the main location of mercury methylation. Thus, accurate quantification of methylmercury (MeHg) fluxes at the sediment-water interface is vital to understanding the biogeochemical cycling of mercury, especially the toxic MeHg species, and their bioaccumulation. Traditional approaches, such as core incubations, are difficult to maintain at in-situ conditions during assays, leading to over/underestimation of benthic fluxes. Alternatively, the 224Ra/228Th disequilibrium method for tracing the transfer of dissolved substances across the sediment-water interface, has proven to be a reliable approach for quantifying benthic fluxes. In this study, the 224Ra/228Th disequilibrium and core incubation methods were compared to examine the benthic fluxes of both 224Ra and MeHg in salt marsh sediments of Barn Island, Connecticut, USA from May to August, 2016. The two methods were comparable for 224Ra but contradictory for MeHg. The radiotracer approach indicated that sediments were always the dominant source of both total mercury (THg) and MeHg. The core incubation method for MeHg produced similar results in May and August, but an opposite pattern in June and July, which suggested sediments were a sink of MeHg, contrary to the evidence of significant MeHg gradients between overlying water and porewater at the sediment-water interface. The potential reasons for such differences are discussed. Overall, we conclude that the 224Ra/228Th disequilibrium approach is preferred for estimating the benthic flux of MeHg and that sediment is indeed an important MeHg source in this marshland, and likely in other shallow coastal waters.

Atmospheric wet deposition of mercury to the Athabasca Oil Sands Region, Alberta, Canada

Event-based wet deposition of mercury, Hg, was collected in a study from 2010 to 2012 at the AMS 6 site 30 km from the nearest oil sands industrial facilities in Fort McMurray, AB, Canada. For the entire study period (21 months), volume weighted mean, VWM, concentration was 11.2 ng L−1 while total Hg wet deposition was 2.3 μg m−2. Mercury enrichment factors ranged from 10 to 5419 in rainfall, 45–599 in mixed precipitation and 73–266 in snowfall samples. This suggests that emissions from local anthropogenic sources of mercury were available for scavenging especially in rainfall. During a 3-day period in June 2011, there was a 5 to 24-fold increase in mercury enrichment in rainfall samples compared to previous samples. Meteorological analysis during this period provides evidence that mercury containing emissions in smoke from forest fires were transported by winds and subsequently deposited in rainfall received at the sampling site thereby causing enrichment. The magnitude of mercury wet deposition at the AMS 6 site was one of the lowest observed fluxes compared to measurements made elsewhere in the United States and Canada, most likely limited by the low precipitation depths that occurred at this semi-arid location. The reduced wet deposition suggests that mercury dry deposition may be significant in the Athabasca Oil Sands Region, AOSR, and should be addressed in future studies.

Use of multiple tools including lead isotopes to decipher sources of ozone and reactive mercury to urban and rural locations in Nevada, USA

Ambient air particulate matter (<2.5μm in diameter) samples were collected on two different filter types in 2014 and 2015 over 24h periods and analyzed for reactive mercury (gaseous oxidized mercury+particulate bound mercury) concentrations and lead isotopes to determine sources of pollution to three sites in Nevada, USA. Two sites were located on the western edge of Nevada (Reno, urban, 1370m and Peavine Peak, rural, high elevation, 2515m); the third location was ~485km east in rural Great Basin National Park, NV (2061m). Reactive mercury samples were collected on cation exchange membranes simultaneously with lead samples, collected on Teflon membranes.Lead isotopic ratios have previously identified trans-Pacific lead sources based on the 206/207 and 208/207 lead ratios. Influence from trans-Pacific air masses was higher from March to June associated with long-range transport of pollutants. Spring months are well known for increased transport across the Pacific; however, fall months were also influenced by trans-Pacific air masses in this study.Western North American background ozone concentrations have been measured and modeled at 50 to 55ppbv. Median ozone concentrations at both rural sites in Nevada were within this range. Sources leading to enhancements in ozone of 2 to 18ppbv above monthly medians in Nevada included emissions from Eurasia, regional urban centers, and global and regional wildfires, resulting in concentrations close to the USA air quality standard. At the high elevation locations, ozone was derived from pollutants being transported in the free troposphere that originate around the globe; however, Eurasia and Asia were dominant sources to the Western USA.Negative correlations between reactive mercury and percent Asian lead, Northern Eurasia and East Asia trajectories indicated reactive mercury concentrations at the two high elevation sites were produced by oxidants from local, regional, and marine boundary layer sources.

Effect of thimerosal on thyroid hormones metabolism in rats.

Mercury seems to exert an inhibitory effect on deiodinases, but there are few studies using Thimerosal (TM) as the mercury source. We aimed to elucidate the effect of TM on thyroid hormones peripheral metabolism. Adult Wistar female rats received 0.25 µg or 250 µg TM/100 g BW, IM, twice a week, for a month. We evaluated serum total T3 and T4, D1 activity using 125I-rT3 as tracer, and D2 activity using 125I-T4. NADPH oxidase activity was measured by Amplex-red/HRP method and mRNA levels by real time PCR. Serum T4 was increased and T3 decreased by the greatest dose of TM. Even though D1 activity in pituitary and kidney was reduced by the highest dose of TM, hepatic D1 activity and D1 mRNA levels remained unchanged. D2 activity was also significantly decreased by the highest dose of TM in all CNS samples tested, except cerebellum, but D2 mRNA was unaltered. mRNA levels of the tested NADPH oxidases were not affected by TM and NADPH oxidase activity was either unaltered or decreased. Our results indicate that TM might directly interact with deiodinases, inhibiting their activity probably by binding to their selenium catalytic site, without changes in enzyme expression.

Historical releases of mercury to air, land, and water from coal combustion

Coal combustion is one of the largest contemporary sources of anthropogenic mercury (Hg). It releases geologically sequestered Hg to the atmosphere, and fly ash can contaminate terrestrial and aquatic systems. We estimate that coal combustion has released a cumulative total of 38.0 (14.8–98.9, 80% C.I.) Gg (gigagrams, 109g or thousand tonnes) of Hg to air, land, and water up to the year 2010, most of which (97%) has occurred since 1850. The rate of release has grown by two orders of magnitude from 0.01Ggyr−1 in 1850 to 1Ggyr−1 in 2010. Geographically, Asia and Europe each account for 32% of cumulative releases and an additional 18% is from North America. About 26.3 (10.2–68.3) Gg, 71% of the total, were directly emitted to the atmosphere, mostly from the industrial (45%) and power generation (36%) sectors, while the remainder was disposed of to land and water bodies. While Europe and North America were the major contributing regions until 1950, Asia has surpassed both in recent decades. By 2010, Asia was responsible for 69% of the total releases of Hg from coal combustion to the environment. Control technologies installed on major emitting sources capture mainly particulate and divalent Hg, and therefore the fraction of elemental Hg in emissions from coal combustion has increased over time from 0.46 in 1850 to 0.61 in 2010. About 11.8 (4.6–30.6) Gg of Hg, 31% of the total, have been transferred to land and water bodies through the disposal or utilization of Hg-containing combustion waste and collected fly ash/FGD waste; approximately 8.8Gg of this Hg have simply been discarded to waste piles or ash ponds or rivers.

Mercury release during thermal treatment of two Chinese coal gangues.

The utilization of coal gangue in power plants has become a new anthropogenic discharge source of mercury and attracted much concern in China. It is crucial to obtain the information about the mercury release during thermal treatment of coal gangue. In this study, the mercury release behavior of two coal gangues selected from two power plants were studied under different thermal treatment conditions of heating rate, residence time, and atmosphere. The results of mercury release profile show that the specified release temperature ranges for the different modes of occurrence of Hg are scarcely affected by the heating rate of 10, 20, and 40°C/min. A higher heating rate could promote the Hg release to some extent. The mercury release ratio gradually increases with the extension of residence time for both coal gangues. The oxidizing environment has a positive effect on mercury release <600°C and has a minor effect >600°C. Mercury in coal gangue is more volatile than coal gangue matrix and the mercury in GD coal gangue is more easily released out than that in ED coal gangue.

Water Consumption as Source of Arsenic, Chromium, and Mercury in Children Living in Rural Yucatan, Mexico: Blood and Urine Levels.

Studies investigating the correlation between metal content in water and metal levels in children are scarce worldwide, but especially in developing nations. Therefore, this study investigates the correlation between arsenic, chromium, and mercury concentrations in drinking and cooking water and in blood and urine samples collected from healthy and supposedly non-exposed children from a rural area in Yucatan, Mexico. Mercury in water shows concentrations above the recommended World Health Organization (WHO) value for drinking and cooking water. Also, 25% of the children show mercury in urine above the WHO recommended value. Multivariate analyses show a significant role for drinking and cooking water as a vector of exposure in children. Also, the factor analysis shows chronic exposure in the case of arsenic, as well as an ongoing detoxification process through urine in the case of mercury. Further studies should be done in order to determine other potential metal exposure pathways among children.

Mercury speciation and mobility in soils of industrial areas in the Baikal region, Southern Siberia, Russia

Mercury speciation and mobility in soils as a result of the chlor-alkali and metallurgy industries in Baikal region was investigated. In the period from 1973 to 1998, chlorine and alkali at the plant were produced using metallic mercury. Within the period of plant operation, the total mercury emissions release to the environment amounted to 1327 tons. The former Angarsk metallurgic plant for the production of arsenic is another technogenic source of mercury. The plant was shut down in 1949, but the technogenic dumps with high concentrations of arsenic, mercury and another heavy metals were located in the town for more than 60 years. These plants are located on the banks of the Angara River and are significant sources of technogenic mercury for the environment of the Baikal region. Mercury speciation was studied in soils near these plants. Mercury species were extracted by sequential extraction, and included water-soluble, acid-soluble, organic, tightly bound and sulfide fractions. High mercury concentrations were found in organic (41–61%) and tightly bound (38–56%) fractions in soils near the chlor-alkali plant. For the metallurgical plant soils, mercury was mainly found in the tightly bound (40–64%) and sulfide (31–51%) fractions. Mercury concentrations in mobile water and acid-soluble fractions of soils were low (0.17–2.27 and 0.04–1.06%, respectively). Such mercury distribution in the fractions was dependent on the primary mercury species that entered the soils from the two technogenic sources. The results indicate high mercury immobilization in soil and low potential bioavailability by plants.

The associations between blood mercury levels and shark meat intake among workers in Gyeongsangbuk-do

BackgroundShark meat is used as sacrificial food in Gyeongsangbuk-do, and is a major source of dietary mercury. This study aimed to evaluate the effects of shark meat intake or the ritual of Jesa on blood mercury levels within workers living in Gyeongsangbuk-do.MethodsThis study was conducted from September 2016 to October 2016 in two cities of Gyeongsangbuk-do. To compare the differences between urban and rural areas, two workplaces each in Daegu as the urban area and Yeongcheon as the rural area were selected. General characteristics and characteristics related to shark meat consumption of the workers were acquired by personal interviews during their health examination. Blood mercury concentrations were analyzed by the gold amalgamation method using a direct mercury analyzer (DMA-80; Milestone Inc., Shelton, CT, USA).ResultsThe shark consumption group had a higher blood mercury concentration than the non-consumption group. The levels of blood mercury increased with the frequency, annual intake, as well as most recent date of shark meat consumption. Moreover, the levels of mercury in blood increased according to the annual frequency of participation in Jesa (times per year) and the annual frequency of shark meat consumption during Jesa (times per year).ConclusionsShark meat intake and the ritual of Jesa contributed to an increase in the blood mercury levels of workers in Gyeongsangbuk-do. Therefore, it is necessary to evaluate dietary exposure, occupational as well as other factors that may influence blood mercury concentrations in workers during their health examination, particularly in regions with high mercury exposures.

The abundance, distribution and speciation of mercury in waters and sediments of the Adriatic Sea

This review focuses on mercury speciation in the Adriatic Sea, a marginal sea of the Mediterranean, which represents its distinct biogeochemical subunit due to anthropogenic mercury loadings. The current knowledge about mercury cycling in the Adriatic is presented through an overview of the state of the art of research in this area: temporal and spatial distributions and occurrence of mercury species in seawater and sediment, and chemical transformations. We summarised research results of mercury speciation in order to describe its presence and fate in the Adriatic Sea. The Adriatic Sea represents a net source of mercury to the Mediterranean Sea due to the highest total mercury concentrations observed in the North Adriatic Sea and the highest methylmercury concentrations in the South Adriatic Pit. However, the biogeochemical cycle of mercury is not completely known and our understanding of mercury transport between compartments and its (bio)transformations is limited. Future research needs to focus on microbial and chemical processes of mercury transformations to improve our understanding of the impacts of mercury contamination on the environment and human health in the Adriatic Sea.

Mercury evidence for pulsed volcanism during the end-Triassic mass extinction

The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (∼201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this apparent pulsing was a local feature, or if pulses in the intensity of CAMP volcanism characterized the emplacement of the province as a whole. Here, six geographically widespread Triassic-Jurassic records, representing varied paleoenvironments, are analyzed for mercury (Hg) concentrations and Hg/total organic carbon (Hg/TOC) ratios. Volcanism is a major source of mercury to the modern environment. Clear increases in Hg and Hg/TOC are observed at the end-Triassic extinction horizon, confirming that a volcanically induced global Hg cycle perturbation occurred at that time. The established correlation between the extinction horizon and lowest CAMP basalts allows this sedimentary Hg excursion to be stratigraphically tied to a specific flood basalt unit, strengthening the case for volcanic Hg as the driver of sedimentary Hg/TOC spikes. Additional Hg/TOC peaks are also documented between the extinction horizon and the Triassic-Jurassic boundary (separated by ∼200 ky), supporting pulsatory intensity of CAMP volcanism across the entire province and providing direct evidence for episodic volatile release during the initial stages of CAMP emplacement. Pulsatory volcanism, and associated perturbations in the ocean-atmosphere system, likely had profound implications for the rate and magnitude of the end-Triassic mass extinction and subsequent biotic recovery.

Characteristics of Mercury Emissions from Modern Dry Processing Cement Plants in Chongqing

Three typical modern dry processing cement plants in Chongqing were chosen to investigate mercury emission characteristics and its source and fate through a mercury mass balance method by analyzing mercury contents in all input and output materials. The results showed that limestone was the main source of mercury in three cement plants followed by coal, and their mercury concentrations were (0.025±0.001)-(0.032±0.002) mg·kg-1and (0.080±0.002)-(0.110±0.012) mg·kg-1, respectively. The highest mercury level in all required input materials was (0.447±0.007)-(0.525±0.009) mg·kg-1 for gypsum, while the mercury content of other raw materials were very low. Most of the mercury released from these cement plants entered into flue gas, and the mercury of gypsum entered into cement. The mercury emission fluxes were calculated to be (73.42±8.10)-(215.18±10.75) g·d-1 in these three selected plants. The mercury emission factors for clinke and cement (EFclinker and EFcement) were (0.016±0.001)-(0.049±0.001) g·t-1 and (0.011±0.000)-(0.036±0.001) g·t-1, respectively, which were significantly lower than that employed in cement industry according to the foreign mercury emission factors in the past.