Average Mercury Research Articles

Enrichment of Sulfate, Acidity and Mercury in Native outcropcoal, Southwest China.

The coal found in the Longtan Formation of the Late Permian is widely distributed in Southwest China, including the northwestern Guizhou, southeastern Sichuan, and northern Yunnan regions. This coal typically has a high sulfur content. Eighty-two coal samples were collected from the coal strata in 11 counties spanning this area, including underground mine coal, native outcrop coal and man-made outcrop coal. The mercury, total fluorine, total sulfur, and sulfate contents and pH values were determined. The results showed that the average mercury content in native outcrop coal was 2233ng/g, whereas that in underground mine coal was 306ng/g, and the relative enrichment factor could reach 6.6. There was no significant difference in the total fluorine content among the three types of coals; furthermore, the total sulfur content in native outcrop coal and man-made outcrop coal was higher than that in underground mine coal because of the local policy, which strictly prohibits the mining of high-sulfur coal. Native outcrop coal is acidic, with a total average pH of 3.54 and an average sulfate content as high as 13,390μg/g. In contrast, underground coal is almost neutral (average pH 7.33), with a low sulfate content (average 3221μg/g). These characterizations indicate that native outcrop coal has been subjected to long-term weathering and the mercury enrichment is likely due to migration, oxidation, and precipitation of Hg from the underground coal seam and enriched in loose and pulverized coal particles. Further investigation is needed to determine whether other outcrop areas are affected by this phenomenon.

Characteristics of Mercury Fluxes between Soil and Air in the Farming-Pastoral Ecotone of Songnen Grassland

In order to understand the characteristics and influencing factors of surface release fluxes in the typical agro-pastoral mosaic region of the Songnen grasslands of northern China, this study selected two sample plots to, respectively, represent the L. chinensis covered grassland (L), and the Z. mays covered fields (Z) in the Waizi area of Changling County, with western Jilin Province as the study area. This study investigated the atmospheric mercury (Total Gaseous Mercury (TGM)) concentrations, surface soil mercury concentrations, the gaseous elemental mercury exchange fluxes, and related environmental factors. The results showed that the TGM concentrations in two sample plots in the study area were basically the same during the summer and autumn months, but were higher in summer than in autumn, and there was a clear diurnal pattern. The average mercury concentrations in the surface soil were also higher in summer than in autumn. Furthermore, the surface soil has a clear mercury release process, and the mercury release were higher in the sheep grass field than the maize field during the same season. The mercury release fluxes in each site within the ecotone were related to the solar radiation and soil temperature values, and the effects of them on the soil mercury release were independent from one another.

Mercury in Selected Abiotic and Biotic Elements in Two Lakes in Poland: Implications for Environmental Protection and Food Safety

Mercury, which tends to bioaccumulate and biomagnify in aquatic food webs, poses a potential health risk to wildlife and to consumers of predatory fish in particular. Its concentration in biota can be high even at low environmental concentrations. Therefore, the aim of this study was to determine mercury in both abiotic (water and sediment) and biotic elements (common reed (Phragmites australis) and fish: pike (Esox lucius), bream (Abramis brama) and roach (Rutilus rutilus)) in the context of assessing the pollution of two lakes in Poland and the safety of fish consumers. The possibility of Hg biomagnification in fish was also considered. Mercury was determined by means of cold vapor atomic absorption spectrometry (CVAAS). The concentrations of Hg in water and bottom sediments of Lake Ińsko were lower than in Lake Wisola. In the bottom sediments of both lakes, a positive correlation was found between the Hg content and organic matter. The concentration of mercury in the organs of common reed did not exceed 0.017 mg/kg dry weight (dw), and its distribution can be presented as follows: root > leaves > stems > rhizomes. In fish organs from both lakes, the average mercury content did not exceed 0.086 mg/kg of wet weight (ww) and in most cases it was the highest in pike. Higher values were only observed in the muscles and skin of roach. This indicates a lack of biomagnification in the relationships between planktivorous-predatory and benthivores-predatory fish. Based on the maximum levels of mercury in fish and the calculated parameters, i.e., estimated daily intake (EDI), target hazard quotient (THQ) and tolerable weekly intake (TWI), the muscles of the examined fish were found to be safe for consumption. The average dietary exposure to total mercury (THg) and methylmercury (MeHg) was below 0.3% of the TWI.

Mercury geochemistry of marine sediments from the eastern Laptev Sea: The spatial distribution, levels, and contamination assessment

Twenty-seven sediment samples from the eastern Laptev Sea were analyzed for mercury and total organic carbon as well as grain-size distribution. The average total mercury (THg) concentrations in sediments are 29 ± 14 μg kg−1. A significant correlation of THg content with total organic carbon and clay and silt fractions was shown. The 210Pb-dated sediment core was used to evaluate the contamination degree and flux of THg in sediments from the eastern Laptev Sea. The average sedimentation rate for the all dated intervals was 0.17 cm/year. The THg flux increased from 20 to 28 μg/m2/year in the period of 1892–1950 to 53–59 μg/m2/year in the modern period of 2011–2015. According to various indices, the ecological risk from THg in studied sediment was low.

Mercury Contents in the Liver, Kidneys and Hair of Domestic Cats from the Warsaw Metropolitan Area

Mercury is a highly toxic element subject to bioaccumulation, increasing its harmful effects on living organisms over time. In the present study, total mercury contents were determined in the liver, kidneys and hair of cats from Warsaw and its suburban areas. The study took into account the influence of the age, sex and living conditions of the animals. Samples were obtained between 2014 and 2016, and mercury contents were determined by atomic absorption spectrometry (AAS). The average mercury concentrations in the tissues studied were 0.025, 0.026 and 0.030 mg∙kg−1 in the hair, kidneys and livers of the individuals tested, respectively. Higher values were recorded in animals from the city area, and an increase in this metal with the age of the cats was also found. The average contents of mercury in the tissues studied were within the range of the recommended reference values, which in this case indicates low environmental exposure of animals to mercury.

Removal of gaseous Hg0 using biomass porous carbons modified by an environmental-friendly photochemical technique

Biomass porous carbon is considered as a potential substitute to activated carbon for sorption removal of gaseous Hg0 due to renewable raw materials and wide sources. However, the lack of sufficient active sites on carbon surface is the major obstacle to its development. The common modification methods (e.g., acid/alkali, sulfide, halide, metal oxide, precious metals, etc.) have some remaining problems such as big energy consumption, high running cost, extreme operational conditions or secondary pollution. In this article, an environmental-friendly UV/H2O2 advanced oxidation process (AOP) was used to modify biomass porous carbons by producing hydroxyl radicals (·OH) to form more containing-oxygen functional groups to capture gaseous Hg0. Different modification techniques and modification parameters, process parameters affecting Hg0 removal, Hg0 sorption removal mechanisms and kinetics were studied. Result indicates that UV/H2O2 AOP modification can not only slightly raise the specific surface areas of adsorbent, but also make the containing-oxygen functional groups on adsorbent surface more abundant, which greatly strengthen the gaseous Hg0 sorption removal. The best H2O2 modification concentration and optimum operating temperature of the gaseous Hg0 sorption removal are 5 wt% and 120 °C, respectively. In the mercury removal test, the average mercury removal efficiency of WSWUV5 and RSWUV5 can reach 90.59% and 88.09% respectively. The containing-oxygen functional groups, mainly relating to C–O and –OH, and chemisorbed oxygen (O*) on porous carbon surfaces were identified as the key active sites, and chemisorption has been confirmed to play a major control role in the gaseous Hg0 sorption removal.

Determination of Mercury in Dental Hard Tissue: An in Vitro Study

The purpose of this study was to determine the levels of mercury in hard tissue from dental amalgam fillings under in vitro conditions. Methods and Results: The study included 30 human teeth that were extracted for various clinical reasons. The teeth were stored in a physiological solution until they were used. The teeth were divided into 3 experimental groups: Group 1 (n=10) – occlusal surface cavity preparation (class I according to Black); Group 2 (n=10) – proximal-occlusal surface cavity preparation (class II); and Group 3 (n=10) – mesio-occlusal-distal [MOD] surface cavity preparation. Each of these groups was divided into 2 subgroups: subgroup 1 (n=5) – amalgam fillings were not polished, and subgroup 2 (n=5) amalgam fillings were polished. The teeth were filled with amalgam, and those in subgroups 2 were polished after 24 hours. The amount of mercury released from the amalgam fillings was determined 9 months after the teeth were filled. Before chemical analysis, the teeth were irrigated 4 times over a period of 10 minutes in an ultrasonic bath. From each tooth, 250mg of the powder was mineralized with royal water (HCl+HNO3 in a ratio of 1:3) in a microwave oven, for 54 minutes. After mineralization, the samples were filtered and analyzed with inductively coupled plasma optical emission spectrometry. The average mercury level after polishing the amalgam filling was significantly smaller (P=0.032) only in Group 1. The average mercury levels in the 3 groups revealed significant differences between both the unpolished samples (one-way ANOVA F = 69.54, P < 0.001) and the polished samples (one-way ANOVA F = 110.54, P < 0.001). Group 3 with MOD surface cavity preparation was characterized by the highest mercury levels. Conclusion: The teeth with an MOD amalgam restoration are characterized by the highest mercury levels. The more mercury is released from unpolished amalgam fillings than from polished amalgam fillings in teeth with occlusal surface cavity preparation (class I according to Black).

Analysis of the results of research into the mercury content in fish and seafood during import-export operations in Ukraine for 2019–2021

The article presents the results of research on the determination of mercury in fish muscles and seafood, conducted based on the State Research Institute for Laboratory Diagnostics and Veterinary-Sanitary Examination by the Atomic Absorption Spectrometry Laboratory as systematic research in the period from 2019 to 2021. Mercury content in fish muscles was determined by atomic absorption spectrometry with direct sample injection. The study was carried out using a Milestone DMA-80 atomic absorption spectrophotometer (Italy). Certified standard samples (MERK) of mercury ion solution composition with an accredited value of 1.0 mg/cm2 were used to construct the calibration curves. The detection limits of mercury in fish and seafood are determined according to the validation data: the LOD detection limit is 0.1 μg/kg, and the LOQ detection limit is 5.0 μg/kg. During the studied period, research was carried out on 3368 samples of fish products: 2587 samples of sea fish, 161 samples of freshwater fish, 130 samples of other types of fish and seafood – 490 pieces, of which four examples of sea fish, namely fish of the tuna family, were found to exceed the maximum permissible level of mercury, which is 0.12% of the total number of studied samples. The mercury content in tuna muscles ranged from 0.356 to 1.889 mg/kg, 1.8 times higher than the MDR. It was found that the average mercury content in the muscles of freshwater fish was 0.006–0.315 mg/kg, which is significantly lower than the average mercury concentration in marine fish. The mercury concentration in the muscles of other types of fish and seafood was 0.008–0.472 mg/kg and did not exceed the regulated norms.

Ag doping Fe-Ti spinel sorbent for Hg0 removal from syngas and the mechanism investigation

A series of Ag doping Fe-Ti spinel sorbents (Ag/Fe-Ti spinel) were synthesized using co-precipitation and impregnation methods and employed to remove elemental mercury (Hg0) from syngas at high temperatures (200–350 °C). The role of H2S on Hg0 elimination over Ag/Fe-Ti spinel and the Hg0 removal mechanism were systematically investigated by experimental and theoretical methods. N2 adsorption–desorption, SEM-EDS, XRD, H2-TPR and XPS were used to characterize the physicochemical properties of samples. The synthesized Ag/Fe-Ti spinel was tested on a fixed-bed reactor for Hg0 removal from the simulated syngas and showed an average mercury removal efficiency above 90 % at 250 °C. Loading Ag effectively enhanced Hg0 removal activity in high-temperature syngas by generating Ag-Hg alloy via the amalgamation reaction. H2S played the most important role in mercury removal, by adsorbing Hg0 on Ag/Fe-Ti spinel sorbent surface to form active sulfur species. H2S-pretreatment experiments indicated that the reaction of H2S and Hg0 occurred via the Langmuir-Hinshelwood mechanism. Stability and cyclic regeneration experiments indicated that the Ag/Fe-Ti spinel had good regeneration performance and reusability. Density functional theory (DFT) calculation was performed to elucidate that strong chemisorption for H2S and HgS occurred over the Ag/Fe-Ti spinel surface with adsorption energies of −300.35 kJ/mol and −408.12 kJ/mol, respectively. XPS and DFT calculations demonstrated the Hg0 removal mechanism, which the chemisorbed Hg0 reacted with active sulfur species to generated surface-bound HgS. Both XPS and Hg0-TPD analysis certified the presence of HgS and elemental S on the surface of spent Ag/Fe-Ti spinel.

Mercury contamination level is repeatable and predicted by wintering area in a long-distance migratory seabird

The environmental presence of mercury has dramatically increased over the past century, leading to increased uptake, especially by top predators such as seabirds. Understanding the exact sources of contamination requires an individual-level approach, which is especially challenging for species that migrate. We took such an approach and located the wintering areas of 80 common terns (Sterna hirundo) through tracking, and, across years, collected feathers grown in those areas to assess their mercury levels using atomic absorption spectrometry. Although feathers of males and females did not differ in their mercury level, we found the average feather mercury level to be highest in birds wintering in the Canary Current (3.87 μg g−1), medium in birds wintering in the Guinea Current (2.27 μg g−1) and lowest in birds wintering in the Benguela Current (1.96 μg g−1). Furthermore, we found considerable inter-annual fluctuations in feather mercury levels, a within-individual repeatability of 41%, that the mercury levels of 17% of feather samples exceeded the admitted toxicity threshold of 5 μg g−1, and that the overall mean concentration of 3.4 μg g−1 exceeded that of other published reports for the species. Further studies therefore should assess whether these levels lead to individual-level carry-over effects on survival and reproductive performance.

Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl.

Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza infection, influenza antibodies and body condition in 749 individuals from 11 species of wild ducks overwintering in California. We found that the odds of prior influenza infection increased more than fivefold across the observed range of blood mercury concentrations, while accounting for species, age, sex and date. Influenza infection prevalence was also higher in species with higher average mercury concentrations. We detected no relationship between influenza infection and body fat content. This positive relationship between influenza prevalence and mercury concentrations in migratory waterfowl suggests that immunotoxic effects of mercury contamination could promote the spread of avian influenza along migratory flyways, especially if influenza has minimal effects on bird health and mobility. More generally, these results show that the effects of environmental contamination could extend beyond the geographical area of contamination itself by altering the prevalence of infectious diseases in highly mobile hosts.

Spectral identification of pyroclastic deposits on Mercury with MASCS/MESSENGER data

The pyroclastic deposits on Mercury are proof of explosive volcanism that occurred on the innermost planet of the Solar System; pyroclastic deposits are usually characterized by a central pit (vent) surrounded by a spectrally bright and red deposit (facula).The pyroclastic deposits on Mercury were mainly identified by analysing images acquired from MDIS onboard the MESSENGER mission, which revealed about 200 deposits.In this work, we focus on the identification of pyroclastic deposits on Mercury by applying spectral conditions on radiometrically and photometrically corrected data acquired by the MASCS spectrometer onboard the MESSENGER spacecraft. In addition, to further optimize the quality of the used spectra, the spectral dataset was limited by applying additional filters on observing conditions and on detector temperature.We selected 8 pyroclastic deposits, out of the 25 deposits recognized by the IAU, as a training field, and we spectrally characterized the area of the deposits by using four spectral parameters, i.e. reflectance and spectral slopes. We defined the range of variability of the parameters able to distinguish the pyroclastic deposits from the Average Mercury Terrain, and we filtered the MASCS data set by applying the spectral conditions. As a result, 52 previously recognized pyroclastic deposits and 16 new potential candidates were revealed across the portion of Mercury's surface observed by MASCS. The method also exposed extended areas such as the High-Reflectance Red Plains (HRP) in Asparangi Planitia, Borealis Planitia, and the floor of Rembrandt crater, in addition to Intermediate Terrains (IT) and Intermediate Plains (IP).Nathair Facula, Agwo Facula, Abeeso Facula and an unnamed facula that we termed “Facula 5” show a redder UV slope than most of the recognized pyroclastic deposits, possibly associated with fine regolith and/or a minor amount of Fe or C-phases in the minerals composing the facula.Among the 16 new bright and red areas, 6 potential candidates strongly suggest a nature connected to explosive volcanism and could be considered as pyroclastic deposits.

Counseling on the Impact of Mercury on ASGM Workers in Padesa Village, Lantung District as a Form of Support for the Implementation of RAD-PPM

Gold mining activities in Padesa Village are carried out traditionally, namely with simple and relatively inexpensive techniques using traditional tools and the process of binding gold from the ground using mercury. The mercury residue in the waters of the village of Padesa is 0,002 mg/L anda the average mercury content in yhe waste reservoir is 0,0695 mg/L, which means that is hhas passed the Permenkes Standard No. 32 of 2017. The strategy for implementing mercury-free alternative technology requires very large costs. This causes people to continue to choose to use coils and mercury. The urgency of this community service activity, the low knowledge and awareness of the Padesa Village community about the dangers of mercury and the management of waste water from logs. It is hoped that this service avtivity aims: (1) Increase the knowledge of the Padesa Village community, Lantung Sub-District on the impact of mercury on health and the environment, (2) Encourage the Padesa Village community, Lantung sub-district to change their behavior in managing waste water from logs, (3)Encouraging the community of Padesa Village, Lantung sub-district to take part in controlling environmental pollution caused by mercury waste, (4)Avoiding the negative impact of mercury pollution on health for workers and residents of Padesa Village. The method used is the provision of education to the community through socialization and counseling activities. The result of this activity was that the average target knowledge before being given counseling (Pretest) was 33,89% and increased to 77,22% after being is an increase (Posttest). The impact of this activity is an increase in target knowledge by 43,33% and a change in the behavior of waste water management.

Mercury concentration in the tissues of the Eurasian otter: a seasonal dependance in Slovakia.

The river otter is considered to be an important bioindicator of water clarity. This study focuses on mercury contamination within this species. Throughout the study, individuals from habitats in the foothills and surroundings of the Liptovská Mara reservoir were analyzed. Twenty-three samples of liver tissue, and twenty-two samples of hair and kidney tissue were collected. Of these samples, the average mercury concentration detected in tissues was 10.6mg/kg in guard hairs; 12.9mg/kg in under hairs; 3.3mg/kg in kidney tissue; and 4.3mg/kg in liver tissue. Analysis of certified reference material (ERM-BB186-Pig Kidney) was used to assist in the development of an accurate method for total mercury determination in animal tissues, to check the quality of measurements, and to validate the measurement method. Our method represented a high average percentage of recovery (> 95%) in the standard reference material matrix and a relative standard deviation (RSD) of 5% or less. Seasonality was determined to be a significant factor influencing the level of contamination of a given individual, both through mercury methylation within the aquatic environment and through fish ingestion by this apex semi-aquatic predator (guard hairs (p = 0.01); underfur (p = 0.04); kidney (p = 0.03); liver (p = 0.03)). Sex, location, and body size were not found to have a significant influence on heavy metal concentrations in river otters sampled in terms of season.

A study on the leakage of mercury vapor from pre-capsulated dental amalgam according to storage temperature

Objective: The aim of this study was to measure the amount of mercury vapor from one pre-capsulated dental amalgam according to the storage temperature and to investigate whether the storage temperature suggested by the manufacturer or ISO is appropriate for the storage.Materials and Methods: GK Amalgam and Ultracaps+ were used in this study. One pre-capsulated dental amalgam was placed in a Tedlar Bag and the Tedlar Bag was filled with 2 L of (4±2) ℃ air. The Tedler Bag was stored at one of the three different temperature conditions; (4±2) ℃, (23±2) ℃ and (30±2) ℃ for 24 hours. By applying Ontario hydro method, mercury vapor in the Tedlar Bag was oxidized in KMnO4-H2SO4 solvent and pre-treated, followed by analyses using the Cold Vapor Atomic Absorption Spectrophotometry. Five measurements were obtained from each group.Results: The average mercury vapor from GK Amalgam was (0.068±0.024), (0.300±0.100) and (0.544±0.133) mg/m3 , and Ultracaps+ was (0.026±0.008), (0.088±0.013) and (0.146±0.023) mg/m3 at (4±2) ℃, (23±2) ℃ and (30±2), respectively. There was a significant difference between GK Amalgam and Ultracaps+ at each temperature, and depending on the storage temperature in each material (p<0.05).Conclusions: It was evident that storage at (23±2) ℃ result in exposure of mercury vapor exceeding 340 to 1,170% of the expo-sure amount compare to the standard set by the Ministry of Labor in Korea. In order to reduce the amount of mercury vapor leaking from pre-capsulated dental amalgam, it is considered an effective method for users to periodically ventilate storage places, store them in refrigerators or keepin sealed container, and manufacturers to produce them in individual packaging.

Survey of Total Mercury Content in Fishery Products

The total mercury content in 112 fishery products, purchased from Osaka city during 2013-2018, was measured using a heating vaporization mercury analyzer. The average total mercury content in all tuna processed products was found out to be 0.115 μg/g (median=0.070 μg/g). Notably, albacore tuna exhibited the highest mercury content with an average concentration of 0.301 μg/g (median=0.296 μg/g). The total mercury concentration of the fishery products, except processed tuna and Kezuribushi (comprising shavings of dried and smoked mackerel, sardine, as well as horse mackerel), was generally low (<0.1 μg/g).The provisional tolerable weekly intake (PTWI) for mercury as set by the Joint FAO/WHO Expert Committee on Food Additives is 4.0 μg/kg body weight/week. On an average, for Japanese diet, the total weekly mercury intake from fishery products for a person weighing 50 kg was estimated to be 0.13 μg/kg body weight/week, which was 3.3% of the PTWI. These values indicate that it was not a problem to consume fishery products normally. However, albacore tuna cans have a relatively high total mercury concentration; thus, pregnant women consuming them daily may exceed the tolerable weekly intake of methylmercury (2 μg/kg body weight/week) as set by the Food Safety Commission of Japan.

Multiscale Fracturing in Medium- to Low-Rank Coals and Its Implications on Coalbed Methane Production in the Baode Area, Eastern Ordos Basin, China

Coal fractures are crucial in affecting the production of methane from coal. Multiscale fracturing and its implications on coalbed methane production have still not been fully understood. Herein, we present a case study, combining underground coal mine surveying and specimen, thin section, and scanning electron microscope observations for illustrating the ~m-, ~cm-, ~mm-, and ~μm-scale fractures present in the Baode area, eastern Ordos Basin, China. Then, the fracture connectivity is evaluated by helium permeability and mercury porosimetry measurement. The coals are mainly of semibright, semidull, and dull macrolithotypes. And main maceral composition is vitrinite, accounting for 73%~95%, with around 26% inertinite. The coals are ultralow-ash and low-ash content, belonging to high-volatile bituminous coal. The ~m scale fractures can penetrate the whole coal seams, dominant by S-N and following E-W direction, which were generated during the Yanshanian and Himalayan movements. The ~cm fractures are generally parallel to the lamina, influenced by the bright and dull coal band extension caused by the depositional differences. The ~mm fractures are mainly shown as endogenous fractures perpendicular to the lamina restricted within bright macrolithotypes. There are also ~mm fractures that are perpendicular to the lamina while penetrating dull components and fractures parallel to the lamina. The ~μm fractures are widely distributed and connect each other. Some of the fractures are filled with carbonate and clay minerals and are beneficial for methane migration, caused by hydraulic fracturing. The average mercury withdrawal efficiency of the coals was 75%. The helium permeability of the coals was between 10 × 10 − 3 and 50 × 10 − 3 μm2, indicating good fracture connectivity. The study findings, which indicated the presence of fractures of different scales in the coals studied, can be used for fully understanding the coalbed methane performance of medium- and low-rank coals.

Impacts of spectral characteristics of dissolved organic matter on methylmercury contents in peatlands, Northeast China.

Dissolved organic matter (DOM) plays an important role in promoting or suppressing methylmercury (MeHg) production in wetlands. However, the effects of DOM spectral characteristics on MeHg levels remain poorly understood in boreal peatlands in Northeast China, where is undergoing remarkable climate warming. In the present work, soil samples were collected from 22 peatlands in the Greater Khingan Mountains (GKM) to test the hypothesis that DOM spectral properties control MeHg levels. DOM was characterized by UV-Vis absorption and fluorescence spectroscopy; the three-dimensional fluorescence excitation-emission matrix (EEM) was used to unveil the origin of DOM. The average total mercury (THg) and MeHg contents were 112.76µg/kg and 12.43µg/kg across all peatlands, respectively. There was a significantly positive correlation between MeHg and the longitudespanning the range from 120 to 123°E (p < 0.05). Proportions of MeHg to THg (%MeHg), 12.3% on average, were positively correlated with DOM humification degree at p < 0.05 level. Protein-like components of DOM (P-like) were negatively related to %MeHg. DOM had positive effects on THg, and P-like components, HIX and BIX can negatively affect THg as well as MeHg. Our findings demonstrate that the spectral characteristics of DOM in soil are crucial to the content of methyl mercury in the GKM soil.

Mercury contamination levels in rivers and resident wells in Padesa and Sepukur Villages, Lantung District, Sumbawa Regency, Indonesia

Traditional mining business activities for processing gold ore in Lantung District are amalgamated using mercury (Hg) from 2015 to 2021 and are still ongoing. On average, there are ten to fifteen logs in each village, the waste being discharged only through ditches or small streams leading to rivers. Mercury that enters the aquatic environment will experience precipitation, dilution, and dispersion, absorbed by organisms living in these waters. Mercury water will be converted into methyl mercury by certain bacteria called biomethylation. In methyl-mercury (MeHg), mercury has toxic properties, firm binding, and high solubility. If consumed by biota, it will experience bioaccumulation in the body, and if consumed by humans for a long time, it can cause various types of diseases up to death. This study aims to determine mercury levels in the rivers and wells of residents in Sepukur Village and Lantung District. The research method is a survey with a sampling technique that is purposive sampling based on the distance from the logs to the residents' wells and rivers. The results showed that mercury levels in the Padesa Village river and springs were 0.002 mg/L. The average mercury level in the Sepukur Village River is 0.0004 mg/L, dug wells are 0.0014 mg/L, and drilled wells are 0.0024 mg/L. It can be concluded that the mercury levels in the springs in the village of Sepukur exceed the standard, and the river is classified in class 3. Mercury levels in the drilled wells of the residents of Sepukur Village exceed the standard, and the dug wells are still within the safe limits of the standard. Meanwhile, the river level in the Village of Sepukur is still relatively safe.

Variation of mercury fractionation and speciation in municipal sewage treatment plant: effects of mercury on the atmosphere.

The speciation of mercury in various processing units of sewage treatment in autumn and winter were studied to understand the conversion and fate of mercury. The results show that the average concentrations of total mercury (THg) in the influent were 130.5 ± 69.8ng/L and 231.3 ± 107.2ng/L in autumn and winter, respectively, and the particulate mercury was the main speciation (accounting for 59.3% and 86.9%, respectively). The proportion of dissolved mercury increased after treatment, and the total removal efficiencies of THg were 78.9% and 90.8%, respectively. The release of mercury into the atmosphere during wastewater treatment was studied for the first time. The dissolved gaseous mercury levels in the influent in autumn and winter were 0.60 ± 0.40ng/L and 0.34 ± 0.21ng/L, respectively. The average gaseous element mercury concentration in aerobic tank air was 6.34 ± 0.49ng/m3. The estimated mercury from aeration was 6.4kg per year in China. The dissolved gaseous mercury will be released to the air if the sewage treatment plant is open-air. Closed sewage treatment and collection of waste gas treatment can reduce the influence of released mercury. Mercury releases into the atmosphere in the process of sewage treatment are one of the fates of mercury in sewage. Closed sewage treatment and collection of waste gas treatment are necessary to reduce the influence of released mercury. The reactive mercury levels in the influents of autumn and winter were 1.28 ± 0.49ng/L and 1.96 ± 0.43ng/L, and these levels account for a small proportion of THg, only 1.7% and 0.8%. Hg2+ were released by the degradation of organic matter in the secondary biological treatment. The THg levels in dehydrated sludge were higher than those in biochemical sludge but lower than the maximum limit of THg in agricultural sludge.