Average Mercury Concentration Research Articles

Mercury health risk assessment among petrochemical workers in Rayong Province, Thailand

ABSTRACTBackground: Mercury occurs naturally in environment; thus, retention of fossil fuels used as feedstock in petrochemical plants is commonly found. The purpose of this study was to assess mercury health risks among petrochemical workers.Methods: In all, 188 operators and 30 office workers were recruited from 3 petrochemical plants. A total of 83 and 56 air samples were collected during normal working days and turnaround (TA) periods, respectively. Three main meals over 5 consecutive days, drinking water and spot urine samples were collected. Demographics and lifestyle data were collected using questionnaires. USEPA guidelines for mercury health risks were applied.Results: The inhalation exposure during normal working days of the two groups was lower than 5% of the Threshold Limit Value (TLV), but during TA some operators’ exposure exceeded the TLV. The average urinary mercury concentrations of the two groups did not significantly differ. The mercury concentration in the water samples was undetected and did not differ in the food samples of the two groups. Sixty-six operators presented a hazard quotient, HQinh greater than 0.2, but none of office staff, and 98 of 218 participants had hazard index, HI >1.Conclusion: Unacceptable mercury health risk among the petrochemical worker mostly cause by mercury in cooked food.

Active methods of mercury removal from flue gases

Due to its adverse impact on health, as well as its global distribution, long atmospheric lifetime and propensity for deposition in the aquatic environment and in living tissue, the US Environmental Protection Agency (US EPA) has classified mercury and its compounds as a severe air quality threat. Such widespread presence of mercury in the environment originates from both natural and anthropogenic sources. Global anthropogenic emission of mercury is evaluated at 2000 Mg year−1. According to the National Centre for Emissions Management (Pol. KOBiZE) report for 2014, Polish annual mercury emissions amount to approximately 10 Mg. Over 90% of mercury emissions in Poland originate from combustion of coal.The purpose of this paper was to understand mercury behaviour during sub-bituminous coal and lignite combustion for flue gas purification in terms of reduction of emissions by active methods. The average mercury content in Polish sub-bituminous coal and lignite was 103.7 and 443.5 μg kg−1. The concentration of mercury in flue gases emitted into the atmosphere was 5.3 μg m−3 for sub-bituminous coal and 17.5 μg m−3 for lignite. The study analysed six low-cost sorbents with the average achieved efficiency of mercury removal from 30.6 to 92.9% for sub-bituminous coal and 22.8 to 80.3% for lignite combustion. Also, the effect of coke dust grain size was examined for mercury sorptive properties. The fine fraction of coke dust (CD) adsorbed within 243–277 μg Hg kg−1, while the largest fraction at only 95 μg Hg kg−1. The CD fraction < 0.063 mm removed almost 92% of mercury during coal combustion, so the concentration of mercury in flue gas decreased from 5.3 to 0.4 μg Hg m−3. The same fraction of CD had removed 93% of mercury from lignite flue gas by reducing the concentration of mercury in the flow from 17.6 to 1.2 μg Hg m−3. The publication also presents the impact of photochemical oxidation of mercury on the effectiveness of Hg vapour removal during combustion of lignite. After physical oxidation of Hg in the flue gas, its effectiveness has increased twofold.

Hg in snow cover and snowmelt waters in high-sulfide tailing regions (Ursk tailing dump site, Kemerovo region, Russia)

Gold-bearing polymetallic Cu-Zn deposits of sulphur-pyrite ores were discovered in the Novo-Ursk region in the 1930s. The average content of mercury (Hg) was approximately 120 μg/g at the time.A comprehensive study of Hg distribution in waste of metal ore enrichment industry was carried out in the cold season on the tailing dump site and in adjacent areas. Mercury concentration in among snow particulate, dissolved and colloid fractions was determined. The maximal Hg content in particulate fraction from the waste tailing site ranged 230–573 μg/g. Such indices as the frequency of aerosol dust deposition events per units of time and area, enrichment factor and the total load allowed to establish that the territory of the tailing waste dump site had a snow cover highly contaminated with dust deposited at a rate of 247–480 mg/(m2∙day). Adjacent areas could be considered as area with low Hg contamination rate with average deposition rate of 30 mg/(m2∙day). The elemental composition of the aerosol dust depositions was determined as well, which allowed to reveal the extent of enrichment waste dispersion throughout adjacent areas. The amount of Hg entering environment with snowmelt water discharge was estimated. As a result of snowmelting, in 2014 the nearest to the dump site hydrographic network got Hg as 7.1 g with colloids and as 5880 g as particles. The results obtained allowed to assess the degree of Hg contamination of areas under the impact of metal enrichment industry.

Long-term dynamics of total mercury in surficial bottom sediments of the Volga River's reservoir in central Russia.

The long-term dynamics of mercury in bottom sediments of Uglich Reservoir were examined. Samples of the 0-5-cm surface layer of bottom sediment collected during research expeditions in 1958, 1977, 1991, and 2012 were analyzed. An increase in the average mercury concentration from 1958 to 1977 (0.440 ± 0.039 and 0.668 ± 0.065mg/kg d.w., respectively) was followed by a decrease in 2012 (0.260 ± 0.021mg/kg d.w.). During all years except 1991, a significant correlation was found between mercury content and the amount of organic matter in the sediments (r = 0.54-0.87, p < 0.01), flow velocity (r = 0.38-0.53, p < 0.01), and the rate of sedimentation in the reservoir (r = - 0.51 to - 0.69, p < 0.01). Calculations based on these results and previously published data from the study region on the density of atmospheric mercury precipitation showed that the watershed as a whole received 2.4-3.0t on an annual basis, and in the same period, the water surface received 9.7-12.8kg of mercury. The bottom sediment contained 4.31 (2012)-7.40 (1977) tons of mercury. Thus, most of the mercury in the Uglich Reservoir is assumed to originate from runoff and terrigenous sources within the watershed.

Mercury in Polish Coking Bituminous Coals

Poland emits 10.58 Mg of mercury to the atmosphere annually. More than 90% of this emission is generated by combustion and thermochemical usage of coal, including coking. In Poland, the coking industry consumes more than 12 million Mg of bituminous coals each year. Contrary to lignites and subbituminous coals used in power plants, there is not much reliable data on mercury content in Polish bituminous coals. The purpose of this paper was to determine mercury content in bituminous coals delivered to Polish coke plants and to analyze possible removal of mercury during coal cleaning processes. Eighty-two samples from 9 mines were analyzed. The average mercury content varied from 28.4 to 182.6 μg kg–1, with a mean value of 75.9 μg kg–1. The analysis of mercury content in three coals treated by (i) flotation, (ii) dense-media washing, and (iii) jig washer cleaning, revealed that mercury content in relation to net calorific value can be reduced by 27% (flotation) to 71% (dense-media washing). In addition, distr...

Assessment of mercury content in Panga (Pangasius hypophthalmus)

Panga (Pangasius hypophthalmus), originating from Vietnam, is one of the most consumed fish because of its low cost, mild taste and presentation (fillets without skin and bones). Nevertheless, due to the high levels of contamination of the rivers where it lives, and to the fact that the panga is a predator, whereby it will accumulate a higher mercury concentration, the main objectives of the present study were to evaluate the toxic risk from mercury ingestion as a result of the consumption of this fish. A total of 80 frozen panga samples natural and marinade from different commercial establishments have been analyzed using cold vapour atomic absorption spectrophotometry (CV-AAS). The results obtained show a wide range of mercury concentrations between 0.10 and 0.69 mg/kg, with an average value of 0.22 mg/kg. In addition, it has been found that the average mercury concentration in the marinated presentation (0.18 mg/kg) is higher than that obtained in the natural panga (0.16 mg/kg). However, no significant differences were found between commercial establishments or in the presentation formats, with the conclusion that they did not influence the mercury content in the samples. Assuming a weekly consumption of 350 g of panga, the contribution rate to Tolerable Weekly Intake (TWI) of mercury (4 μg/kg bw/week) is 32% and 27.5% for women and men, respectively. Based on the results obtained in this study, an exhaustive control of the mercury content in this type of fish is necessary. In addition, a consumption restriction to children will be established.

ASSESSMENT OF TOXICITY AND POLLUTION OF BOTTOM SEDIMENTS IN THE NORTHWESTERN PART OF THE BLACK SEA WITH HEAVY METALS

The northwestern shelf is the most polluted regions of Black sea. The aim of the work was to compare the levels of bottom sediment’s toxicity and pollution with heavy metals (As, Cd, Hg, Pb, Zn, Cu, Ni, Co, Cr) in the Odesa Region and seaside of Kylyia branch of the Danube (further: Seaside of the Danube). In this article we used the methodology of EU Frame Work Directive. The criterion for the quality of bottom sediments was the Target value (TV) indicator, developed in the Netherlands. Acute toxicity of bottom sediments extract on distilled water was determined using laboratory cultures of Hyalea azteca (Saussure, 1858). According of the result of biotesting, in the Odesa Region the bottom sediments of quality class 3 (moderate) were formed under the inflence of bilge waters from the roadstead of ships, trans fer of polluted water from Odesa Sea Commercial Port area and Treatment plant “Northern”. The rest of the bottom sediments of the polygon were assigned to a quality class 2 (good) and a quality class 1 (excellent). At the Seaside of the Danube the bottom sediments of quality class 3 (moderate) were formed by carrying the polluted river waters out of Bystroie (Novostambulskoie) and Starostambulskoie branches. The bottom sediments of the rest of the polygon were assigned to quality class 2 (good) and quality class 1 (excellent). The average content of mercury in the bottom sediments was 0.21∙g–1on dry mass (0.7 TV) in the Odesa Region, and 2.26 g–1 on dry mass (7.53 TV) at the Seaside of the Danube. The greatest impact to pollution of bottom sediments was made by mercury – 11.77 TV, copper 2.09 TV and cobalt – 1.50 TV in the Odesa Region, and mercury – 118.23 TV, nickel – 7.15 TV and cobalt – 4.33 TV at the Seaside of the Danube.

Mercury levels in hair samples of dentists: A comparative study in Sri Lanka.

Elemental mercury is widely used in dentistry as dental amalgam. Hair samples constitute preferred biomarkers to determine the index of mercury exposure. In the absence of any published studies, the aim of the present study was to ascertain the level of mercury in a selected sample of dentists and controls in Sri Lanka. Hair samples (.7g) from dentists working in and around the Colombo district in Sri Lanka (n=50) and controls (n=50) were digested with sulfuric acid-potassium permanganate solution, and reduced to metallic mercury with stannous chloride. Digested samples were analyzed for mercury using an atomic absorption spectrophotometer. The average mercury contents of the test and control samples (n=50 each) were 5.36±2.64ppb and 3.1±1.99ppb, respectively. Based on the estimated ratio of mercury in hair to blood in humans as 250:1, the average content of mercury in the blood of the two groups could be .02ppb and .01ppb, respectively. The number of years in dentistry and number of amalgam restorations performed within 1week were not correlated with the hair concentration of mercury. As the values of both groups were well below 10ng/mL (10ppb), within the concentrations considered as normal, mercury use was not considered an occupational hazard for dentists.

Mercury Exposure and Health Problems in Urban Artisanal Gold Mining (UAGM) in Makassar, South Sulawesi, Indonesia

Urban artisanal gold mining (UAGM) in Makassar, South Sulawesi, Indonesia, has been run by a number of urban gold workers with gold jewelry manufacture as its core activity. The wastes generated from goldsmiths’ activities were further processed by the gold smelters to recover fine gold particles. Smelting gold doré, amalgamation, and burning out the amalgam were the mercury-based gold process usually applied in their work. While working the gold workers are, therefore, potentially exposed to a source of mercury pollution that may cause health problems because of working without proper protection. The aims of this research are to characterize the process of urban artisanal gold mining with the potential mercury exposures during the process, and to assess the health of the gold workers. The results showed that the gold workers had a low educational background, but a relatively high income. The total mercury concentration of gold workers was higher than the control group. They were exposed to intoxicatingly high levels of mercury with the average total mercury concentrations of 6.6 and 10.8 µg/g in the hair of indirect and direct exposed workers, respectively. The health assessment showed that 85% of the gold workers suffered neurological symptoms, such as tremors, and 44%–56% of them experienced restricted fields of vision, slow reflexes, sensory disturbances, unbalanced rigidity, and ataxia. The results also showed that the working years have reasonable correlation with the sum of the positive findings in the 10 neurological symptoms.

Total Mercury, Methylmercury, Inorganic Arsenic and Other Elements in Meat from Minke Whale (Balaenoptera acutorostrata) from the North East Atlantic Ocean

Meat samples of 84 minke whales (Balaenoptera acutorostrata) mainly from the Barents Sea, collected between 1 May and 16 August 2011, were analyzed for total mercury, methylmercury, cadmium, lead, total arsenic, inorganic arsenic and selenium. The average total mercury concentration found was 0.15 ± 0.09 mg/kg, with a range from 0.05 to 0.49 mg/kg. The molar ratio of selenium to mercury varied between 1.0 and 10.3. Cadmium content ranged from 0.002 to 0.036 mg/kg, while the content of lead in whale meat ranged from <0.01 to 0.09 mg/kg. None of the whale samples exceeded established EU maximum levels for metals in fish muscle, but 4.8% and 6.8% of the samples exceeded Japanese maximum levels for total mercury and methylmercury, respectively, in whale meat. There was only minor variations in element concentrations between whales from different geographical areas, and cadmium was the only element were the concentration increased with increasing length.

Distribution of Mercury Concentrations in Tree Rings and Surface Soils Adjacent to a Phosphate Fertilizer Plant in Southern Korea.

This study aimed to determine mercury concentrations in tree rings and surface soils at distances of 4, 26 and 40km from a fertilizer plant located in Yeosu City, Korea. Mercury concentrations in all tree rings were low prior to the establishment of the plant in 1977 and became elevated thereafter. The highest average mercury concentration in the tree rings was 11.96ngg-1 at the Yeosu site located nearest to the plant, with the lowest average mercury concentration of 4.45ngg-1 at the Suncheon site furthest away from the plant. In addition, the highest mercury content in the surface soil was 108.51ng cm-3 at the Yeosu site, whereas the lowest mercury content in the surface soil was 31.47ng cm-3 at the Suncheon site. The mercury levels decreased gradually with increasing distance from the plant.

The distribution and occurrence of mercury in Chinese coals

Mercury is one of the most concerned hazardous elements in coals. 1018 coal samples of different coal-forming periods, coal-accumulating areas and coal ranks all over the country were collected to study the distributions of mercury in Chinese coals. The modes of occurrence of mercury were studied with float-sink experiments of 10 coals from different basins in China and correlation analyses were conducted between concentrations of mercury and maceral and sulfur contents, as well as the ash yield. The theoretic concentrations and affinities of mercury in vitrinite, inertinite, clay and pyrite were then calculated following the methods proposed by Solari. The weighted average concentration of mercury in Chinese coals is 0.154 µg/g, which is similar to that in the word coals in general. The mercury concentrations vary largely in the coals of different coal-forming period and coal-accumulating areas as geological settings play key roles in determining the geochemistry of mercury. The concentrations of mercury in coals from south and southwest China and those from North China of C3–P1 are relatively higher while those from North China of J1–2 and Northeast of J3–K1 relatively lower. The general distribution trends of mercury are very similar to that of ash yield, sulfur contents in coals. Pyrite is the dominant carrier of mercury in most coals, especially in some high-sulfur coals with abundant epigenetic pyrite formed during diagenesis and metamorphism. Mercury has higher affinity to vitrinite than to inertinite in most coals, which accords with the geological origin of macerals and geochemistry of mercury.

Mercury Exposure and Diet in Brown Pelicans (Pelecanus occidentalis) in North Carolina, USA

Methylmercury biomagnifies in food chains and can lower reproductive success in many organisms, particularly in top predators such as Brown Pelicans (Pelecanus occidentalis). To determine and compare variability in mercury exposure in this species, chick feathers and egg membranes were collected from seven breeding sites located in the remote Pamlico Sound and the more human-impacted Cape Fear River in North Carolina, USA. The average concentration of total mercury in egg membrane was 0.20 ± 0.14 ppm dry weight, a level associated with slightly reduced reproductive success in some birds, while chick feather total mercury concentrations (1.13 ± 0.02 ppm fresh weight) were well below the lowest observable adverse effects level. Mercury exposure did not vary between the Cape Fear River and Pamlico Sound, but did vary significantly among three Cape Fear River colonies. Diet analysis using δ13C and δ15N revealed minimal differences in the trophic level and foraging location of prey between islands in close proximity, indicating that differences in mercury availability are not due to differences in diet composition. The source of mercury variation in Brown Pelicans remains unknown and in need of further study.

Assessing mercury contamination in a tropical coastal system using the mussel Perna perna and the sea anemone Bunodosoma caissarum.

Total mercury concentrations in the mussel Perna perna and the sea anemone Bunodosoma caissarum were determined to assess Hg contamination in Guanabara Bay, Rio de Janeiro, Brazil, and an adjacent sea area. Concentrations in the tissues of these species were compared. Average total mercury concentrations ranged from 3.54 to 21.01μgkg-1 (wet wt.) in P. perna and from 4.51 to 23.19μgkg-1 (wet wt.) for B. caissarum. Concentrations varied according to the sampling stations. Distribution of concentrations for both species was similar along the sampling stations, and a significant correlation was observed. Results suggest that B. caissarum could be a suitable biomonitor species for mercury contamination in the study area and could be used as a complementary species for monitoring studies. Further research is, however, needed to assess how environmental conditions and other variables affect Hg concentrations in B. caissarum.

Seasonal Study of Mercury Species in the Antarctic Sea Ice Environment.

Limited studies have been conducted on mercury concentrations in the polar cryosphere and the factors affecting the distribution of mercury within sea ice and snow are poorly understood. Here we present the first comprehensive seasonal study of elemental and total mercury concentrations in the Antarctic sea ice environment covering data from measurements in air, sea ice, seawater, snow, frost flowers, and brine. The average concentration of total mercury in sea ice decreased from winter (9.7 ng L-1) to spring (4.7 ng L-1) while the average elemental mercury concentration increased from winter (0.07 ng L-1) to summer (0.105 ng L-1). The opposite trends suggest potential photo- or dark oxidation/reduction processes within the ice and an eventual loss of mercury via brine drainage or gas evasion of elemental mercury. Our results indicate a seasonal variation of mercury species in the polar sea ice environment probably due to varying factors such as solar radiation, temperature, brine volume, and atmospheric deposition. This study shows that the sea ice environment is a significant interphase between the polar ocean and the atmosphere and should be accounted for when studying how climate change may affect the mercury cycle in polar regions.

Total mercury in fresh and processed tuna marketed in Galicia (NW Spain) in relation to dietary exposure.

Mercury is a toxic trace metal, which can accumulate to levels threatening human and environmental health. In this study, contents of total mercury have been determined by ICP-MS spectrometry in fresh and processed tuna (110 samples) purchased from supermarkets in NW Spain. Mercury was present in all samples analyzed; however, only one sample of fresh tuna (1.070mgkg-1 wet weight (w.w.)) slightly exceeded the limit of the EU (1.0mgkg-1 w.w.). The average mercury concentration in processed tuna was lower than fresh, 0.306mgkg-1 w.w., and ranged from 0.080 to 0.715mgkg-1 w.w. Results were compared with literature data. In regard to the three types of preparation-packaging media for canned tuna, total Hg content was found in the following order: olive oil > natural > pickled sauce; the last showed significant statistical differences (p<0.01) with the other two preparations. Between the two evaluated canned tuna species, significant statistical differences (p=0.008) were observed and Thunnus alalunga presented a greater mean content (0.332±0.114mgkg-1 w.w.) compared to Thunnus albacares (0.266±0.171mgkg-1 w.w.).Taking into account the AESAN recommendation for adults and children, as well as the EU regulations and the tuna consumption by the Spanish population, the Hg levels obtained in this study pose no risk to consumer health. However, additional studies, a monitoring process, and efforts to reduce Hg concentration in tuna would be necessary, as well as considering other sources of exposure to Hg.

Mercury content in soils on the territory of Mezhdurechensk

The geochemical features of mercury content and distribution in the zone of coal producers have been studied (Mezhdurechensk town). Mercury content in soil (30 samples) was determined by atomic absorption method using mercury analyzer PA-915+ with pyrolytic device. Mercury content in soil samples changed from 0.12 to 0.17 mg/kg, the average value being 0.057 mg/kg. Within the town territory five zones with mercury elevated concentrations in soil were distinguished. 25-year observation period showed a 2.8 time decrease in average mercury content in soil. The major contribution to soil pollution in the urban territory was made by the two factors: local and regional. The mercury content in soil is affected by the emissions from boilers operating on coal as well as coal dust from the open pits near the town.

Mercury in Bituminous Coal Used in Polish Power Plants

Abstract Poland is a country with the highest anthropogenic mercury emission in the European Union. According to the National Centre for Emissions Management (NCEM) estimation yearly emission exceeds 10 Mg. Within that approximately 56% is a result of energetic coal combustion. In 121 studied coal samples from 30 coal mines an average mercury content was 112.9 ppb with variation between 30 and 321 ppb. These coals have relatively large contents of chlorine and bromine. Such chemical composition is benefitial to formation of oxidized mercury Hg2+, which is easier to remove in Air Pollution Control Devices. The Hgr/Qir (mercury content to net calorific value in working state) ratio varied between 1.187 and 13.758 g Hg · TJ−1, and arithmetic mean was 4.713 g Hg · TJ−1. Obtained results are close to the most recent NCEM mercury emission factor of 1.498 g Hg · TJ−1. Value obtained by us is more reliable that emission factor from 2011 (6.4 g Hg · TJ−1), which caused overestimation of mercury emission from energetic coal combustion.

Mercury emission and speciation from industrial gold production using roasting process

Gold production has been identified as an important source of anthropogenic mercury emissions. Few measurements have been conducted on the mercury emission in the industrial gold production. In this study, field measurements on mercury concentration and speciation profile in the roasting flue gas were conducted in a two-stage roasting gold smelter, and the corresponding mercury emission factors were obtained using mass balance analysis. The average mercury concentration in the feed gold concentrates was 730.0μg/kg, and the daily input mercury was 94.9g in this research. In the roasting procedure, 38.4%, 27.3% and 9.0% of input mercury was removed into the sulfuric acid, contaminated water and arsenic, respectively, while 22.8% of input mercury flowed into the cyanidation-refining procedure within the roasting residue and the dust collected from the gas cooling tower and the electrostatic precipitator. Finally, 2.3% and 5.9% of input mercury was emitted into the atmosphere with the roasting flue gas and the refining flue gas. Mercury concentration in the roasting flue gas was 4.02μg/m3, where the proportion of Hgp:Hg2+:Hg0 was 11:57:33. The balance calculation results indicated that the atmospheric mercury emission factor was 2.27×10−3gmercury/g gold produced for the tested smelter. Both the emission factor and mercury removal efficiencies of air pollution control devices are useful for development of a more accurate emission inventory.

Annual ambient atmospheric mercury speciation measurement from Longjing, a rural site in Taiwan.

The main purpose of this study was to monitor ambient air particulates and mercury species [RGM, Hg(p), GEM and total mercury] concentrations and dry depositions over rural area at Longjing in central Taiwan during October 2014 to September 2015. In addition, passive air sampler and knife-edge surrogate surface samplers were used to collect the ambient air mercury species concentrations and dry depositions, respectively, in this study. Moreover, direct mercury analyzer was directly used to detect the mercury Hg(p) and RGM concentrations. The result indicated that: (1) The average highest RGM, Hg(p), GEM and total mercury concentrations, and dry depositions were observed in January, prevailing dust storm occurred in winter season was the possible major reason responsible for the above findings. (2) The highest average RGM, Hg(p), GEM and total mercury concentrations, dry depositions and velocities were occurred in winter. This is because that China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. (3) The results indicated that the total mercury ratios of Kaohsiung to that of this study were 5.61. This is because that Kaohsiung has the largest industry density (~60%) in Taiwan. (4) the USA showed average lower mercury species concentrations when compared to those of the other world countries. The average ratios of China/USA values were 89, 76 and 160 for total mercury, RGM and Hg(p), respectively, during the years of 2000-2012.