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Mercury in marine biota has been extensively studied across Inuit Nunaat because it bioaccumulates and biomagnifies in high trophic level species, such as the beluga whale (Delphinapterus leucas), or qilalugaq in Inuktut. Qilalugaait (pl) are a staple in many coastal Inuit communities, including Tuktoyaktuk, Northwest Territories and Arviat, Nunavut. We examine how total mercury (THg) concentrations in two beluga populations are influenced by biased sampling resulting from local harvester preferences. We examined historical THg in skin, muscle, and liver (1980's to 2022) together with local qualitative interviews from two beluga-harvesting communities. Age and length bins were used to compare similar sized and aged whales between locations, where males (350 - 400 cm, and 20-30 years) and females (330-400 cm, and 15-30 years) were segregated. The interviews revealed distinct preferences whereby harvesters in Tuktoyaktuk actively sought larger (length) male whales, whereas harvesters in Arviat, selected wide and even range across size and sex. These local preferences were also evident in the historical dataset, with the median age and lengths were 31 years and 389.0 cm in Tuktoyaktuk (n = 461) and 23 and 336.0 cm in Arviat (n = 146). For males, mean and median THg concentrations were higher in beluga harvested from Tuktoyaktuk than Arviat in all three tissues with age and lengths combined, yet in the selected age and length bins, there was no difference in mean and median THg in the muscle tissue, and in median liver THg. There were significant differences in mean and median skin THg and in mean liver THg concentrations between males. In female whales, THg concentrations did not differ between Tuktoyaktuk and Arviat (in ages and lengths combined and in selected age bins across all tissues), excluding median muscle THg concentration. This study indicated that differences in THg concentrations that were previously observed resulted from hunter preferences in these two communities.

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Quantification mercury (Hg) pools in forests is crucial for understanding the Hg assimilation, flux and even biogeochemical cycle in forest ecosystems. While several investigations focused on Hg pools among broad-leaved, coniferous and mixed forests, there was still absent information on alpine forest. We sampled soil, moss and various tissues of the dominant Qinghai spruce (Picea crassifolia Kom.) to investigate Hg concentrations and pools, and assess Hg accumulation dynamics in the Qilian Mountains, northwestern China. The mean Hg concentration increased in the following order: trunk wood (1.8 ± 0.7 ng g-1) < branch (4.6 ± 0.8 ng g-1) < root (12.2 ± 2.9 ng g-1) < needle (19.3 ± 5.6 ng g-1) < bark (28.7 ± 9.0 ng g-1) < soil (34.1 ± 7.7 ng g-1) < litterfall (42.9 ± 2.9 ng g-1) < moss (62.5 ± 5.0 ng g-1). The soil contained Hg pools two orders of magnitude higher than vegetation and accounted for 92.2 % of the total Hg pool in the alpine forest ecosystem. Moss, despite representing only 2.7 % of total vegetation biomass, contained a disproportionate 16.7 % of the Hg pool. Although species-specific, aboveground spruce tissues exhibited higher Hg pools in alpine forests compared to other forests in China and America. The dynamic accumulation indicated that increasing atmospheric Hg concentration and enhancing tree productivity contributed to rising Hg assimilation in remote alpine forests, particularly after the 1960s. Our results highlight the relatively high levels of Hg pools in aboveground tree tissues of alpine forest and reveal a significant increase in Hg accumulation. We recommend that when assessing Hg dynamics in forest ecosystems, it is crucial to consider both the variability in atmospheric Hg exposure levels and the forest productivity.

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Forests are important sinks of atmospheric mercury. Quantifying mercury pools in forest ecosystem tissues are essential for understanding the global mercury cycle. To reveal the characteristics of Hg concentration and Hg pool distribution in natural forests at different ages, samples from the vegetation layer, organic horizons, coarse wood debris, and mineral soil layers were collected in young forest, middle forest, near-mature forest, and mature forest of Larix gmelinii forests at the Daxing'an Mountain. The results showed that there were differences in the absorption and accumulation of Hg by different tree species and tissues. In Larix gmelinii, the concentration of Hg followed the order of bark > branch > leaf > root > core, whereas in Betula platyphylla, the order was bark > leaf > branch > root > core. The mercury concentration in the organic horizons increased gradually with the decomposition process. There were no obvious regular patterns in the mercury concentrations of each tissue in different age groups Larix gmelinii forests. Furthermore, total biomass mercury pools (overstory, shrub layer, herb layer, moss layer, and coarse woody debris （CWD）) in the young, middle, near-mature, and mature forests of Larix gmelinii forests at Daxing'an Mountain were estimated to be 99.0 µg m-2，207 µg m-2，207 µg m-2 and 194 µg m-2, respectively. On ecosystem scale, total mercury pools were 16.9 mg m-2 (young), 27.5 mg m-2 (middle), 17.0 mg m-2 (near-mature), and 11.8 mg m-2(mature). The mineral soil mercury pool accounts for 94.0%-98.1% of the total ecosystem mercury pool, and its mercury pool proportion gradually decreased with the increase in forest age. These obtained results are quite valuable for further assessing the role of forest ecosystems in the atmospheric mercury cycle and estimating potential mercury emissions from biomass burning during forest wildfires.

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To understand the mercury (Hg) biogeochemical cycle in alpine regions under global warming, it is critical to identify the distribution and sources of Hg in aquatic ecosystems of the Tibet Plateau. The spatial distribution pattern and potential sources of Hg species including total mercury (THg), particulate mercury (PHg), and dissolved mercury (DHg) were investigated in surface waters of the Yangtze and Yellow River source basins during the wet season. The results showed that average ρ(DHg) in surface water of the Yangtze and Yellow River source basins were comparable[(2.96±1.26) ng·L-1 and (2.47±0.83) ng·L-1, respectively], whereas the average ρ(THg)[(10.69±11.14) ng·L-1] and ρ(PHg)[(8.46±11.41) ng·L-1] in the source basin of the Yangtze River were significantly higher than that in surface water of the Yellow River source basin[(3.37±2.03) ng·L-1 and (1.13±1.02) ng·L-1, respectively]. It is worth noting that the ecological risk of Hg in the study area was limited because of low Hg concentration and methylation level. In addition, the correlation analysis illustrated that the THg was mainly concentrated by PHg in the source basin of the Yangtze River. Specifically, the concentration variations in Hg were mainly affected by the input of glacier meltwater, soil erosion, and precipitation. By contrast, the main species of Hg in the source basin of the Yellow River was DHg, the distribution pattern of which was mainly controlled by DOC. Spatially, a significant negative correlation was found between ρ(PHg) and longitude in the source basin of the Yangtze River (R2=0.46, P<0.01). The spatial distribution differences of river slope and soil erosion intensity were identified as the key factors leading to the decreasing trend of ρ(PHg) and ρ(THg) along the river flow in the source basin of the Yangtze River. The results of the PMF model further demonstrated that in the surface waters of the source regions of the Yangtze and Yellow Rivers, 51.4% of Hg derived from long-distance atmospheric deposition, 38.8% from erosion of soil rock or sediment via stream flow, and 9.7% from soil runoff or seepage input.

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This study aimed to quantify the amount of total mercury in bivalves Anadara tuberculosa supplied from Esmeraldas Province and sold in markets in the Metropolitan District of Quito, Ecuador. The determined total mercury concentration was compared to the permissible limits established by the European Commission and World Health Organization-Food and Agriculture Organization and health risk subsequently assessed. Sampling was conducted in five open markets and involved collecting fifteen specimens from each market. Total mercury was measured through cold vapor atomic fluorescence spectrophotometry. Results showed that samples did not exceed the total mercury threshold value (0.5 mg kg-1). However, samples of Anadara tuberculosa from the Ofelia market, which receives fresh products from Eloy Alfaro canton, contained the highest mean levels of mercury contamination, 0.055 mg kg-1. This result could be associated to the influence of illegal mining activity in this area. In addition, methylmercury potential non-carcinogenic risk for consumers exceeded the threshold limit (>1) established by the US Environmental Protection Agency. The daily consumption rate (Rclim) was determined to be 26.61-38.50 g for a child weight of 14.5 kg, and 128.44-185.84 g for an adult weight of 70 kg. Thus, consuming a higher amount of Anadara tuberculosa could negatively affect human health.

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Mercury pollution is a global problem and of particular concern in high emissions areas, such as China. We studied the migratory Kentish Plover, Charadrius alexandrinus, which breeds in coastal northern/central China and the inland Qinghai Lake, and the White-faced Plover C. dealbatus, a year-round resident of coastal southern China. We measured total mercury (THg) concentrations in feather and blood samples of breeding females. We expected low levels at the remote Qinghai Lake, but we found instead that feather THg concentrations were highest there (3.89 ± 1.53 [SD] µg/g DW [n = 34]; compared to 1.29 ± 0.61 µg/g of Kentish Plover elsewhere [n = 35] and 2.08 ± 1.45 µg/g for White-faced Plover [n = 56]), a result is consistent over 2 years. When including only coastal populations in the analysis, there were no differences in THg concentrations between the two species, although White-faced Plover had more variation. Feather THg concentrations for the coastal populations are similar to other studies on plovers and sandpipers globally, with most birds under the threshold of adverse effects (3 µg/g, an estimate that itself may be too low). Nevertheless, the Qinghai Kentish Plover population has mean feather concentrations above this threshold, indicating high exposure during the nonbreeding season, and some individuals have extreme values (e.g., a bird with a blood level of 7.63 µg/g DW from Zhanjiang, south China), so further research and monitoring are needed.

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Cape monkfish (Lophius vomerinus) is one of the long-lived species and top predators in the northern Benguela region. Studies on bioaccumulation of mercury (Hg) in cape monkfish are limited. This study compared the total Hg concentration between monkfish muscle and liver tissue; and related the monkfish total Hg concentrations to fish body size and capture locations (depth and latitude). Monkfish specimens (n = 529) were collected from 2016 to 2018. The mean total Hg concentration was 0.126 ±â€¯0.005 mg/kg in muscle tissues and 0.106 ±â€¯0.005 mg/kg in liver tissues. No significant differences were observed between total Hg concentrations of muscles and liver tissues. Differences in Hg concentrations between monkfish length classes were observed. No significant correlation was found between total Hg concentrations and latitude. A significant increase of total Hg concentration with the depth was observed. The concentrations of Hg were below the World Health Organization (WHO limits for fish (0.5 mg/kg).

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OBJECTIVE: This study sought to obtain national cross-sectional data for blood mercury levels and risk factors for mercury exposure in Chinese children aged 0 to 6years to provide evidence to support preventive measures for reducing childhood blood mercury levels. METHODS: A multi-stage, stratified, clustered random sampling survey was conducted May 2013-Mar 2015. Shanghai, Jilin, Shanxi, Guangdong, Qinghai, Yunnan and Hubei, which are located in seven different geographical regions in China, were selected as the study field. A total of 14,202 children aged 0-6years participated in the study. Whole-blood venous samples (3ml) were collected from the subjects for mercury exposure assessment. The DMA-80 was applied for mercury detection, and a health questionnaire gathering information on related confounders was completed by the subjects' parents of the subjects after they received guidance from the investigators. A general linear model was used for the primary descriptive statistical analysis. Odds ratios (ORs) and 95%CIs for the risk factors were estimated using unconditional logistic regression. RESULTS: A total of 14,202 eligible samples were collected. The mean mercury level was 1.39µg/L. Other results were as follows: median 1.23µg/L, p25 0.86µg/L, p75 1.73µg/L, and GM 1.10µg/L. Of the seven geographical regions, Qinghai, in northwestern China, had a median mercury level of 0.37µg/L, which was significantly lower than the mercury level in Guangdong, in southeastern China (2.01µg/L). The median blood mercury level of children in suburban areas was 1.34µg/L, which was remarkably higher than that of children in rural areas (1.09µg/L). Dichotomous subgroups were generated using the median mercury concentration. Unconditional logistic regression analysis revealed that fish consumption may contribute to increased blood mercury levels (p<0.05). Additionally, we observed significantly positive associations between mercury concentrations and the children's anthropometric characteristics (BMI; p<0.05). CONCLUSIONS: Blood mercury concentrations among Chinese children aged 0-6years were considered low, and children who consumed more marine fish, freshwater fish and shellfish tended to have higher mercury concentrations. Our study suggests that children's growth is likely affected by the positive effects of mercury, which may have implications concerning the positive effects of fish consumption.

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Spent U-type lamps are strongly encouraged to be separately managed in Korea, because U-type lamps are categorized as a household waste and thereby could not be managed properly. Determination of mercury amount in the components of U-type lamp, such as plastics, glass tube and phosphor powder from 3 U-type lamp manufacturers (A, B and C), is carried out to estimate the mercury content in spent U-type lamps. Regardless of lamp manufacturers, the portion of mercury in phosphor powder was higher than 90%, but that in plastics and others was less than 1%. At an air flow rate of 1.0 L/min, the range of the initial mercury concentration in vapor phase for U-type lamp was between 849 and 2076 µg/m3 from 3 companies. The estimated mercury amount in vapor phase of U-type lamp was in the range from 0.206 mg for company A to 0.593 mg for company B. And the portion of mercury in vapor phase in the total amount of mercury was estimated in the range from 3.0% for company A to 6.7% for company B. Hence, it is desirable to get rid of mercury from phosphor powder in order to perform U-type lamps recycling.

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OBJECTIVES: This pilot study aimed to evaluate the effect of dental amalgam, a restorative material, on children by measuring the mercury concentration in the urine as well as the number of teeth filled with dental amalgam. METHODS: Twenty children enrolled in grades 1-4 of two elementary schools in Daegu participated in this study. One trained dentist performed oral examinations and removed amalgam restorations from the teeth with a high and low speed handpiece. In order to measure the urinary mercury concentrations, urine samples were collected from all participants at baseline and immediately and 24 hours after removal of the dental amalgam restorations. RESULTS: The mean number of teeth from which the amalgam restorations was removed was 9.8 while the mean urinary mercury concentrations at baseline, immediately, and 24 hours after removal of dental amalgam restorations were 2.66, 2.76, and 2.76 microg/g creatinine, respectively. The mean urinary mercury concentration increased consistently after amalgam restoration removal. For those participants whose removed amalgamated surfaces were more than 11, the mean urinary mercury concentration immediately after amalgam restoration removal and 24 hours after removal increased consistently but showed no significant difference. CONCLUSIONS: This study demonstrated that dental amalgam restoration was related to urinary mercury concentration, and these findings present a possibility of mercury accumulation in the body. Therefore, we suggest future longitudinal studies to ensure the safety of children exposed to mercury by establishing criteria for amalgam removal.

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OBJECTIVES: The adverse health effects of mercury in dental amalgam have not yet been clarified. This study was conducted to examine the effects of dental amalgam on the concentration of blood mercury in Korean children. METHODS: A total of 1,275 students were enrolled in the elementary school in Seoul, Incheon, and Daegu. The number and location of dental amalgam filling of teeth were ascertained by oral examination. Dietary habits-including frequency of seafood intake-and other demographic factors were obtained from the children's parents. The concentration of blood mercury was measured by an atomic absorption spectrophotometer to which a hydride generator was installed. RESULTS: The geometric mean of blood mercury concentration was 1.91 microg/L. It was found that elementary school students in Seoul and the 4th grade elementary school students have the lowest concentration of blood mercury among the study groups. Both linear and secondary linear increase of the concentration of blood mercury, depending on the number of dental amalgam fillings, were statistically significant (p-trend < 0.01, p-quadratic < 0.01). As a result of multiple regression analysis on the blood mercury concentration of elementary school students, the regression coefficient (beta) of a dental amalgam filling was found to be 0.027 (standard error = 0.014, p = 0.048). CONCLUSIONS: In children, the dental amalgam fillings were significantly contribute to the concentration of blood mercury. To accurately assess the effect of dental amalgam on the concentration of body mercury, further studies using the concentration of urine mercury are needed.

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This research was conducted to investigate the correlations between urinary mercury concentration and each independent variable related with urinary mercury levels. the urinary mercury concentrations of 543 workers exposed to metal mercury vapor in a total of 11 fluorescent lamp manufacturing factories and at the same time mercury concentrations in air were measured from June 1989 to December 1989. And annually mercury consumption per workers, mercury consumption per lamp, numbers of breakage lamps, frequency of mercury infusion, numbers of droppers, and numbers of vacuum exhaustion pumps were also investigated. The results were as follows: 1. The geometric mean of airborne mercury concentration in a total of 11 factories was 47.9 microgram/m3 (5.8~352.2 microgram/m3), six factories(54.5%) of them were exceed the threshold limit value(50.0 microgram/m3). 2. The geometric mean of urinary mercury concentration among 543 workers was 84.3 microgram/l (1.13~533.9 microgram/l), the distribution of workers by urinary mercury concentration showed that 26 workers(4.8%) were above the mercury posioning level(300 microgram/l). 3. The correlation coefficient between urinary mercury concentration and monthly numbers of breakage lamps was the highest(0.74) and next was mercury consumption per lamp (0.67), annually mercury consumption per worker(0.63) in order.

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This research was conducted to study the correlations between the airborne mercury concentration and each independent variable to detect the source of mercury contamination in a total or II fluorescent lamp manufacturing factories- The mercury concentraion in air was measured and informations about production management (operation hour, overtime, vacuum exhaustion system, number of droppers, number of vacuum exhaustion pumps, frequency of mercury infusion, mercury consumption per lamp, number of lamps producted, number of inferior lamps producted, number of breakage lamps, local exhaust ventilation system) were collected from January 1988 to March 1989. The results were as follows: 1. Among the airborne mercury concentrations according to the sampling point the highest mean concentration was 0.162mg/m3(0.016-0.635 mg/m3) at the workplace floor, and 0.074 mg/m3 at the vaccum exhaustion pump site, and 0.06 mg/m3 at the breathing zone in order. 2. The correlation between airborne mercury concentration and each Independent variable was significant in a following order; the number of Inferior lamps productedt(0.485), vacuum exhaustion syatem(-0,405), number of breakage lamps (0.344), operation hourl(0.341), number of vacuum exhaustion pumps(0.337) and local exhaust ventilation systern(0.331). 3. The result of stepwise multiple regression analysis showed that the airborne mercury consumption was affected by number of inferior lamps producted, frequency of mercury infusion, overtime, ventilator, mercury consumption amounts per lamp, local exhaust ventilation system in order. And these six variables explained 36.7% of the variance of airborne mercury concentration.

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This research was conducted to evaluate the effect of improvement in work environment and of segregation in a fluorescent lamp manufacturing factory. Among the total of 80 workers, 8 workers whose mercury concentration in urine reached a hazardous level (200-299 microgram/l) were moved to mercury free workplace. The follow-up examination for their mercury concentration in urine was done three times; on May 3, 1988, September 1, 1988 and April 3, 1989. The results were as follows: 1. Mercury concentration in the air was reduced from 0.140 to 0.107 mg/m3 in 4 months, and to 0.087 mg/m3 in one year after environmental improvement in workplace. However the level still exceeded the Threshold Limit Value. 2. The geometric mean of urinary mercury concentration among 80 workers was 173.0 microgram/l (5.1~458.6 microgram/l). The distribution of workers according to urinary mercury concentration showed that 9 workers (11.2%) were above the mercury poisoning level (300 microgram/l), 24 workers (30.0%) were 200-299 microgram/l, 35 workers (43.8%) were 50-199 microgram/l, and 12 workers (15.0%) were below 50 microgram/l. 3. Among the 24 workers whose urinary mercury concentration was 200-299 microgram/l, 8 were able to be followed up. Their mean urinary mercury concentration before segregation was 244.9 microgram/l, but decreased to 151.4 microgram/l in four months, 128.8 microgram/l in six months, and 46.8 microgram/l in one year after segregation.

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