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Strandings of striped dolphins (SD) and short-finned pilot whales (PW) in Hokkaido, northern Japan, are rare but have recently increased, probably due to global warming. We quantified δ13C, δ15N, and δ18O in muscles of SD (n = 7) and PW (n = 3) stranded in Hokkaido and compared these values with those in muscles (red meat products) of hunted SD and PW in three areas of central and southern Japan. δ18O in stranded SD, except for the calf, decreased with increasing body length (BL), whereas δ13C increased, with no BL-related changes in δ15N. The variability of δ18O (range of maximum and minimum) was larger in the stranded SD (7.5 ‰) than of the hunted SD in three areas (0.9, 1.9, and 1.4 ‰), whereas that of δ15N was smaller in the stranded SD than in the hunted SD. Similarly, the variability of δ18O was larger in the stranded PW in Hokkaido (3.3 ‰) than in the hunted PW in central Japan (1.4 ‰). The larger variability of δ18O and smaller variability of δ15N in stranded SD imply long-term sojourning in coastal waters and feeding on small amounts of limited prey species at low trophic levels before death. [ABSTRACT FROM AUTHOR]

BACKGROUND: To our knowledge, the association of maternal exposure to metallic elements with weight trajectory pattern from the neonatal period has not been investigated. OBJECTIVES: The goals of this study were to identify infant growth trajectories in weight in the first 3 y of life and to determine the associations of maternal blood levels of lead, cadmium, mercury, selenium, and manganese with growth trajectory. METHODS: This longitudinal study, part of the Japan Environment and Children Study, enrolled 103,099 pregnant women at 15 Regional Centres across Japan between 2011 and 2014. Lead, cadmium, mercury, selenium, and manganese levels were measured in blood samples collected in the second (14–27 wk gestational age) or third trimester (≥28 wk). Growth trajectory of 99,014 children was followed until age 3 y. Raw weight values were transformed to age- and sex-specific weight standard deviation (SD) scores, and latent-class group-based trajectory models were estimated to determine weight trajectories. Associations between maternal metallic element levels and weight trajectory were examined using multinomial logistic regression models after confounder adjustment. RESULTS: We identified 5 trajectory patterns based on weight SD score: 4.74% of infants were classified in Group I, very small to small; 31.26% in Group II, moderately small; 21.91% in Group III, moderately small to moderately large; 28.06% in Group IV, moderately large to normal; and 14.03% in Group V, moderately large to large. On multinomial logistic regression, higher maternal lead and selenium levels tended to be associated with increased odds ratios (ORs) of poor weight SD score trajectories (Groups I and II), in comparison with Group III. Higher levels of mercury were associated with decreased ORs, whereas higher levels of manganese were associated with increased ORs of “moderately large” trajectories (Groups IV and V). DISCUSSION: Maternal lead, mercury, selenium, and manganese blood levels affect infant growth trajectory pattern in the first 3 y of life. [ABSTRACT FROM AUTHOR]

A significant coffer in the Royal Swedish collection, inventory number HGK 406, is examined. The aim is to confirm or add new data concerning its age, provenance, and components of manufacture. The scientific analyses include microscopy of cross and thin sections, wood species identification, scanning electron microscopy with energy-dispersive X-ray spectroscopy, X−ray fluorescence microscopy, pyrolysis-gas chromatography-mass spectrometry, strontium isotope ratio measurement, and radiocarbon dating. To a lesser degree, the investigation also includes excerpting and examining historical documents. The results show that the body wood is Thujopsis dolabrata BUN 1248, a strong indication for a Japanese origin of the coffer. The urushi coating is made with sap harvested in Japan from the species Toxicodendron vernicifluum. The decorations include gold powder, red iron oxide, and cinnabar pigments. Radiocarbon dating supports dating of the coffer, also based on its style, as late sixteenth or early seventeenth century. While all the results may not stand alone, the study shows that a methodology with a multidisciplinary approach can produce new knowledge, as well as support or reject hypotheses arrived at from other kinds of sources. [ABSTRACT FROM AUTHOR]

Lifelong health is dependent on prenatal growth and development, influenced by the placental intrauterine environment. Charged with dual functions––exchange of oxygen and nutrients as well as a barrier against toxins––the placenta itself is susceptible to environmental exposure to heavy metals. To examine the use of placenta weight as a biomarker for heavy metal exposure using a large Japanese cohort of pregnant women. The placenta weight, as a biomarker of exposure to heavy metals (cadmium, lead, and mercury), was investigated using data from the Japan Environment and Children's Study (2011–2014). Selenium and manganese were included as factors directly affecting fetal growth or heavy metal toxicity. Maternal blood samples collected in the second or third trimester were used to measure heavy metal concentrations. The association between maternal blood metal concentrations and placenta weight was explored by applying Z scores and multivariable logistic regression analysis and classifying participants into quartiles (Q1, Q2, Q3, and Q4) according to metal concentrations. This study included a total of 73,005 singleton pregnant women who delivered via live births and met the inclusion criteria. The median heavy metal concentrations in the maternal whole blood were 0.662 ng/g cadmium, 5.85 ng/g lead, 3.61 ng/g mercury, 168 ng/g selenium, and 15.3 ng/g manganese. Regression analysis revealed a significant correlation between placenta weight Z scores and maternal blood metal concentrations: cadmium, 0.0660 (standard error = 0.0074, p < 0.001); selenium, −0.3137 (standard error = 0.0276, p < 0.001); and manganese, 0.1483 (standard error = 0.0110, p < 0.001). This study provides a robust examination of the association between heavy metal exposure and placenta weight. Cadmium and manganese showed a positive correlation with significant differences, whereas selenium showed a negative correlation. Essential elements notably affect placenta weight differently. No significant association was noted between lead or mercury and placenta weight. [ABSTRACT FROM AUTHOR]

The detrimental effects of high-level mercury exposure on the central nervous system as well as effects of low-level exposure during early development have been established. However, no previous studies have investigated the effects of mercury level on brain morphometry using advance imaging techniques in young adults. Here, utilizing hair analysis which has been advocated as a method for biological monitoring, data of regional gray matter volume (rGMV), regional white matter volume (rWMV), fractional anisotropy (FA) and mean diffusivity (MD), cognitive functions, and depression among 920 healthy young adults in Japan, we showed that greater hair mercury levels were weakly but significantly associated with diminished cognitive performance, particularly on tasks requiring rapid processing (speed measures), lower depressive tendency, lower rGMV in areas of the thalamus and hippocampus, lower rWMV in widespread areas, greater FA in bilaterally distributed white matter areas overlapping with areas of significant rWMV reductions and lower MD of the widely distributed gray and white matter areas particularly in the bilateral frontal lobe and the right basal ganglia. These results suggest that even normal mercury exposure levels in Japan are weakly associated with differences of brain structures and lower neurobehavioral performance and altered mood among young adults. An analysis of cognitive and brain structural data from over 900 Japanese participants reveals a relationship between increased hair mercury levels and reduced cognitive performance and reductions in gray and white matter volume. [ABSTRACT FROM AUTHOR]

The detrimental effects of high-level mercury exposure on the central nervous system as well as effects of low-level exposure during early development have been established. However, no previous studies have investigated the effects of mercury level on brain morphometry using advance imaging techniques in young adults. Here, utilizing hair analysis which has been advocated as a method for biological monitoring, data of regional gray matter volume (rGMV), regional white matter volume (rWMV), fractional anisotropy (FA) and mean diffusivity (MD), cognitive functions, and depression among 920 healthy young adults in Japan, we showed that greater hair mercury levels were weakly but significantly associated with diminished cognitive performance, particularly on tasks requiring rapid processing (speed measures), lower depressive tendency, lower rGMV in areas of the thalamus and hippocampus, lower rWMV in widespread areas, greater FA in bilaterally distributed white matter areas overlapping with areas of significant rWMV reductions and lower MD of the widely distributed gray and white matter areas particularly in the bilateral frontal lobe and the right basal ganglia. These results suggest that even normal mercury exposure levels in Japan are weakly associated with differences of brain structures and lower neurobehavioral performance and altered mood among young adults. An analysis of cognitive and brain structural data from over 900 Japanese participants reveals a relationship between increased hair mercury levels and reduced cognitive performance and reductions in gray and white matter volume. [ABSTRACT FROM AUTHOR]

Purpose: The MERCURY study aimed to evaluate the effects on visual acuity and psychological symptoms, and safety, of ranibizumab and subsequent treatment in patients with diabetic macular oedema (DME) and impaired visual acuity (VA). We report data from the prespecified 12-month interim analysis. Methods: This was a 24-month, phase 4, open-label, single-arm, prospective, observational study conducted at 20 specialised retinal centres in Japan. Participants were 209 patients with DME and impaired VA, not previously treated with either intravitreal or systemic anti-vascular endothelial growth factor (anti-VEGF) agents, who initiated ranibizumab 0.5 mg per investigator discretion. Following ranibizumab administration, patients were treated per routine clinical practice. Other treatments were allowed. The main outcome measure was the mean change in best-corrected VA (BCVA) in logarithmic minimum angle of resolution (logMAR) from baseline to month 12. An exploratory objective was to assess patients' psychological status using the Hospital Anxiety and Depression Scale (HADS). Results: The mean ± standard deviation BCVA at baseline was 0.43 ± 0.39 logMAR. The mean number of injections of ranibizumab and anti-VEGF agents from baseline to month 11 was 3.2 ± 2.0 and 3.6 ± 2.4, respectively. The BCVA change from baseline to 12 months was − 0.08 ± 0.34 logMAR (p = 0.011), showing a significant improvement; the HADS-anxiety score also decreased significantly (p = 0.001) and the depression score decreased numerically (p = 0.080). Conclusion: MERCURY study data confirm the effectiveness of real-world treatment initiated with ranibizumab in Japanese patients with DME. In addition, treatment was able to positively influence anxiety via VA improvement. [ABSTRACT FROM AUTHOR]

Approximately 30 years after mercury pollution remediation finished in Minamata Bay, we report here the present state of the subtidal benthic communities in Minamata Bay. The benthos was sampled at stations in Minamata Bay five times between July 2018 and 2019, capturing seasonal variations. Sediment characteristics were relatively stable across seasons. Sediments contained >80% silt–clay and had total organic carbon (TOC), total nitrogen (TN), and residual total Hg content (THg) approximately 20 mg/g, 2.0 mg/g, and 2.5 mg/kg (dry‐weight basis), respectively, with a C/N ratio of ~11. THg was positively correlated with TOC, whereas TOC was negatively correlated with the C/N ratio, suggesting that TOC is a proxy for sediment microalgal matter (i.e., settling phytoplankton and/or microphytobenthos), a potential food for macrobenthos. Macrobenthos abundance was very low (approximately 100 individuals/m2) and the maximum effective number of species was three in all seasons. We detected effects of THg on species richness and composition of the community, but not on total macrobenthos abundance, biomass, species diversity, or relative species abundance. The TOC gradient was significantly related to both species composition and relative abundance of the community. However, the total variation explained by both TOC and THg for community composition was low (10% at most). These results suggests that other environmental factors, such as the alteration of hydrodynamic and physicochemical regimes caused by the reclamation for pollution mitigation, may also have had a long‐lasting effect on community assembly and the present poor macrofauna levels in Minamata Bay. [ABSTRACT FROM AUTHOR]

A colony of about 30 000 pairs of Black-tailed Gull Larus crassirostris nest on Kabushima (Kabu Island), which is located on the northeast mainland coast of Japan (Sanriku Coast, Honshu Island). There, the surface-water Hg concentration is higher than in the North Pacific Ocean. We collected carcasses from the breeding colony to assess the level of mercury (Hg) contamination. We measured Hg concentrations in 10 body tissues, including the endocrine glands. The relative mercury concentrations in the tissue samples (µg/g dry weight) were as follows: adrenal glands > livers > kidneys > blood > pituitaries > gonads > breast muscles > thyroid glands > pancreases > brain stems. Correlations existed between blood mercury levels and all body tissues except for the adrenal glands. Based on these results, we suggest that mercury levels in blood may not be a good indicator for hypothalamic-pituitary-adrenal axis impacts in Black-tailed Gulls. [ABSTRACT FROM AUTHOR]

The Bepi-Colombo mission was launched in October 2018, headed for Mercury. This mission is a collaboration between Europe and Japan. It is dedicated to the study of Mercury and its environment. It will be inserted into Mercury orbit in December 2025 after a 7-year long cruise. Probing of Hermean Exosphere By Ultraviolet Spectroscopy (PHEBUS) is an ultraviolet Spectrograph and is one of the 11 instruments on-board the Mercury Planetary Orbiter (MPO). It is dedicated to the study of the exosphere of Mercury, its composition, dynamics and variability and its interface with the surface of the planet and the solar wind. The PHEBUS instrument contains four distinct detectors covering the spectral range from 55 nm up to 315 nm and two additional narrow windows at 404 nm and 422 nm. It also has a one-degree of freedom mechanism that allows observations along a cone with an half angle of 80 ∘ . This paper follows a detailed presentation of the PHEBUS instrument design that was presented by Chassefière et al. (Planet. Space Sci. 58:201–223, 2010). Here we present an update of the science objectives and measurement requirements following the results published by the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission. We also present results of the ground calibration campaigns of the flight unit that is currently on-board MPO. In the last part, we present some details of the observations that will be performed during the cruise to Mercury, such as stellar observation campaigns, interplanetary background observations and planetary flybys. [ABSTRACT FROM AUTHOR]

[Display omitted] • Prenatal selenium exposure was inversely associated with allergic disease risks. • The inverse associations were more evident for lower mercury exposure. • Selenium-rich foods but not predatory fish are recommended for pregnant women. • Selenium exposure may be beneficial for allergic disease risk reduction. Prenatal exposure to metallic elements may adversely affect early childhood health. However, more evidence is needed as population-based cohort studies are currently limited. We aimed to examine the associations between prenatal metallic (mercury, selenium, and manganese) exposure and the risk of allergic diseases in early childhood until three years of age. The data from 94,794 mother-infant pairs, who participated in the Japan Environment and Children's study, were used in this study. Prenatal metallic element exposure was measured in maternal blood collected during mid-pregnancy. The incidence of atopic dermatitis, food allergies, asthma, and allergic rhinitis during the first three years of life was prospectively investigated using self-reports of physician-diagnosed allergies. A multivariable modified Poisson regression model was used to estimate the cumulative incidence ratio and their 95% confidence intervals of allergic diseases associated with prenatal exposure to mercury, selenium, and manganese. We further evaluated the interaction between mercury and selenium exposures in this association. We confirmed 26,238 cases of childhood allergic diseases: atopic dermatitis, food allergies, asthma, and allergic rhinitis in 9,715 (10.3%), 10,897 (11.5%), and 9,857 (10.4%), 4,630 (4.9%), respectively. No association was found between prenatal mercury or manganese exposure and the risk of allergic diseases. Prenatal selenium exposure was inversely associated with atopic dermatitis, food allergies, allergic rhinitis, and any allergic diseases, but not with asthma. These inverse associations were more pronounced for lower mercury exposures than for higher exposures. Our findings suggest that prenatal exposure to selenium may be beneficial for reducing the risk of atopic dermatitis, food allergies, allergic rhinitis, and any allergic diseases in early childhood, especially with lower prenatal mercury exposure. [ABSTRACT FROM AUTHOR]

Aurihydrargyrumite, a natural Au6Hg5 phase, was found in Iyoki, Uchiko, Ehime Prefecture, Shikoku Island, Japan. Aurihydrargyrumite with a metallic silver luster occurs as a submicron- to 2 µm-thick layer on the outermost surface of the placer gold. A prismatic face may be formed by {001} and {100} or {110}. The streak is also silver white and its Mohs hardness value is ca. 2.5. Its tenacity is ductile and malleable, and its density, as calculated based on the empirical formula and powder unit-cell data, is 16.86 g⋅cm-3. The empirical formula of aurihydrargyrumite, on the basis of 11 Au + Hg, is Au5.95Hg5.05. Aurihydrargyrumite is hexagonal, P63/mcm, with the lattice parameters a = 6.9960(10) Å, c = 10.154(2) Å and V = 430.40(15) ų, which is identical with the synthetic Au6Hg5 phase. The seven strongest lines in the powder X-ray diffraction (XRD) pattern [d in Å(I/I0)(hkl)] were 2.877(29)(112), 2.434(42)(113), 2.337(100)(104), 2.234(87)(211), 1.401(39)(314), 1.301(41)(404), and 1.225(65)(217). Aurihydrargyrumite forms through the weathering of mercury-bearing placer gold by involvement of self-electrorefining. This new mineral has been approved by the IMA-CNMNC (2017-003) and it is named for its composition, being a natural amalgam of gold (Latin: aurum) and mercury (Latin: hydrargyrum). [ABSTRACT FROM AUTHOR]

The methylmercury contamination of Minamata Bay during the WWII postwar period resulted in thousands of Japanese citizens suffering horrific neurological injury. Fear and miscommunication destroyed and changed family and social structure. In addition, the Minamata poisoning caused momentous changes in the civic discourse in Japan and was an instrumental event in the democratization of the country. This manuscript describes the effects that the environmental contamination and human poising had in the transition of Japan from a feudal society to a democratic one. [ABSTRACT FROM AUTHOR]

The Carnian Pluvial Episode (CPE, ∼233 Ma) was characterized by multiple negative carbon-isotope excursions, turnovers in marine and terrestrial biota, and a Tethys-wide humid climate accompanied by abundant terrigenous sediment and freshwater input into sedimentary basins. A general temporal coincidence between the CPE and the emplacement of the Wrangellia Large Igneous Province (Wrangellia LIP) has been well documented, however, it remains unclear whether fluctuations in the intensity of the LIP's activity could be linked to the biotic and climate changes at the CPE. We here present mercury (Hg) concentration and isotope ratio records from a pelagic deep-water succession (Section N-O, Inuyama, Japan) that encompasses the CPE interval. Data reveal concurrent peaks in the Hg concentrations and ratios of Hg to TOC and enrichment factors Th EF , Al EF , Zn EF , and Ni EF implying that excess Hg loading in the sediments occurred, likely due to volcanic activity, prior to the CPE siliciclastic input. Furthermore, Δ 199 Hg values show a negative shift across the boundary between the Julian 1 and Julian 2, followed by a positive shift up to near-zero values at the Julian/Tuvalian transition. The near-zero Δ 199 Hg values at the Julian/Tuvalian boundary are associated with an increase in Hg and Cu loading, suggesting a peak of volcanogenic Hg and Cu input that may indicate a climax in the Wrangellia LIP activity. Most notably, the Julian/Tuvalian transition is where evidence of the most pronounced changes in carbonate platform evolution, biological turnover and climate change associated with the event has been highlighted. Our results therefore suggest that variations in the intensity of LIP volcanism may have played a major role in driving biotic and climate changes during the CPE. Our results provide a model for other mass extinction events associated with LIPs (e.g., the end-Permian) where low-intensity background volcanism was punctuated by high-intensity pulses, these latter being the real killers. • First record of Hg abundances and Hg isotopes from the CPE pelagic successions. • Hg enrichments are related to the multiple eruption phases of the Wrangellia LIP. • Near-zero Δ 199 Hg values coincide with excess Hg and Cu input at the Middle Carnian. [ABSTRACT FROM AUTHOR]

During 2014–2016, the Aso volcano, located in the center of the Kyushu Islands, Japan, erupted and emitted large amounts of volcanic gases and ash. Two episodes of the eruption were observed; firstly Strombolian magmatic eruptive episodes from 25 November 2014 to the middle of May 2015, and secondly phreatomagmatic and phreatic eruptive episodes from September 2015 to February 2016. Bulk chemical analyses on total mercury (Hg) and major ions in water soluble fraction in volcanic ash fall samples were conducted. During the Strombolian magmatic eruptive episodes, total Hg concentrations averaged 1.69 ± 0.87 ng g − 1 (N = 33), with a range from 0.47 to 3.8 ng g − 1 . In addition, the temporal variation of total Hg concentrations in volcanic ash varied with the amplitude change of seismic signals. In the Aso volcano, the volcanic tremors are always observed during eruptive stages and quiet interludes, and the amplitudes of tremors increase at eruptive stages. So, the temporal variation of total Hg concentrations could provide an indication of the level of volcanic activity. During the phreatomagmatic and phreatic eruptive episodes, on the other hand, total Hg concentrations in the volcanic ash fall samples averaged 220 ± 88 ng g − 1 (N = 5), corresponding to 100 times higher than those during the Strombolian eruptive episode. Therefore, it is possible that total Hg concentrations in volcanic ash samples are largely varied depending on the eruptive type. In addition, the ash fall amounts were also largely different among the two eruptive episodes. This can be also one of the factors controlling Hg concentrations in volcanic ash. [ABSTRACT FROM AUTHOR]

This study presents a method for the isotope analysis of gaseous elemental mercury (GEM, Hg 0 (g) ) using cold vapor multicollector inductively coupled plasma mass spectrometry. Isotopic compositions of Hg in the atmospheric samples collected from urban-industrial (Ichikawa) and coastal (South Boso Peninsula) regions in Chiba, Japan were investigated. Values of mass-dependent fractionation (MDF) of δ 202 Hg range from − 2.36‰ to − 0.11‰ and mass-independent fractionation (MIF) of Δ 199 Hg range between − 0.31‰ and 0.01‰. There was a rough linear correlation between δ 202 Hg values and Hg concentrations of our GEM samples ( r 2 = 0.31, p < 0.05). Also, Δ 199 Hg values were positively correlated with SO 2 concentrations; however, air mass source(s) was not identified using NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory model. We suggest that our sampling site, Ichikawa, was largely impacted by nearby anthropogenic sources (high GEM concentration with low δ 202 Hg value), and a mixing with back ground air (low GEM concentration with high δ 202 Hg value). [ABSTRACT FROM AUTHOR]

[Display omitted] • Neurodevelopmental delay until 4 years relates to maternal blood selenium ≥ 168 ng/g. • Neurodevelopmental delay until 4 years is not related to prenatal mercury level. • Mercury and selenium in cord blood are not associated with neurodevelopmental delay. Neurodevelopmental delay is associated with neurodevelopmental disorders. Prenatal metal exposure can potentially cause neurodevelopmental delays in children. This study examines whether prenatal exposure to mercury (Hg) and selenium (Se) is associated with the risk of neurodevelopmental delays in children up to 4 years of age. Children enrolled in a prospective birth cohort of the Japan Environment and Children's Study were examined. Hg and Se levels in maternal (n child = 48,731) and cord (n child = 3,083) blood were analyzed by inductively coupled plasma-mass spectrometry. Neurodevelopmental delays were assessed in children between the ages of 0.5 to 4 years using the Ages and Stages Questionnaires, Third Edition. The association between exposure and outcomes was examined using the generalized estimation equation models. In maternal blood, compared to participants with Se levels in the first quartile (83.0 to < 156 ng/g), the odds ratio (95 % confidence intervals) for problem-solving ability in children of mothers in the third (168 to < 181 ng/g) and fourth quartiles (181 to 976 ng/g) were 1.08 (1.01 to 1.14) and 1.10 (1.04 to 1.17), respectively. Furthermore, communication, gross and fine motor skills, and problem-solving delays were also observed. However, prenatal Hg levels in maternal and cord blood and Se levels in the latter were not associated with neurodevelopmental delays in children. Thus, the findings of this study suggest an association between Se levels in maternal blood and slightly increased risks of neurodevelopmental delays in children up to the age of 4 years. [ABSTRACT FROM AUTHOR]

Exposure to several metallic elements has been suggested as a risk factor for gestational diabetes mellitus (GDM), but inconsistent findings have been reported. This study aimed to examine the association between the maternal whole blood concentration of metallic elements (Hg, Pb, Cd, Mn, and Se) and GDM using the dataset of the Japan Environment and Children's Study (JECS), a nationwide birth cohort study, which was designed to examine the adverse effects of pre/post-natal exposure to hazardous environment. The data of 78,964 pregnant women who were participants of JECS were used. Blood samples were collected from the pregnant women at second/third trimester of gestation. We employed logistic regression analysis, quantile g-computation (QGC) and a distributed lag nonlinear model (DLNM) to examine the association between the blood concentration of metallic elements and the risk of GDM. The prevalence of GDM was 2.1%. In the logistic regression analyses, maternal blood Hg was associated with an increased risk of GDM. In QGC analysis, although metallic elements mixtures were not related to an increased risk of GDM, Hg (52.6%) may be the main contributor. According to the results of DLNM, for maternal exposure to Hg, 4.99 ng/g was identified as its susceptible minimum window for elevated risk of GDM. Our findings highlighted an association between Hg exposure and an increased risk of GDM. Studies of the underlying mechanisms and potential contributing factors, including fish intake, of this association are warranted. • We investigated whether exposure to metals could be a risk factor for gestational diabetes 3 mellitus. • The risk of gestational diabetes mellitus increased with increasing levels of mercury exposure. • The minimum blood level of mercury considered to be a risk for gestational diabetes mellitus was 4.99 ng/g. [ABSTRACT FROM AUTHOR]

In the 1950s, large-scale food poisoning caused by methylmercury was identified in Minamata, Japan. Although severe intrauterine exposure cases (ie, congenital Minamata disease patients) are well known, possible impacts of methylmercury exposure in utero among residents, which is likely at lower levels than in congenital Minamata disease patients, are rarely explored. In 2014, the authors examined neurological and neurocognitive functions among 18 exposed participants in Minamata, focusing on fine motor, visuospatial construction, and executive functions. More than half of the participants had some fine motor and coordination difficulties. In addition, several participants had lower performance for neurocognitive function tests (the Rey-Osterrieth Complex Figure test and Keio version of the Wisconsin card sorting test). These deficits imply diffuse brain damage. This study suggests possible neurological and neurocognitive impacts of prenatal exposure to methylmercury among exposed residents of Minamata. [ABSTRACT FROM AUTHOR]

Submarine fumaroles are located in the 200-m deep basin of the northern part of Kagoshima Bay. To estimate the influence of mercury emitted from these fumaroles, the seasonal changes in total mercury (T-Hg), reactive mercury (RM), dissolved gaseous mercury (DGM), and monomethylmercury (MMHg) in water were studied. Seawater samples were collected from five separate locations in the northern part from May, 2011 to May, 2012 using a CTD-Rosette water sampler; the samples were taken every 50 m, starting from the surface. T-Hg, DGM, RM, and MMHg in the seawater columns (n = 132) were in the range of 0.05–3.04 ng L − 1 , 0.003–1.08 ng L − 1 , 0.006–1.47 ng L − 1 , 0.02–0.69 ng L − 1 for an entire sample. Although the average T-Hg values at the surface and middle layers (0–100 m) for each sample showed no significant seasonal variation throughout the year, those at the deeper layer (150–200 m) were high from summer to autumn and low in winter. The seasonal changes and vertical distributions of DGM, RM, and MMHg concentrations were similar to those of T-Hg. A thermocline was observed from spring to autumn and ceased in winter. Because the thermocline prohibits vertical circulation of seawater, the fumarole impact may increase during those months. [ABSTRACT FROM AUTHOR]

A large-scale food poisoning caused by methylmercury was identified in Minamata, Japan, in the 1950s. The severe intrauterine exposure cases are well known, although the possible impact of low-to-moderate methylmercury exposure in utero are rarely investigated. We examined neurocognitive functions among 22 participants in Minamata, mainly using an intelligence quotient test (Wechsler Adults Intelligent Scale III), in 2012/2013. The participants tended to score low on the Index score of processing speed (PS) relative to full-scale IQ, and discrepancies between PS and other scores within each participant were observed. The lower score on PS was due to deficits in digit symbol-coding and symbol search and was associated with methylmercury concentration in umbilical cords. The residents who experienced low-to-moderate methylmercury exposure including prenatal one in Minamata manifested deficits in their cognitive functions, processing speed in particular. [ABSTRACT FROM PUBLISHER]

Persistent organic pollutants and mercury are known environmental chemicals that have been found to be ubiquitous in not only the environment but also in humans, including women of reproductive age. The purpose of this study was to evaluate the association between personal lifestyle characteristics and environmental chemical levels during the perinatal period in the general Japanese population. This study targeted 322 pregnant women enrolled in the Hokkaido Study on Environment and Children’s Health. Each participant completed a self-administered questionnaire and a food-frequency questionnaire to obtain relevant information on parental demographic, behavioral, dietary, and socioeconomic characteristics. In total, 58 non-dioxin-like polychlorinated biphenyls, 17 dibenzo-p-dioxins and -dibenzofuran, and 12 dioxin-like polychlorinated biphenyls congeners, perfluorooctane sulfonate, perfluorooctanoic acid, and mercury were measured in maternal samples taken during the perinatal period. Linear regression models were constructed against potential related factors for each chemical concentration. Most concentrations of environmental chemicals were correlated with the presence of other environmental chemicals, especially in the case of non-dioxin-like polychlorinated biphenyls and, polychlorinated dibenzo-p-dioxins and -dibezofurans and dioxin-like polychlorinated biphenyls which had similar exposure sources and persistence in the body. Maternal smoking and alcohol habits, fish and beef intake and household income were significantly associated with concentrations of environmental chemicals. These results suggest that different lifestyle patterns relate to varying exposure to environmental chemicals. [ABSTRACT FROM AUTHOR]

Abstract: Fifty-one kinds of coals, which are practically used in Japanese power plants and industries, were analyzed for Hg by an automatic mercury analyzer (AMA) based on an official method (heat vaporization atomic absorption spectrometry). Almost all coals were imported coals from various countries. These coals are supplied in a powdery form as standard samples by a Japanese organization and called “SS-coals”. Since the sample amount of coal used in the AMA measurement is usually small, the particle size of coal may greatly affect the measurement, however there have been no systematic studies on the matter. Some of the SS-coals, which were much finer than frequently-used certified reference materials (NIST SRM coals), showed a great deviation in data (relative standard deviation (RSD) is high) in the determination of Hg. The SS-coals were ground further into fine powder, and the resulting coals (ground SS-coals) gave lower RSD values. The mean values of Hg content when the as-received SS-coals were measured many times (more than six runs) became about the same as those for the ground SS-coals. The deviation in data in the Hg determination was discussed with the possibility of localization of Hg in coal body at a microscopic level. The content of Hg in coal (bituminous coals) correlated not with that of sulfur (or pyritic sulfur) but with that of ash. Also, it was found that the coals of high inherent moisture exclusively had low Hg contents. [Copyright &y& Elsevier]

Abstract: To better understand the methylation and demethylation of mercury (Hg) in the atmosphere, monomethyl mercury (MMHg) concentrations in wet deposition samples collected in the Minamata Bay area from September, 2009 to August, 2010 were determined. The concentrations of total Hg (dissolved Hg + particulate Hg) and dissolved reactive Hg were also measured. The volume-weighted mean concentrations of dissolved MMHg and total Hg were 0.061 and 5.9 ng L−1, respectively. Almost 90% of total Hg was in the dissolved phase and dissolved reactive Hg was the dominant Hg species in the wet deposition. The wet deposition fluxes of total Hg and reactive Hg increased in the rainy season (summer and fall), while the concentrations and wet deposition fluxes of MMHg were higher in winter and spring than in summer. Factors affecting this seasonal variation of MMHg were also considered. The MMHg in wet depositions may be decomposed by the increased levels of UV radiation in summer months, although MMHg can also be emitted from anthropogenic and biogenic sources and/or produced by photochemical reactions. Long-range transport from the Asian continent may also contribute to the seasonal variation of the wet MMHg deposition flux. [Copyright &y& Elsevier]

Abstract: To estimate the current contamination levels in Minamata Bay, the vertical and horizontal distributions of mercury in the sediment were investigated. Sediment core samples were collected in 2002, 2006, 2008, and 2010 at 12 locations by gravity core sampling in Minamata Bay and Fukuro Bay, which is located in the southern part of Minamata Bay. The average total mercury concentrations during each year in the surface sediment were 2.47–3.34 and 3.50–4.66mgkg−1 for Minamata Bay and Fukuro Bay, respectively; significant variation in the values was not observed during the study period. The total mercury concentration in Fukuro Bay increased with increasing depth and reached a maximum at 8–14cm from the surface and decreased with increasing depth in the deeper layer. In Minamata Bay, the total mercury concentration did not change significantly from the surface to a depth of 10cm and the values were considerably higher than the background level. In the lower layers of the long cores taken from both areas, the total mercury concentration decreased with depth, and the deepest layers exhibited relatively uniform low values. These values can be considered to represent the background concentration in the absence of anthropogenic influence. The depth of the sediment affected by the effluent was estimated to be 20±7cm and 33±4cm for Minamata Bay and Fukuro Bay, respectively. Furthermore, it was estimated from the average concentration and volume of the contaminated layer that approximately 1ton of discharged mercury remained in the sediment of the two bays. [Copyright &y& Elsevier]

Methylmercury (MeHg) and polychlorinated biphenyls (PCBs) are environmentally persistent neurodevelopmental toxicants. In Japan, the most common source of human exposure is the consumption of contaminated fish and seafood. We investigated the accumulation of MeHg and PCBs in the brains of dams and offspring mice maternally exposed to MeHg and/or PCBs. Pregnant mice (C57BL/6Cr) were assigned to one of four exposure groups: control, MeHg alone (MeHg in diet at 5 mg/kg as Hg), PCB alone (Aroclor1254 by gavage at the dose of 18 mg/kg body weight/3 days) and MeHg+PCB. Levels of MeHg and PCBs were measured in the whole brains of dams and offspring mice on postnatal day 21 (PND21) and at 9 weeks of age. Total mercury, MeHg and PCB congener concentrations were determined by CVAAS, GC-ECD and HRGC/HRMS, respectively. For the mercury concentrations, there were no significant differences between MeHg alone and MeHg+PCB except for pups at 9 weeks. The maternal PCB levels were not significantly different between MeHg+PCB and PCB alone. In pup brain on PND21, MeHg+PCB resulted in a significantly higher PCB level than PCB alone. Although the levels of lightly chlorinated (= 4CBs) homologues were lower for MeHg+PCB than for PCB alone, those of highly chlorinated (>= 5CBs) homologues were significantly higher on PND21 for MeHg+PCB. The PCB composition in dams and pups shifted to higher chlorinated homologues compared with the composition of administered Aroclor1254. For these reasons, further detailed studies are necessary to clarify the interactional effects of PCB metabolism after coexposure to MeHg and PCBs. [ABSTRACT FROM AUTHOR]

While the end-Triassic mass extinction has been linked to emplacement of the Central Atlantic Magmatic Province (CAMP), evidence for environmental stresses appears hundreds of thousands of years prior to the extinction in some sections from the Panthalassic Ocean. In this study, we measured carbon, sulfur, and mercury concentrations in the Kurusu section, near Inuyama, Japan. These bedded radiolarian cherts are part of the Mino Terrane, an accretionary complex of late Paleozoic and Mesozoic sediments deposited at abyssal water depths in the open ocean, providing a unique window into the Triassic-Jurassic transition in pelagic settings. The rhythmically bedded nature of the sediments allowed construction of a floating astronomical age model tied to the radiolarian-defined Triassic-Jurassic boundary. Average linear sedimentation rates (LSR) of 0.07–0.48 cm kyr−1 and total organic carbon (TOC) concentrations of 0.07–0.22% yielded estimates of primary productivity rates (PPR) based on published transfer functions ranging from 2400 to 63,000 mg C cm−2 kyr−1, which are generally comparable to PPRs in the modern equatorial and subtropical Pacific. While mercury (Hg) concentrations are strongly correlated with sedimentary sulfide content throughout the section, a distinct increase in the ratio of Hg to sulfide near the Triassic-Jurassic boundary may record Hg input from CAMP volcanism. Below this level, a series of discrete spikes in sulfide content appear during the ~ 1.2 Myr before the extinction, recording a precursor interval of environmental stress that also correlates with changes in the composition of the planktonic community. We infer that these changes reflect the development of stratification in the water column, with more reducing conditions characterizing the thermocline below the surface mixed layer. Based on the evidence from Kurusu and comparisons to other Panthalassic sections, we propose a model in which water-column stratification began to develop in the open Panthalassic Ocean over one million years before the Triassic-Jurassic boundary. Evidence from sections deposited at slope depths suggests that this rising chemocline may have begun to impinge on the slopes of island arcs and the South American continental margin by ~ 400 kyr before the boundary. The end-Triassic extinction coincided with both the main phase of CAMP eruptions and the irruption of acidic, reducing deep waters into photic zone and shelf environments. • Pelagic cherts at Kurusu, Japan span from the early Rhaetian to late Hettangian/early Sinemurian. • A pre-extinction late Rhaetian 'crisis interval' characterized by episodic sulfide deposition has a duration of ~1.2 Myr. • This 'crisis interval' is linked to enhanced primary productivity. • Hg is strongly correlated with sulfur content, reflecting a dominant sulfide host phase. • The end-Triassic mass extinction corresponds with a unique interval of high Hg flux. [ABSTRACT FROM AUTHOR]

Large-scale food poisoning caused by methylmercury was identified in Minamata, Japan, in the 1950s (Minamata disease). Although the diagnostic criteria for the disease remain current, few studies have been carried out to assess the diagnostic accuracy of the criteria. From a 1971 population-based investigation, data from 2 villages were selected: Minamata (high-exposure area;n= 779) and Ariake (low-exposure area;n= 755). The authors examined the prevalence of neurologic signs characteristic of methylmercury poisoning and the validity of the criteria. A substantial number of residents in the exposed area exhibited neurologic signs even after excluding officially certified patients. Using paresthesia of the extremities as the gold standard of diagnosis, the criteria had a sensitivity of 66%. The current diagnostic criteria as well as the official certification system substantially underestimate the incidence of Minamata disease. [ABSTRACT FROM AUTHOR]

Some countries have established fish advisories to manage fish consumption to minimize methylmercury exposure. Our objective was to compare the fish advisories and the resultant consumer behavior in the United States of America (USA) and Japan. Both countries have national consumption guidelines, but American states enjoy greater independence in issuing guidelines for local water bodies and vary in the information that is provided for the public. The proportion of the American public that has heard of state fish advisories is thought to be close to 30%. There is a concern that this low level of awareness extends to pregnant women. In Japan, the current problem is the lack of comprehensive studies on the public awareness of fish advisories. Nonetheless, there is evidence that fish consumption has decreased in both countries. In USA, there is a possibility that the strong emphasis on mercury toxicity drives the general population towards a trend of lower fish consumption. In Japan, the fish advisory encourages seafood consumption for nutritional benefits. Consequently, the decrease may be due to the shift towards a "Western diet". Also, the Japanese fish advisory seems to be less active in advocating the issue of fish consumption and mercury exposure, which may be partly responsible for the possible lesser attention of the consumers. Cultural factors may explain for the baseline difference in consumption and account partly for the change in Japanese consumer behavior. However, the dissimilarities in fish advisories may also be responsible for the variations in consumer behavior. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of estimated historical methylmercury exposure on the functional health of residents living in the Shiranui Sea communities in Japan. Functional health was measured by self-reported activities of daily living (ADL). Study areas were categorized into high, medium and low methylmercury exposure areas according to their location or distance from the Shiranui Sea. We estimated the adjusted prevalence odds ratios of impaired ADL in relation to exposure using a logistic regression model. Compared with residents in the low-exposure area, residents in the high-exposure area were significantly associated with a higher prevalence odds ratio (OR) for impaired ADL after adjustment for confounding factors (adjusted ORs = 2.8, 95% CI: 1.3–6.2). These results showed strong dose-response relationships (p for trend = 0.0050). Our findings suggest that historical methylmercury exposure might cause functional impairment in later in life depending on the exposure level. [ABSTRACT FROM PUBLISHER]

Abstract: Background: Studies conducted in the Faeroe Islands and Japan suggest a negative impact of mercury on heart rate variability (HRV) among children while the results regarding blood pressure (BP) are less consistent. Objective: To assess the impact of mercury on HRV and BP among Nunavik Inuit children. Methods: A cohort of 226 children was followed from birth to 11 years old. Mercury concentration in cord blood and in blood and hair at 11 years old were used as markers of prenatal and childhood exposure, respectively. HRV was measured using ambulatory 2h-Holter monitoring while BP was measured through a standardized protocol. Simple regression was used to assess the relationship of mercury to BP and HRV parameters. Multiple linear regressions were performed adjusting for covariates such as age, sex, birth weight, body mass index (BMI), height, total n-3 fatty acids, polychlorinated biphenyls (PCB 153), lead, selenium and maternal smoking during pregnancy. Results: Median cord blood mercury and blood mercury levels at 11 years old were 81.5nmoL/L (IQR: 45.0–140.0) and 14.5nmol/L (IQR: 7.5–28.0), respectively. After adjusting for the covariates, child blood mercury was associated with low frequency (LF) (β =−0.21, p =0.05), the standard deviation of R–R intervals (SDNN) (β =−0.26, p =0.02), the standard deviation of R–R intervals measured over 5min periods (SDANN) (β =−0.31, p =0.01) and the coefficient of variation of R–R intervals (CVRR) (β =−0.06, p =0.02). No significant association was observed with BP. Conclusion: Mercury exposure during childhood seems to affect HRV among Nunavik Inuit children at school age. [Copyright &y& Elsevier]

Objectives: To assess whether polychlorinated biphenyls (PCBs), methylmercury, lead, or parental child-rearing attitudes was most crucial for maladaptive behavior problems, we examined Japanese 30-month-old children followed up from pregnancy. Methods: The Child Behavior Checklist (CBCL) was used to assess the behavior problems in 306 children. The associations of cord-blood total PCBs (ΣPCB), total mercury (THg), and lead with each CBCL subscale were examined by multivariate analyses. Results: The median values in cord blood of the 306 children were 48.3 (5 and 95 percentiles, 18.6–116.3) ng/g-lipid for ΣPCB, 10.2 (4.1–24.5)ng/g for THg, and 1.0 (0.5–1.7)μg/dl for lead. The internalizing score of the CBCL was significantly correlated with ΣPCB (r=0.113) in the children, though no significant correlation was seen between any CBCL score and either THg or lead. The significant correlation disappeared when conducting multiple regression analysis with possible confounders; at that time, the birth order, home environment, and maternal intelligence quotient were significantly related to the internalizing score. Three CBCL scores and ΣPCB levels were significantly higher in the first-born children than in the second-born or following children, and the partial correlation coefficient with the adjustment for all confounders except birth order was significant between the internalizing score and ΣPCB in the latter children (r=0.175). Conclusions: Internalizing behavior appears to be affected by prenatal exposure to PCBs at low levels. Under lower-level exposures, however, behavior problems may be more strongly associated with parental child-rearing attitudes involved in birth order, than with such hazardous chemicals. [Copyright &y& Elsevier]

The Japan coastal areas are still environmentally friendly, though there are multiple air emission sources originating as a consequence of several developmental activities such as automobile industries, operation of thermal power plants, and mobile-source pollution. Mercury is known to be a potential air pollutant in the region apart from SOX, NOX, CO and Ozone. Mercury contamination in water bodies and other ecosystems due to deposition of atmospheric mercury is considered a serious environmental concern. Identification of sources contributing to the high atmospheric mercury levels will be useful for formulating pollution control and mitigation strategies in the region. In Japan, mercury and its compounds were categorized as hazardous air pollutants in 1996 and are on the list of "Substances Requiring Priority Action" published by the Central Environmental Council of Japan. The Air Quality Management Division of the Environmental Bureau, Ministry of the Environment, Japan, selected the current annual mean environmental air quality standard for mercury and its compounds of 0.04 μg/m3. Long-term exposure to mercury and its compounds can have a carcinogenic effect, inducing eg, Minamata disease. This study evaluates the impact of mercury emissions on air quality in the coastal area of Japan. Average yearly emission of mercury from an elevated point source in this area with background concentration and one-year meteorological data were used to predict the ground level concentration of mercury. To estimate the concentration of mercury and its compounds in air of the local area, two different simulation models have been used. The first is the National Institute of Advanced Science and Technology Atmospheric Dispersion Model for Exposure and Risk Assessment (AIST-ADMER) that estimates regional atmospheric concentration and distribution. The second is the Hybrid Single Particle Lagrangian Integrated trajectory Model (HYSPLIT) that estimates the atmospheric concentration distribution in the vicinity of industrial facilities. [ABSTRACT FROM AUTHOR]

Background. Large-scale poisonings caused by methyl mercury (MeHg) have occurred in Japan (Minamata in the 1950s andNiigata in the 1960s) and Iraq (in the 1970s). The current WHO neurological risk standard for adult exposure (hair level: 50 μg/g) was based partly on evidence from Niigata which did not consider any cases who were diagnosed later and/or exposed to low level of MeHg (hair mercury level less than 50 μg/g). Methods. Early in the Niigata epidemic in June 1965 there were two extensive surveys. From these two surveys, we examined 103 adults with hair mercury measurement who consulted two medical institutions. We compared the prevalence and the distribution of neurological signs related to MeHg poisoning between exposure categories. Result. We found 48 subjects with neurological signs related to MeHg poisoning who had hair mercury concentration less than 50 μg/g. Among the neurological signs, sensory disturbance of the bilateral distal extremities was observed more frequently, followed by disequilibrium, hearing impairment, and ataxia, in groups with hair MeHg concentration both below 50 μg/g and over 50 μg/g. Conclusion. The present study suggests the possibility that exposure to MeHg at levels below the current WHO limits could cause neurologic signs, in particular, sensory disturbance. [ABSTRACT FROM AUTHOR]

Abstract: Mercury can have profound and complicated effects on the immune system, and epidemiological evidence regarding the relationship between mercury exposure and allergic disorders has been sparse. We investigated the associations between mercury levels in maternal and children''s hair and the risk of wheeze and eczema in Japanese children at 29–39 months of age. Study subjects were 582 Japanese mother–child pairs. Presence or absence of wheeze and eczema symptoms was determined based on the criteria of the International Study of Asthma and Allergies in Childhood. Adjustment was made for maternal age; residential municipality at baseline; maternal and paternal education; maternal and paternal history of allergic disorders; maternal energy-adjusted fish intake during pregnancy; maternal smoking during pregnancy; number of child''s older siblings; child''s sex; household smoking in the same room as the child; breastfeeding duration; and children''s fish intake at the fourth survey. The prevalence of wheeze and eczema was 18.6% and 17.2%, respectively. The range of hair mercury levels was 0.26−6.05μg/g in mothers and 0.13−9.51μg/g in children. Neither maternal nor children''s hair mercury levels were related to the risk of wheeze or eczema. Maternal and children''s hair mercury levels in the second quartile were non-significantly inversely related to the risk of wheeze (adjusted odds ratios [95% confidence intervals] were 0.77 [0.41−1.44] and 0.57 [0.29−1.11], respectively) while those in the third quartile were non-significantly inversely associated with the risk of eczema (adjusted odds ratios [95% confidence intervals] were 0.77 [0.40−1.45] and 0.66 [0.33−1.30], respectively). The current study provides no evidence that hair mercury levels in either mothers or children are positively associated with the risk of wheeze or eczema in children aged 29–39 months in Japan, where fish intake is high. [Copyright &y& Elsevier]

Abstract: Ferrous metal production is thought to be a major mercury emission source because it uses large amounts of coal and iron ore, which contain trace amounts of mercury impurities. However, there is limited information about mercury emissions during the production process. In this study, we focused on the coke-oven process, sintering furnace process, and blast furnace process. We measured the mercury concentration in the raw materials, products, and byproducts to estimate the amount of mercury emitted and to investigate the behavior of mercury during the processes. Average mercury concentrations were 30.8 μg kg−1 in 54 samples of iron ore and 59.9 μg kg−1 in 33 samples of coal. The total mercury used for ferrous metal production in Japan was estimated to be 8.45 tons in 2005, with 4.07 tons from iron ore, 3.76 tons from coal, and 0.478 tons from limestone. Emissions from the sintering process accounted for more than 90% of the total emissions, and mercury in the exhaust gas was reduced using an activated coke tower and desulfurization equipment installed downstream of an electrostatic precipitator. When byproduct gas generated from coke-oven and blast furnace processes were included, mercury emissions estimates based on actual measurements were 4.08 tons y−1 (in 2005). Thus, about 50% of the mercury input in ferrous metal production was emitted to the atmosphere. The emission factor was calculated as 0.0488 g Hg ton−1 for crude steel production. The introduction of activated coke tower or desulfurization equipment in sintering furnace facilities would reduce mercury emissions. [Copyright &y& Elsevier]

Abstract: Introduction: It is well-known that prenatal or postnatal exposure to methylmercury can produce neurological signs in adults and children, exemplified by a case of large-scale poisoning in Minamata, Japan, in the 1950s. However, evidence regarding whether pre- or postnatal exposure to methylmercury causes psychiatric symptoms (e.g., impairment of intelligence and mood and behavioral dysfunction) is still limited—excluding cases of fetal Minamata disease patients. Methods: We evaluated the effects of pre- or postnatal exposure to methylmercury on psychiatric symptoms using data derived from a 1971 population-based survey in Minamata and neighboring communities. We adopted residential areas as an exposure indicator and psychiatric symptoms as the outcome. Then, we estimated the adjusted prevalence odds ratio (POR) and confidence interval (CI) of psychiatric symptoms in relation to residential area. Results: There were 904 participants in Minamata (high exposure area), 1700 in Goshonoura (middle exposure area), and 913 in Ariake (low exposure area). Compared to the Ariake area, participants in the Minamata area manifested psychiatric symptoms more frequently: PORs for impairment of intelligence and mood and behavioral dysfunction were 5.2 (95% CI: 3.7–7.3) and 4.4 (95% CI: 2.9–6.7), respectively. Furthermore, participants with psychiatric symptoms in the Minamata area more frequently had neurological signs. Peaks in prevalence of psychiatric symptoms occurred around age 20 and in older age adults in the area. These findings did not change when we excluded those who had been officially certified as Minamata disease patients by that time. Conclusions: The present study suggests a relationship between pre- or postnatal exposure to methylmercury and psychiatric symptoms among the general population in Minamata even after excluding officially certified patients. [Copyright &y& Elsevier]

Methylmercury (Me-Hg) poisoning (Minamata disease: MD) is one of the most severe types of disease caused by humans to humans in Japan. The disease is a special class of food-borne methylmercury intoxication in humans as typified by the outbreak that began in 1953 in Minamata and its vicinity in Kumamoto Prefecture, Japan. There are 450 autopsy cases in Kumamoto and 30 autopsy cases in Niigata Prefecture related to MD in Japan. Two hundred and one cases in Kumamoto and 22 cases in Niigata showed pathological changes of MD. This report provides a brief research history and overview of the pathological changes of MD, and also presents representative cases of adult, infantile and fetal forms of MD among the 450 MD-related autopsy cases in Kumamoto Prefecture. [ABSTRACT FROM AUTHOR]

Abstract: To scrutinize whether the provisional tolerable weekly intake (PTWI, 3.4 µg/kg body weight/week) of methylmercury in Japan is safe for adults, we conducted an intervention study using heart rate variability (HRV) that has been considered to reflect cardiac events. Fifty-four healthy volunteers were recruited and divided into experimental and control groups. The experimental group was exposed to methylmercury at the PTWI level through consumption of bigeye tuna and swordfish for 14 weeks, and HRV parameters were compared between the two groups. In the experimental group, mean hair mercury levels, determined before and after the dietary methylmercury exposure and after 15-week wash-out period following the cessation of exposure, were 2.30, 8.76 and 4.90 µg/g, respectively. The sympathovagal balance index of HRV was significantly elevated after the exposure, and decreased to the baseline level at the end of this study. Still, such changes in HRV parameters were not found in the control group with a mean hair mercury level of around 2.1 µg/g. In conclusion, the PTWI does not appear to be safe for adult health, because methylmercury exposure from fish consumption induced a temporary sympathodominant state. Rather, long-term exposure to methylmercury may pose a potential risk for cardiac events involving sympathovagal imbalance among fish-consuming populations. [Copyright &y& Elsevier]

Abstract: Recent studies suggest potential adverse effects of methylmercury exposure on cardiovascular disease, although the evidence of association with hypertension is still inconsistent. Therefore, we evaluated the effects of methylmercury exposure on hypertension in Minamata. We used data derived from the 1971 population-based survey in Minamata and neighboring communities. We also utilized data on hair mercury content of the participants (derived from a 1960 investigation). We adopted two exposure indices (residential area and hair mercury content) and two hypertension outcomes (past history of hypertension and hypertension defined by measurements in the examination). Then, we estimated the adjusted prevalence odds ratio (POR) and its confidence interval (CI) of both hypertension outcomes in relation to residential area and hair mercury content. In the Minamata area (high exposure area), 87% (833) of the eligible population (aged ≥10 years) participated in the 1971 investigations. In the Goshonoura area (middle exposure area) and the Ariake area (low exposure area), 93% (1450) and 77% (755), respectively, of the eligible population participated. Compared with subjects in the Ariake area, the subjects in the Minamata area manifested hypertension more frequently, and PORs observed for two hypertension outcomes were 1.6 (95% CI: 1.2–2.1) and 1.4 (95% CI: 1.1–1.9), respectively. Furthermore, dose-response trends with hair mercury content were observed for both hypertension outcomes. The present finding supports the causal relationship between methylmercury exposure and hypertension. [Copyright &y& Elsevier]

Objective: To examine whether an FFQ can be used for assessing exposure to methylmercury (MeHg) by estimating MeHg intake from seafood consumption using the FFQ and confirming the accuracy of the estimated value. Design: Seafood consumption of pregnant women was assessed using the FFQ. Total mercury (T-Hg) concentrations of maternal red blood cells (RBC) and hair were measured as exposure indices of MeHg. Setting: A prospective birth cohort study, the Tohoku Study of Child Development (TSCD), which has been ongoing since 2001. Subjects: The subjects were 609 pregnant Japanese women who were enrolled in the TSCD. Results: MeHg intake was estimated from seafood consumption determined using the FFQ and the MeHg concentrations in each type of seafood. The accuracy of the estimated value was confirmed by comparison with T-Hg in RBC and hair. Estimated MeHg intake was 42·3μg/week, and 43·0% of that was from large predatory fish. Compared with the Japanese tolerable weekly intake, in total 12·5% of the subjects exceeded it. T-Hg concentrations in RBC and hair were significantly correlated with estimated MeHg intake: r=0·325 (P<0·0001) for RBC and r=0·305 (P<0·0001) for hair. Conclusions: Estimated MeHg intake based on the FFQ was significantly associated with T-Hg concentrations in RBC and hair. Although the estimated value involves uncertainties, the FFQ appears to be a useful tool for assessment of exposure to MeHg. [ABSTRACT FROM AUTHOR]

Abstract: We analyzed the total mercury (T-Hg) and stable isotopes of 13C and 15N in the muscle of spiny dogfish (Squalus acanthias) caught off the coast of Japan. The average body length of the female spiny dogfish sampled (94.9±20.2cm, 50.5–131.0cm, n =40) was significantly larger than that of the males sampled (77.8±10.8cm, 55.5–94.0cm, n =35), although the ages of the samples were unknown. The T-Hg concentration in the muscle samples rapidly increased after maturity in the females (larger than about 120cm) and males (larger than about 90cm), followed by a continued gradual increase. Contamination level of T-Hg in female muscle samples (0.387±0.378μg(wetg)−1, n =40) was slightly higher than that in male muscle samples (0.316±0.202μg(wetg)−1, n =35), probably due to the greater longevity of females. In contrast, the contamination level of T-Hg in females smaller than 94.0cm in length (0.204±0.098μg(wetg)−1, n =20) was slightly lower than that in the males, probably due to the faster growth rate of females. Although the ∂ 13C and ∂ 15N values in the muscle samples increased with an increase in body length, there were no significant differences between the females (−17.2±0.4‰ and 12.4±0.9‰, respectively) and males (−17.3±0.4‰ and 12.4±0.8‰, respectively). A positive correlation was found between ∂ 13C and ∂ 15N values, suggesting trophic enrichment due to the growth. [Copyright &y& Elsevier]

The paper reviewed studies about total gaseous mercury, atmospheric particulate of mercury and average dry deposition fluxes of mercury in Korea, Japan, China and Taiwan. This study compared sample collection and analytical methods for mercury in Asian countries. Analytical results indicated that the primary mercury sources are anthropogenic source (for example coal burning) and high temperature processes. This study also elucidates the sources, analytical tools, and the average concentrations for atmospheric mercury (Hg) for these Asian countries during 2000–2008. This study indicated that the total gaseous mercury concentrations were higher in urban area than that in suburban area in Asian countries (Korea, Japan, China and Taiwan). As for the seasonal variations, in general, the average total gaseous mercury concentrations were higher in winter than that in summer especially in China. In addition, the average total gaseous mercury concentrations were higher in mining areas than that in the rest of the other areas. And the total gaseous mercury concentrations were decreasing as this distance increasing. These phenomena revealed that the total gaseous mercury concentrations are reduced by long-distance transportation especially in the main land of China. [Copyright &y& Elsevier]

Abstract: BEPI COLOMBO is a joint mission between ESA and JAXA that is scheduled for launch in 2014 and arrival at Mercury in 2020. A comprehensive set of ion sensors will be flown onboard the two probes that form BEPI COLOMBO. These ion sensors combined with electron analyzers will allow a detailed investigation of the structure and dynamics of the charged particle environment at Mercury. Among the ion sensors, the Mass Spectrum Analyzer (MSA) is the experiment dedicated to composition analysis onboard the Mercury Magnetospheric Orbiter (MMO). It consists of a top-hat for energy analysis followed by a Time-Of-Flight (TOF) section to derive the ion mass. A notable feature of MSA is that the TOF section is polarized with a linear electric field that provides an enhanced mass resolution, a capability that is of importance at Mercury since a variety of species originating from the planet surface and exosphere is expected. MSA exhibits two detection planes: (i) one with moderate mass resolution but a high count rate making MSA appropriate for plasma analysis, (ii) another with a high (above 40) mass resolution though a low count rate making it appropriate for planetology science. Taking advantage of the spacecraft rotation, MSA will provide three-dimensional distribution functions of magnetospheric ions, from energies characteristic of exospheric populations (a few eVs or a few tens of eVs) up to the plasma sheet energy range (up to ∼40keV/q) in one spin (4s). [Copyright &y& Elsevier]

We present the history of Minamata disease in a chronological order from the public health point of view. Because the appropriate public health response – to investigate and control the outbreak – as set out in the Food Sanitation Act was not conducted, no one knew how many became ill following the outbreak. Exposure could not be stopped. In our discussion, we offer two reasons as to why the Japanese public health agencies did not apply the Act: social circumstances in the 1950s and 1960s that placed emphasis on industrial development, and the Japanese medical community’s lack of knowledge about the Act. The history of Minamata disease shows us the consequences when public health responses are not implemented. Minamata disease should be an invaluable lesson for future public health responses.Journal of Public Health Policy (2009) 30, 54–67. doi:10.1057/jphp.2008.30 [ABSTRACT FROM AUTHOR]

Abstract: Pitting damage influences the lifetime of Japan Spallation Neutron Source (JSNS) mercury target. The lifetime estimation was carried out taking into account the fatigue crack growth from the bottom of pits. Material crack propagation coefficients in the equation of Paris law were obtained based on the results of 3-point bending fatigue tests on the specimens with various pitting damages. Based on the estimated crack growth rate and the relationship between pitting damage and the number of impact pulses, the relationship between the total crack length and the number of pulses was estimated. The crack length increased rapidly over the crack length of 430μm and the fatigue failure occurred at 8.4×107 pulses. The lifetime of the JSNS mercury target that suffers the pitting damage and repeated stress simultaneously with failure probability of 10% was 270h at 1MW operation. [Copyright &y& Elsevier]

Abstract: Total mercury (T-Hg) and methylmercury (MeHg) concentrations were determined in water at the bottom, in the suspended solid, and in the surface sediment of Minamata Bay to assess the remobilization of mercury from the sediment into the water column. The water and sediment samples were taken from the bottom of the bay using a gravity core sampler at nine locations in October 2002 and six locations in April 2005. The average concentration of T-Hg and the proportion of MeHg in the sediment were 3.71±1.90 mg/kg and 0.27±0.28%, respectively. The water contained 1.80±1.00 ng L−1 of T-Hg, which was higher than the value reported for the upper-middle depth of Minamata Bay. The results suggest that the sediment is an important source of mercury in the water of Minamata Bay. The percentage of MeHg in the water at the bottom was 50.7±24.6%, also considerably higher than in the upper-middle layer of the water column, suggesting that MeHg may be the predominant form of mercury released from the sediment into the water. The percentage of MeHg was lower in the resuspended sediment than in the surface sediment. The amount of mercury eluted from the sediment into the water was estimated at 0.46 kg and 0.11 kg per year for T-Hg and MeHg, respectively. [Copyright &y& Elsevier]

The variability of atmospheric mercury in elemental, reactive, and particulate forms has been studied at a remote site (Cape Hedo Observatory, CHO) at Okinawa Island (Japan) March 23 to May 2, 2004, downwind of the major Asian source regions. Under prevailing meteorological conditions, episodes of higher levels of atmospheric mercury and other atmospheric species are observed at CHO. The mean (±1σ) concentrations of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate-bound mercury (PHg) are 2.04±0.38ngm−3, 4.5±5.4pgm−3 and 3.0±2.5pgm−3, respectively. In Asian outflow the combined contribution of RGM and PHg constitutes less than 1% of the GEM in the boundary layer, which indicates that most mercury export in the marine boundary layer is due to the GEM form, and direct outflow of RGM and PHg is very low. While the data from Okinawa suggest minimal export of RGM and PHg, this does not preclude greater export of these species at higher elevations. Based on the correlations of PHg and submicron aerosol mass (SAM), we found a ΔPHg/ΔSAM ratio of 0.20μgg−1 (R =0.58, p <0.01), which we believe to be characteristic of East Asian industrial aerosols during outflow. A diurnal variation is observed in RGM with a peak near noon. Using a rate constant of 9×10−14 cm3 molecule−1 s−1 for the OH oxidation rate (Sommar, J., Gardfeldt, K., Stromberg, D., Feng, X., 2001. A kinetic study of the gas phase reaction between the hydroxyl radical and atomic mercury. Atmospheric Environment 35, 3049–3054; Pal, B., Ariya, P.A., 2004a. Gas-phase HO center dot-initiated reactions of elemental mercury: kinetics, product studies, and atmospheric implications. Environmental Science and Technology 38 (21), 5555–5566.) and a typical OH concentration of 1–5×106 cm−3 would result in RGM production rates of 0.6–3.0pgm−3 h−1. Although OH may not be the sole oxidant, this is consistent with the observed change in concentration during daytime of 1.4±1.5pgm−3 h−1. A significant correlation is found between GEM and CO; GEM and SAM; and PHg and SAM. Lower ΔSAM/ΔCO and ΔGEM/ΔCO are observed for transport events with rainfall and for air parcels remaining in the mixed layer. Back trajectory analysis along with the correlation study suggests that the air from China has a higher GEM concentration compared to the air coming from southern Japan. [Copyright &y& Elsevier]

Total mercury (T-Hg), methyl mercury (M-Hg), cadmium (Cd), selenium (Se), zinc (Zn) and copper (Cu) concentrations in the organs of melon-headed whales from a mass stranding on the Japanese coast were analyzed. The mean concentration of T-Hg in the liver (126±97 μg/wet g, n =13) was markedly higher than those in kidney (6.34±2.36 μg/wet g, n =12) and muscle (4.90±2.33 μg/wet g, n =15). In contrast, the mean concentration of M-Hg in the liver (9.08±2.24 μg/wet g) was similar to those in the kidney (3.47±0.91 μg/wet g) and muscle (3.78±1.53 μg/wet g). The mean percentage of M-Hg in the T-Hg found in the liver (13.1±10.3) was significantly lower than those in the kidney (58.3±15.0) and muscle (78.9±8.4). The molar ratio of T-Hg to Se in the liver was effectively 1.0, but those in the kidney and muscle were markedly lower. Conversely, the mean concentration of Cd was markedly higher in the kidney (24.4±7.4 μg/wet g) than in the liver (7.24±2.08 μg/wet g) and muscle (less than 0.05 μg/wet g). These results suggest that the formation of Hg–Se compounds mainly occurs in the liver after the demethylation of M-Hg, and Cd preferentially accumulates in the kidney of melon-headed whales. [Copyright &y& Elsevier]

A new cod fish tissue certified reference material, NMIJ CRM 7402-a, for methylmercury analysis was certified by the National Metrological Institute of Japan in the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST). Cod fish was collected from the sea close to Japan. The cod muscle was powdered by freeze-pulverization and was placed into 600 glass bottles (10 g each), which were sterilized with γ-ray irradiation. The certification was carried out using species-specific isotope dilution gas chromatography inductively coupled plasma mass spectrometry (SSID–GC–ICPMS), where 202Hg-enriched methylmercury (MeHg) was used as the spike compound. In order to avoid any possible analytical biases caused by nonquantitative extraction, degradation and/or formation of MeHg in sample preparations, two different extraction methods (KOH/methanol and HCl/methanol extractions) were performed, and one of these extraction methods utilized two different derivatization methods (ethylation and phenylation). A double ID method was adopted to minimize the uncertainty arising from the analyses. In order to ensure not only the reliability of the analytical results but also traceability to SI units, the standard solution of MeHg used for the reverse-ID was prepared from high-purity MeHg chloride and was carefully assayed as follows: the total mercury was determined by ID–ICPMS following aqua regia digestion, and the ratio of Hg as MeHg to the total Hg content was estimated by GC–ICPMS. The certified value given for MeHg is 0.58 ± 0.02 mg kg−1 as Hg. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]