Mercury is a metal that has long been used because of its many advantages from the physical and chemical points of view. However, mercury is very toxic to many life forms, including humans, and mercury poisoning has repeatedly been reported. The main chemical forms of mercury are elemental mercury (Hg(0)), divalent mercury (Hg(2+)) and methylmercury (CH(3)-Hg(+)), the toxicities and metabolisms of which differ from each other. Methylmercury is converted from divalent mercury and is a well-known neurotoxicant, having been identified as the cause of Minamata disease. It bioaccumulates in the environment and is biomagnified in the food web. Human exposure to methylmercury is mainly through fish and seafood consumption. Methylmercury easily penetrates the blood-brain barrier and causes damage to the central nervous system, particularly in fetuses. In this paper, we summarize the global mercury cycle and mercury metabolism, toxicity and exposure evaluation, and the thresholds for the onset of symptoms after exposure to different chemical forms of mercury, particularly methylmercury.

OBJECTIVES AND METHODSIn order to study the fatty acid transfer from the mother to fetus, their fatty acid profiles were compared by 37 pairs of maternal and umbilical cord plasma specimens obtained from healthy Japanese women at delivery.

RESULTSThe fetal/maternal fatty acid concentration ratios differed among individual fatty acids. The ratios were low for linoleic acid (LN, 0.12±0.04) and linolenic acid (LnN, 0.07±0.05) but high for arachidonic acid (AA, 0.66±0.17) and docosahexaenoic acid (DHA, 0.44±0.13). Significant correlations were observed between the maternal and fetal EPA (r=0.74) and DHA (r=0.40) concentrations.

CONCLUSIONSThese results suggest that DHA and AA are preferentially transferred to the fetus. Fetal fatty acid profile reflects the maternal intake of EPA and DHA.

Goal: To make mercury exposure assessment among private gold miners, who live in Jargalant and Bornuur soums ofTuv province.Objectives:1. To collect human bio-samples, including hair, urine and blood, then determine mercury concentrations.2. To asess the mercury exposure situation for those of two soum civilizationsMaterials and MethodsThe MoH-lead investigations were undertaken in collaboration with the Institute of Public Health from UMIT University in Hall, Austria as well as national Mongolian partners from the National Emergency Management Agency (NEMA), the National Public Health Institute , the and other institutions. The Mongolian WHO office supported the mission. The urine samples were analyzed by the Department of Forensic Toxicology, Institute of Forensic Medicine, University of Munich, (LMU) Germany and the National Institute for Minamata Disease, Japan. The blood samples were analyzed by the Chemical Hazards and Poisons Division, Centre for Radiation, Chemical and Environmental Hazards, HPA, Chilton, Didcot, Oxon, UK through the Health and Safety Laboratory, Harpur Hill, Buxton, Derbyshire, UK.Results and Conclusions• The median level of mercury in urine for the control area is 0.10 μg/l, compared to 2.88 μg/l for the group exposed by living in the area and 4.37 μg/l for the group working with mercury. The blood results do differ significantly as well (median 0.24 μg/l for control group, median 0.33 μg/l for the group living in an exposed area, median 0.55 μg/l for the group working with mercury).• The hair results do differ significantly as well (median 0.11/0.08 (root/tip) μg/l for control group, median 0.0.25/0.19 (root/tip) μg/l for the group living in an exposed area, median 0.31/0.26 (root/tip) μg/l for the group working with mercury).• Laboratory tests performed on urine, blood and hair samples collected in Bornuur and Jargalant Soum indicate that the population is very likely to have been recently exposed to mercury. The participants from Bornuur soum and Jargalant soum show results above HBM I to a high percentage and even above HBM II, indicating a much higher exposure to mercury compared to Khushaat soum.

OBJECTIVESIt is crucial to consider covariates relevant for outcome variables in developing dose-effect relations of environmental hazardous toxins. The aim of this study was to clarify the covariates affecting hand tremor and postural sway in children.

METHODSHand tremor and postural sway, as well as hair mercury concentrations, were measured in 155 boys and 148 girls at age 7 years.

RESULTSCurrent mercury concentrations in child hair ranged from 0.35 to 6.32 μg/g (geometric mean, 1.71 μg/g for boys and 1.58 μg/g for girls), and were not significantly correlated with the neuromotor parameters. All hand tremor and postural sway parameters, except for tremor intensity at 1-6 Hz with non-dominant hand, were significantly larger in the boys than in the girls. Using multiple regression analysis, some postural sway parameters were related negatively to age in the boys and girls (p<0.05), and positively to height (p<0.05). Similarly, hand tremor parameters were positively related to age, height and heart rate either in the boys or in the girls (p<0.05). Also, there were positive relationships between tremor intensity at 1-6 Hz and transversal and sagittal sways at 1-2 Hz and 2-4 Hz (p<0.05).

CONCLUSIONSHeart rate and postural sway, together with age, sex, and height, should be considered in interpreting hand tremor in children. Hand tremor or postural sway may not be so sensitive or specific to methylmercury exposures at levels of less than 7 μg/g in hair.

OBJECTIVEThe aim of this study was to determine the level of exposure of mercury (Hg) miners and smelter workers to elemental mercury (Hg(0)) vapor in China, who work in Hg mines without using protective equipment against Hg(0) vapor. In addition, the level of methylmercury (MeHg) intake by the workers was estimated from the MeHg concentration in their hair.

METHODSUrinary total mercury (THg) and hair THg and MeHg concentrations were measured in 26 Hg miners and smelter workers (i.e., exposed group), and 48 unexposed people (unexposed group).

RESULTSThe exposed group showed high geometric mean THg concentrations in urine (258 ng/ml, 226 μg/g creatinine) and hair (20.0 μg/g). The urinary THg concentration of the smelter workers in particular was extremely high (338 μg/g creatinine in urine). The highest urine THg concentration reached 4577 μg/g creatinine. THg concentrations in urine and hair showed a significant correlation in the exposed group (r=0.62), indicating the adhesion of Hg(0) vapor to hair. However, no such significant correlation was found in the unexposed group. Hair MeHg concentration in the exposed group (1.97 μg/g) was about threefold higher than that in the unexposed group (0.60 μg/g).

CONCLUSIONSThis study shows that smelter workers in a Chinese Hg mine are exposed to extremely high levels of Hg(0) vapor, and that Hg miners are exposed to higher levels of MeHg than the unexposed subjects. Further study is needed to determine the cause of the higher hair MeHg concentration in the exposed group.

OBJECTIVESExposure misclassification is a major obstacle to obtain accurate dose-response relationships. In order to solve this problem, the impact of hair treatment on total mercury in hair was assessed in Japanese women.

METHODSA cross-sectional study was carried out among 327 women at age 24-49 years to determine hair mercury levels and estimate daily mercury intakes from seafood by using a food frequency questionnaire.

RESULTSHair mercury levels in the women and daily mercury intake ranged from 0.11 to 6.86 (median 1.63) μg/g and from 0.77 to 144.9 (median 15.0) μg/day, respectively. The hair mercury was positively correlated with the daily mercury intake (p<0.001). When the women were divided into two subgroups based on artificial hair-waving, hair coloring/dyeing, residence (non-fishing and fishing areas), and working status, a significant difference in the hair mercury level was observed between the women with and without artificial hair-waving only (p<0.001). The multiple regression analysis showed that the log-transformed hair mercury level was significantly related to the log-transformed daily mercury intake (standardized regression coefficient βs=0.307) and artificial hair-waving (βs=-0.276); but not to hair coloring/dyeing, residence, working status or age. Permanent hair treatment was estimated to reduce total mercury in hair by approximately 30%, after adjusting for daily mercury intake and other possible factors.

CONCLUSIONSThese findings suggest that hair mercury is not the best biomarker of methylmercury exposure when a study population includes women with artificial hair-waving.