Results of the first national human biomonitoring in Slovenia: Trace elements in men and lactating women, predictors of exposure and reference values.

The first national human biomonitoring in Slovenia surveyed cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), manganese (Mn), selenium (Se), copper (Cu) and zinc (Zn) in a childbearing population (18-49 years) selected from lactating primiparous women and men (N = 1084). The overall aim was to estimate trace elements' levels and geographical variations in order to identify sources of possible exposures and set the national reference values. The study population was selected evenly from 12 study areas across Slovenia, including rural, urban and known or potentially contaminated environments. Within 6-8 weeks after delivery, venous blood, spot urine, scalp hair and breast milk samples were collected to determine the selected elements. The data analysis included descriptive statistics and multiple linear regression using elemental concentrations in biological matrices, questionnaire data and environmental datasets. Essential elements showed no significant deficiencies or excessive levels in the study population and were largely determined by sex and/or the participating women's physiological status (postpartum, lactation), as well as by certain dietary sources. Toxic elements' levels were mainly below the levels considered to present increased health risk. Lifestyle and nutritional habits appeared as significant determinants of exposure to Cd (smoking and game meat consumption), Hg (seafood and amalgam fillings), As (seafood) and Pb (alcohol consumption, smoking, game meat consumption and type of water supply). A distinctive geographical pattern was confirmed, due to past mining activities combined with naturally elevated background levels in the cases of Pb (Mezica Valley), Hg (Idrija and Posocje) and As exposure (Zasavje). Increased seafood consumption in the coastal study area contributed to higher Hg and As (arsenobetaine) levels. Extensive sample size database accompanied with life-style and environmental data improved the prediction of exposure patterns, set the reference values for the childbearing population living in Slovenia, and provided a strong basis for evaluating spatial and temporal trends in exposure. To our best knowledge, this is the first study to establish reference values for lactating primiparous women.

Relations between mercury fractions and microbial community components in seawater under the presence and absence of probable phosphorus limitation conditions.

Microbial transformations of toxic monomethylmercury (MMHg) and dissolved gaseous mercury (DGM) at the lower levels of the marine food web are not well understood, especially in oligotrophic and phosphorus-limited seas. To examine the effects of probable phosphorus limitation (PP-limitation) on relations between mercury (Hg) fractions and microorganisms, we determined the total mercury (THg), total methylated mercury (MeHg), DGM, and microbiological and chemical parameters in the Central Adriatic Sea. Using statistical analysis, we assessed the potential microbial effects on Hg transformations and bioaccumulation. Only in the absence of PP-limitation conditions (NO-PP-limitation) is MeHg significantly related to most chemical and microbial parameters, indicating metabolism-dependent Hg transformations. The heterotrophic activity of low nucleic acid bacteria (abundant in oligotrophic regions) seems responsible for most of Hg methylation under NO-PP-limitation. Under these conditions, DGM is strongly related to microbial fractions and chlorophyll a, indicating biological DGM production, which is probably not metabolically induced, as most of these relations are also observed under PP-limitation. MMHg biomagnification was observed through an increased bioaccumulation factor from microseston to mesozooplankton. Our results indicate that Hg transformations and uptake might be enhanced under NO-PP-limitation conditions, emphasizing their impact on the transfer of Hg to higher trophic levels.

Bioaccumulation of As, Hg, and Se in tunas Thunnus albacares and Katsuwonus pelamis from the Eastern Pacific: tissue distribution and As speciation.

With the aim of knowing the distribution of As, Hg, and Se in skipjack (Katsuwonus pelamis, Linnaeus, 1758) and yellowfin tuna (Thunnus albacares, Bonnaterre, 1788) from the Eastern Pacific, elemental concentrations were determined in the muscle and liver; As species were also analyzed in the stomach content. Additionally, health risk for consumers was assessed. For both tunas, levels of As and Se were significantly higher (p < 0.05) in the liver than in the muscle. In K. pelamis, Hg concentrations in the muscle were significantly higher (p < 0.05) than those in the liver. In T. albacares, As, Hg, and Se showed a trend to increase with fish dimensions. Arsenic extractability was better in the muscle than in the liver of both species; in K. pelamis, As species were better extracted than in T. albacares. In both tuna species, the most extractable arsenic was arsenobetaine (AsB) and a minor part was dimethylarsinic acid (DMA). The liver contained mainly AsB with some DMA and arsenocholine (AsC). Hazard indexes (HI) indicated no risk from Hg and Se intake through these tuna species. Considering the individual contribution to the HI, Hg contributed more (80 to 86%) than Se. In the context of health risk, none of the As and Hg values were above the permissible limits; however, two samples of T. albacares (9%) and three samples of K. pelamis (12%) had Se concentrations over the limits. If Hg and Se in the edible portion of tuna are considered under the approach of the HBVSe, tuna consumption is beneficial.

Prenatal mercury exposure, neurodevelopment and apolipoprotein E genetic polymorphism.

The aim of the present study was to evaluate the association between prenatal exposure to mercury (Hg) and neurodevelopment of the child, taking into account genetic polymorphism of apolipoprotein E (Apoe) and other relevant confounders. Six hundred and one mother-child pairs were recruited from the central Slovenia region and 243 from Rijeka, on the Croatian coast of the northern Adriatic. The total Hg in cord blood, Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) assessment at 18 months of age and Apoe genotyping was performed on 361 children; 237 of them were from Slovenia and 124 from Croatia. The results showed negative association between low-to-moderate Hg exposure in children with normal neurodevelopmental outcome and cognitive and fine motor scores at 18 months of age as assessed by Bayley III. The Hg-related decrease in cognitive score was observed only in children carrying at least one Apoe ε4 allele, while the decrease in fine motor scores was independent of the Apoe genotype. Adjusting for selenium (Se) and lead (Pb) levels, a positive association between Se and the language score and a negative association between Pb and the motor score was observed, but not in the subgroup of children carrying the ε4 allele.

Exposure to mercury in susceptible population groups living in the former mercury mining town of Idrija, Slovenia.

500 years of mercury (Hg) mining in the town of Idrija has caused severe pollution in Idrija and its surroundings. Following the closure of the mine in 1995, the environment remains contaminated with Hg. Sources of elemental-, inorganic- and methyl Hg exposure were identified, potential environmental level of exposure to Hg was evaluated and actual internal exposure to Hg was assessed in selected susceptible population groups comprising school-age children and pregnant women living in Idrija and in control groups from rural and urban environments. The study of pregnant women (n=31) was conducted between 2003 and 2008, and the study of school-age children (n=176) in 2008. Potential interaction of Hg with selenium (Se) in plasma was assessed in both study populations, while in pregnant women antioxidative enzyme activity (glutathione peroxidase, superoxide dismutase and catalase) in erythrocytes of maternal and cord blood was also assessed. Actual exposure to Hg as indicated by levels of Hg in children's blood (geometric mean (GM) 0.92µg/L), mother's blood (GM 1.86µg/L), children's urine (GM 1.08µg/g crea.), mother's urine (GM 2.51µg/L), children's hair (GM 241ng/g) and mother's hair (GM 251ng/g) was higher in the two study groups from Idrija than in the control groups from rural areas, but was still at the level of a "normal" population and reflects mainly exposure to elemental Hg (Hg°) from dental amalgam and, to a certain extent atmospheric Hg°. Furthermore, the internal doses of Hg received during pregnancy did not decrease the bioavailability of Se. Based on observation in children, the increase in Se protein expression is suggested to be a consequence of moderately elevated exposure to Hg°. The observed changes in activity of antioxidative enzymes, as biomarkers of oxidative stress, appear to be mainly associated with pregnancy per se and not with an increased exposure to Hg. In view of the continuing increased potential for Hg exposure and the low number of pregnant women studied, the results warrant a further longitudinal study of a larger group of pregnant women residing in the area of the former mercury mine.

[Fetal and perinatal exposure to mercury and selenium: baseline evaluation of a cohort of children in Friuli Venezia Giulia, Italy]. / Esposizione fetale e perinatale a mercurio e selenio: valutazione alla baseline di una coorte di bambini del Friuli Venezia Giulia.

OBJECTIVE: neurotoxicity of prenatal exposure to high concentrations of mercury (Hg) is well known; however, the doseresponse relationship at low exposure levels has not been quantified yet. This article illustrates the measurement of prenatal exposure to Hg and the pathway of exposure through the diet in Friuli Venezia Giulia, Italy. DESIGN: description of a prospective cohort at the baseline. SETTING AND PARTICIPANTS: 242 mother- infant pairs living in Friuli Venezia Giulia were enrolled between 1999 and 2001. MAIN OUTCOME MEASURES: We measured the concentrations of Hg in the hair of mothers and children and of Hg and selenium (Se) in breast milk. The diet during pregnancy was estimated through a food frequency questionnaire (FFQ) with a detailed section regarding fish. We calculated the correlations between Hg and Se in the biological samples and estimated the association between Hg concentrations and fish consumption. RESULTS: in general, Hg levels in hair and milk were positively associated with the consumption of fish from the lagoon of Grado and Marano. However, they were low in comparison with those of other fish-eating populations and below theWHO alert limits, likely because of the small consumption of fish among pregnant women, estimated from the FFQ. The concentration of Se in milk was also smaller than that reported in other international studies. CONCLUSION: in Friuli Venezia Giulia, fetal and perinatal Hg exposure is low. The children of the cohort will be followed- up at school age to measure possible neurodevelopmental effects of such low exposures to Hg.

Human exposure to mercury in the vicinity of chlor-alkali plant.

The main objectives of our study were to estimate the impact of a mercury cell chlor-alkali (MCCA) complex in Rosignano Solvay (Tuscany, Italy) on the local environment and to assess mercury exposure of inhabitants living near the plant. Measurement campaigns of atmospheric Hg near the MCCA plant showed that the impact of the emitted Hg from the industry on the terrestrial environment is restricted to a close surrounding area. Total gaseous mercury concentrations in ambient air of inhabited area around the MCCA plant were in the range of 8.0-8.7 ng/m3 in summer and 2.8-4.2 ng/m3 in winter. Peaks of up to 100 ng/m3 were observed at particular meteorological conditions. Background levels of 2 ng/m3 were reached within a radius of 3 km from the plant. Reactive gaseous mercury emissions from the plant constituted around 4.2% of total gaseous mercury and total particulate mercury emission constituted around 1.0% of total gaseous mercury emitted. Analysis of local vegetables and soil samples showed relatively low concentrations of total mercury (30.1-2919 microgHg/kg DW in the soil; <0.05-111 microgHg/kg DW in vegetables) and methylmercury (0.02-3.88 microgHg/kg DW in the soil; 0.03-1.18 microgHg/kg DW in vegetables). Locally caught marine fish and fresh marine fish from the local market had concentrations of total Hg from 0.049 to 2.48 microgHg/g FW, of which 37-100% were in the form of methylmercury. 19% of analysed fish exceeded 1.0 microgHg/g FW level, which is a limit set by the European Union law on Hg concentrations in edible marine species for tuna, swordfish and shark, while 39% of analysed fish exceeded the limit of 0.5 microgHg/g FW set for all other edible marine species. Risk assessment performed by calculating ratio of probable daily intake (PDI) and provisional tolerable daily intake (PTDI) for mercury species for various exposure pathways showed no risks to human health for elemental and inorganic mercury, except for some individuals with higher number of amalgam fillings, while PDI/PTDI ratio for methylmercury and total mercury exceeded the toxicologically tolerable value due to the potential consumption of contaminated marine fish.

Total mercury, methylmercury and selenium in mercury polluted areas in the province Guizhou, China.

The province of Guizhou in Southwestern China is currently one of the world's most important mercury production areas. Emissions of mercury from the province to the global atmosphere have been estimated to be approximately 12% of the world total anthropogenic emissions. The main objective of this study was to assess the level of contamination with Hg in two geographical areas of Guizhou province. Mercury pollution in the areas concerned originates from mercury mining and ore processing in the area of Wanshan, while in the area of Quingzhen mercury pollution originates from the chemical industry discharging Hg through wastewaters and emissions to the atmosphere due to coal burning for electricity production. The results of this study confirmed high contamination with Hg in soil, sediments and rice in the Hg mining area in Wanshan. High levels of Hg in soil and rice were also found in the vicinity of the chemical plant in Quingzhen. The concentrations of Hg decreased with distance from the main sources of pollution considerably. The general conclusion is that Hg contamination in Wanshan is geographically more widespread, due to deposition and scavenging of Hg from contaminated air and deposition on land. In Quingzhen Hg contamination of soil is very high close to the chemical plant but the levels reach background concentrations at a distance of several km. Even though the major source of Hg in both areas is inorganic Hg, it was observed that active transformation of inorganic Hg to organic Hg species (MeHg) takes place in water, sediments and soils. The concentration of Hg in rice grains can reach up to 569 microg/kg of total Hg of which 145 microg/kg was in MeHg form. The percentage of Hg as MeHg varied from 5 to 83%. The concentrations of selenium can reach up to 16 mg/kg in soil and up to 1 mg/g in rice. A correlation exists between the concentration of Se in soil and rice, indicating that a portion of Se is bioavailable to plants. No correlation between Hg and Se in rice was found. Exposure of the local population to Hg may occur due to inhalation of Hg present in air (in particular in Hg mining area) and consumption of Hg contaminated food (in particular rice and fish) and water. Comparison of intake through these different routes showed that the values of Hg considerably exceed the USA EPA Reference Concentration (RfC) for chronic Hg exposure (RfC is 0.0004 mg/m(3)) close to the emission sources. Intake of Hg through food consumption, particularly rice and fish, is also an important route of Hg exposure in study area. In general, it can be concluded that the population mostly at risk is located in the vicinity of smelting facilities, mining activities and close to the waste disposal sites in the wider area of Wanshan. In order to assess the real level of contamination in the local population, it is recommended that biomonitoring should be performed, including Hg and MeHg measurements in hair, blood and urine samples.