Maternal APOE ε2 as a possible risk factor for elevated prenatal Pb levels.

Lead (Pb) is a global contaminant associated with multiple adverse health effects. Humans are especially vulnerable during critical developmental stages. During pregnancy, exposure to Pb can occur through diet and release from maternal bones. Apolipoprotein E gene (APOE) variants (ɛ2, ɛ3, ɛ4 alleles) may influence sex steroid hormones, bone metabolism, and Pb kinetics. We examined the interplay among maternal APOE (mAPOE) genotypes, fetal sex, parity, and Pb in maternal and cord blood (mB-Pb, CB-Pb) using linear regression models. Our study involved 817 pregnant women and 772 newborns with measured adequate levels of zinc and selenium. We compared carriers of the ε2 and ε4 alleles to those with the ε3/ε3 genotype. The geometric means (range) of mB-Pb and CB-Pb were 11.1 (3.58-87.6) and 9.31 (1.82-47.0) ng/g, respectively. In cases with female fetuses, the maternal mAPOE ε2 allele was associated with higher, while the mAPOE ε4 allele was associated with lower mB-Pb and CB-Pb levels. Nulliparity increased the strength of the observed associations. These findings highlight the significance of mAPOE genetics, fetal sex, and parity in prenatal Pb kinetics. Notably, the maternal ε2 allele may increase the risk of Pb exposure.

Regional air quality study by assessing trace metal atmospheric deposition.

This study addresses the atmospheric deposition of trace elements investigated in Albania, Croatia and Macedonia in 2010 as part of the European Moss Study. This study provides data on the concentration of ten metals (Cd, Cr, Cu, Ni, Pb, V, Zn, Fe, Al, and Li) in naturally growing mosses. In general, all concentration data follow a lognormal distribution. Cd, Cr, Ni, and Zn show strong fluctuations in the moss samples from Albania and Macedonia, and Pb, Fe, and Al in the mosses from Croatia. The concentrations of Cd, Cu, and Zn were higher in the samples from Croatia than in those from Albania and Macedonia; the concentrations of Cr, Ni, V, Fe, Al, and Li were higher in the samples from Albania than in those from Croatia and Macedonia; and a higher concentration of Pb was found in the samples from Macedonia. The observed relationship between the concentration of lithogenic elements (Al, Fe, and V) and the air quality index (AQI) confirms that moss species have a high capacity to retain atmospheric deposition particles. The anthropogenic emission sources of these elements from local and long-range transport were considered to be the most important factors affecting air quality in the studied areas.

Pregnancy exposome and child psychomotor development in three European birth cohorts.

Characterization of the exposome, the totality of all environmental factors that one is exposed to from conception onwards, has been recommended to better evaluate the role of environmental influences on developmental programming and life-course vulnerability to major chronic diseases. In the framework of the Health and Environment-wide Associations based on Large population Surveys (HEALS) project we considered the pregnancy exposome exploiting two databases (PHIME and REPRO_PL) that include birth cohorts from three EU countries (Croatia, Slovenia and Poland). The databases contained information on several chemical exposures, socio-demographic, lifestyle and health related factors from conception to child birth, and neuropsychological scores assessed by the Bayley Scales of Infant and Toddler Development in the first two years of life. Our main goal was to assess consistency of environmental influences on neurodevelopment, if any, across European countries differing for geographical, socio-demographic characteristics and levels of chemical exposures to metals such as lead (Pb), mercury (Hg), cadmium (Cd) and trace elements, including micronutrients such as zinc (Zn) and selenium (Se). To this aim, we first selected variables common to the different databases, then applied univariate and multivariate regression analyses to identify factors linked to neurodevelopment, and finally performed meta-analysis to detect potential heterogeneity among cohorts and pooled estimates. Significant differences in exposure levels among the three sub-cohorts were observed as for Hg and Se; exposure levels under study were relatively low and within the range described in existing EU biomonitoring studies. The univariate analyses did not show any common pattern of association as only in the Polish cohort chemical exposure had an impact on neuropsychological outcome. In the meta-analysis, some consistent trends were evident, relative to the adverse influence of Pb on children's language and cognition and the positive influence of Se on language abilities. The effects of the neurotoxic metal Hg positively influenced the motor scores in the Polish cohorts, while it decreased the motor scores in the Slovenia and Croatian sub-cohorts. The only socio-demographic factor consistently associated to the outcome among cohorts was child's sex, with females performing better than males on cognitive and language scores. These findings point to the need of harmonizing existing cohorts or creating prospective study designs that facilitate comparisons in the exposome over time, places and kind of environmental exposures.

Study of nitrogen pollution in the Republic of North Macedonia by moss biomonitoring and Kjeldahl method.

In the summer of 2005 and 2010, moss samples were collected from 72 sampling sites evenly distributed all over the territory of Republic of North Macedonia. Kjeldahl method was used to determine the nitrogen content in the samples. Descriptive statistics and distribution maps were prepared. Data obtained from these two surveys were compared, and additional comparison was done with data obtained from similar studies in the South-Eastern European countries and Finland as a clean area. The median value of N content in the samples collected in 2005 is 1.21%, varies from 0.70% to 1.54%, while the content of N in samples collected in 2010 ranges between 0.68% and 1.75% with the median value of 1.06%. High contents of N were found in the Northern and Central parts of the country mainly as a result of agricultural activities, industry and traffic.

Mercury speciation in meconium and associated factors.

Meconium is formed early in gestation and it is normally not excreted until after birth. Thus it may provide a longer and cumulative record of exposure to mercury (Hg). The present study aims to speciate Hg in meconium samples (N = 488) from Slovenian and Croatian new-borns prenatally exposed to low levels of methyl-Hg (MeHg) from maternal seafood intake and to Hg0 from maternal dental amalgam fillings. We had complete data of total Hg (THg) and MeHg in meconium and THg in maternal hair (MH), while THg and MeHg in maternal blood (MB) were available only for Croatian mothers. Personal data namely maternal seafood intake, age, pre-pregnancy BMI, parity, smoking, estimated gestational age at birth, sex, and birth weight were available for the majority of participants, except the number of dental amalgams which was in most cases missing for Croatian mothers. The median THg concentration in meconium was 11.1 (range: 0.41-375.2) ng/g and inorganic Hg (Hg(II)) presented 98.8% (range: 82%-100%, CV: 2%) of THg. We observed significant correlation between meconium and MH Hg levels, with the highest correlation between hair THg and meconium MeHg. Correlation analysis including MB (available only for Croatian population) showed a significant positive correlation between THg in meconium and THg in MB (Rs = 0.642). Additionally, MeHg from MB was correlated with MeHg in meconium (Rs = 0.898), while the correlation between Hg(II) in MB and meconium was positive, but not significant. Maternal seafood intake was significantly correlated with meconium MeHg (Rs = 0.498) and Hg(II) (Rs = 0.201). Multiple linear regression (performed on the Slovenian population, N = 143) confirmed a positive association between meconium MeHg and seafood intake. Furthermore, meconium Hg(II) was positively associated with the number of maternal dental amalgam fillings, but linear regression models did not confirm correlation between seafood intake and meconium Hg(II) levels. We assume that Hg0 released from maternal dental amalgam fillings and MeHg from seafood intake were both transported through the placental barrier and portioned between different foetal compartments including meconium. Weak correlation between maternal seafood intake and Hg(II) levels in meconium suggests that there is certain evidence of MeHg demethylation. However, because this correlation was not confirmed by the multiple regression, MeHg demethylation during prenatal life cannot be neither confirmed nor excluded. Further investigations at higher level of exposure are needed to confirm this observations. We can conclude that meconium is a suitable biomarker for MeHg and Hg0 exposure during pregnancy. However, comparability of the results reported in meconium in different studies is hindered by a lack of standardized sampling protocols, storage, and analysis.

Arsenic metabolites; selenium; and AS3MT, MTHFR, AQP4, AQP9, SELENOP, INMT, and MT2A polymorphisms in Croatian-Slovenian population from PHIME-CROME study.

The relationships between inorganic arsenic (iAs) metabolism, selenium (Se) status, and genetic polymorphisms of various genes, commonly studied in populations exposed to high levels of iAs from drinking water, were studied in a Croatian-Slovenian population from the wider PHIME-CROME project. Population consisted of 136 pregnant women in the 3rd trimester and 176 non-pregnant women with their children (n = 176, 8-9 years old). Their exposure to iAs, defined by As (speciation) analyses of biological samples, was low. The sums of biologically active metabolites (arsenite + arsenate + methylated As forms) for pregnant women, non-pregnant women, and children, respectively were: 3.23 (2.84-3.68), 1.83 (1.54-2.16) and 2.18 (1.86-2.54) ng/mLSG; GM (95 CI). Corresponding plasma Se levels were: 54.8 (52.8-56.9), 82.3 (80.4-84.0) and 65.8 (64.3-67.3) ng/mL; GM (95 CI). As methylation efficiency indexes confirmed the relationship between pregnancy/childhood and better methylation efficiency. Archived blood and/or saliva samples were used for single nucleotide polymorphism (SNP) genotyping of arsenic(3+) methyltransferase - AS3MT (rs7085104, rs3740400, rs3740393, rs3740390, rs11191439, rs10748835, rs1046778 and the corresponding AS3MT haplotype); methylene tetrahydrofolate reductase - MTHFR (rs1801131, rs1801133); aquaporin - AQP 4 and 9 (rs9951307 and rs2414539); selenoprotein P1 - SELENOP (rs7579, rs3877899); indolethylamine N-methyltransferase - INMT (rs6970396); and metallothionein 2A - MT2A (rs28366003). Associations of SNPs with As parameters and urine Se were determined through multiple regression analyses adjusted using appropriate confounders (blood As, plasma Se, ever smoking, etc.). SNPs' influence on As methylation, defined particularly by the secondary methylation index (SMI), confirmed the 'protective' role of minor alleles of six AS3MT SNPs and their haplotype only among non-pregnant women. Among the other investigated genes, the carriers of AQP9 (rs2414539) were associated with more efficient As methylation and higher urine concentration of As and Se among non-pregnant women; poorer methylation was observed for carriers of AQP4 (rs9951307) among pregnant women and SELENOP (rs7579) among non-pregnant women; MT2A (rs28366003) was associated with higher urine concentration of AsIII regardless of the pregnancy status; and INMT (rs6970396) was associated with higher As and Se concentration in non-pregnant women. Among confounders, the strongest influence was observed for plasma Se; it reduced urine AsIII concentration during pregnancy and increased secondary methylation index among non-pregnant women. In the present study of populations with low As exposure, we observed a few new As-gene associations (particularly with AQPs). More reliable interpretations will be possible after their confirmation in larger populations with higher As exposure levels.

Combined prenatal exposure to mercury and LCPUFA on newborn's brain measures and neurodevelopment at the age of 18 months.

OBJECTIVES: Prenatal exposure of long chain polyunsaturated fatty acids (LCPUFA) are essential for normal fetal growth and neurodevelopment. Availability of LCPUFA depends mostly on maternal fish consumption. Fish consumption also exposes the fetus to mercury which is well known neurotoxicant. We analyzed the associations of combined LCPUFA and mercury from fish consumption during pregnancy on newborn's brain measures and child neurodevelopment in a northern Adriatic coastal area. PATIENTS AND METHODS: The prospective cohort study included 257 mother - infant pairs enrolled in a susceptible population of the Public Health Impact on long-term, low-level, Mixed Element exposure (PHIME) EU Sixth Framework Programme from 2 recruitment areas of the northern part of the Adriatic coast. Umbilical cord blood taken at delivery was used for measuring concentration of total mercury (THg) and specific LCPUFA - docosahexaenoic acid (DHA) and arachidonic acid (ARA). Neonatal cranial sonography was performed at the age of 3 days in 57 newborns. Neurodevelopmental assessment of cognitive, motor and language skills were conducted at 257 children at the age of 18 months using the Bayley Scales of Infant and Toddler Development, Third Edition. The participants were divided into two groups depending on the THg concentration in the umbilical cord blood (exposed > 5.8 µg/L and unexposed < 5.8 µg/L). Dietary habits and exposures to environmental and social factors were assessed through questionnaires. RESULTS: There is a statistically significant difference in the cerebellum length (p = 0.032) and the superior frontal gyrus width (p = 0.023) between the exposed and the unexposed group. In combined analysis, including possible protective variables as DHA and ARA (R2 = 0.22, p = 0.001), the negative contribution of THg on cerebellum length (beta = -0.16, p = 0.001) persisted. We found no correlation between THg concentration in umbilical cord blood and child neurodevelopment scores at the age of 18 months. Language score with receptive and expressive subscores was significantly associated with fish consumption (p < 0.05). CONCLUSION: This analysis demonstrates the existence of morphological brain changes in newborns that are prenatally exposed at mercury concentrations what was diminished in combined analyse including LCPUFA. Our results emphasizes the importance of LCPUFA's and mercury common influence as a predictor of developmental outcome. Fish consumption, not solely LCPUFA contributes to better language development of children at the age of 18 months.

Prenatal selenium status, neonatal cerebellum measures and child neurodevelopment at the age of 18 months.

OBJECTIVES: The aim of this study was to evaluate the association of maternal blood selenium (Se) levels and cord blood Se levels with neonatal cerebellum measures and child neurodevelopment at the age of 18 months. Moreover, to investigate whether the neonatal cerebellum measures could be used as a potential biomarker for selenium homeostasis during pregnancy. STUDY GROUP AND METHODS: The study population consisted of 205 mother-child pairs from Croatian Mother and Child Cohort. Maternal blood and cord blood were obtained at delivery and selenium level was analyzed by Inductively Coupled Plasma Mass Spectrometry. Cranial ultrasonography examination was performed on 49 newborns - cerebellum length and width have been measured. Neurodevelopmental assessment of cognitive, language and motor skills were conducted on 154 children, using The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III), at the age of 18 months. RESULTS: The mean levels of selenium in maternal blood and cord blood were 92.6 ng/g and 97.0 ng/g, respectively. Maternal blood selenium levels were moderately and negatively correlated (r = -0.372; p = 0.008) with cerebellum length, while cord blood selenium levels were positively correlated with cerebellum width (r = 0.613; p = 0.007) among female children group. Maternal blood selenium levels were weakly and positively correlated (r = 0.176; p = 0.029) with child's cognitive abilities. CONCLUSION: To the best of our knowledge, our study is the first one investigating the association between neonatal brain measures and selenium levels in mother-child pairs. Our results indicate that prenatal selenium intake correlated with cerebellum length and width measured by cranial ultrasonography. Hence, cerebellum may be used as a potential biomarker and a target "organ" for early detection of possible adverse effects of prenatal status to various micronutrients.

Mercury speciation in prenatal exposure in Slovenian and Croatian population - PHIME study.

In recent years, several studies have addressed the issue of prenatal exposure to methylmercury (MeHg); however, few have actually analysed MeHg blood concentrations. Our study population included mothers and their new-borns from Slovenia (central region; N = 584) and Croatia (coastal region; N = 234). We have measurements of total Hg (THg) and MeHg in maternal hair, maternal peripheral blood, and cord blood. Cord blood Hg concentrations were low to moderate (median THg = 1.84 ng/g and MeHg = 1.69 ng/g). The proportion of THg as MeHg (%MeHg) in maternal and cord blood varied between 4% and 100% (coefficient of variation, CV = 32%) and between 8% and 100% (CV = 20%), respectively. Our data shows that variability of %MeHg was higher at lower blood THg levels. Concentrations of MeHg in maternal blood and cord blood were highly correlated (Rs = 0.943), in the case of inorganic Hg correlation was significant but weaker (Rs = 0.198). MeHg levels in maternal blood and cord blood were positively associated with seafood intake, maternal age, and negatively associated with pre-pregnancy BMI. Additionally, MeHg in maternal blood was positively associated with plasma selenium levels, and cord blood MeHg was negatively associated with parity. The results of multiple linear regression models showed that speciation analysis provides more defined estimation of prenatal exposure in association modelling. Associations between Hg exposure and cognitive performance of children (assessed using Bayley Scales of Infant and Toddler development) adjusted for maternal or child Apolipoprotein E genotypes showed higher model R2 and lower p-values when adjusted for MeHg compared to THg. This study demonstrates that Hg speciation improves the association between exposure and possible negative health effects.

Biomarkers of exposure in environment-wide association studies - Opportunities to decode the exposome using human biomonitoring data.

BACKGROUND: The European Union's 7th Framework Programme (EU's FP7) project HEALS - Health and Environment-wide Associations based on Large Population Surveys - aims a refinement of the methodology to elucidate the human exposome. Human biomonitoring (HBM) provides a valuable tool for understanding the magnitude of human exposure from all pathways and sources. However, availability of specific biomarkers of exposure (BoE) is limited. OBJECTIVES: The objective was to summarize the availability of BoEs for a broad range of environmental stressors and exposure determinants and corresponding reference and exposure limit values and biomonitoring equivalents useful for unraveling the exposome using the framework of environment-wide association studies (EWAS). METHODS: In a face-to-face group discussion, scope, content, and structure of the HEALS deliverable "Guidelines for appropriate BoE selection for EWAS studies" were determined. An expert-driven, distributed, narrative review process involving around 30 individuals of the HEALS consortium made it possible to include extensive information targeted towards the specific characteristics of various environmental stressors and exposure determinants. From the resulting 265 page report, targeted information about BoE, corresponding reference values (e.g., 95th percentile or measures of central tendency), exposure limit values (e.g., the German HBM I and II values) and biomonitoring equivalents (BEs) were summarized and updated. RESULTS: 64 individual biological, chemical, physical, psychological and social environmental stressors or exposure determinants were included to fulfil the requirements of EWAS. The list of available BoEs is extensive with a number of 135; however, 12 of the stressors and exposure determinants considered do not leave any measurable specific substance in accessible body specimens. Opportunities to estimate the internal exposure stressors not (yet) detectable in human specimens were discussed. CONCLUSIONS: Data about internal exposures are useful to decode the exposome. The paper provides extensive information for EWAS. Information included serves as a guideline - snapshot in time without any claim to comprehensiveness - to interpret HBM data and offers opportunities to collect information about the internal exposure of stressors if no specific BoE is available.

Prenatal exposure to low-level methylmercury alters the child's fine motor skills at the age of 18 months.

OBJECTIVES: To compare motor, cognitive and language characteristics in children aged 18 months who were prenatally exposed to low-level methyl-mercury (MeHg), and to analyze the eventual differences in these characteristics in relation to cord blood THg concentration. PATIENTS AND METHODS: The total number of 205 child-mother pairs was included in the study, and total cord blood mercury was measured in 198 of them. Out of the 198 already measured samples, 47 of them have also been tested for methyl-mercury in cord blood. Data regarding the 47 samples of MeHg levels has been used for calculating the correlation between cord blood THg and cord blood MeHg. MeHg and THg showed a significant correlation (r=0.95, p<0.05). One month after the delivery, mothers were asked to complete the questionnaire regarding socioeconomic factors, breastfeeding of their infants, and dietary habits during pregnancy. Neurodevelopmental assessment of motor, cognitive and language skills were conducted on 168 children using The Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III). Regarding the cord blood THg concentration, 135 children were divided in 4 quartile groups. Their neurodevelopmental characteristics have been compared. RESULTS: The cord blood THg concentration median and inter-quartile range was 2.98ng/g (1.41-5.61ng/g). There was a negative correlation between cord blood THg concentration and fine motor skills (rho=-0.22, p=0.01). It is evident that children grouped in 2nd ,3rd and 4th quartile had statistically significant lower fine motor skills assessment related to those grouped in 1st quartile (2nd quartile -1.24, p=0.03; 3rd quartile -1.28, p=0.03; 4th quartile -1.45, p=0.01). The differences in fine motor skills assessments between children in 2nd and 3rd and 3rd and 4th quartile were not statistically significant. CONCLUSION: Intrauterine exposure to low-level THg (MeHg) is associated with alterations in fine motor skills at the age of 18 months.

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.

Mercury in Eisenia fetida and soil in the vicinity of a natural gas treatment plant in northern Croatia.

In the last two decades (1990-2012), as part of a mercury monitoring programme, earthworms and soils have been collected from four locations in the vicinity of a natural gas production and treatment plant near the village of Molve, Croatia. The aim of this study was to determine the concentration of mercury in the collected samples, monitor its changes over a longer period of time and determine the bioaccumulation of total mercury in earthworms (Eisenia fetida) from the soil. Total mercury concentrations in earthworms from the surroundings of four boreholes (Molve 9-12) ranged within 0.195-1.050, 0.129-1.0, 0.229-1.236 and 0.223-0.799 µg g-1 dry weight, while total mercury concentrations in different soil types at the same locations within 0.055-0.350, 0.035-0.250, 0.031-0.240 and 0.071-0.475 µg Hg g-1 of soil. The calculated mercury bioaccumulation factor ranged between 0.9 and 17.5. Mercury levels in soil and earthworms, as a tool for soil pollution assessment, suggested low mercury exposure and risks for human health in the monitored area.

Influence of cadmium on metallothionein expression and products of lipid peroxidation in the organs of hares (Lepus europaeus Pallas).

Cadmium occurs naturally in the environment and as an anthropogenic pollutant. Exposure to low concentrations of cadmium is inevitable and may produce toxic effects. Another important aspect of cadmium toxicity is its interaction, often antagonistic, with essential elements such as selenium. The aim of this study was to highlight the risks of long-term exposure to low cadmium concentrations, using a scientific and chemical approach and hares (Lepus europaeus Pallas) as model organisms in a field study. Two study areas were monitored. Levels of cadmium and selenium were quantified in the organs of hares, the expression of metallothioneins I + II and the products of lipid peroxidation were determined. The median cadmium concentrations (wet weight) in the muscle, liver, kidney and brain of hares from an exposed group ranged from 0.033 to 0.037, 0.763 to 1.054, 3.090 to 16.594 and 0.016 to 0.087 µg g(-1), respectively; whereas, the median selenium concentrations (wet weight) ranged from 0.100 to 0.108, 0.153 to 0.332, 0.677 to 0.701 and 0.078 to 0.116 µg g(-1), respectively. Expression of the metallothioneins I + II proteins was observed in tissues. Lipid peroxidation (LPO) levels, measured as malondialdehyde (MDA) equivalents, increased with the cadmium concentration. Further research on long-term exposure to low concentrations of cadmium in the environment is needed.

Study of nitrogen pollution in Croatia by moss biomonitoring and Kjeldahl method.

During the summer and autumn of 2006 moss samples were collected from 98 sampling sites evenly distributed all over the territory of Croatia. Moss sampling was repeated in 2010 when additional sampling sites were added and a total of 121 samples were collected. Kjeldahl method was used to determine the nitrogen content in the samples. Descriptive statistics and distribution maps were prepared. Data obtained from these two surveys were compared, and additional comparison was done with data obtained from similar studies in neighbouring countries and Finland as a clean area. The median value of N content in the samples collected in 2006 is 1.60% and varies from 0.79% to 3.16%. The content of N in samples collected in 2010 ranges between 0.71% and 2.93% with the median value of 1.49%. High contents of N (2.32% - 3.17%) were found in the regions of Slavonia, Podravina, Posavina and cities Zagreb and Sisak as a result of agricultural activities, industry and traffic.

A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts.

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, [Formula: see text]), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration of atmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m(-3), that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m(-3)) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m(-3). We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au-Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical-chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.

Biomonitoring of air pollution with mercury in Croatia by using moss species and CV-AAS.

Moss samples from four dominant species (Hypnum cupressiforme, Pleurozium schreberi, Homalothecium sericeum and Brachythecium rutabulum) were collected during the summer and autumn of 2010 from 121 sampling sites evenly distributed over the territory of Croatia. Samples were totally digested by using microwave digestion system, whilst mercury was analysed by using cold vapour atomic absorption spectrometry (CV-AAS). Descriptive statistics were done from analyses of mercury in all moss samples. The content of mercury ranged from 0.010 to 0.145 mg kg(-1) with a median value of 0.043 mg kg(-1). Hg distribution map shows the sites of the country with higher levels of this element. High contents of Hg were found in moss samples collected from the regions of Podravina and Istria as a result of anthropogenic pollution. Comparison of median values and ranges with those found in moss samples in 2006 shows slight reduction of mercury air pollution. When compared to the results obtained from recent studies conducted in Slovenia, Macedonia and especially in Norway-which serves as a reference considering the fact that it is a pristine area-mercury air pollution in Croatia is insignificant.

Mercury, arsenic and selenium exposure levels in relation to fish consumption in the Mediterranean area.

In order to assess mercury (Hg), selenium (Se) and arsenic (As) exposure in the Mediterranean area, total mercury (THg), monomethylmercury (MeHg), Se and As levels were measured in umbilical cord blood and breast milk from Italian (n=900), Slovenian (n=584), Croatian (n=234) and Greek (n=484) women. THg, MeHg, As, and Se levels were also determined in blood samples of the same mothers from Italy and Croatia. In addition, THg and MeHg were determined in the same women's hair from all the countries involved in this study and As and Se levels were determined in the mother's urine samples from Italy, Croatia and Greece. Besides recording the consumption of other food items, the frequencies of fish consumption were assessed by detailed food frequency questionnaires, since fish represents an important source of Hg, Se and As in humans. The highest levels of THg and As were found in cord blood (Med((THg))=5.8 ng/g; Med((As))=3.3 ng/g) and breast milk (Med((THg))=0.6 ng/g; Med((As))=0.8 ng/g) from Greek women, while the highest Se levels were found in cord blood (Med=113 ng/g) from Italy. Significant linear correlations were found between Hg, Se and As in blood, cord blood and breast milk. In addition, significant relations were found between the frequencies of total fish consumption and biomarkers of As, MeHg and Se exposure, with the strongest Spearman rank coefficients between frequencies of total fish consumption and THg levels in cord blood (r(s)=0.442, p<0.001) or THg levels in hair (r(s)=0.421, p<0.001), and between frequencies of total fish consumption and As levels in cord blood (r(s)=0.350, p<0.001). The differences in Hg and As exposure between countries were probably due to different amounts of fish consumption and the consumption of different species of fish of different origin, while the highest Se levels in women from Italy were probably the consequence of the more frequent consumption of different non specific food items. Moreover, fish consumption, the possible common source of As, Hg and Se intake, could explain the correlations between the elements determined in cord blood, mother's blood or breast milk.

Neurodevelopmental effects of low-level prenatal mercury exposure from maternal fish consumption in a Mediterranean cohort: study rationale and design.

BACKGROUND: Mercury is a neurotoxic environmental pollutant. However, the literature on the neurodevelopmental effect of low-level prenatal mercury exposure from maternal fish intake is inconsistent. We assessed the association between prenatal mercury exposure and infant neurodevelopment in coastal areas of 4 Mediterranean countries. METHODS: This was a prospective cohort study that planned to enroll approximately 1700 mother-infant pairs. Pregnant women and their newborn children were recruited in selected hospitals of the study areas. Biological samples, including maternal hair and cord blood, were collected from mothers and children, and the concentrations of mercury and other elements were measured. Exposures to lifestyle, environmental, and social factors were assessed through questionnaires. The main outcome was child neurodevelopment at 18 months, as measured by the Bayley Scales of Infant and Toddler Development, Third Edition. CONCLUSIONS: This cohort has a number of strengths. First, mercury concentration was measured in several biological samples, which allows for a better understanding of mercury kinetics and is useful for sensitivity analyses. Therefore, we expect to be able to adjust for the potential confounding effects of lifestyle and social factors and for the effects of other elements that were measured in the biological samples. Finally, this is a multinational study and thus permits assessment of the relation between mercury and child neurodevelopment in different populations.

Air pollution study in Croatia using moss biomonitoring and ICP-AES and AAS analytical techniques.

Moss biomonitoring technique was applied in a heavy-metal pollution study of Croatia in 2006 when this country participated in the European moss survey for the first time. This survey was repeated in 2010, and the results are presented in this study. For this purpose, 121 moss samples were collected during summer and autumn 2010. The content of 21 elements was determined by inductively coupled plasma-atomic emission spectrometry and atomic absorption spectrometry. Principal component analyses was applied to show the association between the elements. Six factors (F1-F6) were determined, of which two are anthropogenic (F3 and F6), two are mixed geogenic-anthropogenic (F1 and F5), and two are geogenic factors (F2 and F4). Geographical distribution maps of the elements over the sampled territory were constructed using geographic information systems technology. Comparison of the median values of some of the anthropogenic elements-such as arsenic, cadmium, chromium, copper, mercury, nickel, lead, vanadium, and zinc-with those from the 2006 study shows that anthropogenic pollution has changed insignificantly during the last 5 years. The data obtained in the investigation in Norway are taken for comparison with pristine area, which indicates that Croatia is somewhat polluted but still, shows a more favourable picture when compared with two neighbouring countries.