Maternal Hair Hg Research Articles

Maternal diet quality during pregnancy and biomarkers of potentially toxic trace element exposure: Data from the ELFE cohort

The contribution of the diet to potentially toxic trace element exposure in pregnancy has been rarely addressed. The objective of the present study was to determine the association between the maternal diet during pregnancy and biomarkers of exposure for arsenic (As), mercury (Hg) and lead (Pb) at delivery. As was assessed in maternal urine, Hg in maternal hair, and Pb in cord blood, as a proxy for in utero exposure. Based on 2995 women from the ELFE nationwide birth cohort, higher scores for dietary patterns considered healthy were associated with higher concentrations of As and Hg in maternal matrices. Levels of cord blood Pb were inconsistently associated with dietary patterns considered healthy, and lower with a dietary pattern driven by milk and breakfast cereals. Lower levels of Hg were associated with higher Western dietary pattern scores. In conclusion, higher levels of maternal urinary As and hair Hg are associated with diets considered as “Healthy”, while cord blood Pb was not strongly correlated with dietary exposure.

Impact of GSTT1 AND GSTM1 variants and hair mercury concentration in maternal blood pressure among coastal pregnant women in Central Java, Indonesia

The GSTT1 and GSTM1 genes have a role in mercury metabolism and excretion, as well as blood pressure response, impacting birth outcomes. The present study assesses whether GSTT1 and GSTM1 deletion variants and maternal hair Hg concentration are associated with blood pressure and birth outcomes among the Indonesian coastal pregnant mother population. A cross-sectional study was conducted on 139 pregnant women in the Jepara coastal area of Central Java, Indonesia. Maternal characteristics during pregnancy, including blood pressure and birth outcomes, were collected. GSTT1 and GSTM1 gene variants were detected using polymerase chain reaction (PCR). Hair Hg levels were measured using the reducing-vaporization mercury analyzer. The mean maternal hair Hg concentration was 0.727±0.558 μg/g. GSTT1 genotype homozygous deletion was found in 41.7% of subjects, while no GSTM1 deletion was found. No statistically significant difference was found between deletion and non-deletion groups for hair Hg. GSTT1 deletion genotype shows protection but is inconclusive toward diastolic hypertension (p=0.048, OR 0.285, CI 0.077–1.052) and insignificant with birth outcomes (all p>0.05). High hair Hg concentration and positive history of cardiovascular diseases increase the risk of systolic and diastolic hypertension during pregnancy with OR 6.871 (CI 95% 1.445–32.660) and 8.518 (CI 95% 2.126–34.125), respectively, while not in birth outcomes. Maternal Hg exposure and history of cardiovascular diseases are independent risk factors for pregnant hypertension, whereas the GSTT1 homozygous deletion genotype has no role in diastolic hypertension and birth outcomes among the Indonesian coastal pregnant mother population.

The First Exposure Assessment of Mercury Levels in Hair among Pregnant Women and Its Effects on Birth Weight and Length in Semarang, Central Java, Indonesia.

(1) Background: Methylmercury (MeHg) exposure during pregnancy is an important issue due to its possible adverse health effects on fetus. To contribute the development of assessment system of Hg exposure through fish consumption and health effects on children, we examined the hair Hg levels in pregnant women and birth weight and length. (2) Methods: In 2018, a cohort study was conducted on 118 pregnant women-infant pairs from six community health centers in the northern coastal area in Central Java Indonesia. Data on mothers’ characteristics during pregnancy, birth outcomes, and fish consumption were collected. Total Hg concentrations were determined from hair samples. (3) Results: The median (min-max) of the maternal hair Hg level was 0.434 (0.146–8.105) µg/g. Pregnant women living in lowland areas, near the sea, showed higher hair Hg concentration and fish consumption than those in highland areas {[0.465 (0.146–8.105) vs. 0.385 (0.150–1.956) µg/g; p = 0.043] and [(85.71 (0–500.0) vs. 49.76 (0.0–428.57) g/day; p < 0.01], respectively}. The maternal hair Hg level had no association with baby’s birth weight and length. (4) Conclusions: The median maternal hair Hg is at a low level and had no association with infant birth weight and length in this study subjects.

Prenatal exposure to neurotoxic metals and micronutrients and neurodevelopmental outcomes in early school age children from Poland.

Exposure to environmental factors, such as neurotoxic metals and micronutrients, during critical periods of development can contribute to long-term consequences in offspring's health, including neurodevelopmental outcomes. The aim of this study was to evaluate the association between simultaneous prenatal exposure to metals [lead (Pb), cadmium (Cd), mercury (Hg)] and micronutrients [selenium (Se), zinc (Zn), copper (Cu)] and neurodevelopmental outcomes in school-age children from the Polish Mother and Child Cohort (REPRO_PL). Metals and micronutrients concentrations were measured in cord blood (Pb, Cd, Se, Zn, Cu) and in maternal hair (Hg) collected during the 3rd trimester of pregnancy. Behavioral and emotional problems, as well as children's cognitive and psychomotor development, were assessed in 436 school-age children using the Strengths and Difficulties Questionnaire (SDQ, filled in by the mothers) and the Polish adaptation of the Intelligence and Development Scales (IDS, administered by trained psychologists). Multivariate regression models were applied after imputation of missing values, using two approaches: (i) a joint analysis taking into account all metals and micronutrients simultaneously, and (ii) an ExWAS study (single-exposure model). In the SDQ, Hyperactivity/Inattention problems and Total difficulties were associated with higher Hg concentrations in maternal hair (0.18, 95% CI: 0.05; 0.3; and 0.14, 95% CI: 0.01; 0.3, respectively), whereas Emotional symptoms were inversely associated with Se and Zn levels in cord blood (-0.13, 95% CI: -0.3; 0.004; and -0.10, 95% CI: -0.2; 0.02, respectively). In the IDS, cord blood Pb levels were found to be negatively associated with Fluid and Crystallized IQ (-0.12, 95% CI: -0.3; 0.02; and -0.14, 95% CI: -0.3; 0.007, respectively) as well as Mathematical skills (-0.15, 95% CI: -0.3; 0.01). The current research has been able to simultaneously assess the exposure to various interacting chemicals during the prenatal period. We demonstrate that prenatal co-exposures to Pb, Hg, Zn and Se have long-term influences on the neuropsychological outcome of school-age children.

Mercury levels in pregnant women in Japanese general population and child birth size

In Japan, approximately 80-90% of human mercury (Hg) exposure is derived from fish consumption. In Japan, a methyl-Hg (MeHg) poisoning due to intake of contaminated fish, Minamata Disease occurred in 1956. Since then, Japanese government established environmental standards and emission reduction and guidelines to maintain fish intake. Consequence, MeHg intake remained unchanged since 1994, as mean levels of 8.4 µg/person/day among Japanese general population. In this presentation, we introduce birth cohort studies conducted in Japan, and discuss their association to children’s birth size.We have conducted the Hokkaido study on Environment and Children’s Health: Sapporo cohort. Pregnant women were enrolled in 2002 to 2005, with total 514 agreement. The maternal hair Hg levels of 1.41 µg/g at delivery. Prenatal exposure to MeHg has no association with newborn anthropometric measurements, although the incidence of babies born small-for gestational age by weight may reduce with higher concentrations of Hg in hair. Fish is the main exposure source of Hg but also of long-chain polyunsaturated fatty acids. High frequency of fish consumption may mask the adverse effects of MeHg on birth size with the beneficial effect of essential nutrition. Other studies in Japan are 1. Tohoku region of Japan with 486 infants in 2001-2003. Median total Hg in whole cold blood is 10.1 ng/g and found no association with a reduction of birth weight among all infant. 2. Japan Environment and Children’s Study with approximately 100,000 mothers enrolled from 2011-2014. Total Hg in maternal blood were median 3.66 ng/g. Only slight association was found that compared to infants of lowest maternal Hg quartile, infants of highest maternal Hg quartile had a reduced birth head circumference. Consider as a whole, the results suggest that there are no associations with prenatal Hg exposure and birth size at this level.

Prenatal Mercury Exposure in Pregnant Women from Suriname's Interior and Its Effects on Birth Outcomes.

Prenatal mercury (Hg) exposure was determined in a sub-cohort of the Caribbean Consortium for Environmental and Occupational Health’s environmental epidemiologic prospective cohort study of pregnant women living in Suriname’s interior. The associations between Hg exposure, low birth weight (LBW, <2500 g) and preterm birth (PTB, <37 weeks) were explored. Correlation analysis, Fisher’s exact test and logistic regression analyses were conducted to evaluate the associations between maternal hair Hg levels and birth weight, LBW and PTB, and between potential confounders, LBW and PTB, respectively. Among 204 singleton births were 198 live births, five stillbirths and one miscarriage. The mean participant age was 26 years; 15.7% of participants had PTBs and 8.1% delivered a child with a LBW. The median hair Hg level was 3.48 μg/g hair. Low hair Hg exposure, based on lowest tertile < 2.34 μg/g, was associated with LBW (OR = 7.2; 95% CI 1.5–35.6; p = 0.015); this association was independent of maternal age, ethnic background, household income and village location, and no correlation was found between hair Hg and PTB. Young maternal age was associated with PTB (RR = 5.09, 95% CI: 1.92–13.85; p = 0.0004) while maternal age was not associated with hair Hg or LBW. The impact of prenatal Hg exposure on pediatric neurodevelopment is currently being evaluated in the infant sub-cohort.

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.

Global burden of intellectual disability resulting from prenatal exposure to methylmercury, 2015

We describe analyses to estimate the global burden of disease associated with methylmercury (MeHg). An intelligence quotient < 70, indicating intellectual disability (ID), was selected as the critical disease, maternal hair Hg concentration during pregnancy selected as the critical exposure biomarker, and a dose-effect relationship of an 0.18 point IQ reduction per µg/g increase in maternal hair Hg was assumed, based on a meta-analysis. A systematic review was conducted to obtain country-specific data on the distribution of maternal hair Hg concentrations. The country-specific incidence of MeHg-associated ID was calculated, and a random effects model was used to impute the incidence for countries for which no exposure data could be found. The global burden of MeHg-associated ID was quantified in terms of Disability-Adjusted Life Years (DALYs) using the World Health Organization (WHO) Global Health Estimates methodology, and presented by 14 subregions. In 2015, the global total for MeHg-associated cases of ID was 226,655; 210,074 of these cases (93%) were mild cases of ID. The highest rate of ID (6 cases per 100,000 population) was found in the Americas D subregion. The global DALY estimate was 1,963,869. The Western Pacific B subregion contributed the most to this total (696,417), although the Americas D subregion had the greatest rate (54 DALYs per 100,000 population). The burden of disease associated with MeHg is therefore highly subregion-dependent even in areas that are geographically related. The priority given to reducing this burden can therefore be expected to vary considerably by subregion depending on other health needs.

Maternal polymorphisms in glutathione-related genes are associated with maternal mercury concentrations and early child neurodevelopment in a population with a fish-rich diet

IntroductionGlutathione (GSH) pathways play a key role the metabolism and elimination of the neurotoxicant methylmercury (MeHg). We hypothesized that maternal genetic variation linked to GSH pathways could influence MeHg concentrations in pregnant mothers and children and thereby also affect early life development. MethodsThe GCLM (rs41303970, C/T), GCLC (rs761142, T/G) and GSTP1 (rs1695, A/G) polymorphisms were genotyped in 1449 mothers in a prospective study of the Seychellois population with a diet rich in fish. Genotypes were analyzed in association with maternal hair and blood Hg, fetal blood Hg (cord blood Hg), as well as children's mental (MDI) and motor development (PDI; MDI and PDI assessed by Bayley Scales of Infant Development at 20 months). We also examined whether genotypes modified the association between Hg exposure and developmental outcomes. ResultsGCLC rs761142 TT homozygotes showed statistically higher mean maternal hair Hg (4.12 ppm) than G carriers (AG 3.73 and GG 3.52 ppm) (p = 0.037). For the combination of GCLC rs761142 and GCLM rs41303970, double homozygotes TT + CC showed higher hair Hg (4.40 ppm) than G + T carriers (3.44 ppm; p = 0.018). No associations were observed between GSTP1 rs1695 and maternal hair Hg or between any genotypes and maternal blood Hg or cord blood Hg. The maternal GSTP1 rs1695 rare allele (G) was associated with a lower MDI among children (β = −1.48, p = 0.048). We also observed some interactions: increasing Hg in maternal and cord blood was associated with lower PDI among GCLC rs761142 TT carriers; and increasing Hg in hair was associated with lower MDI among GSTP1 rs1695 GG carriers. ConclusionsMaternal genetic variation in genes involved in GSH synthesis is statistically associated with Hg concentrations in maternal hair, but not in maternal or fetal blood. We observed interactions that suggest maternal GSH genetics may modify associations between MeHg exposure and neurodevelopmental outcomes.

Tribal Commercial Fish Harvests in the Upper Laurentian Great Lakes Consistently Demonstrate Nutritional Importance Along with Risks.

Introduction: The Great Lakes Native American tribes are traditionally a fishing culture; however due to fear of fish contamination they only consume one third of the recommended fish intake. The Inter-Tribal Fisheries and Assessment Program (ITFAP) in Sault Ste. Marie, MI regularly monitors contaminant concentrations in the fillet portions of lake trout and whitefish from lakes Superior, Huron, and Michigan. A risk quantification analysis of Methylmercury (MeHg) adjusted for nutritional benefit in fish caught during the 2012, 2013, and 2014 tribal fish harvests was conducted. Methods: The Ginsberg and Toal (2009, 2015) method was used to estimate the health benefits (decreased risk of cardiovascular disease (CHD)) and neurodevelopment (predicted improved visual recall memory (VRM) of infants exposed in-utero) if each species was consumed at 6 ounces/week. The CHD model estimates the difference of 23% higher risk/1 ppm hair Hg from the 14.6% lower risk/100 mg Omega-3. The neurodevelopment model estimates the difference in -3.5 VRM points/1 ppm maternal hair Hg from t +3.04 VRM points/100 mg maternal Omega-3. These estimates were applied to the average MeHg concentrations in the ITFAP fish samples and reported Omega-3 values for each species/lake. Results: Clear benefits relative to risks were observed for both species. Predicted benefits for whitefish were +3.9 VRM points/ -22.5% CHD risk (L. Superior), +1.7 VRM points/-14.1% CHD risk (L. Michigan), and +2.2 VRM points/-16% CHD risk (L. Huron). Estimated health benefits for lake trout were: + 4.1 VRM points/-26.8% CHD risk (L. Superior), +9.0 VRM points/-49% CHD risk (L. Michigan), and +5.7 VRM points/-35.2% CHD risk (L. Huron). Discussion: This is consistent with previous findings that tribal harvests provide clear health benefits and further demonstrate the importance of traditionally-caught fish for tribal health. It also justifies culturally-responsive outreach to help navigate dietary trade-offs.

Traditional living in the Amazon: Extended breastfeeding, fish consumption, mercury exposure and neurodevelopment

Background: Features of traditional living in the Amazon Basin (high fish consumption and long breastfeeding) are likely to expose children to Mercury (Hg).Aim: To study neurodevelopment in 690 children in relation to prolonged breastfeeding and mercury exposure.Subjects and methods: Three groups of breastfeeding children were formed: Group 1 (breastfed for 6 months), Group 2 (7–12 months) and Group 3 (extending up to 24 months). Neurodevelopment was assessed as age of walking, age of talking and the Bayley Scales of Infant Development–BSID. Mercury exposure was assessed from Thimerosal-containing vaccines and fish consumption from hair Hg (HHg).Results and conclusions: HHg increased in children and decreased in mothers at 24 months. Frequency of fish consumption was significantly correlated with maternal HHg at birth (Spearman’s r = 0.8583; p = 0.0001); likewise, there was a significant correlation between duration of breastfeeding and children’s HHg (Spearman’s r = 0.15; p = 0.0018). Extended breastfeeding did not influence the Mental Development Index–MDI or Psychomotor Development Index–PDI, but maternal education and HHg (marker of fish consumption) interacted positively and significantly with both. Frequency of maternal fish consumption and education had a positive association with BSID scores; it is speculated that maternal education and nutrients in fish have an opposing effect on Hg exposure.

Polymorphisms in ATP-binding cassette transporters associated with maternal methylmercury disposition and infant neurodevelopment in mother-infant pairs in the Seychelles Child Development Study

BackgroundATP-binding cassette (ABC) transporters have been associated with methylmercury (MeHg) toxicity in experimental animal models. AimsTo evaluate the association of single nucleotide polymorphisms (SNPs) in maternal ABC transporter genes with 1) maternal hair MeHg concentrations during pregnancy and 2) child neurodevelopmental outcomes. Materials and methodsNutrition Cohort 2 (NC2) is an observational mother-child cohort recruited in the Republic of Seychelles from 2008–2011. Total mercury (Hg) was measured in maternal hair growing during pregnancy as a biomarker for prenatal MeHg exposure (N=1313) (mean 3.9ppm). Infants completed developmental assessments by Bayley Scales of Infant Development II (BSID-II) at 20months of age (N=1331). Genotyping for fifteen SNPs in ABCC1, ABCC2 and ABCB1 was performed for the mothers. ResultsSeven of fifteen ABC SNPs (ABCC1 rs11075290, rs212093, and rs215088; ABCC2 rs717620; ABCB1 rs10276499, rs1202169, and rs2032582) were associated with concentrations of maternal hair Hg (p<0.001 to 0.013). One SNP (ABCC1 rs11075290) was also significantly associated with neurodevelopment; children born to mothers with rs11075290 CC genotype (mean hair Hg 3.6ppm) scored on average 2 points lower on the Mental Development Index (MDI) and 3 points lower on the Psychomotor Development Index (PDI) than children born to mothers with TT genotype (mean hair Hg 4.7ppm) while children with the CT genotype (mean hair Hg 4.0ppm) had intermediate BSID scores. DiscussionGenetic variation in ABC transporter genes was associated with maternal hair Hg concentrations. The implications for MeHg dose in the developing child and neurodevelopmental outcomes need to be further investigated.

Body Burden of Mercury in Different Bio-Samples of Mothers in Shenyang City, China

Mercury is an accumulative and neuro-toxic heavy metal which has a wide range of adverse effects in human health. However, few studies are available on body burden of Hg level in different bio-samples of pregnant women in Chinese population. Therefore, this study evaluated mercury levels in different maternal bio-samples in Shenyang city, China and investigated the correlation of mercury levels in different bio-samples. From October to December 2008, 200 pregnant women about to deliver their babies at ShengJing Hospital (Shenyang city, northeast of China) participated in this study. The geometric mean (GM) of Hg levels in cord blood, maternal venous blood, breast milk, and maternal urine were 2.18µg/L, 1.17µg/L, 1.14µg/L, and 0.73µg/L, respectively, and the GM of maternal hair Hg level was 404.45 µg/kg. There was a strong correlation between cord blood and maternal blood total Hg level (r=0.713, P&lt;0.001). Fruit consumption was suggested as a protective factor to decrease the prenatal Hg exposure risk (OR=0.15, p=0.018). This study provides evidence about Hg burden of mothers and the risk factors of prenatal Hg exposure in Shenyang city, China.

Body burden of Hg in different bio-samples of mothers in Shenyang city, China.

Hg is an accumulative and neuro-toxic heavy metal which has a wide range of adverse effects in human health. However, few studies are available on body burden of Hg level in different bio-samples of pregnant women in Chinese population. Therefore, this study evaluated Hg levels in different maternal bio-samples in Shenyang city, China and investigated the correlation of Hg levels in different bio-samples. From October to December 2008, 200 pregnant women about to deliver their babies at ShengJing Hospital (Shenyang city, northeast of China) participated in this study. The geometric mean (GM) of Hg levels in cord blood, maternal venous blood, breast milk, and maternal urine were 2.18 µg/L, 1.17 µg/L, 1.14 µg/L, and 0.73 µg/L, respectively, and the GM of maternal hair Hg level was 404.45 µg/kg. There was a strong correlation between cord blood and maternal blood total Hg level (r = 0.713, P<0.001). Frequency of fish consumption more than or equal to 3 times per week during pregnancy was suggested as a significant risk factor of prenatal Hg exposure (unadjusted OR 3.5, adjusted OR 2.94, P<0.05). This study provides evidence about Hg burden of mothers and the risk factors of prenatal Hg exposure in Shenyang city, China.

Economic benefits of methylmercury exposure control in Europe: Monetary value of neurotoxicity prevention

BackgroundDue to global mercury pollution and the adverse health effects of prenatal exposure to methylmercury (MeHg), an assessment of the economic benefits of prevented developmental neurotoxicity is necessary for any cost-benefit analysis.MethodsDistributions of hair-Hg concentrations among women of reproductive age were obtained from the DEMOCOPHES project (1,875 subjects in 17 countries) and literature data (6,820 subjects from 8 countries). The exposures were assumed to comply with log-normal distributions. Neurotoxicity effects were estimated from a linear dose-response function with a slope of 0.465 Intelligence Quotient (IQ) point reduction per μg/g increase in the maternal hair-Hg concentration during pregnancy, assuming no deficits below a hair-Hg limit of 0.58 μg/g thought to be safe. A logarithmic IQ response was used in sensitivity analyses. The estimated IQ benefit cost was based on lifetime income, adjusted for purchasing power parity.ResultsThe hair-mercury concentrations were the highest in Southern Europe and lowest in Eastern Europe. The results suggest that, within the EU, more than 1.8 million children are born every year with MeHg exposures above the limit of 0.58 μg/g, and about 200,000 births exceed a higher limit of 2.5 μg/g proposed by the World Health Organization (WHO). The total annual benefits of exposure prevention within the EU were estimated at more than 600,000 IQ points per year, corresponding to a total economic benefit between €8,000 million and €9,000 million per year. About four-fold higher values were obtained when using the logarithmic response function, while adjustment for productivity resulted in slightly lower total benefits. These calculations do not include the less tangible advantages of protecting brain development against neurotoxicity or any other adverse effects.ConclusionsThese estimates document that efforts to combat mercury pollution and to reduce MeHg exposures will have very substantial economic benefits in Europe, mainly in southern countries. Some data may not be entirely representative, some countries were not covered, and anticipated changes in mercury pollution all suggest a need for extended biomonitoring of human MeHg exposure.

Mercury and docosahexaenoic acid levels in maternal and cord blood in relation to segmental maternal hair mercury concentrations at parturition

Fish is a major source of harmful methylmercury (MeHg) and beneficial docosahexaenoic acid (DHA) in the developing brain. In this study, we investigated the correlations among maternal and umbilical cord (cord) MeHg and DHA levels at parturition, and mercury (Hg) concentration in 1-cm incremental segments hair samples which grew during gestation representing monthly MeHg exposure levels throughout the period. Whole blood Hg and plasma DHA levels were measured in blood sample pairs collected from 54 mothers at early gestation and parturition, and in cord blood. Maternal hair samples were collected at parturition, and Hg concentrations were measured in 1-cm incremental segments. Hg level in mothers at parturition was slightly lower than that at early gestation and the level in cord blood were approximately 1.9 times higher than that in mothers at parturition. On the other hand, DHA level in mothers at parturition was approximately 2.3 and 1.6 times higher than those in mothers at early gestation and in cord plasma, respectively. These results indicate that kinetics of these chemicals in mothers during gestation and placental transfer are completely different. However, Hg and DHA levels had significant positive correlation in fetal circulation. The cord blood Hg showed the strongest correlation with maternal hair Hg in the first 1-cm segment from the scalp at parturition (r=0.87), indicating that fetal MeHg level reflects maternal MeHg burden at late gestation. In contrast, maternal and cord plasma DHA concentrations at parturition showed the highest correlation coefficients with Hg in the fifth (r=0.43) and fourth (r=0.38) 1-cm hair segments, suggesting that maternal and fetal DHA levels reflects maternal fish intake during mid-gestation.

Perinatal lead and mercury exposure in Austria

Objective The heavy metals lead (Pb) and mercury (Hg) are ubiquitous environmental pollutants with high neurotoxic potential. We aimed to compare perinatal Pb and Hg concentrations and to explore the potential association between Pb and Hg exposure and newborn anthropometry. Study design Pregnant women were recruited in 2005 at the General Hospital Vienna for participation in this longitudinal study. Pb and Hg concentrations were measured in maternal blood and hair, placenta, cord blood, meconium, and breast milk of 53 mother-child pairs by CV-AAS, GF-AAS, and HPLC-CV-ICPMS. We conducted bivariate analyses and categorical regression analysis (CATREG) to evaluate the determinants of Pb and Hg exposure, and of infant anthropometry. Results Median Pb and total Hg contents were low, i.e., 25 μg/L (maternal blood-Pb), 13 μg/L (cord blood-Pb), 0.7 μg/L (maternal blood-Hg), and 1.1 μg/L (cord blood-Hg). Hg levels in maternal and fetal tissues were frequently correlated ( r > 0.3, P < 0.05, respectively). Regarding Pb, only maternal blood and cord blood concentrations correlated ( P = 0.043). Cord blood levels indicated higher Hg exposure but lower Pb exposure relative to maternal blood contents. Adjusted CATREG models indicated the significant predictors of birth length (placenta-Pb, gestational length, meconium-Pb), birth weight (placenta-Pb, gestational length, maternal blood-Pb), and head circumference (maternal education, maternal height). Besides one significant correlation between maternal hair Hg and birth length, the mercury levels were not associated with newborn anthropometry. Conclusions Our data implicate that different modes of action may exist for placentar transfer of Pb and Hg as well as that low Pb exposure levels can result in lower birth weight. The findings related to newborn anthropometry need to be confirmed by the examination of larger study groups. Further research is needed to clarify the mechanisms of Pb and Hg transfer via the placenta, and to explore how prenatal Pb exposure is related to intrauterine growth.

Fish consumption by traditional subsistence villagers of the Rio Madeira (Amazon): Impact on hair mercury

Background: Subsistence ribeirinhos of the Amazon Basin depend on fish for their principal source of protein, but fish availability changes with seasonal high and low waters.Aim: To assess taxa and quantity of fish consumed and estimate attendant exposure to methyl-Hg in a traditional subsistence high fish-eating community of the Amazon Basin.Subjects and methods: 120 villagers in 18 households were followed for 6 months (August to February) for weighed portions of fish consumed.Results: Mean daily per capita fish consumption was high (406 g/day) with fish meals ranging from 4 to 14 times/week and an integrated yearly consumption of 148.2 kg/person. Median total-Hg concentrations in fish ranged from 0.011 to 0.409 ppm; six of the more consumed fish species comprised more than 50% of the fish consumed. The villagers mean hair-Hg concentration was high (17.4 ± 11.5 μg/g), with both inter- and intra-household variation despite similar high fish consumption; only 7% showed hair-Hg concentrations < 5 μg/g, but 75% had hair-Hg levels above 10 μg/g. Maternal hair-Hg was significantly correlated with respective children's hair-Hg (Spearman r = 0.5390; p < 0.0001). The high daily fish intake of these villagers is predominantly of species with much lower Hg concentrations.Conclusion: In Amazonian lifestyle of ribeirinho communities traditional fish consumption is high and depends on available species; fish is also the principal via of meHg exposure and attendant hair-Hg concentrations.

Monoamine oxidase activity in placenta in relation to manganese, cadmium, lead, and mercury at delivery

BackgroundEnvironmental prenatal exposure to potentially neurotoxic metals poses a particular challenge with regard to the study of early toxic effects. Monoamine oxidase activity, shown to be influenced by metals in experimental studies, could be a useful biomarker in humans. ObjectiveTo examine the relationship between blood metal concentrations at delivery and placenta MAO activity. MethodsThe study was performed in 163 pregnancies. Maternal and cord blood samples were obtained for manganese (Mn), lead (Pb), and cadmium (Cd) determination. Mercury (Hg) was also analysed in maternal hair. Placental samples were stored immediately after expulsion and total MAO activity was measured. ResultsMAO activity was significantly positively correlated with maternal and cord blood Mn concentrations in subjects with high MAO activity. In subjects with low MAO activity, maternal hair Hg was negatively correlated with MAO. ConclusionOur results suggest the use of placental MAO as a potential surrogate marker of Mn toxicity in the newborn and its correlation with psychomotor development should be further investigated.

Prenatal exposure to mercury and neurobehavioral development of neonates in Zhoushan City, China

Exposure to hazardous Hg can adversely affect children's neurodevelopment. However, few data are available on either Hg levels in neonates and their mothers or the impact of prenatal exposure to Hg on neonates’ neurobehavioral development in the Chinese population. Therefore, this study examined Hg levels in neonates and their mothers and the relationship between prenatal exposure to Hg and neonates’ neurobehavioral development in Zhoushan City, Zhejiang Province, China. Between August and October 2004, 417 women who delivered their babies at Zhoushan Women's and Children's Health Hospital, an island city in east China were invited to take part in this study. A total of 408 complete questionnaires, 405 maternal hair samples, and 406 umbilical cord samples were collected. Neonatal behavioral neurological assessments (NBNA) were conducted for 384 neonates. The geometric mean (GM) of Hg level in cord blood was 5.58 μg/L (interquartile range: 3.96–7.82 μg/L), and the GM of maternal hair Hg level was 1246.56 μg/kg (interquartile range: 927.34–1684.67 μg/kg), a level much lower than other reported fish-eating populations, indicating Hg exposure in Zhoushan city is generally below those considered hazardous. However, according to the reference dose of Hg levels (RfD 5.8 μg/L) derived by EPA, 69.9% of newborns had levels at or above the RfD, an estimated level assumed to be without appreciable harm. There was a strong correlation between maternal hair and cord blood Hg levels ( r=0.82, P<0.01). Frequency of fish consumption was associated with hair Hg ( r=0.48, P<0.01) and cord blood Hg levels ( r=0.54, P<0.01). Increased prenatal Hg exposure was associated with decreased behavioral ability for males (OR=1.235, 95%CI of OR=1.078–1.414, P<0.001), but not for females. Our results provide some support for the hypothesis that there is neurodevelopmental risk for males from prenatal MeHg exposure resulting from fish consumption. But the findings of this study may be due to chance, and long-term follow-up research is needed to evaluate cumulative effects of exposure to mercury.