Consumption of tomato products is associated with lower blood mercury levels in Inuit preschool children

Environment in Children's Health: A New Challenge for Risk Assessment

In the last few years, many studies have focused on the effects of environmental contaminant exposure during the prenatal period or infancy as predictors of health outcomes in the future. In these time windows, due to their rapid growth, and physiologic and metabolic development, we can observe a higher vulnerability to the effects of environment, with respect to adulthood. The evidence of possible influences, partly mediated by epigenetic mechanisms, involve neurobehavioral responses and immune, endocrine, and respiratory systems, acting directly on the child or indirectly when mediated by placental transfer or breast feeding. In particular, due to a greater intake of air, food, and fluids relative to body weight, crawling behaviors and short stature, the risk of excessive exposure is greater in children. However, data on the long-term implications of early exposures are scarce. Additionally, so that physicians and institutions for child care and assistance of pregnant women can take actions to counteract the effects of chemical pollution (i.e., by educational opportunities), a risk assessment perspective that responds to the biocomplexity of the human being is needed. The present paper provides an overview of physiologic and behavioral characteristics during the perinatal period and in childhood, suggesting in a more integrated way, the need of a new risk-assessment approach to managing chronic disease in pediatric patients.

New directions in understanding the role of environmental contaminants in child development: Four themes

Environmental contaminants, which include several heavy metals, persistent organic pollutants, and other harmful chemicals, impair several domains of child development. This article describes four themes from recent research on the impact of environmental contaminants on child development. The first theme, disparities in exposure, focuses on how marginalized communities are disproportionately exposed to harmful environmental contaminants. The second theme, complexity of exposures, encapsulates recent emphases on timing of exposures and mixtures of multiple exposures. The third theme, mechanisms that link exposures to outcomes, focuses on processes that elucidate how contaminants impact outcomes. The fourth theme, mitigating risks associated with exposures, sheds light on potential protective factors that could ameliorate many of the harmful effects of contaminant exposures. Developmental scientists are well positioned to contribute to interdisciplinary research that addresses these themes, which could foster additional conceptual and empirical innovations and inform policies and practices to mitigate risks and improve children's well-being.

Seafood, wine, rice, vegetables, and other food items associated with mercury biomarkers among seafood and non-seafood consumers: NHANES 2011-2012

Fish/seafood consumption is a source of mercury; other dietary sources are not well described. This cross-sectional study used National Health and Nutrition Examination Survey (NHANES) 2011-2012 data. Participants self-reported consuming fish/seafood (N = 5427) or not (N = 1770) within the past 30 days. Whole blood total mercury (THg), methylmercury (MeHg), and urinary mercury (UHg) were determined. Diet was assessed using 24 h recall. Adjusted regression models predicted mercury biomarker concentrations with recent food consumption, while controlling for age, sex, education, and race/ethnicity. Geometric mean THg was 0.89 µg/L (95% confidence interval (CI): 0.78, 1.02) (seafood consumers) and 0.31 µg/L (95% CI: 0.28, 0.34) (non-seafood consumers); MeHg and UHg concentrations follow similar patterns. In adjusted regressions among seafood consumers, significant associations were observed between mercury biomarkers with multiple foods, including fish/seafood, wine, rice, vegetables/vegetable oil, liquor, and beans/nuts/soy. Among non-seafood consumers, higher THg was significantly associated with mixed rice dishes, vegetables/vegetable oil, liquor, and approached statistical significance with wine (p < 0.10); higher MeHg was significantly associated with wine and higher UHg was significantly associated with mixed rice dishes. Fish/seafood consumption is the strongest dietary predictor of mercury biomarker concentrations; however, consumption of wine, rice, vegetables/vegetable oil, or liquor may also contribute, especially among non-seafood consumers.

Predictors of urinary and blood Metal(loid) concentrations among pregnant women in Northern Puerto Rico

Given the potential adverse health effects related to toxic trace metal exposure and insufficient or excessive levels of essential trace metals in pregnant women and their fetuses, the present study characterizes biomarkers of metal and metalloid exposure at repeated time points during pregnancy among women in Puerto Rico. We recruited 1040 pregnant women from prenatal clinics and collected urine, blood, and questionnaire data on demographics, product use, food consumption, and water usage at up to three visits. All samples were analyzed for 16 metal(loid)s: arsenic (As), barium (Ba), beryllium (Be), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), titanium (Ti), uranium (U), vanadium (V), and zinc (Zn). Urine samples were additionally analyzed for molybdenum (Mo), platinum (Pt), antimony (Sb), tin (Sn), and tungsten (W). Mean concentrations of most metal(loid)s were higher among participants compared to the general US female population. We found weak to moderate correlations for inter-matrix comparisons, and moderate to strong correlations between several metal(loid)s measured within each biological matrix. Blood concentrations of Cu, Zn, Mn, Hg, and Pb were shown to reflect reliable biomarkers of exposure. For other metals, repeated samples are recommended for exposure assessment in epidemiology studies. Predictors of metal(loid) biomarkers included fish and rice consumption (urinary As), fish and canned food (blood Hg), drinking public water (blood Pb), smoking (blood Cd), and iron/folic acid supplement use (urinary Cs, Mo, and Sb). Characterization of metal(loid) biomarker variation over time and between matrices, and identification of important exposure sources, may inform future epidemiology studies and exposure reduction strategies.

Twenty "must-read" research articles for primary care providers in Nunavik: scoping study and development of an information tool

While health needs in Nunavik are distinct, there is a scarcity of knowledge transfer intended for local primary care providers. We aimed to build an information tool in the form of a newsletter and a website to share with them a selection of relevant research articles. To identify such articles, a scoping study of Inuit health research published between 2012 and 2017 was conducted. Selection criteria were adapted from the framework of information mastery. After a database search yielding 2896 results, publications were screened for eligibility. Next, the 226 eligible articles were evaluated and scored for their relevance, their methods (including community participation), their local applicability and their clinical utility. The 20 highest-scored articles were selected for dissemination in a newsletter. They were summarised and presented in 6 thematic emails: Child Development, Infectious Diseases, Traditional and Modern Medicine, Metabolism, Nutrition and Contaminants, and Inuit Perspectives. The newsletter was sent to over 190 health workers and regional stakeholders in Nunavik and was also published online. We hope that this project will foster knowledge sharing and inter-sectorial collaboration between research, public health and clinical care. Trends in Inuit health research are discussed.

Co-administration of a Rhododendron tomentosum extract does not affect mercury tissue concentrations and excretion rate in methylmercury-treated adult male rats

Objectives

Consumption of fish/seafood is clearly linked to higher mercury levels in human tissue samples. However, correlations between methylmercury (MeHg) intakes calculated from dietary surveys and mercury body burdens are usually weak and can vary across populations. Different factors may affect MeHg absorption, distribution, metabolism and excretion, including co-exposures to phytochemicals and antibiotics, which were shown to affect mercury body burdens in rodents. Based on the observation that rat pups developmentally exposed to MeHg and a Rhododendron tomentosum extract (Labrador Tea) presented significantly higher blood mercury levels at weaning compared to pups exposed to MeHg alone, the modulation of MeHg toxicokinetics by Labrador Tea was further investigated in adult rats.

Results

Total mercury levels were quantified in the blood, liver, kidney and feces of adult male rats exposed to MeHg (1.2 mg/kg bodyweight/day, for 3 weeks) administered either alone or in combination with Labrador Tea (100 mg/kg bodyweight/day) or with an antibiotics cocktail (to inhibit MeHg demethylation by gut bacteria). While the reduced fecal excretion and higher blood mercury levels expected from antibiotics-treated rats were observed, mercury levels in samples from Labrador Tea-treated rats were not significantly different from those measured in samples from rats exposed to MeHg alone.

Electronic supplementary material

The online version of this article (10.1186/s13104-019-4409-7) contains supplementary material, which is available to authorized users.

Children's Hair Mercury Concentrations and Seafood Consumption in Five Regions of Japan

Exposure to methylmercury (MeHg) during the foetal and postnatal periods is known to have adverse effects on children's development. However, little attention has been paid to MeHg exposure during early childhood in Japan. To examine the regional differences in MeHg exposure and seafood consumption and the association between MeHg exposure and seafood consumption and dental metal restorations, we measured the total mercury (T-Hg) concentration in hair as an MeHg exposure index, and using questionnaires, we measured the frequency and amount of seafood consumption and the presence of dental metal restorations in 118 children aged 3-6 years in five regions of Japan. The arithmetic and geometric means of the T-Hg concentrations in hair were 1.03 and 0.87 ppm, respectively, and approximately 40% of the children exceeded the United States Environmental Protection Agency recommendation of 1.0 ppm. Significant regional differences in the hair T-Hg concentrations were found among the five regions, and the regional differences were consistent with the traditional regional patterns of eating fatty fish. According to the regression analysis, the consumption of fatty fish, particularly tuna/swordfish, had a significant effect on hair T-Hg concentrations, whereas age, sex, the materials used for dental metal restorations, and other types of seafood or fish/shellfish had no significant effects.

Spatial, Temporal, and Dietary Variables Associated with Elevated Mercury Exposure in Peruvian Riverine Communities Upstream and Downstream of Artisanal and Small-Scale Gold Mining

Artisanal and small-scale gold mining (ASGM) is a primary contributor to global mercury and its rapid expansion raises concern for human exposure. Non-occupational exposure risks are presumed to be strongly tied to environmental contamination; however, the relationship between environmental and human mercury exposure, how exposure has changed over time, and risk factors beyond fish consumption are not well understood in ASGM settings. In Peruvian riverine communities (n = 12), where ASGM has increased 4–6 fold over the past decade, we provide a large-scale assessment of the connection between environmental and human mercury exposure by comparing total mercury contents in human hair (2-cm segment, n = 231) to locally caught fish tissue, analyzing temporal exposure in women of child bearing age (WCBA, 15–49 years, n = 46) over one year, and evaluating general mercury exposure risks including fish and non-fish dietary items through household surveys and linear mixed models. Calculations of an individual’s oral reference dose using the total mercury content in locally-sourced fish underestimated the observed mercury exposure for individuals in many communities. This discrepancy was particularly evident in communities upstream of ASGM, where mercury levels in river fish, water, and sediment measurements from a previous study were low, yet hair mercury was chronically elevated. Hair from 86% of individuals and 77% of children exceeded a USEPA (U.S. Environmental Protection Agency) provisional level (1.2 µg/g) that could result in child developmental impairment. Chronically elevated mercury exposure was observed in the temporal analysis in WCBA. If the most recent exposure exceeded the USEPA level, there was a 97% probability that the individual exceeded that level 8–10 months of the previous year. Frequent household consumption of some fruits (tomato, banana) and grains (quinoa) was significantly associated with 29–75% reductions in hair mercury. Collectively, these data demonstrate that communities located hundreds of kilometers from ASGM are vulnerable to chronically elevated mercury exposure. Furthermore, unexpected associations with fish mercury contents and non-fish dietary intake highlight the need for more in-depth analyses of exposure regimes to identify the most vulnerable populations and to establish potential interventions.

Current progress on understanding the impact of mercury on human health

Mercury pollution and its impacts on human health is of global concern. The authors of this paper were members of the Plenary Panel on Human Health in the 12th International Conference on Mercury as a Global Pollutant held in Korea in June 2015. The Panel was asked by the conference organizers to address two questions: what is the current understanding of the impacts of mercury exposure on human health and what information is needed to evaluate the effectiveness of the Minamata Convention in lowering exposure and preventing adverse effects. The authors conducted a critical review of the literature published since January 2012 and discussed the current state-of-knowledge in the following areas: environmental exposure and/or risk assessment; kinetics and biomonitoring; effects on children development; effects on adult general populations; effects on artisanal and small-scale gold miners (ASGM); effects on dental workers; risk of ethylmercury in thimerosal-containing vaccines; interactions with nutrients; genetic determinants and; risk communication and management. Knowledge gaps in each area were identified and recommendations for future research were made. The Panel concluded that more knowledge synthesis efforts are needed to translate the research results into management tools for health professionals and policy makers.

A suggested approach for imputation of missing dietary data for young children in daycare

Background

Parent-reported 24-h diet recalls are an accepted method of estimating intake in young children. However, many children eat while at childcare making accurate proxy reports by parents difficult.

Objective

The goal of this study was to demonstrate a method to impute missing weekday lunch and daytime snack nutrient data for daycare children and to explore the concurrent predictive and criterion validity of the method.

Design

Data were from children aged 2-5 years in the My Parenting SOS project (n=308; 870 24-h diet recalls). Mixed models were used to simultaneously predict breakfast, dinner, and evening snacks (B+D+ES); lunch; and daytime snacks for all children after adjusting for age, sex, and body mass index (BMI). From these models, we imputed the missing weekday daycare lunches by interpolation using the mean lunch to B+D+ES [L/(B+D+ES)] ratio among non-daycare children on weekdays and the L/(B+D+ES) ratio for all children on weekends. Daytime snack data were used to impute snacks.

Results

The reported mean (± standard deviation) weekday intake was lower for daycare children [725 (±324) kcal] compared to non-daycare children [1,048 (±463) kcal]. Weekend intake for all children was 1,173 (±427) kcal. After imputation, weekday caloric intake for daycare children was 1,230 (±409) kcal. Daily intakes that included imputed data were associated with age and sex but not with BMI.

Conclusion

This work indicates that imputation is a promising method for improving the precision of daily nutrient data from young children.

Assessment of neurotoxic effects of mercury in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) from the Canadian Arctic

Marine mammals are indicator species of the Arctic ecosystem and an integral component of the traditional Inuit diet. The potential neurotoxic effects of increased mercury (Hg) in beluga whales (Delphinapterus leucas), ringed seals (Pusa hispida), and polar bears (Ursus maritimus) are not clear. We assessed the risk of Hg-associated neurotoxicity to these species by comparing their brain Hg concentrations with threshold concentrations for toxic endpoints detected in laboratory animals and field observations: clinical symptoms (>6.75 mg/kg wet weight (ww)), neuropathological signs (>4 mg/kg ww), neurochemical changes (>0.4 mg/kg ww), and neurobehavioral changes (>0.1mg/kg ww). The total Hg (THg) concentrations in the cerebellum and frontal lobe of ringed seals and polar bears were <0.5mg/kg ww, whereas the average concentration in beluga whale brain was >3mg/kg ww. Our results suggest that brain THg levels in polar bears are below levels that induce neurobehavioral effects as reported in the literature, while THg concentrations in ringed seals are within the range that elicit neurobehavioral effects and individual ringed seals exceed the threshold for neurochemical changes. The relatively high THg concentration in beluga whales exceeds all of the neurotoxicity thresholds assessed. High brain selenium (Se):Hg molar ratios were observed in all three species, suggesting that Se could protect the animals from Hg-associated neurotoxicity. This assessment was limited by several factors that influence neurotoxic effects in animals, including: animal species; form of Hg in the brain; and interactions with modifiers of Hg-associated toxicity, such as Se. Comparing brain Hg concentrations in wildlife with concentrations of appropriate laboratory studies can be used as a tool for risk characterization of the neurotoxic effects of Hg in Arctic marine mammals.

More than half of US youth consume seafood and most have blood mercury concentrations below the EPA reference level, 2009-2012

BACKGROUND

Consuming seafood has health benefits, but seafood can also contain methylmercury, a neurotoxicant. Exposure to methylmercury affects children at different stages of brain development, including during adolescence.

OBJECTIVE

The objective was to examine seafood consumption and blood mercury concentrations in US youth.

METHODS

In the 2009-2012 NHANES, a cross-sectional nationally representative sample of the US population, seafood consumption in the past 30 d and blood mercury concentrations on the day of examination were collected from 5656 youth aged 1-19 y. Log-linear regression was used to examine the association between frequency of specific seafood consumption and blood mercury concentration, adjusting for race/Hispanic origin, sex, and age.

RESULTS

In 2009-2012, 62.4% ± 1.4% (percent ± SE) of youth consumed any seafood in the preceding month; 38.4% ± 1.4% and 48.5% ± 1.5% reported consuming shellfish and fish, respectively. In 2009-2012, the geometric mean blood mercury concentration was 0.50 ± 0.02 μg/L among seafood consumers and 0.27 ± 0.01 μg/L among those who did not consume seafood. Less than 0.5% of youth had blood mercury concentrations ≥5.8 μg/L. In adjusted log-linear regression analysis, no significant associations were observed between frequency of breaded fish or catfish consumption and blood mercury concentrations, but frequency of consuming certain seafood types had significant positive association with blood mercury concentrations: high-mercury fish (swordfish and shark) [exponentiated β coefficient (expβ): 2.40; 95% CI: 1.23, 4.68]; salmon (expβ: 1.41; 95% CI: 1.26, 1.55); tuna (expβ: 1.38; 95% CI: 1.29, 1.45); crabs (expβ: 1.35; 95% CI: 1.17, 1.55); shrimp (expβ: 1.12; 95% CI: 1.05, 1.20), and all other seafood (expβ: 1.23; 95% CI: 1.17, 1.32). Age-stratified log-linear regression analyses produced similar results.

CONCLUSION

Few US youth have blood mercury concentrations ≥5.8 μg/L, although more than half of US youth consumed seafood in the past month.

Effect of dietary calcium intake on lead exposure in Inuit children attending childcare centres in Nunavik

High blood lead levels (BLLs) can be found in Inuit from Nunavik. At the same time, various nutrients such as calcium could lower lead absorption and toxicity. We examined the effect of dietary calcium intakes on BLLs in 245 preschool Inuit children attending childcare centres in Nunavik. Calcium intake was assessed with one 24-h dietary recall and BLLs were determined by inductively coupled plasma mass spectrometry in whole blood samples. Multiple imputation was performed to deal with missing data. Median blood lead concentration was 0.08 μmol/L. A high proportion of children did not meet the Estimated Average Requirement for vitamin D intake (73 %) and, to a lower extent, for calcium (20 %). Calcium intake was negatively associated with BLLs (p = 0.0001) while child's age and energy intake were positively associated with BLLs (p = 0.015 and p = 0.024, respectively). Consuming traditional foods rich in calcium as well as milk and alternatives may protect against lead exposure.

Contribution of dietary patterns to blood heavy metal concentrations in Korean adults: findings from the Fifth Korea National Health and Nutrition Examination Survey 2010

The aim of the present study was to evaluate the associations between dietary patterns and blood levels of lead and mercury in Korean adults. A total of 858 Korean adults (≥20 years) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) V-1 2010 were included in this study. Data of biochemical measurements including blood lead and mercury levels, nutrients intakes and anthropometric measurements were acquired. 'Balanced diet', 'Grain and kimchi', and 'Alcohol and noodle' dietary patterns were derived from a factor analysis, and the subjects were divided into tertiles by each dietary pattern score. A logistic multiple regression analysis showed that the balanced diet pattern was negatively associated with blood levels of lead before and after adjustment. On the other hand, the alcohol and noodle pattern was positively associated with blood lead and mercury levels. These results indicate that the alcohol and noodle dietary pattern characterized by high alcohol consumption and lack of various foods, and the balanced dietary pattern, including vegetable, fish, meat and milk intake, was associated with the blood concentrations of heavy metals in Korean adults.