Blood Mercury Research Articles

Respiratory conditions in children exposed to mining waste dust, a cohort study in Bruminha project

Background/aim: On January 25th, 2019, the tailings dam I of the “Córrego do Feijão” mine, owned by Vale, collapsed in Brumadinho, state of Minas Gerais, Brazil. This disaster reached a vast territorial extension and produced a 12 million m³ of mining rejects, with accumulation and dissemination of mud and dust in the affected areas and exposing the local population to metal residues. Children are one of the more susceptible groups to the toxic effects of metal waste. This study evaluates the toxic effects of metal residues exposure on the respiratory system of 0-4 years old children living in the affected areas. Methods: This is a prospective cohort that will follow 200 children for 4 years. We will apply baseline and follow-up questionnaires to collect sociodemographic and health information from parents and children, besides clinical assessment of children and collection of biological samples for the measurement of Arsenic, Cadmium, Lead and Mercury in urine (in the 1st and 2nd years) and blood (in the 3rd and 4th years) matrices. The obtained data will be analyzed using frequency measures and regression models. Expected results: The first field stage is foreseen for May 2020, where it is intended to outline a pattern and profile of exposure to metals and their effects on the respiratory and immune systems in the population studied. Conclusions: This summary presents a proposal for investigating the occurrence of respiratory disorders in children living in communities affected by the disaster in Brumadinho and it intends to contribute to the priority setting related to the development of surveillance and health care actions for these populations.

Identifying Multiple Exposure Burden with National Biomonitoring Data

Background The main impetus for the current assessment and management of hazardous chemicals is on its doses and health effect, but fewer studies have evaluated types of chemical mixtures, number of exposed chemicals and the vulnerable groups in general public. This study investigated exposure load through national biomonitoring program to pursue the exposure complexity over general population and to assess multipollutant exposure burden. Methods We obtained data from the Korean National Environmental Health Survey (2015-2017) and 6,167 participants were recruited including 571 preschoolers(3 to 5), 887 school-aged children(6 to 11) , 922 adolescent(12 to 18) and 3,787 adults(19 and older). All subjects were sampled for urinary levels of mercury, cadmium, polycyclic aromatic hydrocarbon(PAH) metabolites, volatile organic compound(VOC) metabolites, phthalate metabolites, parabens, environmental phenols, pyrethroid metabolite and cotinine. Additionally, blood lead and blood mercury levels were measured for ages 12 and older. In total, 26 chemicals were included in the analysis. We conducted several exposure load calculations with binary values for each individual analyte with different age groups and thresholds(limit of detection(LOD), 50th, 75th ,95th). Results Using LOD as exposure thresholds, 20% of all participants(age 3 to 86) were exposed to more than 25 chemicals. With 50th, 75th ,95th percentile thresholds, 20% of each population were exposed to more than 18, 11 and 2 chemicals, respectively. For participants who had the highest exposure to each chemical(95th percentile) cadmium was the most frequent chemical and 17.2% of all population had more than one heavy metal(mercury, lead, cadmium) exposure. For each age group, the most frequent chemical differed; cadmium for adults, bisphenol F and A for adolescent, monobenzyl phthalate for school-aged children, and 1-hydroxyphenanthrene for preschoolers. Conclusions These results can improve multipollutant exposure burden assessment, especially for the highly susceptible population and can strengthen national chemical management practice.

The study on the detection method for mercury in blood with direct mercury analyzer

Objective: To establish a method for determining mercury in blood with direct mercury analyzer. Methods: After the whole blood sample was extracted by solvent and removed by nitric acid, it was then measured by direct mercury analyzer. Results: After optimizing the conditions of the instrument, the linear range was 0.3-60.0 μg/L and the curve correlation coefficient was higher than 0.999. The lower limit of quantitations was 0.3 μg/L and the minimum quantitative concentration was 3.0 μg/L. The recovery and relative standard deviations (RSD) was 95.2%-97.6% and 1.4%-3.3%. Conclusion: The method is stable, reliable, easy to operate and has high sensitive. It can be used to determine mercury in blood.

Element profiles in blood and teeth samples of children with congenital heart diseases in comparison with healthy ones

BackgroundSome elements were claimed to play a role in the pathogenesis of congenital heart defects (CHD) and influence the general well-being and health of these children. ObjectivesWe aimed to assess the levels of some elements simultaneously in the blood and teeth samples of children with cyanotic and acyanotic CHD compared with healthy children. MethodsA total of 39 children with CHD (11 with cyanotic and 28 with acyanotic CHD) and 42 age- and sex-adjusted controls were enrolled. Levels of 13 elements, including magnesium, phosphorus, calcium, chromium, manganese, iron, copper, zinc, strontium, cadmium, lead, mercury, and molybdenum, were assessed using inductively coupled plasma mass spectrometry. ResultsChildren with cyanotic and acyanotic CHD had significantly lower teeth calcium and calcium/phosphorus ratio as compared to the controls after adjusting for confounders. The mean blood iron level was found to be significantly higher in the cyanotic CHD group compared to the other groups. In addition, children with acyanotic CHD had significantly higher teeth copper levels, higher blood molybdenum and lower blood magnesium levels compared to the healthy control group. Blood cadmium and mercury levels were found to be significantly elevated in both the cyanotic and acyanotic CHD groups compared to the healthy control group. There were no differences in toxic metal levels of teeth in cases with CHD. ConclusionMonitoring adequate and balanced gestational micronutrient intake might support not only maternal health but also fetal cardiac development and infant well-being. Supplementation of magnesium should be evaluated in patients having CHD.

Decreased plasma thiol antioxidant capacity precedes neurological signs in a rat methylmercury intoxication model

The main target organ for MeHg is the nervous system, and its neurological dysfunction remains irreversible. Therefore, predictive biomarkers associated with individual susceptibility to MeHg and future clinical severity are needed to protect against the progression of MeHg toxicity. In this study, we demonstrated that plasma thiol antioxidant capacity (-SHp) is a useful predictive biomarker associated with future clinical severity using MeHg-intoxicated rats administered 1 mg/kg/day for 4 weeks. Blood samples were collected from the subclavian vein of each rat once a week to examine total blood mercury concentrations and the levels of plasma oxidative stress markers. Time course analyses of the correlation between these weekly blood examination values and hind limb crossing signs score after 4 weeks of MeHg exposure were performed, and plasma -SHp levels after 2 weeks of MeHg exposure showed strong correlations with future hind limb crossing sign scores. Neuropathological changes also developed in parallel with hind limb crossing sign scores. Quantitative analysis of vacuolar areas in the spinal cord showed a strong correlation with hind limb crossing sign scores. In conclusion, evaluation of plasma -SHp levels allowed us to detect individuals at risk for health damage and could protect the sensitive population against MeHg toxicity.

Link between blood mercury levels and skin cancer in the USA

British Journal of DermatologyVolume 183, Issue 3 p. e76-e76 Plain Language SummaryFree Access Link between blood mercury levels and skin cancer in the USA First published: 02 September 2020 https://doi.org/10.1111/bjd.19362AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Abstract Non-melanoma skin cancer (NMSC), also known as keratinocyte cancer, includes squamous cell carcinoma and basal cell carcinoma and affects more than 5 million people aged over 65 years in the USA every year. We need to understand more about the causes of skin cancer in order to prevent it. Exposure to mercury is an occupational hazard in the nuclear weapons industry, some chemical plants and dentistry. Workers exposed to mercury are at greater risk of brain and lung cancers than the rest of the population, but little is known about their risk of skin cancer. In addition, few studies have focused on how mercury exposure, mainly from eating fish, affects the general population. Previous studies looked at mercury exposure in terms of occupation but did not look at actual mercury levels in the body. These public health doctors and dermatologists from the USA looked for a link between blood mercury levels and NMSC using data from the National Health and Nutrition Examination Survey (NHANES), which collected health information from a large cross-section of Americans using questionnaires and blood tests. Among 29,413 adults recruited to NHANES from 2003 to 2016, 468 reported having had NMSC. Overall those with higher blood levels of mercury were nearly twice as likely to have NMSC. The results from this study support the possibility of a role for mercury exposure in causing NMSC. Linked Article: Rhee J et al. Br J Dermatol 2020; 183:480–487. Volume183, Issue3September 2020Pages e76-e76 RelatedInformation

Neuropsychological effects of long-term occupational exposure to mercury among chloralkali workers.

Mercury is one of the most well-known toxic metals for humans. Chloralkali workers are exposed to mercury vapours extensively, which may be associated with neurotoxicity. The aim of this study was to determine the associations between mercury concentration in blood and air samples, and mercury's neuropsychological effects among chloralkali workers. This study was conducted on 50 chloralkali workers as the exposed group and 50 non-industrial office workers as the unexposed group. All subjects were assessed using the Hamilton Depression Rating Scale, Piper Chronic Fatigue Scale and Essential Tremor Rating Scale. Mercury concentration was measured in blood and air samples using cold vapour atomic absorption spectrometry. There was significantly more severe fatigue, depression and tremor in the exposed group compared with the unexposed group. The mean concentration of blood mercury in the exposed group was 22.59±12.5μgL-1 which was significantly higher than the unexposed group (1.28±1.05μg L-1). Based on multiple linear regression, shift work, smoking, fatigue, depression and tremor were predictor variables for blood mercury concentration. This study indicated that this sample of chloralkali workers suffered from neuropsychological problems such as fatigue, depression and tremor, which is probably related to mercury exposure.

A descriptive analysis of blood mercury test results in British Columbia to identify excessive exposures.

The objective of this study was to describe who in British Columbia (BC) is tested for blood mercury, the distribution of their results, and the adequacy of follow-up testing. The BC Centre for Disease Control (BCCDC) obtained records of clinician-ordered analyses of blood mercury conducted by BC laboratories during 2009 and 2010. We conducted a descriptive analysis with statistical testing of who was tested, the distribution of their blood mercury concentrations, whose results exceeded Health Canada's proposed guidance values (8μg/L (40nmol/L) for children/adolescents ≤ 18years and women 19-49years, and 20μg/L (100nmol/L) for other adults), and patterns of repeat testing. Mercury test results for 6487 individuals were reviewed. Adults ≥ 50years had the highest testing rates. The median blood mercury concentration for all tested persons was 1.8μg/L. Nine percent of women aged 19-49years had results exceeding Health Canada's provisional guidance value of 8μg/L. Data from one of BC's two biomarker laboratories indicated that some residents of Vancouver and nearby suburbs have higher exposure to mercury than other BC residents. Of 127 individuals who had results in 2009 exceeding provisional guidance values, only 45% were tested again within 12months. Collating and analyzing all clinical biomarker testing such as blood mercury at a provincial population level allows for assessment of the adequacy and appropriateness of follow-up testing and suggests which regional and demographic strata are at higher levels of exposure.

Human biomonitoring of metals in sub-Arctic Dene communities of the Northwest Territories, Canada

A human biomonitoring project investigating environmental exposures to metals from hair, blood and urine samples was implemented in the Northwest Territories, Canada, between January 2016 and March 2018. This study reports the metal biomarker levels from nine Dene communities located in the Dehcho and Sahtú regions to identify contaminants of interest.Levels of metals in the urine (n = 198), blood (n = 276) and hair (n = 443) samples were generally similar to those seen in other biomonitoring studies in Canada, but lead levels in blood (GM = 16 μg/L; 95th percentile = 71 μg/L) and urine (GM = 0.59 μg/L, 0.69 μg/g of creatinine; 95th percentile = 4.2 μg/L, 4.0 μg/g of creatinine) were higher than those observed in the Canadian Health Measure Survey (CHMS, cycles 2 and 5). Hair mercury (but not blood mercury) appeared higher than observed in participants from the CHMS cycle 5. The vast majority of participants had biomarker levels below the biomonitoring guidance values established for mercury and lead. Based on a comparative analysis of biomarker statistics relative to a nationally-representative survey, metals and essential trace elements of particular interest for follow-up research include: lead, manganese, mercury, and selenium.This project provided baseline biomarker levels in participating regions, which is essential to track changes in the future, and identify the contaminants to prioritize for further investigation of exposure determinants.

Blood and Urine Inorganic and Organic Mercury Levels in the United States from 1999 to 2016

BackgroundMercury is an environmental hazard. Organic mercury is biologically more toxic than inorganic mercury. Therefore, we studied recent trends in the blood levels of organic and inorganic mercury in the United States. MethodsA total of 56,445 participants that had blood mercury and urine mercury measurements in National Health and Nutrition Examination Survey (NHANES) 1999-2016 were included. The organic mercury level was obtained by subtracting the inorganic mercury level from the total mercury level. Results were analyzed using SPSS complex sample module version 25. Pregnant women, children ages <20 years, and different ethnicities were analyzed as subgroups. ResultsBlood organic mercury level increased from (geometric mean [95% confidence interval]) 0.08 [0.07-0.10] to 0.17 [0.16-0.18] µg/L during 1999-2016. It increased significantly (P <0.001) from 0.03 [0.02-0.03] to 0.07 [0.06-0.07] µg/L in children ages <20 and from 0.14 [0.09-0.21] to 0.36 [0.16-0.83] µg/L in pregnant women in this period (P <0.001). In 2013-2016, non-Hispanic Asians had the highest blood organic mercury level among different ethnicities, 0.93 [0.82-1.05] µg/L (P <0.001). Blood inorganic mercury level decreased from 0.31 [0.31-0.31] in 1999-2000 to 0.21 [0.21-0.22] µg/L in 2015-2016 (P <0.001). Urine mercury level decreased from 0.75 [0.71-0.80] in 1999-2000 to 0.16 [0.16-0.17] µg/L in 2015-2016 (P <0.001). ConclusionBlood organic mercury increased over the period 1999-2016 in the US population, including children and pregnant women, whereas there was a steady decline in both blood inorganic mercury and urine mercury levels.

Risk Analysis of Specific Environmental Heavy Metals as a Trigger of CD4 &amp; CD8 Among Cases of Multiple Sclerosis:Case - control study.

Background: Environmental pollutants might be among the etiological factors for multiple sclerosis. The high rise of CD8 and CD4 are the common accepted pathway for the chronic inflammation to myelin sheath proteins developing the different clinical types of MS. Objectives: To measure the level of blood lead, cadmium, mercury, CD4 and CD8 among the different clinical types of MS cases compared to controls, to find out if there is correlation between the level of the measured heavy metals and the degree of disability among the studied cases of multiple sclerosis. Methodology: Case-Control study was conducted at El Hussein University Hospital, Cairo, Egypt during the period (April 2017- February 2020). The calculated sample size was 50 for cases and controls. Subjects were selected by simple random technique. Results: Mean blood lead of cases was higher that observed among controls (62.1±3.2 μg/L versus 19.3±1.5μg/L) with statistical significant difference p=0.000001). In regard to blood mercury: mean among cases was higher than controls (25.1 ± 0.88 μg/L versus 2.3 ± 0.2 μg/L) with statistically significant difference between two groups by Levine’s t test (t=5.5, p=0.000001). There was a positive correlation between lead and Mercury with CD4 and CD8 among cases of Relapsing Remitting MS and among cases of Primary Progressive MS. Conclusion: Lead and Mercury might be a risk factor for trigger CD4 and CD8 among the studied cases of MS.

Blood mercury and plasma polychlorinated biphenyls concentrations in pregnant Inuit women from Nunavik: Temporal trends, 1992–2017

The Inuit of Nunavik (Northern Quebec, Canada) are exposed to polychlorinated biphenyls (PCBs) and mercury (Hg) through their consumption of marine country foods. A temporal trend study was initiated in 1992 to monitor circulating levels of PCBs and Hg in pregnant Inuit women, since the fetus is most at risk of adverse health effects. We set out (1) to describe temporal trends of PCBs and Hg levels in pregnant Nunavik women between 1992 and 2017; (2) to determine the prevalence of participants exceeding the guidance values in 2017; (3) to investigate relations between marine country food intake and contaminant levels over the study period. A total of 559 pregnant women provided a blood sample for contaminant analysis from 1992 to 2017. PCB congeners were quantified in plasma (serum) by gas chromatography (GC) coupled to electron capture detection or mass spectrometry (MS). We determined whole blood mercury concentration by cold vapor atomic absorption or inductively-coupled plasma MS. We performed multilevel modeling to assess temporal trends in contaminant levels and relations with marine country food consumption. Concentrations of total PCBs and Hg decreased by 84% and 65% between 1992 and 2017, respectively. Nevertheless, 10% and 22% of women in 2017 exceeded guidance values for PCBs and Hg, respectively. While the decline in marine country food intake is the only factor associated with decreasing Hg levels, other factors may explain the decline in PCB levels. Despite the significant decline in PCBs and Hg levels from 1992 to 2017, exposure to these contaminants is still quite prevalent among pregnant Nunavik women. Most of the decline in Hg exposure is likely due to a shift away from marine country foods to store-bought foods, which is a concern given the cultural and nutritional importance of country foods and the high food insecurity that prevails in Nunavik.

Trace elements and APOE polymorphisms in pregnant women and their new-borns

We investigated the relationship between lipid binding glycoprotein apolipoprotein E (apoE; gene APOE) polymorphisms (ε4 allele carriers versus no carriers = ε4+/ε4−) and trace elements (TEs) (e.g., (methyl)mercury, arsenic, lead, cadmium, selenium, manganese, copper, and zinc) in mothers (N = 223) and their new-borns (N = 213) exposed to potentially toxic metal(loid)s from seafood consumption. The apoE isoform encoded by the ε4 allele is believed to have beneficial effects in early life but represents a risk factor for age-associated diseases. Under certain conditions ε4 carriers are more susceptible to oxidative stress and metal(loid) toxicity. DNA from Croatian pregnant women (N = 223, third trimester) and their new-borns (N = 176), was genotyped for APOE by TaqMan® SNP assay – rs429358 and rs7412. Seafood intake data and TE levels in maternal urine, milk, hair, peripheral venous blood, mixed cord blood, and new-borns’ urine were available from previous studies. We compared TEs between ε4+ and ε4− carriers using Mann-Whitney U tests and applied multiple linear regression models to analyse the TE’s dependence on the presence of allele ε4 (genotypes ε3/ε4, ε4/ε4) in combination with other explanatory variables. We identified 17% (n = 37) and 20% (n = 35) ε4 allele carriers in mothers and new-borns, respectively. The Mann-Whitney U test showed that mothers with the ε4 allele had significantly higher mean levels of (methyl)mercury in peripheral venous blood, cord blood, and hair; arsenic in urine and cord blood; and selenium in peripheral venous blood and plasma. However, taking confounders into account, only the maternal plasma selenium remained statistically significant in the linear regression models (ε4 carriers vs non-carriers: 62.6 vs 54.9 ng/mL, p < 0.001). Literature suggestions of possible ε4 allele impact on Hg levels were not observed, while superior selenium status observed in healthy pregnant women carrying allele ε4 could be linked to the proposed APOE ε4 beneficial effects early in life.

Mercury Exposure and Associations with Hyperlipidemia and Elevated Liver Enzymes: A Nationwide Cross-Sectional Survey.

Mercury (Hg) has obesogenic properties. However, the associated health outcomes of population-level mercury exposure were unclear. This study investigated the relationships between blood mercury levels and obesity-related outcomes such as hyperlipidemia and elevated liver enzymes. Using the second cycle of the Korean National Environmental Health Survey (n = 6454), we performed logistic regression to examine the effects of Hg on hyperlipidemia and elevated liver enzymes. The blood mercury levels were significantly higher in the hyperlipidemia group (n = 3699, male: 4.03 μg/L, female: 2.83 μg/L) compared to the non-hyperlipidemia group (n = 2755, male: 3.48 μg/L, female: 2.69 μg/L), and high blood mercury levels were associated with an 11% higher risk of hyperlipidemia. The elevated liver enzymes group had higher mean blood mercury levels (n = 1189, male: 4.38 μg/L, female: 3.25 μg/L) than the normal group (n = 5265, male: 3.64 μg/L, female: 2.70 μg/L), and elevated blood mercury was associated with a 35% higher risk of elevated liver enzymes. Moreover, the effect was constant after adjusting for personal medications. These results indicate that mercury exposure is significantly associated with hyperlipidemia and elevated liver enzymes.

The Relationship between Mercury Exposure Indices and Dietary Intake of Fish and Shellfish in Women of Childbearing Age.

Women of childbearing age who are susceptible to mercury exposure were studied to understand the relation between mercury intake through fish and shellfish consumption and mercury exposure indices from blood, hair, and urine samples. A total of 711 women of childbearing age from coastal areas with a high concentration of mercury exposure in Korea were studied. Data were collected on demographic characteristics, dietary intake of fish and shellfish using the simple Food Frequency Questionnaire. Mercury concentration was estimated from the collected samples of blood, hair, and urine. The geometric mean of blood methyl mercury concentration of mercury exposure through seafood was 3.06 μg/L for the low tertile, 3.12 μg/L for the middle tertile, and 3.60 μg/L for the high tertile, indicating a clear tendency of blood methyl mercury to increase as the mercury exposure by fish and shellfish intake ascended. For total blood mercury and hair mercury, the middle and high tertiles had higher values than the low. Mercury exposure through fish and shellfish intake is a main factor for an increase of blood methyl mercury concentration in women of childbearing age. More attention needs to be paid to mercury exposure through seafood intake, considering the serious effect mercury concentration has on women of childbearing age.

The sex-specific effects of blood lead, mercury, and cadmium levels on hepatic steatosis and fibrosis: Korean nationwide cross-sectional study

AimThe potential effects of heavy metals on non-alcoholic fatty liver disease (NAFLD) remain unknown. We investigated the sex-specific relationships of blood lead (BPb), mercury (BHg), and cadmium (BCd) levels with hepatic steatosis (HS) and fibrosis (HF). MethodWe included 4420 participants from the 2016–2017 Korea National Health and Nutrition Examination Survey. High-risk alcoholics and patients with chronic hepatitis B or C infections or liver cirrhosis were excluded. We calculated the hepatic steatosis index (HSI) and fibrosis-4 index (FIB-4) values; we defined the presence of HS and HF as an HSI ≥ 36 and FIB-4 score >2.67, respectively. We adjusted for age, smoking and alcohol consumption statuses, hypertension, obesity, diabetes, hypertriglyceridemia, and BPb, BHg, and BCd levels. ResultIn males (n = 1860), the HSI was correlated negatively with the BPb level and positively with the BHg level (both p < 0.01). The FIB-4 score was correlated positively with the BPb and BCd levels (both p < 0.01). In females (n = 2560), the HSI and FIB-4 score were correlated positively with the BPb, BHg, and BCd levels (all p < 0.01). After adjustments, the BHg level increased the risk of HS in both males (OR = 1.065, p = 0.003) and females (OR = 1.061, p = 0.048), and the BCd level increased the risk of HF in females (OR = 1.668, p = 0.012). ConclusionBlood heavy metal levels were generally correlated positively with the HSI and FIB4 score, more so in females than males. The BHg level was associated with HS in males and females, and the BCd level was associated with HF in females. Further studies on NAFLD progression according to heavy metal status and sex are warranted.

Examining Links Between Diet and Lead Exposure in Young Children: 2009 to 2014 National Health and Nutrition Examination Survey.

Despite recommendations to consume iron-, calcium-, and vitamin C-rich foods for managing blood lead levels (BLLs), limited evidence exists on how specific foods affect children's BLLs. Using data from 12- to 36-month olds (n=992) from the 2009 to 2014 National Health and Nutrition Examination Survey, we assessed how foods rich in these nutrients associate with BLLs, and with potential inadvertent exposures to cadmium and mercury. Food intake was assessed from one 24-hour dietary recall. Foods were categorized into 10 energy-adjusted groups, with intake categorized as none (reference) and tertiles. BLLs were natural log-transformed. Linear regressions tested associations between food groups and BLLs. Logistic regressions were conducted for blood cadmium and mercury. Median (5%, 95% range) BLLs were 1.01 (0.39, 3.21) µg/dL. Majority of food groups (7 of 10) showed little association with BLLs. Compared to no intake, cereal (tertile 3: β [95% confidence interval]=-0.22 [-0.41, -0.02]) and milk (Ptrend < 0.002; nonsignificant tertiles) consumption was associated with lower BLLs. Meat (tertile 2: 0.23 [0.01, 0.45]) and fruit drink (tertile 2: 0.20 [0.03, 0.38]; tertile 3: 0.25 [0.02, 0.49]) intake was associated with higher BLLs. Fruit drink consumption was associated with lower likelihood of having blood cadmium >0.11 µg/dL (tertile 3: odds ratio: 0.05 [0.01, 0.36]). No associations were observed with blood mercury. Among young children, consumption of iron-, calcium-, and vitamin C-rich foods showed weak or no association with BLLs. Few associations were observed for blood cadmium or mercury. Food-based approaches to BLL management may have limited utility when exposure is low.

Subsistence fishing in the Eeyou Istchee (James Bay, Quebec, Canada): A regional investigation of fish consumption as a route of exposure to methylmercury

Fishing is part of the traditional activities of Indigenous people in Canada. However, it is also a route of exposure to methylmercury, a known neurotoxicant, and this is a concern for those who rely on fish as part of their diet. The probable weekly intake (PWI) of methylmercury from six species of fish was calculated for Indigenous community members (N = 1406), grouped by age and sex, and compared to Canadian and international provisional reference doses to assess exposure. Mixed-effects regression models were also used to estimate the input of methylmercury into the blood, and Hazard Quotients (HQ) were used to assess potential effects. Of the species of fish in our study, walleye and lake trout contributed the most to methylmercury intake. There was a positive association between the consumption of walleye and the total blood mercury concentrations of mercury in women and men (R2A = 0.40 and 0.47, respectively), and to a lesser extent, children. Similar results were observed for the consumption of lake trout. The 95th-percentile HQ for girls (3.16) and boys (3.18) from the consumption of lake trout was relatively high, and to a lesser extent, so was the HQ for walleye and pike. The consumption of some species of fish increases the exposure to methylmercury, however, taking a balanced approach, there are health benefits associated with the consumption of fish that must be considered. To mitigate future exposure to methylmercury, we recommend follow-up blood monitoring and local-geospatial-based assessments.

Risk factors associated with developing anxiety in Inuit adolescents from Nunavik

This study aimed to examine the relation between anxiety among the at-risk population of Inuit adolescents and diverse developmental risk factors including exposure to environmental chemicals, a subject of concern in Nunavik. Anxiety was assessed in 89 Inuit participants (mean age = 18.4 years; range = 16.2–21.9) with the Screen for Child Anxiety Related Emotional Disorders (SCARED) and the State-Trait Anxiety Inventory (STAI). Potential risk factors for anxiety were documented at birth, 11 years of age and 18 years of age, including blood levels of chemicals (mercury, lead, PCBs) and nutrients, as well as age, sex, estimated IQ, drug and alcohol use, bullying, exposure to domestic violence, food insecurity, crowding and socio-economic status. Results showed that participants scored high on both measures of anxiety, particularly the SCARED, for which the mean score was above the clinical threshold. Multiple regression results show that significant risk predictors obtained from the SCARED scores were female sex (β = 0.32), higher current blood mercury concentration (β = 0.26), food insecurity (β = 0.26) and bullying experiences in the last year (β = 0.21). The significant predictors for the STAI trait anxiety were food insecurity (β = 0.25) and lower estimated IQ (β = −0.31), whereas food insecurity (β = 0.21), lower blood levels of vitamin E (β = −0.25) and higher cord blood mercury concentrations (β = 0.25) were found for STAI situational anxiety. Further regression analyses suggested that the adolescent-related variables were the most important risk factors. Our findings show that Inuit adolescents are at risk for anxiety via multiple contributing factors, particularly current exposure to mercury, food insecurity and female sex.

A population-based mercury exposure assessment near an artisanal and small-scale gold mining site in the Peruvian Amazon.

Human exposure to mercury is a leading public health problem. Artisanal and small-scale gold mining (ASGM) is a major source of global mercury emissions. Although occupational mercury exposure to miners (via mercury vapor inhalation) is known, chronic mercury exposure to nearby residents that are not miners (via mercury-contaminated fish consumption) is poorly characterized. We conducted a population-based mercury exposure assessment in 23 communities (19 rural, 4 urban) around the Amarakaeri Communal Reserve, which is bordered on the east by heavy ASGM activity. We measured total mercury in hair (N = 2083) and blood (N = 476) from March-June 2015 and performed follow-up measurements (N = 723 hair and N = 290 blood) from February-April 2016. Mercury exposure risk was highest in communities classified as indigenous, or native, regardless of proximity to mining activity. Residence in a native community (vs. non-native) was associated with mercury levels 1.9 times higher in hair (median native 3.5 ppm vs. median non-native 1.4 ppm total mercury) and 1.6 times higher in blood (median native 7.4 ng/mL vs median non-native 3.2 ng/mL total mercury). Unexpectedly, proximity to mining was not associated with exposure risk. These findings challenge common assumptions about mercury exposure patterns and emphasize the importance of population-representative studies to identify high risk sub-populations.