Assessment of Dietary Mercury Intake and Blood Mercury Levels in the Korean Population: Results from the Korean National Environmental Health Survey 2012-2014

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.

Infantile allergic diseases: a cohort study prenatal fish intake and mercury exposure context

BACKGROUND

Allergic diseases (ADs) have been increasingly reported in infants and children over the last decade. Diet, especially the inclusion of fish intake, may help to lower the risk of ADs. However, fish also, can bioaccumulate environmental contaminants such as mercury. Hence, our study aims to determine what effects the type and frequency of fish intake have on ADs in six-month-old infants, independently and jointly with mercury exposure.

METHODS

This study is part of the prospective birth cohort: Mothers and Children's Environmental Health (MOCEH) study in South Korea. Data was collected on prenatal fish intake, prenatal mercury concentration and ADs for infants aged six months for 590 eligible mother-infant pairs. Logistic regression analysis was conducted to evaluate the risk of prenatal fish intake and mercury concentration on ADs in infants. Finally, interaction between fish intake and mercury concentration affecting ADs in infants was evaluated. Hazard ratios of prenatal fish intake on ADs in 6 month old infants were calculated by prenatal mercury exposure.

RESULTS

Logistic regression analysis showed that white fish (OR: 0.53; 95% CI 0.30-0.94; P < 0.05) intake frequency, once a week significantly decreased the risk of ADs in infants. Stratification analysis showed that consuming white fish once a week significantly reduced the hazard of ADs (HR: 0.44; 95% CI 0.21-0.92; P < 0.05) in infants in the high-mercury (≥ 50th percentile) exposure group.

CONCLUSION

The result indicates that prenatal white fish intake at least once a week reduces the risk of ADs in infants, especially in the group with high prenatal mercury exposure.

Mercury in Selected Abiotic and Biotic Elements in Two Lakes in Poland: Implications for Environmental Protection and Food Safety

Mercury, which tends to bioaccumulate and biomagnify in aquatic food webs, poses a potential health risk to wildlife and to consumers of predatory fish in particular. Its concentration in biota can be high even at low environmental concentrations. Therefore, the aim of this study was to determine mercury in both abiotic (water and sediment) and biotic elements (common reed (Phragmites australis) and fish: pike (Esox lucius), bream (Abramis brama) and roach (Rutilus rutilus)) in the context of assessing the pollution of two lakes in Poland and the safety of fish consumers. The possibility of Hg biomagnification in fish was also considered. Mercury was determined by means of cold vapor atomic absorption spectrometry (CVAAS). The concentrations of Hg in water and bottom sediments of Lake Ińsko were lower than in Lake Wisola. In the bottom sediments of both lakes, a positive correlation was found between the Hg content and organic matter. The concentration of mercury in the organs of common reed did not exceed 0.017 mg/kg dry weight (dw), and its distribution can be presented as follows: root > leaves > stems > rhizomes. In fish organs from both lakes, the average mercury content did not exceed 0.086 mg/kg of wet weight (ww) and in most cases it was the highest in pike. Higher values were only observed in the muscles and skin of roach. This indicates a lack of biomagnification in the relationships between planktivorous-predatory and benthivores-predatory fish. Based on the maximum levels of mercury in fish and the calculated parameters, i.e., estimated daily intake (EDI), target hazard quotient (THQ) and tolerable weekly intake (TWI), the muscles of the examined fish were found to be safe for consumption. The average dietary exposure to total mercury (THg) and methylmercury (MeHg) was below 0.3% of the TWI.

Selenium Status: Its Interactions with Dietary Mercury Exposure and Implications in Human Health

Selenium is an essential trace element in humans and animals and its role in selenoprotein and enzyme antioxidant activity is well documented. Food is the principal source of selenium, and it is important that selenium status in the body is adequately maintained for physiological functions. There has been increasing attention on the role of selenium in mitigating the toxic effects of mercury exposure from dietary intake in humans. In contrast, mercury is a neurotoxin, and its continuous exposure can cause adverse health effects in humans. The interactions of selenium and mercury are multi-factorial and involve complex binding mechanisms between these elements at a molecular level. Further insights and understanding in this area may help to evaluate the health implications of dietary mercury exposure and selenium status. This review aims to summarise current information on the interplay of the interactions between selenium and mercury in the body and the protective effect of selenium on at-risk groups in a population who may experience long-term mercury exposure.

Risk assessment of mercury through dietary exposure in China

Mercury (Hg) is a widespread heavy metal causing various damages to health, while insufficient studies assessed its exposure risk across China. This study explored concentrations in food items and dietary exposure risks across China by comprehensively analyzing the researches on total Hg (THg) in eight food items and methylmercury (MeHg) in aquatic foods published between 1980 and 2021. According to the included 695 studies, the average THg concentration in all food items was 0.033 mg/kg (ranging from 0.004 to 0.185 mg/kg), with the highest concentration in edible fungi. The average daily dietary THg exposure from all foods was 12.9 μg/day. Plant-based foods accounted for 62.7% of the dietary THg exposure. Cereals and vegetables were the primary source of THg exposure. The MeHg concentration in aquatic foods was 0.08 mg/kg, and the average dietary exposure was 3.8 μg/day. Monte Carlo simulations of the dietary exposure risk assessment of THg and MeHg showed that approximately 6.4 and 7.0% of residents exceeded the health-based guidance value set by the European Food Safety Authority, with higher exposure risk in Southwest and South China. The nationwide target hazard quotient index of THg was greater than 1, suggesting that the non-carcinogenic risk of dietary exposure to THg needed further concern. In summary, this study has a comprehensive understanding of dietary Hg exposure risks across China, which provide a data basis for Hg exposure risk assessment and policy formulation.

Importance of hydraulic residence time for methylmercury accumulation in sediment and fish from artificial reservoirs

Excessive methylmercury (MeHg) accumulation in dietary fish is a global concern due to its harmful effects on human health, however, environmental factors affecting MeHg accumulation in reservoir ecosystems are not clearly known. In this study, we aim to identify the main sources of MeHg in the water column and the critical factors related to MeHg concentration and methylation rate constant (k_m) in sediment and total Hg concentration in fish using five-year (2016-2020) monitoring data of the five artificial reservoirs. The preliminary mass budgets constructed using the measurement and online data showed that sediment transport dominated over runoff in the long residence time reservoirs (400-475 days), while runoff dominated over sediment transport in the short residence time reservoirs (10 days). Whereas the sediment k_m showed a comparable variation with the algal biomass, the sediment MeHg concentration and the length-normalized Hg concentration in the barbel steed and bluegill increased in the longer residence time reservoirs with lower algal biomass. As MeHg accumulation in sediment and fish tends to increase in the slowly overturning reservoirs, the hydraulic residence time should be carefully managed to meet the best protection of human health from chronic Hg exposure by fish consumption.

Profile of Environmental Chemicals in the Korean Population-Results of the Korean National Environmental Health Survey (KoNEHS) Cycle 3, 2015-2017

The Korean National Environmental Health Survey (KoNEHS) program provides useful information on chemical exposure, serves as the basis for environmental health policies, and suggests appropriate measures to protect public health. Initiated on a three-year cycle in 2009, it reports the concentrations of major environmental chemicals among the representative Korean population. KoNEHS Cycle 3 introduced children and adolescents into the analysis, where the blood and urine samples of 6167 participants were measured for major metals, phthalates, phenolics, and other organic compounds. Lead, mercury, cadmium, metabolites of DEHP and DnBP, and 3-phenoxybenzoic acid levels of the Korean adult population tended to decrease compared to previous survey cycles but remained higher than those observed in the US or Canada. Both bisphenol A (BPA) and trans,trans-muconic acid concentrations have increased over time. Heavy metal concentrations (blood lead, and cadmium) in children and adolescents were approximately half that of adults, while some organic substances (e.g., phthalates and BPA) were high. BPA showed higher levels than in the US or Canada, whereas BPF and BPS showed lower detection rates in this cycle; however, as these are increasingly used as a substitute for BPA, further research is necessary. As environmental chemicals may affect childhood health and development, additional analyses should assess exposure sources and routes through continuous observations.

Neuroendocrine Tumors: Clinical, Histological and Immunohistochemical Perspectives and Case Report-Mature Teratoma in a 16-Year-Old Girl

A mature teratoma is a germinal neoplasm that differentiates from embryonic multipotent cells into three germ layers. There may also be glandular tissue. The literature describes a total of 658 cases of ovarian neuroendocrine neoplasms, mainly in women over 40 years of age. The authors, together with a systemic review, present a case of a 16-year-old girl diagnosed with and treated for a neuroendocrine tumor. Case description: A 16-year-old girl visited the Paediatric Gynaecology Outpatient Clinic because of abdominal pains that intensified during menstruation. Standard painkillers and diastolic drugs were ineffective. An ultrasound examination revealed a large tumor with a heterogeneous structure in her right ovary. A sparing operation was carried out. During laparotomy, the lesion was enucleated, leaving healthy tissue. Histopathological examination revealed the typical features of teratoma, as well as the coexistence of a G1 neuroendocrine tumor. Immunohistochemical examination (IHC) showed the presence of markers characteristic for this type of tumor. The patient requires constant monitoring in the Endocrinology and Oncological Gynaecology Clinic. Conclusion: Tissue of neuroendocrine neoplasm within a teratoma is rare in this age group of patients; thus, there are currently no standards for long-term follow-up. This case adds to the body of evidence and demonstrates a possible good prognosis with non-aggressive behavior in G1 neuroendocrine tumors and teratomas in young patients.

Association between Blood Mercury Levels and Non-Alcoholic Fatty Liver Disease in Non-Obese Populations: The Korean National Environmental Health Survey (KoNEHS) 2012-2014

Mercury is widely distributed in the environment, and a plausible association between mercury exposure and hepatic damage has been reported. Non-alcoholic fatty liver disease (NAFLD), which comprises a spectrum of liver diseases, has recently been recognized in non-obese subjects. However, there have been no studies on the relationship between internal mercury levels and NAFLD in non-obese individuals. Therefore, we investigated the association between blood mercury levels and NAFLD in non-obese subjects. Cross-sectional data (n = 5919) were obtained from the Korean National Environmental Health Survey (2012–2014). NAFLD was defined using the hepatic steatosis index (HSI). Blood mercury levels were log-transformed and divided into quartiles based on a weighted sample distribution. The association between blood mercury levels and NAFLD was analyzed using a multivariate logistic analysis after body mass index stratification. The geometric mean of blood mercury in the overweight group was significantly higher than that of the non-obese group (p < 0.001). The weighted frequencies of patients with NAFLD based on the HSI were 3.0–7.2% for the non-obese subjects and 52.3–63.2% for the overweight subjects. In the multivariate analysis, blood mercury levels were positively associated with NAFLD for both the overweight and non-obese groups (all p for trend < 0.001). Increased blood mercury levels are closely associated with NAFLD. In particular, mercury could be a risk factor for NAFLD in the non-obese population.

Indoor particulate matter and blood heavy metals in housewives: A repeated measured study

BACKGROUND

Particulate matter (PM) less than 2.5 μm in diameter and 10 μm (PM₁₀) contains heavy metals, but whether exposure to PM is significantly associated with the burden of heavy metal exposure in the population is unknown. We investigated the association between exposure to PM and blood concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) in Korean housewives.

MATERIALS & METHODS

From July 2017 to January 2020, we recruited 115 housewives in Ulsan, Republic of Korea. After excluding participants with missing information, we finally included 88 Korean housewives in our study. We measured the concentrations of indoor PM using a gravimetric method 24 h before blood sampling and the concentrations of Cd, Pb, and Hg in blood, twice at a 1-year interval. We used a linear mixed effect model to estimate the associations between indoor PM and blood heavy metals.

RESULTS

Exposure to PM₁₀ was significantly associated with blood concentrations of Cd among Korean housewives. A 10 μg/m³ increase of PM₁₀ the previous day was associated with a 2.8% (95% confidence interval (CI) = 1.1%, 4.6%) and a 1.5% (95% CI = -0.1%, 3.1%) increase in blood concentrations of Cd and Pb in the linear mixed effect model, respectively.

CONCLUSION

There was a significant association between indoor PM exposure and blood Cd concentrations among Korean housewives. This result suggests that the body burden of heavy metals is significantly associated with air pollution.

Trends in sensor development toward next-generation point-of-care testing for mercury

Mercury is one of the most common heavy metals and a major environmental pollutant that affects ecosystems. Since mercury and its compounds are toxic to humans, even at low concentrations, it is very important to monitor mercury contamination in water and foods. Although conventional mercury detection methods, including inductively coupled plasma mass spectrometry, atomic absorption spectroscopy, and gas chromatography-mass spectrometry, exhibit excellent sensitivity and accuracy, they require operation by an expert in a sophisticated and fully controlled laboratory environment. To overcome these limitations and realize point-of-care testing, many novel methods for direct sample analysis in the field have recently been developed by improving the speed and simplicity of detection. Commonly, these unconventional sensors rely on colorimetric, fluorescence, or electrochemical mechanisms to transduce signals from mercury. In the case of colorimetric and fluorescent sensors, benchtop methods have gradually evolved through technology convergence to give standalone platforms, such as paper-based assays and lab-on-a-chip systems, and portable measurement devices, such as smartphones. Electrochemical sensors that use screen-printed electrodes with carbon or metal nanomaterials or hybrid materials to improve sensitivity and stability also provide promising detection platforms. This review summarizes the current state of sensor platforms for the on-field detection of mercury with a focus on key features and recent developments. Furthermore, trends for next-generation mercury sensors are suggested based on a paradigm shift to the active integration of cutting-edge technologies, such as drones, systems based on artificial intelligence, machine learning, and three-dimensional printing, and high-quality smartphones.

Potential sources, scavenging processes, and source regions of mercury in the wet deposition of South Korea

In this study, the potential sources, scavenging processes, and emission regions for Hg in wet deposition were investigated in rural (Jeju), suburban (Gwangju), and urban sites (Incheon and Seoul) of South Korea. The annual volume-weighted mean concentrations of Hg in wet deposition were four to five times higher in Incheon (16.6 ng L^-1) and Seoul (22.5 ng L^-1) than in Jeju (4.0 ng L^-1) and Gwangju (4.1 ng L^-1). The variations in the Hg concentrations in wet deposition of Jeju and Gwangju were related to Cl^-, Na⁺, Mg²⁺, and K⁺ originating from marine and crustal sources, and those in Incheon and Seoul were related to SO₄^2-, NO₃^-, and NH₄⁺ emitted from anthropogenic sources. The below-cloud scavenging was considered a major inclusion process of Hg in Jeju and Gwangju, while the within-cloud scavenging was suggested in Incheon and Seoul, based on the results of correlation analysis with Hg and major ions in wet deposition, and meteorological data. The cluster analysis of backward trajectories demonstrated that the Hg concentration in wet deposition was highest in the cluster transported from Hebei and Shandong of China in Gwangju, but in Seoul, the Hg concentrations of each cluster were comparable. This suggests that regional transport is the major source of Hg in the wet deposition of Gwangju while local transport provides substantial amount of Hg in the wet deposition of Seoul. This was further supported by the results of concentration-weighted trajectories: the most probable source region was east China for Gwangju, and the mid-west of South Korea and east China for Seoul. It is noted that the peak methylmercury concentrations were found every spring with simultaneous increases in atmospheric Al, Ca, Mg, and Fe concentrations, indicating a concurrence with Asian dust. The formation process of methylmercury in Asian dust should be confirmed in future studies.

Total blood mercury and its determinants in New Zealand children and adults

BACKGROUND

Mercury is a widespread persistent environmental pollutant associated with adverse health effects.

OBJECTIVE

This first national biomonitoring survey of blood total mercury (tHg) conducted in New Zealand aimed to provide baseline data and identify exposure determinants.

METHODS

Blood was collected from 191 children (age 5-18 years) and 304 adults (20-65) in 2014-2016 and analysed for tHg using inductively coupled plasma mass spectrometry. Linear regression was used to assess associations with demographic and lifestyle factors.

RESULTS

Blood mercury was detected in 93% of children and 99% of adults, with geometric means (GMs) of 0.86 and 1.65 µg/L, respectively. The 60-65-year olds had the highest GM (2.34 µg/L). Regression indicated that tHg was 40% higher in boys compared to girls. Eating fish ≥ 3 times/week (compared to ≤once/week) was associated with 2.7 and 1.7 times higher tHg in children and adults, respectively. Shellfish consumption was also associated with higher tHg. High daily tap water consumption (≥2 L for children, ≥3 L for adults) was associated with lower tHg. In adults, smoking and milk consumption were associated with higher tHg.

SIGNIFICANCE

Fish and shellfish consumption is a strong determinant of New Zealanders blood tHg levels, with water and milk consumption possibly acting as modulating factors.

Role of MT1A Polymorphism and Environmental Mercury Exposure on the Montreal Cognitive Assessment (MoCA)

PURPOSE

Many age-related structural and functional changes in the brain have important consequences. Long-term exposure to mercury and the impact of functional polymorphisms of metal-regulating proteins such as metallothioneins (MTs) can result in neurological-neurobehavioral effects in elderly individuals. Therefore, the aims of this study are to examine the associations between biomarkers of mercury exposure and cognitive impairment and to investigate the effect of the rs8052394 single nucleotide polymorphism (SNP) of the potential modifier gene MT1A on different domains of the Montreal Cognitive Assessment (MoCA).

MATERIALS AND METHODS

We studied 436 participants aged ≥55 years from the Electricity Generating Authority of Thailand study. They underwent a physical examination, an extensive cognitive assessment with the MoCA (cutoff <26 points), and a biochemical analysis related to diabetes and dyslipidemia. The blood mercury level was determined by inductively coupled plasma mass spectrometry. Genotyping of the MT1A rs8052394 SNP was performed by the restriction fragmentation length polymorphism method.

RESULTS

The mean age of the study population was 58.8±3.01 years, and most had ≥12 years of education (75.7%). The primary study finding was that the prevalence of mild cognitive impairment (MCI) in older Thai adults was 39.7%. The frequency distributions of the G allele of the rs8052394 SNP of the MT1A gene were significantly associated with the total and sub-domain MoCA scores. The prevalence of MCI was significantly associated with increased age, hypertriglyceridemia, hyperhomocysteinemia, the third tertile of blood mercury concentration, and the rs8052394 variant genotype of MT1A (P values for all odds ratios <0.05).

CONCLUSION

These findings suggested that neurocognitive effects associate with mercury exposure and genetic susceptibility in toxicokinetics. Public health strategies can be used to implement as a comprehensive action plan to educate vulnerable populations on how to reduce mercury exposure. Concurrently, impact of such genetic predisposition requires replication for identifying and protecting susceptible individuals from mercury toxicity.

A Study on Hair Mercury Levels of University Students

Total mercury (THg) and methylmercury (MeHg) concentrations were measured in hair of 98 Chinese university students to study their levels of Hg exposure and influencing factors. The results showed that Hg exposure for university students was at a low level with concentrations lower than the USEPA recommended reference level (1 µg/g) across all hair samples. The percentage of MeHg to THg (%MeHg) in hair was about 50%, lower than the previously reported value of 70-100%, probably associated with the low %MeHg in the diet of university students. Fish and rice consumption were not a primary factor affecting hair Hg levels of university students, while smoking could be one main pathway of Hg exposure. In addition, the similarly dietary structure in the studied university narrowed the difference of Hg exposure levels among students.

A global perspective on mercury cycling in the ocean

Mercury (Hg) is a ubiquitous metal in the ocean that undergoes in situ chemical transformations in seawater and marine sediment. Most relevant to public health is the production of monomethyl-Hg, a neurotoxin to humans that accumulates in marine fish and mammals. Here we synthesize 30 years of Hg measurements in the ocean to discuss sources, sinks, and internal cycling of this toxic metal. Global-scale oceanographic survey programs (i.e. CLIVAR and GEOTRACES), refined protocols for clean sampling, and analytical advancements have produced over 200 high-resolution, full-depth profiles of total Hg, methylated Hg, and gaseous elemental Hg throughout the Atlantic, Pacific, Arctic, and Southern Oceans. Vertical maxima of methylated Hg were found in surface waters, near the subsurface chlorophyll maximum, and in low-oxygen thermocline waters. The greatest concentration of Hg in deep water was measured in Antarctic Bottom Water, and in newly formed Labrador Sea Water, Hg showed a decreasing trend over the past 20 years. Distribution of Hg in polar oceans was unique relative to lower latitudes with higher concentrations of total Hg near the surface and vertical trends of Hg speciation driven by water column stratification and seasonal ice cover. Global models of Hg in the ocean require a better understanding of biogeochemical controls on Hg speciation and improved accuracy of methylated Hg measurements within the international community.

The exposure level of environmental harmful substances related to the secondhand smoke in Korean non-smoker adults: data from the second Korean National Environmental Health Survey (KoNEHS 2012-2014): a cross-sectional study

Background

We aimed to find the exposure level of environmental harmful substances related to the secondhand smoke (SHS) using a nationally representative data of the general population in Korea.

Methods

Total 3,533 people were included in this study. We compared the proportion exceeding 95 percentile of the concentrations of harmful substances by sex according to SHS exposure. 16 kinds of substances related to tobacco smoke were analyzed including heavy metals, polycyclic aromatic hydrocarbons, volatile organic compounds, and environmental phenol. For 16 kinds of substances, the odds ratios (ORs) for exceeding 95 percentile of each harmful substance were calculated by multiple logistic regression according to SHS exposure. Age, education level, marital status, body mass index, drinking, and exercise were adjusted as covariates. Cotinine level was additionally adjusted to increase reliability of our results.

Results

SHS was associated with high exposure of mercury, methylhippuric acid, fluorene, and cotinine. In women, SHS was associated with mercury, methylhippuric acid, fluorene, and cotinine, while in men, it was associated with cotinine. After adjusting covariates, ORs of blood mercury, methylhippuric acid and hydroxyfluorene in the exposed gruop were greater than that in the non-exposed group. Especially in female, methylhippuric acid and hydroxyfluorene showed consistent result.

Conclusions

Our finding demonstrates that SHS is related to several harmful substances. Therefore, to reduce the health effects of SHS, it is necessary to educate and publicize the risk of SHS. Future studies are necessary to more accurately analyze factors such as exposure frequency, time, and pathway of SHS.

Dietary intake of arsenic, cadmium, mercury and lead by the population of Catalonia, Spain: Analysis of the temporal trend

In 2017, a monitoring study was conducted in Catalonia (Spain) to analyse, in widely consumed foodstuffs, the concentrations of arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb), as well as those of inorganic As (InAs) and methylmercury (MeHg). Health risks were estimated for various population groups, classified according to age. A continued reduction of dietary exposure to these elements was observed when comparing the results from the current and previous studies performed during the last 17 years. This reduction would be associated to a decrease of As, Cd, Hg and Pb concentrations in food, as well as by changes in dietary habits. None of the adult groups exceeded the safety threshold established by the EFSA, but toddlers, infants and children exceeded the PTWI for Cd and MeHg. The greatest intake of Cd and MeHg corresponded to infants, being due to the consumption of cuttlefish and hake. The consumption of these species should be reduced to two or three weekly portions, being combined with the intake of other non-predator species. Anyhow, the current results indicate that is necessary to conduct further periodical surveys, paying special attention to the trend in the intake of Cd and MeHg.

Study Design, Rationale and Procedures for Human Biomonitoring of Hazardous Chemicals from Foods and Cooking in Korea

Objectives: A nationwide biomonitoring program identified the long-term trends of environmental exposures to hazardous chemicals in the general population and found geographical locations where body burdens of an exposed group significantly differed from those of the general population. The purpose of this study is to analyze the hazardous compounds associated with foods and cooking in the nationwide general population for evaluation of the environmental exposures and health risk factors and for the establishment of the reference levels at the national level. Methods: During 2009–2010, the National Institute of Food and Drug Safety Evaluation (NIFDS) conducted a nationwide human biomonitoring study, including a questionnaire survey and environmental exposure assessments for specific hazardous compounds from foods and cooking among the general population in South Korea. Results: A total of 2139 individuals voluntarily participated in 98 survey units in South Korea, including 889 (41.6%) men and 1250 women (58.4%). Bio-specimens (serum and urine) and questionnaires were collected from the study population. Acrylamides, heterocyclic amines (HCAs), phenols, and phthalates were analyzed from urine, and perfluorinated compounds (PFCs) and organic chloride pesticides (OCPs) were analyzed from serum samples. The information on exposure pathway and geographical locations for all participants was collected by questionnaire interviews, which included demographic characteristics, socioeconomic status, history of family diseases, conditions of the indoor and outdoor environment, lifestyles, occupational history, and food and dietary information. Conclusion: We describe the design of the study and sampling of human biospecimen procedures including bio-sample repository systems. The resources produced from this nationwide human biomonitoring study and survey will be valuable for use in future biomarkers studies and for the assessment of exposure to hazardous compounds associated with foods and cooking.

Blood and seminal plasma mercury levels and predatory fish intake in relation to low semen quality

Declining human sperm quality has been demonstrated in several recent studies. Age, environmental factors, and nutritional factors can affect semen quality. Mercury (Hg) is considered a male reproductive toxicant. Animal studies indicated that exposure to Hg can cause DNA damage, sperm dysfunction, and decreased sperm motility. Some previous studies also revealed that blood Hg levels in infertile or subfertile males were higher than those in normal males. In this study, we recruited 84 male participants from a reproductive medical center and investigated the Hg, lead, and selenium levels in blood and seminal plasma. Participants were divided into two groups, low- and high-quality semen groups, according to the World Health Organization reference values for human semen characteristics. The distribution of blood reproductive hormones and information on participants' lifestyle and medical history were collected from structured questionnaires. Average Hg levels in blood were 9.3±5.9 versus 8.9±5.9 and in seminal plasma were 1.26±0.61 versus 1.05±0.52 μg/L in the low- and high-quality semen groups, respectively. There was a dose-dependent relationship between blood Hg levels and normal sperm morphology (p=0.02). Participants with predatory fish intake and high blood Hg level had lower sperm with a normal morphology. Therefore, predatory fish intake may be a critical risk factor for elevated Hg levels in males and cause low semen quality.

Insights into the Potential Role of Mercury in Alzheimer's Disease

Mercury (Hg), which is a non-essential element, is considered a highly toxic pollutant for biological systems even when present at trace levels. Elevated Hg exposure with the growing release of atmospheric pollutant Hg and rising accumulations of mono-methylmercury (highly neurotoxic) in seafood products have increased its toxic potential for humans. This review aims to highlight the potential relationship between Hg exposure and Alzheimer's disease (AD), based on the existing literature in the field. Recent reports have hypothesized that Hg exposure could increase the potential risk of developing AD. Also, AD is known as a complex neurological disorder with increased amounts of both extracellular neuritic plaques and intracellular neurofibrillary tangles, which may also be related to lifestyle and genetic variables. Research reports on AD and relationships between Hg and AD indicate that neurotransmitters such as serotonin, acetylcholine, dopamine, norepinephrine, and glutamate are dysregulated in patients with AD. Many researchers have suggested that AD patients should be evaluated for Hg exposure and toxicity. Some authors suggest further exploration of the Hg concentrations in AD patients. Dysfunctional signaling pathways in AD and Hg exposure appear to be interlinked with some driving factors such as arachidonic acid, homocysteine, dehydroepiandrosterone (DHEA) sulfate, hydrogen peroxide, glucosamine glycans, glutathione, acetyl-L carnitine, melatonin, and HDL. This evidence suggests the need for a better understanding of the relationship between AD and Hg exposure, and potential mechanisms underlying the effects of Hg exposure on regional brain functions. Also, further studies evaluating brain functions are needed to explore the long-term effects of subclinical and untreated Hg toxicity on the brain function of AD patients.

Determination of Mercury Daily Intake and Hair-to-Blood Mercury Concentration Ratio in People Resident of the Coast of the Persian Gulf, Iran

The objectives of this study were to understand the mercury daily intake and hair-to-blood mercury ratio in fishermen and non-fishermen families in the coast of the Persian Gulf in Iran. The mean mercury concentration in the hair of fishermen and non-fishermen families was 5.76 and 2.27 μg/g, respectively. The mean mercury concentrations of RBCs were obtained for fishermen families and non-fishermen families: 35.96 and 17.18 μg/L, respectively. Hair mercury concentrations in 17% of people were higher than 10 μg/g, the No Observed Adverse Effects Level set by the World Health Organization. 78% of people had a blood mercury value > 5.8 μg/L, the standard level set by the U.S. Environmental Protection Agency. A significant correlation (r = 0.94, p = 0.000) was seen between log hair and RBCs mercury concentrations. The mean mercury daily intake for fishermen and non-fishermen families was 0.42 and 0.20 µg/kg BW per day, respectively. The mean mercury daily intake of fishermen families was higher than the provisional tolerable daily intake (0.23 µg/kg BW per day) suggested by the Joint Expert Committee on Food Additives. Mercury daily intake significantly correlated with fish consumption (r = 0.50, p = 0.000) and log hair mercury (r = 0.88, p = 0.000). The total mean of hair-to-blood mercury concentration ratio was 306. We conclude that the use of mercury concentrations in the hair and RBCs could have been suitable biomarkers for predicting mercury exposure of people with a high rate of fish consumption.

Essential and non-essential trace elements among working populations in Ghana

BACKGROUND

Lead battery repair workers (LBRW) and electronic repair workers (ERW) may be exposed to inorganic components during work. This study aimed at determining essential and non-essential trace elements in male LBRW, ERW, referents and a group of female petty traders (FPT) in Kumasi (Ghana), taking into account iron status and inflammation.

METHODS

Altogether 64 LBRW, 64 ERW, 65 referents and 26 FPT were investigated in this cross-sectional study. Urine, whole blood and serum were collected for determination of trace elements. C-reactive protein and ferritin were determined in serum.

RESULTS

The LBRW had higher blood concentrations of manganese (B-Mn) and lead (B-Pb) and antimony in urine (U-Sb), and lower concentrations of cobalt in blood (B-Co). Being ERW was associated with higher concentrations of blood cadmium (B-Cd), urinary tin (U-Sn) and serum chromium (S-Cr). Concentrations of selenium (B-Se), Co and mercury (B-Hg) in whole blood and iodine in urine (U-I) were relatively high. Marginal iron status appeared to be a determinant for elevated concentrations of Co in particular, but also Mn and Cd in blood. Systemic inflammation was associated with the concentrations of copper and Se. The concentrations of Hg in whole blood were highly associated with Se and arsenic (As) in whole blood, indicating fish consumption as a common source of intake of these elements. However, Hg in whole blood was only slightly associated with Se in serum.

CONCLUSIONS

The ERW had elevated concentrations of B-Cd, S-Cr, and U-Sn, while B-Mn, B-Pb, and U-Sb concentrations were higher among the LBRW. Iron status and inflammation had substantial impact on some element concentration. This population had high concentrations of B-Se, B-Hg and B-Co and U-I.

Blood mercury concentration in relation to metabolic and weight phenotypes using the KNHANES 2011-2013 data

PURPOSE

We assessed the association of blood mercury concentration with metabolic and weight phenotypes.

METHODS

Blood mercury concentration, metabolic syndrome components, and body mass index (BMI) were measured in 6006 Korean adults (2963 men, 3043 women, mean age 44.7 ± 14.7 years), using the 2011-2013 Korean National Health and Nutrition Examination Survey data. Metabolic and weight phenotypes were classified based on BMI and metabolic syndrome (MetS) presence as metabolically healthy and normal weight (MHNW), metabolically unhealthy and normal weight (MUNW), metabolically healthy and obese (MHO), and metabolically unhealthy and obese (MUO).

RESULTS

The geometric mean of blood mercury concentration was 3.37 μg/L (95% CI 3.32-3.43). A higher quartile of blood mercury concentration was associated with older age, male sex, higher education, alcohol use, current smoking, low physical activity, greater energy intake, and hypertension history. After adjusting for confounding factors (age, sex, education, income, health behaviors, and energy intake), blood mercury concentration tended to increase across the MHNW, MUNW, MHO, and MUO groups in all subjects and each sex (P for trend < 0.01). Compared to the lowest mercury quartile group, adjusted odds ratios (95% CI) for MHO and MUO in those with the highest mercury quartile were, respectively, 1.67 (1.34, 2.09) and 2.02 (1.59, 2.56) in all subjects: 1.58 (1.25, 1.99) and 1.72 (1.37, 2.16) for men; 1.33 (0.94, 1.88) and 1.90 (1.34, 2.70) for women.

CONCLUSIONS

Blood mercury concentration was associated with both metabolic syndrome and obesity, and the association was dose dependent across metabolic and weight phenotypes.

The Cut-off Value of Blood Mercury Concentration in Relation to Insulin Resistance

Background

Increased blood mercury concentration is associated with inflammation, and chronic inflammation can cause insulin resistance. We examined the cut-off value of blood mercury in relation to an increased score on the homeostasis model assessment for insulin resistance (HOMA-IR).

Methods

We used data from the Korean National Health and Nutrition Examination Survey (2008-2010). Relevant data from 5,184 subjects (2,523 men and 2,661 women) were analyzed cross-sectionally. General linear analysis was performed to evaluate the relationship between HOMA-IR score and blood mercury concentration. In addition, we determined the cut-off value of blood mercury concentration in relation to increased HOMA-IR score (> 2.34) using an ROC curve.

Results

The mean value of blood mercury concentration in men and women was 5.88 μg/L and 4.11 μg/L, respectively. In men, comparing to the first quartile, HOMA-IR score increased significantly in the third and fourth blood mercury quartiles. In women, however, the increase in HOMA-IR score was not significant. The cut-off value that best represented the association between increased HOMA-IR score and blood mercury concentration in men was found to be 4.71 μg/L.

Conclusion

Blood mercury concentration was associated with increased HOMA-IR score in men, and the cut-off value of blood mercury concentration that was correlated with increased HOMA-IR score was around 4.71 μg/L.

Blood mercury concentrations are associated with decline in liver function in an elderly population: a panel study

BACKGROUND

Mercury is a toxic heavy metal and is known to affect many diseases. However, few studies have examined the effects of mercury exposure on liver function in the general population. We examined the association between blood mercury concentrations and liver enzyme levels in the elderly.

METHODS

We included 560 elderly participants (60 years or older) who were recruited from 2008 to 2010 and followed up to 2014. Subjects visited a community welfare center and underwent a medical examination and measurement of mercury levels up to five times. Analyses using generalized estimating equations model were performed after adjusting for age, sex, education, overweight, alcohol consumption, smoking, regular exercise, high-density lipoproteins cholesterol, and total calorie intake. Additionally, we estimated interaction effects of alcohol consumption with mercury and mediation effect of oxidative stress in the relationship between mercury levels and liver function.

RESULTS

The geometric mean (95% confidence interval (CI)) of blood mercury concentrations was 2.81 μg/L (2.73, 2.89). Significant relationships were observed between blood mercury concentrations and the level of liver enzymes, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT), after adjusting for potential confounders (P < 0.05). The odds ratios of having abnormal ALT levels were statistically significant in the highest mercury quartile compared to those with the lowest quartile. Particularly, regular alcohol drinkers showed greater effect estimates of mercury on the liver function than non-drinkers groups. There was no mediation effect of oxidative stress in the relationship between blood mercury concentrations and liver function.

CONCLUSIONS

Our results suggest that blood mercury levels are associated with elevated liver enzymes and interact with alcohol consumption for the association in the elderly.