Urinary Mercury Concentration Research Articles

Heavy Metals and Trajectories of Anti-Müllerian Hormone During the Menopausal Transition.

Experimental and epidemiological studies have linked metals with women's reproductive aging, but the mechanisms are not well understood. Disrupted ovarian folliculogenesis and diminished ovarian reserve could be a pathway through which metals impact reproductive hormones and outcomes. The study aimed to evaluate the associations of heavy metals with anti-Müllerian hormone (AMH), a marker of ovarian reserve. The study included 549 women from the Study of Women's Health Across the Nation with 2252 repeated AMH measurements from 10 to 0 years before the final menstrual period (FMP). Serum AMH concentrations were measured using picoAMH ELISA. Urinary concentrations of arsenic, cadmium, mercury, and lead were measured using high-resolution inductively coupled plasma mass spectrometry. Multivariable linear mixed regressions modeled AMH as a function of time before the FMP interaction terms between metals and time to the FMP were also included. Adjusting for confounders, compared with those in the lowest tertile, women in the highest tertile of urinary arsenic or mercury concentrations had lower AMH concentrations at the FMP (percent change: -32.1%; 95% CI, -52.9 to -2.2, P-trend = .03 for arsenic; percent change: -40.7%; 95% CI, -58.9 to -14.5, P-trend = .005 for mercury). Higher cadmium and mercury were also associated with accelerated rates of decline in AMH over time (percent change per year: -9.0%; 95% CI, -15.5 to -1.9, P-trend = .01 for cadmium; -7.3%; 95% CI, -14.0 to -0.1, P-trend = .04 for mercury). Heavy metals including arsenic, cadmium, and mercury may act as ovarian toxicants by diminishing ovarian reserve in women approaching the FMP.

Reductions in plasma and urine mercury concentrations following N,N′bis-(2-mercaptoethyl) isophthalamide (NBMI) therapy: a post hoc analysis of data from a randomized human clinical trial

Environmental mercury exposure possesses a significant risk to many human populations. At present there are no effective treatments for acute mercury toxicity. A new compound, N,N′bis-(2-mercaptoethyl) isophthalamide (NBMI), a lipophilic chelating agent was created to tightly/irreversibly bind mercury. A post hoc dose-dependent analysis of NBMI therapy was undertaken on data from a randomized controlled NBMI human treatment trial on 36 Ecuadorian gold miners with elevated urinary mercury concentrations. Study subjects were randomly assigned to receive 100 milligram (mg) NBMI/day, 300 mg NBMI/day, or placebo for 14 days. For each study subject daily mg NBMI dose/Kilogram (Kg) bodyweight were determined and plasma and urine mercury concentrations (micrograms (µg)/Liter (L)) on study day 1 (pre-NBMI treatment), 15 (after 14 days of NBMI treatment) and 45 (30 days after NBMI treatment) were correlated with NBMI dosing using the linear regression statistic in SAS. Regression revealed significant inverse correlations between increasing per mg NBMI/Kg bodyweight/day and reduced concentrations of urinary and plasma mercury on study day 15 (reduced by in urine = 18–20 µg/L and plasma = 2 µg/L) and study day 30 (reduced by in urine = 15–20 µg/L and plasma = 4 µg/L) and significant correlations between reductions in mercury concentrations in urine and plasma. Significant 30% reductions in urinary mercury concentrations per mg NBMI/Kg bodyweight/day administered for 14 days were observed. This study supports the dose-dependent ability of NBMI therapy to significantly reduce mercury concentrations, particularly in the urine, in an acutely mercury exposed human population. NBMI therapy should be evaluated in other mercury exposed populations.

Association between urinary concentrations of toxic metals/metalloids and oxidative stress in Brazilians living in areas affected by the Fundão dam failure

The Fundão Dam failure has been the most significant environmental disaster in Brazil. The catastrophe released large amounts of mining waste into the environment, including toxic metals/metalloids, which are recognized to induce carcinogenic effects. The urinary levels of 8-hydroxy-2′-deoxyguanosine (8OHdG), a widely accepted oxidative stress and carcinogenesis biomarker, provide a potential tool for assessing the disaster's health implications. This study investigated the association between urinary levels of some toxic metals/metalloids and 8OHdG in Brazilian individuals living in areas affected by the Fundão dam failure. Urinary concentrations of arsenic (As), cadmium (Cd), mercury (Hg), nickel (Ni), and lead (Pb) were determined using inductively coupled plasma mass spectrometry, while 8OHdG was analyzed by liquid chromatography-tandem mass spectrometry. Non-parametric bootstrap regression was used to estimate the associations between the urinary levels of toxic elements and 8OHdG. The results showed that except for Hg, urinary concentrations of all metals/metalloids analyzed here exceeded the reference ranges for the Brazilian population. The regression analysis revealed that As (0.337; CI 95%: 0.203; 0.474), Cd (0.268; CI 95%: 0.036; 0.520), and Ni (0.296; CI 950.108; 0.469) were positively associated with creatinine-adjusted urinary 8OHdG levels. Associations were not found for Hg (0.0122; CI 95%: −0.155; 0.183) and Pb (0.201; CI 95%: −0.040; 0.498). The current findings suggest that high exposure to toxic metals/metalloids might increase 8OHdG levels with potential adverse health effects. This study is the first one in which the relationship between toxic metals/metalloids and oxidative stress biomarkers is investigated in populations affected by environmental disasters. Further prospective studies are necessary to monitor exposure levels and explore additional health impacts.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.

Levels of Arsenic, Cadmium, and Mercury in Urine of Indigenous People Living Close to Oil Extraction Areas in the Peruvian Amazon.

Association between dental amalgam restoration and urine mercury concentrations among young women in Korea: a cross-sectional study.

The association between dental amalgam fillings and urine mercury concentrations was investigated in this study to assess the health risks associated with dental amalgams. This cross-sectional study included 99 women in their 20s who visited the dental clinic in Daegu, Korea. The 99 participants were composed of 68 subjects who had dental amalgam fillings (exposure group) and 31 subjects who did not have dental amalgam fillings (nonexposure group). Oral examinations were conducted by a single dental hygienist, sociodemographic features were investigated as confounding variables, and urine mercury concentrations were measured using an automatic mercury analyzer. The mean±standard deviation of the urine mercury concentrations of the exposure and nonexposure groups were 1.50±1.78 μg/g creatinine and 0.53±0.63 μg/g creatinine, respectively. The exposure group showed significantly higher levels than the nonexposure group (p<0.01). The urine mercury concentration significantly increased with an increase in the number of teeth filled with amalgam, cavity surfaces involved, and number of defective amalgam fillings, and according to the latest exposure time (p<0.001). In the multiple regression analysis of amalgam-related factors and urine mercury concentrations after correction for confounding factors, the urine mercury concentration in the group with six or more amalgam-filled teeth, 11 or more cavity surfaces, and two or more defective amalgams was significantly higher than that in the nonexposure group (p<0.001). According to this study, exposure to dental amalgams was confirmed to significantly affect urine mercury concentrations.

Exposure to multiple metals and diabetes mellitus risk in dong ethnicity in China: from the China multi-ethnic cohort study.

Metals play an important role in the development of diabetes mellitus (DM). The association of metals with diabetes among the Dong ethnicity in China remains poorly understood. The current study aimed to evaluate the association of single metal exposure and multi-metal co-exposure with DM risk. Urinary concentrations of arsenic, cadmium, chromium, copper, iron, lead, manganese, mercury, molybdenum, nickel, strontium, vanadium, and zinc were measured using inductively coupled plasma-mass spectrometry (ICP-MS) among 4479 Dong ethnic participants aged 30-79years from the China Multi-Ethnic Cohort (CMEC) study. Based on tertiles, the metal exposure can be divided into three groups: low, middle, and high exposure. Multivariate logistic regression models and principal component analysis were performed to determine exposure to single-metal and multi-metal co-exposure in relation to DM. A decrease in risk of DM was associated with iron (OR = 0.78, 95% CI: 0.61-1.00 and 0.68, 0.53-0.88 for the middle and high vs. low) and strontium (OR = 0.87, 95% CI: 0.69-1.12 and 0.67, 0.51-0.86 for the middle and high vs. low), respectively. A principal component 3 (PC3) characterized by iron and strontium showed an inverse association with DM. A principal component 4 (PC4) characterized by manganese and lead positively associated with DM. Exposure to high concentrations of urinary iron and strontium may reduce the risk of diabetes mellitus. This study revealed an increase in the risk of diabetes mellitus by co-exposure to high concentrations of urinary manganese and lead.

Low-Level Environmental Mercury Exposure and Thyroid Cancer Risk Among Residents Living Near National Industrial Complexes in South Korea: A Population-Based Cohort Study.

Background: Previous studies suggested that mercury may be linked to thyroid cancer due to its bioaccumulation in the thyroid gland, but no studies have evaluated the association between mercury exposure and thyroid cancer risk. We examined the relationship between mercury exposure and thyroid cancer risk, with the potential modification of hematological parameters. Methods: We performed a secondary analysis of a prospective cohort study among residents living near industrial complexes in South Korea (recruited from 2003 to 2011). Incident thyroid cancer cases (C73, ICD-10 code) were identified from the National Cancer Registry and Statistics Korea. Urinary mercury concentrations were measured using thermal decomposition amalgamation atomic absorption spectrometry (TDA-AAS). Cox proportional hazards regression models (adjusted for age, sex, educational level, smoking status, and employment) were used to estimate the hazard ratio (HR) and confidence interval [CI] between mercury exposure and the incidence of thyroid cancer. Results: We documented 69 cases of thyroid cancer in a total of 5213 participants during follow-up (median 8.7 years). The geometric mean of urinary mercury concentration was 1.8 μg/L for thyroid cancer cases and 1.2 μg/L for noncases (p for difference = 0.001). After adjusting for potential confounders, those in the highest tertile of urinary mercury levels had a twofold higher risk of thyroid cancer (HR = 1.97 [CI 1.03 - 3.80] in the highest tertile vs. the lowest tertile, p for trend = 0.043). This association was stronger for those with lower mean corpuscular volume and mean corpuscular hemoglobin status. Conclusions: Urinary mercury concentration was positively associated with the risk of thyroid cancer among residents living near national industrial complexes, and this association was influenced by red blood cell indices status. These results provide some evidence suggesting the adverse effects of environmental metal pollution in the development of thyroid cancer.

Urine concentrations of selected trace metals in a cohort of Irish adults

Human biomonitoring studies are of increasing importance in regulatory toxicology; however, there is a paucity of human biomonitoring data for the Irish population. In this study, we provide new data for urinary biomarker concentrations of aluminium, arsenic, cadmium, chromium, copper, mercury, manganese, lead and selenium. One hundred urine samples, collected between 2011 and 2014 from healthy participants of the EuroMOTOR project, were randomly selected. Metal concentrations were measured via ICPMS. Descriptive statistics for each of the metals stratified by gender were performed. There were 58 male and 42 female participants and metals were detectable for all samples. Geometric mean urinary concentrations for each metal in males were as follows: aluminium 8.5 μg/L, arsenic 8.1 μg/L, cadmium 0.3 μg/L, chromium 0.5 μg/L, copper 5.1 μg/L, mercury 0.4 μg/L, manganese 0.3 μg/L, lead 1.3 μg/L and selenium 10.8 μg/L; and in females: aluminium 8.5 μg/L, arsenic 10.2 μg/L, cadmium 0.4 μg/L, chromium 0.6 μg/L, copper 5.6 μg/L, mercury 0.3 μg/L, manganese 0.2 μg/L, lead 1.6 μg/L and selenium 13.7 μg/L. We observed higher geometric mean concentrations in women for arsenic, cadmium, chromium, copper, lead and selenium, with equal geometric mean concentrations for aluminium and manganese, leaving only mercury with lower geometric mean concentrations in women. Aluminium, cadmium, chromium, lead and urinary concentrations of metals were slightly elevated compared to European data, while for arsenic, copper, manganese and selenium, Irish levels were lower. Our findings highlight that there are differences in urinary metal concentrations between European populations.

Analysis of Whole Blood and Urine Trace Elements in Children with Autism Spectrum Disorders and Autistic Behaviors

The relationship between trace elements and neurological development is an emerging research focus. We performed a case–control study to explore (1) the differences of 13 trace elements chromium (Cr), manganese (Mn), cobalt (Co), zinc (Zn), arsenic (As), selenium (Se), molybdenum (Mo), cadmium (Cd), stannum (Sn), stibium (Sb), mercury (Hg), titanium (TI), and plumbum (Pb) concentration in whole blood and urine between autism spectrum disorder (ASD) children and their typical development peers, and (2) the association between the 13 trace elements and core behaviors of ASD. Thirty ASD subjects (cases) and 30 age-sex-matched healthy subjects from Baise City, Guangxi Zhuang Autonomous Region, China, were recruited. Element analysis was carried out by inductively coupled plasma-optical emission spectrometry. Autistic behaviors were assessed using Autism Behavior Checklist (ABC), Childhood Autism Rating Scale (CARS), and Children Neuropsychological and Behavior Scale (CNBS). The whole blood concentrations of Mo (p = 0.004), Cd (0.007), Sn (p = 0.003), and Pb (p = 0.037) were significantly higher in the ASD cases than in the controls. Moreover, Se (0.393), Hg (0.408), and Mn (− 0.373) concentrations were significantly correlated between whole blood and urine levels in ASD case subjects. There were significant correlations between whole blood Sb (0.406), Tl (0.365), Mo (− 0.4237), Mn (− 0.389), Zn (0.476), and Se (0.375) levels and core behaviors of ASD. Although the mechanism of trace element imbalance in ASD is unclear, these data demonstrate that core behaviors of ASD may be affected by certain trace elements. Further studies are recommended for exploring the mechanism of element imbalance and providing corresponding clinical treatment measures.

Dietary exposure to metal mixtures throughout infants' first year of life in the New Hampshire Birth Cohort Study

BACKGROUND AND AIM: Recent reports have raised concerns about infants’ exposure to metals and metalloids (here, “metals”) via their first solid foods. Although early exposure to metals may cause lifelong health effects, epidemiologic studies on infants' dietary exposure to metal mixtures are still scarce. We aimed to assess the impact of diet on urinary metal concentrations over the first year of life among 348 children from the New Hampshire Birth Cohort Study. METHODS: We used inductively coupled plasma mass spectroscopy (ICP-MS) to measure infant urinary arsenic speciation, cadmium, cobalt, chromium, copper, iron, mercury, manganese, molybdenum, lead, antimony, selenium, uranium, vanadium and zinc concentrations. Caregivers completed a 3-day food diary before infant urine collection at 6 weeks and 4, 6, and 12 months of age. RESULTS:We determined the weights of each metal and the impact of the mixture at 6 weeks and 12 months of age. Using quantile g-computation we found that urinary concentration of arsenic, molybdenum and cobalt increased from ~6 weeks to 12 months of age, and that urinary selenium and copper decreased. We observed similar findings in a subset of infants (n = 19) during weaning from 4 to 6 months of age. We are now focusing on identifying specific groups of foods responsible for these changes. CONCLUSIONS:Determining dietary contributors to infants’ exposure to potential harmful metals is a critical step in preventing their long-term consequences. KEYWORDS: mixture, heavy metals, food, biomarkers of exposure

Prenatal exposure to metal mixtures and lung function in children from the New Hampshire Birth Cohort Study

BACKGROUND AND AIM: Prenatal environmental exposure to metals and metalloids (referred to as “metals”) has been associated with childhood lung development, but limited data exist on metal mixtures. We aimed to investigate the association between gestational exposure to metal mixtures and childhood lung function among 267 maternal-child dyads from the New Hampshire Birth Cohort Study. METHODS: Maternal ~24-28-week gestational urinary arsenic speciation, aluminum, cadmium, cobalt, chromium, copper, iron, mercury, manganese, molybdenum, nickel, tin, lead, antimony, selenium, thallium, uranium, vanadium and zinc concentration were assessed using inductively coupled plasma mass spectroscopy (ICP-MS). Forced vital capacity (FVC), forced expiratory volume in the first second of exhalation (FEV1), and forced expiratory flow between 25% and 75% of FVC (FEF25-75) standardized z-scores were obtained at a median age of 7.4 years. We used quantile g-computation for each outcome and urinary metals adjusted for maternal smoking status, children’s age, sex and height. RESULTS:Urinary concentrations of cobalt, lead, nickel, cadmium, and chromium were inversely associated with lung function z-scores. Arsenic concentrations were inverse associated specifically with FVC and FEV1 z-scores. In contrast, lung function z-scores increased with vanadium, molybdenum, and thallium urine concentrations. CONCLUSIONS:Our findings suggest that prenatal exposure to metal mixtures impact lung function, with varying direction and magnitudes of effects. KEYWORDS: mixture, heavy metals, children’s environmental health, respiratory outcomes, biomarkers of exposure

The effect of polyunsaturated fatty acids on cardiovascular risk factors and urinary mercury in workers employed at electrolytic production of chlorine.

While inorganic mercury is being gradually withdrawn from industry, environmental exposure to mercury is recognized as one of the greatest present toxicological problems. The aim of this study was to evaluate the effect of polyunsaturated fatty acids (PUFAs) supplementation on selected cardiovascular risk factors and the urinary mercury (Hg-U) concentration in workers occupationally exposed to mercury vapor. Overall, 38 workers of an electrolyzer hall (Hg-U: 46.6±35.7 μg/g creatinine) and a control group of 60 employees not exposed to Hg (Hg-U: 4.3±15.5 μg/g creatinine) were included in a clinical cross-over study. Clinical and laboratory tests were carried out 4 times: before and after a 3-month period of PUFAs supplementation (1000 mg daily), then after a 3-month break, and then after another 3-month period of PUFAs supplementation. The baseline heart rate (HR) and serum triglyceride levels were higher in the Hg-exposed workers than in the controls, whereas systolic blood pressure (SBP) and cholesterol (C) levels exceeded normal values in both groups. There was a positive correlation between high-density lipoprotein 3 cholesterol (HDL3-C) and Hg-U levels. The PUFAs use was associated with a decrease in both HR and SBP. After the first stage of supplementation, a decrease in the Hg-U concentration was observed. In a multivariate logistic regression model, decreases in Hg-U were associated only with exposure to mercury; ORΔHg = 0.562 (95% CI: 0.323-0.979), p < 0.042. After the second 3-month period of PUFAs supplementation, a significant association between HDL3-C and a Hg-U decrease was shown: ORHDL3 = 1.222 (95% CI: 1.01-1.46), p < 0.033. In the workers exposed to mercury vapor, PUFAs supplementation led to some beneficial effects on HR and SBP. The first stage of supplementation was associated with a decrease in Hg-U in which HDL3 metabolism probably plays an important role. Int J Occup Med Environ Health. 2021;34(4):551-64.

Registration status, mercury exposure biomarkers, and neuropsychological assessment of artisanal and small-scale gold miners (ASGM) from the Western Region of Ghana

The artisanal and small-scale gold mining (ASGM) sector is estimated to be the largest anthropogenic source of mercury pollution worldwide, and not surprisingly human exposures in this sector are amongst the highest of all population groups. While formalization of the sector has been proposed as a solution to help improve health and safety within ASGM sites, there are few empirical studies in support of this notion. The objective of this study was to assess if individuals working in ASGM sites that are registered have reduced mercury exposures and better neuropsychological scores than workers from unregistered sites. To achieve this objective, we studied biological samples (urine, hair) and survey data from a study of 404 ASGM workers (of which, 295 worked in registered ASGM sites) conducted in Tarkwa (Ghana) in 2014. Between miners working in registered and unregistered sites, there were few differences in socio-demographic characteristics. Median urinary mercury concentration (specific gravity-corrected) among those from unregistered mines was nearly 3-fold higher than those from the registered mines (18.5 versus 6.6 μg/L), and in the overall population the median concentration was 10.0 μg/L, and ranged from 0.3 to 2499 μg/L. Mercury biomarkers varied across ASGM work categories (e.g., those who burned or amalgamated had the highest) and users of personal protective equipment. Nearly 30% of the study population indicated having some challenges concerning, for example, reduced appetite, hair loss, or excess salivation. Ataxia and rigidity of gait were absent in most of the participants, and for those with slight, moderate, or marked responses, there were no differences between miners from registered and unregistered sites, across work groups, as well as in reference to mercury biomarker measures. For the pencil tapping, Frostig, matchbox, and Wechsler tests, no striking differences were found though a correlation was found between urinary mercury levels and matchbox scores among those who amalgamate and burn, and scores were similar to past studies using the same tests in ASGM sites. We believe this is the first study to compare mercury exposures and neuropsychological test results between miners from registered and unregistered ASGM sites. In doing so, the research findings provide the necessary evidence for stakeholders and parties of the Minamata Convention considering various response options to help fulfill their obligations.

Selenium (Se) as well as mercury (Hg) may influence the methylation and toxicity of inorganic arsenic, but further research is needed with combination of Inorg-arsenic, Se, and Hg

Selenium (Se) as well as mercury (Hg) may influence the methylation and toxicity of inorganic arsenic, but further research is needed with combination of Inorg-arsenic, Se, and Hg

Characteristics and treatment of elemental mercury intoxication: A case series.

Background and aimsElemental mercury toxicity is a rare condition which can be difficult to diagnose due to its nonspecific signs and symptoms. The purpose of this investigation is to describe the presenting characteristics and treatment of adult and pediatric patients with elemental mercury poisoning.MethodsA retrospective review was performed in six patients with elemental mercury exposure or intoxication who were treated in an outpatient medical toxicology clinic. Clinical signs and symptoms, laboratory assessments, and public health responses were reviewed.ResultsHeadache, anorexia, rash, and personality changes were commonly reported symptoms in pediatric patients; the adult patients were asymptomatic or reported signs and symptoms included myalgias, tremors, and hypertension. Delays in diagnosis were common. Symptomatic patients had 24‐hour urine mercury concentrations greater than 20 mcg/L. Treatment, including removal from the exposure source as well as chelation with dimercaptosuccinic acid, resulted in resolution of signs and symptoms within 6 months of diagnosis.ConclusionThe evaluation and treatment of patients with suspected elemental mercury poisoning frequently require a multidisciplinary approach including medical toxicologists and public health officials. A heightened awareness of the clinical presentations of this condition, as well as early identification and removal of patients from the source of exposure and consideration of chelation therapy, can result in accelerated patient recovery.

Impact of environmental mercury exposure on the blood cells oxidative status of fishermen living around Mundaú lagoon in Maceió – Alagoas (AL), Brazil

Mercury in the aquatic environment can lead to exposure of the human population and is a known toxic metal due to its capacity for accumulation in organs. We aimed to evaluate the mercury level in the blood and urine of fishermen and correlate it with the level of oxidative stress in blood cells. We show in this case-control study that the fishermen of the exposed group (case) of Mundaú Lagoon (Maceió - Alagoas, Brazil) have higher concentrations of total mercury in the blood (0.73–48.38 μg L−1) and urine (0.430–10.2 μg L−1) than the total mercury concentrations in blood (0.29–17.30 μg L−1) and urine (0.210–2.65 μg L−1) of the control group. In the blood cells of fishermen, we observed that the lymphomononuclear cells produced high levels of reactive oxygen species (61.7%), and the erythrocytes presented increased lipid peroxidation (151%) and protein oxidation (41.0%) and a decrease in total thiol (36.5%), GSH and the REDOX state (16.5%). The activity of antioxidant system enzymes (SOD, GPx, and GST) was also reduced in the exposed group by 26.9%, 28.3%, and 19.0%, respectively. Furthermore, hemoglobin oxygen uptake was decreased in the exposed group (40.0%), and the membrane of cells presented increased osmotic fragility (154%) compared to those in the control group. These results suggest that mercury in the blood of fishermen can be responsible for causing impairments in the oxidative status of blood cells and is probably the cause of the reduction in oxygen uptake capacity and damage to the membranes of erythrocytes.

Association between metal exposure and Follicle Stimulating Hormone (FSH) and thyroid hormone among women of reproductive age: Korean Nationwide Biomonitoring Studies

BackgroundHeavy metals including mercury, lead, and cadmium are known as endocrine disrupting chemicals. There are few epidemiological studies available to present the relationship between metal exposures and changes in hormones. Infertility, polycystic syndrome, and uterine myoma are quite prevalent among women, which are related to hormonal abnormalities. In this study, we analyzed measurement data from nationwide biomonitoring studies in Korea and examine the association between co-exposure to heavy metals and sex and thyroid hormone among women of reproductive age. MethodsThis study involved 3,088 women of reproductive age (15-49 years) included in the 2th Korean National Environmental Health Survey in 2012-2014 and the 6th Korea National Health and Nutrition Examination Survey in 2013. The concentrations of mercury, lead, and cadmium in either urine or blood, serum follicle-stimulating hormone (FSH), thyroid stimulating hormone (TSH), triiodothyronine (T3), tetraiodothyronine (T4), and free tetraiodothyronine (FT4) were analyzed using multiple regression analysis. Age, body mass index, smoking status, alcohol, income, and urinary creatinine were adjusted in the statistical model. The statistical analysis was performed using R (ver. 3.6.3). ResultsMercury in urine was negatively associated with FSH [β (95% CI): -0.064 (-0.120, -0.008)]. Mercury in blood was positively associated with the FT4 [0.119 (0.030, 0.208)]. Lead in blood was positively associated with FSH [0.119 (0.030, 0.208)]. Cadmium had no significant association with any hormones. The results are comparable to other previous studies analyzing the association between single metal exposure and hormonal effects. Still, the effect (β) of metals seems greater in co-exposure models. Many the previous studies of the single exposure to heavy metals have reported that exposure to lead and cadmium increases FSH. For thyroid hormones, significant hormones or directions were different from the previous findings. ConclusionsFSH levels is related to infertility. Further studies of metals exposure are needed to protect the women of reproductive age.

Identifying a critical window of maternal metal exposure for maternal and neonatal thyroid function in China: A cohort study

BackgroundChina, a developing country, has a particularly serious problem with metal pollution. We evaluated the association of metal exposure during pregnancy with maternal and neonatal thyroid function, and identified the critical window for maternal metal exposure effects on maternal and neonatal thyroid functions. MethodsThe maternal urinary concentrations of mercury (Hg), cadmium (Cd), arsenic (As) and cesium (Cs) were determined in pregnant women during their first (n = 389) or third (n = 257) trimesters in a prospective cohort from 2014 to 2015 in Nanjing, China, using an inductively coupled plasma mass spectrometry (ICP-MS) instrument. Maternal serum-free thyroxine (FT4) and thyroid-stimulating hormone (TSH) were measured by electrochemiluminescent microparticle immunoassays in the second and third trimesters. Neonatal TSH levels were detected 72 h after birth. ResultsHg (>0.162 µg/L), Cd (>0.084 µg/L), As (>0.348 µg/L) and Cs (>0.093 µg/L) were detectable in 76.9%, 90.1%, 100% and 100% of maternal urine samples from women in the first trimester of pregnancy. In the multiple adjusted linear regression models, maternal exposures to Hg and Cd in the first trimester were positively associated with maternal TSH levels in the second trimester (P < 0.01, P = 0.02). Moreover, maternal exposures to Cd and Cs in the first trimester were positively associated with neonatal TSH levels (P = 0.04, P = 0.02). In the Bayesian kernel machine regression (BKMR) model, the results were stable and consistent with the linear regression model. ConclusionsMaternal exposure to Hg, Cd and Cs in the first trimester was related to TSH levels in mothers and newborns. Efforts to identify maternal and neonatal thyroid disruptors should carefully consider the effects of exposure to these metals.

Artisanal and small-scale gold mining: A cross-sectional assessment of occupational mercury exposure and exposure risk factors in Kadoma and Shurugwi, Zimbabwe

In artisanal and small-scale gold mining (ASGM) the toxic metal mercury is used for gold extraction. The objective of this cross-sectional study was to assess mercury concentrations in urine and blood and mercury-related symptoms of participants identifying themselves as miners from Kadoma and Shurugwi, Zimbabwe. Moreover, we aimed to explore possible risk factors influencing mercury body burden. In 2019, urine and blood samples of 207 participants were collected and analyzed for mercury using atomic absorption spectroscopy. All participants answered questions regarding their exposure risks. The median urine mercury value was 4.75 μg/L with a maximum of 612 μg/L. Median mercury concentration in creatinine corrected urine values was 3.98 μg/g with a maximum value of 478 μg/g. The median blood mercury value was 2.70 μg/L with a maximum of 167 μg/L. Correlations between exposure risks factors such as the lack of retort use and elevated mercury values were demonstrated. ASGM is very common in Zimbabwe. Thus, mercury exposure is a major occupational health risk for miners. Moreover, this study emphasizes the impact of exposure risk factors on the mercury body burden.

The association between mercury concentrations and lipid profiles in the Korean National Environmental Health Survey (KoNEHS) cycle 3.

BackgroundHigh concentrations of mercury intake from seafood are known to cause various side effects in humans, including on the nervous system. Various studies have reported the effects of mercury concentrations in humans; however, the association between dyslipidemia, a cardiovascular disease risk factor, and mercury remains controversial. Therefore, this study aimed to investigate the association between mercury accumulation and cholesterol concentrations in a Korean population.MethodsWe analyzed data of a sample of 3,228 respondents obtained from the Korean National Environmental Health Survey cycle 3, surveyed between 2015 and 2017, to determine how lipid profiles changed according to the blood mercury concentrations (BHg) and urine mercury concentrations (UHg). Multiple regression analysis was used to determine the effects of mercury concentrations among various factors affecting blood cholesterol levels.ResultsThe arithmetic mean (AM) of BHg was 2.91 (2.81–3.02) μg/L, and the geometric mean (GM) was 2.71 (2.59–2.85) μg/L. The AM of UHg was 0.52 (0.48–0.56) μg/L, and the GM was 0.35 (0.33–0.38) μg/L. Lipid profiles were more related to the BHg than to the UHg. Total cholesterol (total-C), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels increased significantly as BHg increased in males, and total-C, triglyceride, and LDL-C levels increased significantly in females. Multiple regression analysis indicated that BHg were significantly associated with total-C, HDL-C, and LDL-C levels.ConclusionsWe found an association between mercury exposure and the risk of dyslipidemia; however, further studies are required to elucidate a causal association.