Total Mercury Levels Research Articles

Effects of a decade of selenium emission reductions on mercury accumulation in aquatic biota in the Sudbury region of Ontario

Control of smelting emissions in the Sudbury (Ontario, Canada) area has dramatically decreased the amount of selenium (Se) deposited onto the surrounding landscape. Historically, Se emissions in Sudbury correlated with lower total mercury (Hg) and methylmercury levels (MeHg) in tissues of zooplankton, amphipods (Hyalella azteca), mayflies (Stenonema femoratum), and young-of-the-year perch (Perca flavescens). In 2017, ten years following emission reductions, we evaluated whether changes in Se deposition affected total Hg and MeHg burden in lake biota. We show that total Se concentrations in the water of the majority of lakes have increased despite decreases in Se depositions, most likely due to the long residence time of Se in the watershed and the water column. As a result, Se in water continues to correlate with lower total Hg and MeHg accumulation in tissues of zooplankton, amphipods, mayflies, and perch. These results suggest that Se continues to exhibit a protective effect on Hg accumulation in biota, even years after emissions have greatly decreased. We expect this work to inform efforts aiming at long-term recovery of aquatic environments affected by smelter emissions and aid in designing remediation strategies involving Se additions.

An association of blood mercury levels and hypercholesterolemia among Korean adolescents

PurposeA few experimental studies have suggested that mercury exposure might be associated with dyslipidemia, possibly through its interference with the activities of genes and enzymes involved in lipid metabolism. Mercury exposure has been associated with the risk of dyslipidemia and cardiovascular disease in previous adult studies. However, only a few studies have been conducted in pediatric populations. We aimed to assess the associations between total blood mercury concentrations and lipid profiles in Korean adolescents. MethodsThe study population comprised 1890 adolescents (963 males and 927 females; age: 10–19 years) who participated in the Korea National Health and Nutrition Examination Survey 2010–2013 and 2016 and whose fasting blood samples were obtained to determine their blood mercury concentrations and lipid profiles. We analyzed the distribution of lipid profiles and the prevalence of dyslipidemia based on the total blood mercury concentrations. ResultsThe geometric mean of the blood mercury concentration was 1.89 μg/L and was significantly higher in males (1.96 μg/L) than in females (1.83 μg/L). The total cholesterol and low-density lipoprotein (LDL) cholesterol levels significantly increased as the blood total mercury concentration increased in males, not in females. High-density lipoprotein cholesterol and triglyceride levels did not show significant associations with total blood mercury levels. The prevalence of hyper-LDL-cholesterolemia also significantly increased in the highest blood mercury quartile group compared with that in the lowest blood mercury quartile group in males (P-for-trend <0.001). Male adolescents in the highest total blood mercury quartile group were found to be at higher risk of hypercholesterolemia than those in the lowest quartile group after adjusting for the covariates including obesity [odds ratios (95% confidential interval): 3.72 (1.03–13.4)]. Total blood mercury quartile showed a positive linear relationship with the risk of hyper-LDL-cholesterolemia after controlling for the covariates in males. ConclusionOur results suggest the potential association between mercury exposure and the risk of hyper-LDL-cholesterolemia in male adolescents.

Prenatal Se concentrations and anthropometry at birth in the INMA study (Spain)

We assessed whether prenatal selenium (Se) exposure is associated with anthropometry at birth, placental weight and gestational age. Study subjects were 1249 mother-child pairs from the Valencia and Gipuzkoa cohorts of the Spanish Childhood and Environment Project (INMA, 2003–2008). Se was determined in serum samples taken at the first trimester of pregnancy. Socio-demographic and dietary characteristics were also collected by questionnaires. Mean (SD) serum Se concentration was 79.57 (9.64) μg/L. Se showed weak associations with both head circumference and gestational age. The association between serum Se concentration and birth weight and length was negative, and direct for placental weight and probability of preterm birth, although the coefficients did not reach statistical significance. Individuals with total mercury (THg) levels >15 μg/L reversed the serum Se concentration effect on head circumference. Significant interactions were found between sex and both gestational age and prematurity. Spontaneous birth gestational ages were estimated to be lower for males and their probability of prematurity was higher. In conclusion, prenatal Se exposure may be associated with lower head circumference and lower gestational ages at spontaneous birth. Interactions with THg exposure and gender should be considered when assessing these relationships.

Blood metal levels and serum testosterone concentrations in male and female children and adolescents: NHANES 2011-2012.

Environmental exposure to metals is ubiquitous, but its relation to androgen hormone levels is not well understood, especially in children and adolescents. This study aimed to explore the relationship between blood metal concentrations (lead, cadmium, total mercury, selenium, and manganese) and serum total testosterone (TT) levels in 6-19-year-old children and adolescents in the National Health and Nutrition Examination Survey (NHANES) 2011-2012. Weighted multivariable linear regression models using NHANES sampling weights were employed to evaluate the association between log-transformed serum TT and each metal categories in male and female children (age 6-11years) and adolescents (age 12-19 years). We established that blood cadmium and manganese levels were associated with significantly higher serum TT levels in the female adolescents. Additionally, the blood selenium levels in male adolescents were related to significantly higher serum TT. No significant associations between blood lead or total mercury levels and TT were observed in children or adolescents of either sex. These findings suggest that environmental exposure to certain metals could affect serum TT levels in adolescents, which might have important implications for the health of adolescents. Further research is required to confirm and extend our present findings.

Dietary exposure assessment of total mercury and methylmercury in commercial rice in Sri Lanka

Methylmercury (MeHg) in rice has attracted growing health concern over the past decade, due to the accumulation of high MeHg levels, which may pose potential health risk to humans. Rice is the staple food in Sri Lanka; nevertheless, the presence of micro pollutants, such as MeHg has been not investigated. Therefore, commercial rice samples from the Sri Lankan market (n = 163) were measured to reveal the total mercury (THg) and MeHg levels. THg (mean: 1.73 ± 0.89 ng/g, range: 0.21–6.13 ng/g) and MeHg concentrations (mean: 0.51 ± 0.37 ng/g; range: 0.03–3.81 ng/g) were low. Compared to the fish MeHg exposure, the rice MeHg exposure was generally lower in different consumption groups, suggesting that rice plays a less role than fish in MeHg exposure in Sri Lanka. Babies (infants and toddlers) at one year old may face fish MeHg exposure (0.17 μg/kg bw/day) higher than the reference dose for MeHg (RfD)-0.1 μg/kg bw/day, which was more than 5 times that of rice MeHg exposure (0.031 μg/kg bw/day). Future studies in Sri Lanka should focus on health impacts under long-term overexposure of MeHg, especially in vulnerable populations. Some diet changes should be made to mitigate MeHg exposure levels in Sri Lankans.

Aqueous Coriandrum sativum L. extract promotes neuroprotection against motor changes and oxidative damage in rat progeny after maternal exposure to methylmercury

This study aimed to investigate the effects of Coriandrum sativum aqueous extract (CSAE) on the rat progeny of mothers exposed to methylmercury (MeHg). The presence of bioactive compounds and CSAE's antioxidant capacity been evaluated, and the offspring were assessed for their total mercury levels, motor behavioral parameters and oxidative stress in the cerebellum. The analysis of the bioactive compounds revealed significant amounts of polyphenols, flavonoids, and anthocyanins, as well as a variety of minerals. A DPPH test showed the CSAE had important antioxidant activity. The MeHg + CSAE group performed significantly better spontaneous locomotor activity, palmar grip strength, balance, and motor coordination in behavioral tests compared the MeHg group, as well as in the parameters of oxidative stress, with similar results to those of the control group. The MeHg + CSAE group also had significantly reduced mercury levels in comparison to the MeHg group. Based on the behavioral tests, which detected large locomotor, balance, and coordination improvements, as well as a reduction in oxidative stress, we conclude that CSAE had positive functional results in the offspring of rats exposed to MeHg.

Tuna Consumption, Mercury Exposure, and Knowledge about Mercury Exposure Risk from Tuna Consumption in University Students.

We examined the relationships among tuna consumption, hair mercury levels, and knowledge of mercury exposure risk from tuna consumption in university students that were offered tuna daily at university-run dining halls. Hair total mercury levels in tuna consumers were higher than those in non-tuna consumers (average = 0.466 µg/g ± 0.328 standard deviation [SD], n = 20 vs 0.110 µg/g ± 0.105 SD, n = 33, respectively; p < 0.0001, Mann-Whitney U test), with tuna eaters exhibiting a positive relationship between self-reported tuna consumption at dining halls and hair mercury levels (R2 = 0.868, p < 0.0001, n = 17, linear regression). For all tuna eaters surveyed, more than half (54%) self-reported eating ≥3 tuna meals/wk, potentially exceeding the US Environmental Protection Agency's reference dose for methylmercury of 0.1 µg/kg body weight/d. Seven percent of study participants reported they consumed >20 tuna meals/wk, which was related to hair mercury levels >1 µg/g, a level of concern. Study participants had an overall lack of knowledge and confidence in their knowledge about mercury exposure risk from tuna consumption, with >99% of participants reporting low knowledge and low confidence in survey answers. Our study highlights the importance of education about the risks of tuna consumption, particularly in institutional settings where individuals have unlimited access to tuna products. Environ Toxicol Chem 2019;38:1988-1994. © 2019 SETAC.

Levels of mercury in Nile tilapia (Oreochromis niloticus), water, and sediment in the Migori gold mining belt, Kenya, and the potential ramifications to human health

Background: Understanding mercury levels in gold mining areas where locals consume fish is important in evaluating the risk to the population. This study determined the levels of total mercury (T-Hg) in Nile tilapia, water, and sediment in the Migori gold mining belt and the potential risk to human health. Methods: Water, sediment, and fish were sampled from 10 sites in Rongo and Nyatike and analyzed for T-Hg using cold vapor atomic absorption spectroscopy. Geo-accumulation index (IGeo) was used to evaluate sediment quality, and the estimated daily intake of fish per meal (EDIm), the target hazard quotient (THQ), and the maximum allowable fish consumption rate (CRmw) were calculated as health risk indices. Results: Sediment from 6 sites were moderately polluted with T-Hg, while 2 sites were strongly polluted. Water from all the sites had T-Hg levels higher than the FAO recommended level for surface water. About 78% (38/49) of all tissues sampled had T-Hg levels above the 0.5 µg/g limit for consumption by the general human population. About 31% (15/49) of muscle tissues had T-Hg levels above the 0.5 µg/g limit, while 88% (43/49) of brain, 69% (34/49) of liver, and 69% (34/49) of muscle tissues had T-Hg levels above the 0.2 µg/g limit for consumption by at-risk groups. There were positive correlations between T-Hg levels in brain, muscle and pond sediment, T-Hg levels in brain and water pH and temperature, and negative correlations between T-Hg levels in brain and levels in water, T-Hg levels in brain and weight of fish. EDIm and THQ ranged from 2.43-15.84 µg/g and 24.3-158.4 µg/g wet weight respectively while CRmw ranged from 1-4 fish. Conclusions: Consumption of Nile tilapia from the studied area carries a significant risk of Hg exposure in frequent fish-eaters, pregnant women, and developing children, but is safe for the general population.

Risk assessment of methylmercury in pregnant women and newborns in the island of Madeira (Portugal) using exposure biomarkers and food-frequency questionnaires

ABSTRACTMethylmercury (MeHg) is a contaminant present in fish which exerts a severe impact on health predominantly exhibiting neurotoxicity that might irreversibly affect fetal neurodevelopment. Fish consumption in Portugal is the third highest in the world, particularly high in regions with fishing tradition such as the Madeira Archipelago. Therefore, this study aimed at assessing the risk of exposure to MeHg in a population of pregnant women residing in Madeira. Blood samples from pregnant women (533) and umbilical cord (194) were collected from volunteer participants collected at primary health services in Madeira (Portugal) and analyzed for total mercury (HgT) level. A food-frequency questionnaire was used to estimate exposure and indices of risk while HgT in blood were correlated with estimated exposure. Analysis of HgT levels in blood indicated that 30% of pregnant women surpassed the maximum safe level of 10 µg/L recommended by the WHO, which was derived from the consumption of predatory fish, rich in MeHg. In addition, HgT levels in cord blood were 1.3 fold higher than in maternal blood, indicating the high risk of exposure to MeHg in this population. It is thus important to provide nutritional advice concerning fish consumption as a food choice in order to reduce fetal exposure and potential neurologic damage.

Total Mercury Levels in Commercial Fish in Market of the Republic of Srpska, Bosnia and Herzegovina.

The mercury concentration was quantified in frozen and canned fish found in the market of the Republic of Srpska, Bosnia and Herzegovina. Using the method of amalgamation by atomic absorption spectrophotometry with a direct mercury analyzer (DMA-80), significant differences in mercury concentrations among the analyzed fish were found. Frozen pangasius and canned tuna had the highest mercury concentration (59.1μg/kg and 54.1μg/kg, respectively). Also, fish from Vietnam had the highest level of total mercury in comparison to fish from other countries. Determined levels of mercury in our samples were below the limit set by the European and Bosnian and Herzegovinian legislation (500μg/kg wet weight). We have concluded that consumption of commercial fish in the market of the Republic of Srpska does not present any health risk for the average consumer. Nevertheless, a surveillance system of mercury content in fishery products, especially in certain species that concentrate mercury, is crucial for public health protection.

Mercury in archaeological human bone: biogenic or diagenetic?

We investigated mercury (Hg) in human bone from archaeological sites in the Iberian Peninsula where the cultural use of cinnabar (HgS) as a pigment, offering or preservative in burial practices has been documented from the 4th to 2nd millennia cal B.C. (Late Neolithic, Copper Age and Bronze Age). Previous analyses have shown high levels of total mercury (THg) in human bone at numerous Neolithic and Chalcolithic sites in this region, but the question remains if this mercury entered the bones via diagenetic processes in the soil, especially where cinnabar powder and paint was found associated with the burials, or if it entered the bone via biogenic pathways from exposure to mercury from using cinnabar in life. We analyzed the humerus, femur, and tibia from a total of 30 individual burials from four Neolithic to Bronze Age sites in Iberia and found low to high values of THg in these bones, with the humerus showing significantly more THg concentrations than other skeletal elements when the THg was greater than 1 ppm. This pattern of Hg deposition in skeletal material from different sites and ages strongly suggests a biogenic origin for the mercury. In addition, absence of detectable Hg in bones with high to low values of THg using SEM EDS analysis further discounts diagenetic intrusion of Hg or cinnabar particles into the bone from the soil. It is likely that greater stress and bone remodeling rates from use of heavy tools and other activities in life are responsible for higher THg in the humerus than other skeletal elements, but additional research is needed to verify this.

Chronic Methylmercury Exposure Induces Production of Prostaglandins: Evidence From A Population Study and A Rat Dosing Experiment.

Methylmercury (MeHg) is a well-known environmental neurotoxicant affecting millions worldwide who consume contaminated fishes and other food commodities. Exposure to MeHg has been shown to associate positively with some chronic diseases including cardiovascular diseases, but the mechanism is poorly characterized. MeHg had been shown to affect prostaglandin (PG) regulations in in vitro studies, but neither in vivo nor human studies investigating the effects of MeHg on PG regulations has been reported. Thus, the current study aimed to investigate the association between MeHg exposure and serum PG concentrations in a cross-sectional study among human adults followed by a validation investigation on the cause-effect relationship using a rat model. First, a total of 121 women were recruited from two cities: Wanshan and Leishan in Guizhou, China. Statistical analysis of the human data showed a positive association between blood total mercury (THg) levels and serum concentrations of PGF2α, 15-deoxy-PGJ2, and PGE2 after adjusting for site effects. In the animal study, adult female Sprague-Dawley rats were dosed with 40 μg MeHg/kg body weight/day for 12 weeks. Serum 15-deoxy-PGJ2 and 2,3 d-6-keto-PGF1α concentrations were found to increase significantly after 6 and 10 weeks of MeHg dosing, respectively, while serum PGF2α concentration increased significantly after 12 weeks of MeHg dosing. Combined results of our human and rat studies have shown that chronic MeHg exposure induced dysregulation of PG metabolism. As PGs are a set of mediators with very diverse functions, its abnormal production may serve as the missing mechanistic link between chronic MeHg exposure and various kinds of associated clinical conditions including neurodegeneration and cardiovascular diseases.

Concentrations of cadmium, lead, and mercury in blood among US cigarettes, cigars, electronic cigarettes, and dual cigarette-e-cigarette users

Data from National Health and Nutrition Examination Survey for 2013–2016 were used to compare observed levels of cadmium, lead, and total mercury in blood among US residents aged ≥12 years who were users of cigars, cigarettes, cigars and cigarettes, e-cigarettes and dual users of cigarettes and e-cigarettes. Total sample size available for analysis was 1139. Adjusted geometric means (AGM) among cigarette, cigar, e-cigarette, cigarette and cigar, and cigarette-e-cigarette users were comparable for blood cadmium lead, and total mercury. Cigar only users had lower AGM than cigar and cigarette users for total mercury (0.56 vs. 0.97 μg/L, p = 0.03). There is no evidence yet that can show concentrations of blood and urine cadmium, lead, and mercury among e-cigarette users are any different than among cigarette and/or dual users of cigarettes and e-cigarettes.

MON-037 An Association of Blood Mercury Levels and Hypercholesterolemia among Korean Adolescents

Purpose: Mercury exposure has been associated with the risk of dyslipidemia and cardiovascular disease in previous adult studies. However, there is little research on pediatric populations on this subject. We aimed to assess the associations between total blood mercury concentrations and lipid profiles in Korean adolescents. Methods: The study population comprised 1,890 adolescents (963 boys and 927 girls; aged 10-19 years), who participated and obtained fasting blood samples for blood mercury concentrations and lipid profiles in the Korea National Health and Nutrition Examination Survey (KNHANES) 2010-2013, 2016. We analyzed the distribution of lipid profiles and prevalence of dyslipidemia according to total blood mercury concentrations. Results: The geometric mean of the total blood mercury levels were 1.97 and 1.83 μg/L in boys and girls, respectively. As the blood mercury concentration increases, total cholesterol and low-density lipoprotein (LDL) cholesterol levels significantly increased. However, high-density lipoprotein (HDL) cholesterol and triglyceride levels did not show significant associations with total blood mercury levels. The prevalence of hyper-LDL-cholesterolemia also significantly increased in the highest blood mercury quartile group compared with the lowest group (8.9% vs. 5.1%, P-for-trend = 0.002). After adjusting for the covariates including obesity, those in the highest total blood mercury quartile were found to be at an increased risk of hypercholesterolemia than in the lowest quartile in boys [odds ratios (95% confidential interval): 3.72 (1.03-13.4)]. The association between total blood mercury quartile and the risk of hyper-LDL-cholesterolemia showed a positive linear relationship after controlling for the covariates in boys [Quartile 2 = 7.5, Quartile 3 = 10.3, Quartile 4 = 16.3]. Conclusion: Our results suggest the potential association between mercury exposure and the risk of hyper-LDL-cholesterolemia in adolescents. Keywords: Adolescent, Blood, Mercury, Dyslipidemia

Changes in total mercury, methylmercury, and selenium blood levels during different life history stages of the Baltic grey seal (Halichoerus grypus grypus)

Using the blood of grey seal pups, the blood and milk of female grey seals inhabiting the Hel Marine Station of Gdansk University's Institute of Oceanography (HMS), we monitored the transfer of total mercury (THg), methylmercury (MeHg), and selenium (Se) with blood during foetal life and nursing. Changes in the concentration of mercury and selenium were characterised in the pups' blood during their first three months of life when they transition from suckling, to a post-weaning fast, to eating fish.In the blood of pregnant females, there was a significant decrease in THg and MeHg concentrations throughout the gestation, indicating the transfer of these toxins through the placenta into the foetus. At no other stage of the pup's development was there such a high level of THg and MeHg as on the day of birth, despite the incorporation of mercury into the lanugo during foetal growth. This suggests that the maternal transfer of mercury during gestation may be the time of greatest mercury exposure for a young seal pup. The consumption of milk caused a rapid increase in weight and a lowering of the mercury level in the blood in the subsequent days of the pups' life. The postweaning fast was the period of the lowest mercury concentration. The switch to a diet consisting of fish caused a systematic increase in the concentration of mercury in the blood of the pups.Milk was the significant source of selenium for pups and the selenium concentration in females' blood was reduced during lactation.The nursing period seemed to have the greatest impact on the mercury and selenium blood levels in examined seals. Natural development of the grey seal pup created an opportunity to decrease the levels of toxic substances obtained through the maternal transfer during foetal growth.

Assessment of Total Mercury in Hair, Urine and Fingernails of Small-Scale Gold Miners in the Amansie West District, Ghana.

Background.Mercury (Hg) is a heavy metal that can cause several adverse health effects based on its form (organic, inorganic or elemental), duration and pathway of exposure. Measurement of mercury present in human biological media is often used to assess human exposure to mercury at mining sites.Objectives.The aim of the present study was to measure the concentrations of total mercury in urine, hair, and fingernails of miners and inhabitants of Amansie West District, Ghana.Methods.Concentrations of total mercury were measured in sixty–eight miners and twelve non–miners in the study area using cold vapor atomic absorption spectrophotometry with an automatic mercury analyzer (HG 5000).Results.Total mercury in nails and hair of smelter miners was 3.32 ± 0.36 and 6.59 ± 0.01 μg/g, respectively. Total mercury concentrations in hair samples obtained from smelter miners were above the 1 μg/g guideline set by the United States Environmental Protection Agency (USEPA). Moreover, the total mercury concentration in urine samples was 6.97 ± 0.06 μg/L, far below the >25 μg/L level considered to be a high level of mercury contamination. The total mercury accrued by the individuals was not dependent on age, but was positively associated with duration of stay.Conclusions.Based on the total mercury (THg) levels analyzed in the biological media, artisanal gold mining activities in Amansie West District are on the increase with a potential risk of developing chronic effects. However, the majority of the population, particularly those engaged in artisanal small–scale gold mining, are unmindful of the hazards posed by the use of mercury in mining operations. The results showed that THg in urine, hair, and fingernails more efficiently distinguished mercury exposure in people close to mining and Hg pollution sources than in people living far from the mining sites. Further education on cleaner artisanal gold mining processes could help to minimize the impact of mercury use and exposure on human health and the environment.Participant Consent.ObtainedEthics Approval.This study was approved by the Ghana Environmental Protection Agency and the Ministry of Local Government and Rural Development in Manso Nkwanta.Competing Interests.The authors declare no competing financial interests.

Association of blood mercury levels during pregnancy with infant birth size by blood selenium levels in the Japan Environment and Children's Study: A prospective birth cohort

BackgroundIt is necessary to determine whether there are adverse health effects of prenatal exposure to long-term, low levels of mercury and selenium. However, there are limited that reports on the association between mercury levels by selenium levels and birth size. Therefore, we examined whether maternal mercury levels during pregnancy had any effect on infant birth size, and size, and whether selenium levels influenced this relationship. ObjectivesTo examine the association between mercury and selenium levels during pregnancy with infant birth size. MethodsThe Japan Environment and Children's Study is a prospective birth cohort conducted between 2011 and 2014. Total mercury levels and total selenium levels in maternal blood during the second and third trimesters were measured using Inductively Coupled Plasma-Mass Spectrometry. Birth weight and small-for-gestational-age were confirmed by medical records. Small-for-gestational-age was defined as birth weight below the 10th percentile according to standard percentile for gender, parity, and gestational age. Multiple linear and logistic regression analyses were used to examine the association between maternal mercury exposure and birth weight or small-for-gestational-age adjusted for confounders (including maternal age and body mass index pregnancy). ResultsOverall, 15,444 pregnant women were included in this study. Median (inter-quartile range) of blood mercury and selenium levels were 3.66 (2.59–5.18) ng/g and 170.0 (158.0–183.0) ng/g, respectively. Compared to infants of mothers with the highest blood selenium level, those of mothers with the lowest blood selenium level had neither a significant birth weight increase (9 g, 95% confidence interval: −6, 25) nor a significant odds ratio for small-for-gestational-age (0.903, 95% confidence interval: 0.748, 1.089). Compared to infants of mothers with the lowest blood mercury level, those of mothers with the highest blood mercury level had neither a significant birth weight reduction (−12 g, 95% confidence interval: −27, 4) nor a significant odds ratio for small-for-gestational-age (0.951, 95% confidence interval: 0.786, 1.150). Compared to infants of mothers with the lowest quartile of maternal blood mercury level, all infants of mothers with the highest quartile of maternal blood mercury level had a reduced birth head circumference of 0.073 cm (95% confidence interval: −0.134, −0.011). ConclusionsThere was no association between maternal blood mercury levels and small-for-gestational-age and birth weight among 15,444 pregnant women. In a Japanese population, which has a relatively higher blood mercury level than reported in Western population, reduced birth size was not found to be associated with blood mercury levels, with the exception of birth head circumference.

Spatial variability in total and organic mercury levels in Antarctic krill Euphausia superba across the Scotia Sea

Total and organic mercury concentrations were determined for males, females and juveniles of Euphausia superba collected at three discrete locations in the Scotia Sea (South Orkney Islands, South Georgia and Antarctic Polar Front) to assess spatial mercury variability in Antarctic krill. There was clear geographic differentiation in mercury concentrations, with specimens from the South Orkney Islands having total mercury concentrations 5 to 7 times higher than Antarctic krill from South Georgia and the Antarctic Polar Front. Mercury did not appear to accumulate with life-stage since juveniles had higher concentrations of total mercury (0.071 μg g−1 from South Orkney Islands; 0.014 μg g−1 from South Georgia) than adults (0.054 μg g−1 in females and 0.048 μg g−1 in males from South Orkney Islands; 0.006 μg g−1 in females and 0.007 μg g−1 in males from South Georgia). Results suggest that females may use egg laying as a mechanism to excrete mercury, with eggs having higher concentrations than the corresponding somatic tissue. Organic mercury makes up a minor percentage of total mercury (15–37%) with the percentage being greater in adults than in juveniles. When compared to euphausiids from other parts of the world, the concentration of mercury in Antarctic krill is within the same range, or higher, highlighting the global distribution of this contaminant. Given the high potential for biomagnification of mercury through food webs, concentrations in Antarctic krill may have deleterious effects on long-lived Antarctic krill predators.

Records of Southern Sea Lion (Otaria flavescens) (Mammalia: Carnivora: Otariidae) and Total Mercury (THg) Levels in Muscle Tissue of a Specimen on the East Coast of Rio de Janeiro State, Southeastern Brazil

This study aims to present records of southern sea lions (Otaria flavescens) on the coast of Arraial do Cabo, located on the east coast of Rio de Janeiro State, southeastern Brazil, and information on the levels of total mercury (THg) found in muscle tissue of a specimen collected in the study area. Between July 2003 and February 2017, 5 occurrences of southern sea lions were recorded in the study area. Four of these records were of live animals, while one was of a carcass in advanced state of decomposition. In relation to the concentrations of THg found in the muscle tissue of the analyzed individual, they ranged from 0.047 to 0.067 mg/kg, with a mean value found of 0.057 mg/kg, a standard deviation of 0.010 and a coefficient of variation of 17.5%.

Biomonitoring of mercury in hair of children living in the Valencian Region (Spain). Exposure and risk assessment

In this study, we assessed total mercury levels in hair specimens of 661 children, aged 6 to 11, participating in the BIOVAL programme, a human biomonitoring study carried out by the Health Department of the Regional Government of Valencia (Spain). The reference value (95th percentile) determined for this population, within this programme, was 3.25 μg g−1. Hg concentrations ranged between 0.03 μg g−1 and 8.71 μg g−1, with a geometric mean of 0.79 (CI 95%: 0.73–0.85) μg g−1. This mean value was five times higher than the average levels found in children of 17 other European countries (0.145 μg g−1). About 13% of children had hair mercury levels above the FAO/WHO JECFA guideline of 2.3 μg g−1 and 18% of children had levels above the EFSA health-based guidance value of 1.9 μg. Multiple regression analysis revealed that fish consumption, mother's country of birth (Spain or abroad) and the employment situation of parents were the main predictors of mercury in hair.