Association of aquatic food consumption, long-chain polyunsaturated n-3 fatty acid intake, and blood mercury levels with cognitive function in middle-aged and older adults.

BACKGROUND & AIMS: Aquatic food is rich in nutrients which benefit the human brain and cognitive health; however, concerns about heavy metal accumulation in aquatic food remain. This study evaluated the associations between aquatic food consumption, long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs) intake, and blood mercury levels with cognition in middle-aged and older adults. METHODS: This cross-sectional study used baseline data from the Lifestyle and Healthy Aging of Chinese Square Dancer Study. Aquatic food consumption and LC n-3 PUFAs intake were obtained from a food frequency questionnaire. Blood mercury levels were measured using inductively coupled plasma mass spectrometry. A composite z-score was developed to represent global cognition by averaging the z-scores for each cognitive domain. Participants with mild cognitive impairment (MCI) were diagnosed according to Petersen's criteria. Multivariate linear and logistic regression models were used to examine the association between the exposure factors and cognitive performance including cognitive scores and MCI. RESULTS: Of 2621 middle-aged and older adults, the mean (SD) age was 63.71 (5.15) years, and 85.73% were females. Compared with the lowest quartile, those in the highest quartile for aquatic food consumption were associated with higher composite z-scores (ß = 0.156, 95% CI: 0.088-0.225) and lower MCI odds (OR = 0.598, 95% CI: 0.425-0.841). A similar positive relationship between LC n-3 PUFAs intake and composite z-score and an inverse association between LC n-3 PUFAs intake and MCI were also observed. In addition, the participants in the highest quartile for blood mercury levels had higher composite z-scores than those in the lowest quartile. CONCLUSIONS: In this cross-sectional study, higher aquatic food consumption, LC n-3 PUFAs intake, and blood mercury levels were related to better cognitive function. Further studies in Chinese populations are required to confirm these findings.

Mercury levels in Nile perch fillets in processing industries in Uganda.

Mercury levels of Nile perch fillets to be exported from selected fish processing industries in Uganda were determined by hot digestion in strong acids, followed by analysing the extracts with Inductive Coupled Plasma-Mass Spectroscopy (ICP-MS). There was a clear link between atmospheric mercury and methylmercury accumulation in fish tissues, thus exposing a possible threat for human health. A quantitative cross-sectional study design was undertaken from two fish processing factories around Kampala city. Simple random sampling was utilised where ten fish products were picked for analysis. The results obtained from the analysis of samples from both factories presented mercury levels far below the FAO/WHO guideline level of 0.5 mg/kg for mercury in fish. The mercury levels for both factories were higher than the oral daily recommended dose of 0.001 mg/kg body weight for the vulnerable population raising eyebrows for the general population, since fish is a major contributor to mercury intake for consumers.

Mercury Exposure in Artisanal Mining: Assessing the Effect of Occupational Activities on Blood Mercury Levels Among Artisanal and Small-Scale Goldminers in Ghana.

A cross-sectional survey of 425 male artisanal and small-scale goldminers (ASGM) was conducted to examine the relationship between the occupational activities of the miners and their blood mercury levels while controlling for relevant biosocial and socio-cultural factors. The data was subjected to descriptive and inferential statistics. Initial findings showed that 43.29% of the ASGM miners had blood mercury levels above the occupational exposure threshold. Among the occupational factors, ASGM miners who amalgamate gold, burn amalgam, and ASGM miners who smelt gold were 2.260, 1.881, and 2.094 times respectively more likely to have high blood mercury levels as compared to ASGM miners who did not carry out these activities. Also, ASGM miners who suck excess mercury with their mouth (OR = 0.197, p < 0.001) were less likely to have high blood mercury levels. For the biosocial and socio-cultural attributes, high blood mercury levels was less likely among older ASGM miners (OR = 0.507, p < 0.05). Inversely, high blood mercury levels was more likely among ASGM miners who are married (OR = 1.627, p < 0.05), ASGM miners with junior (OR = 2.240, p < 0.001) and senior (OR = 1.575, p < 0.05) high school education, and ASGM miners who have 6-10 years (OR = 3.802, p < 0.001) and above 10 years (OR = 2.591, p < 0.001) work experience. ASGM miners who amalgamate gold, burn amalgam, and smelt gold are exposed to mercury and are at risk of mercury poisoning. This could, however, be minimized with the right capturing devices and personal protective equipment. This notwithstanding, unsafe, and unsustainable occupational practices such as working in mercury contaminated water and sucking excess mercury with the mouth should be discouraged.

Levels of mercury in Moroccan breast milk and the affecting factors: CONTAMILK study.

This study aims to evaluate the level of mercury in the breast milk of Moroccan mothers and its association with several maternal parameters and habits, and to estimate the daily intake of the newborns. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of mercury in 70 colostrum samples. Indeed, a structured questionnaire was administrated during milk collection to report data concerning the maternal socioeconomic and anthropometric parameters, as well as dietary habits and smoking habits in the family, etc. The median of mercury in breast milk was 3,56 µg/L (range 1.64-124 µg/L) and exceeded normal levels of 1.7 µg/l, suggested by the World health organization in 99% of milk samples. Significant associations were found between mercury levels and the occurrence of previous miscarriages, anemia before pregnancy and vitamin & mineral supplementation during pregnancy, as well the frequency of consumption of cereals and the use of lipstick. The estimated daily intake was higher than the tolerable daily intake of the World health organization and the European food safety authority in 30% of newborns. These results need to be confirmed by multicenter studies to investigate the levels of mercury in the breast milk of the Moroccan population.

Risk of Mercury exposure during childhood: a review of Sri Lankan situation.

Sri Lanka had ratified the Minamata convention in the year 2017 and is planning to phase out Mercury by 2020. Mercury thermometers and compact fluorescent light bulbs are abundant at hospitals, households and schools. Limitations in safe disposal and containment mechanisms have enhanced the unregulated e-waste collection and extraction. Sri Lanka has plentiful lagoons, fishing bays, and inland irrigation systems. Fish consumption is high, especially around the coastal belt. Mercury can bioaccumulate in humans by the consumption of fish from contaminated sources. Children are at risk of exposure in their living environments and via food. A multicountry study done across three oceans on Mercury threat to women & children revealed, lagoon pollution from industrial Mercury emissions in Sri Lanka, possessing high Mercury among local females who consume fish from that lagoon. The mean hair Mercury level in coastal areas with high fish consumption exceeded the reference dose even among children. Aquatic life and crop studies revealed a mixed picture of Mercury levels which some are lower and some are higher than the permissible levels. Studies on environmental Mercury levels and correlations with health effects among children will help to fill the data gap. Public awareness of the health effects of Mercury and mechanisms of Mercury disposal should be established.

Association between Blood Heavy Metal Levels and Predicted 10-Year Risk for A First Atherosclerosis Cardiovascular Disease in the General Korean Population.

BACKGROUND: Atherosclerotic cardiovascular disease (ASCVD) is a preventable type of disease, thus, specifying factors that increase the occurrence of this type of disease is needed. Heavy metals such as cadmium (Cd), lead (Pb), and mercury (Hg) have been suggested as possible factors influencing the development of cardiovascular disease. We aimed to link blood heavy metal levels (Cd, Pb, Hg) with 10-year ASCVD risk scores. METHODS: A population of 993 men and 1431 women who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) were included. The 2013 American College of Cardiology/American Heart Association (ACC/AHA) pooled cohort equations risk prediction model and Korean Risk Prediction Model (KRPM) were used as means for risk prediction. Following multivariate adjustment; blood Cd; Pb; and Hg levels were divided into quartiles for analysis using linear trends estimation and multiple regression models. RESULTS: There was an overall positive trend between blood Cd, Pb, and Hg levels and 10-year ASCVD risk scores; KRPM risk score increasing by quartile for blood Cd (men p < 0.0001, women p = 0.0024), Pb (men p = 0.0097, women p = 0.0330), Hg (men p = 0.0096, women p = 0.0030) rates and pooled cohort equations risk score increasing by quartile for Cd (men p < 0.0001, women p = 0.0034) and Hg (men p = 0.0099, women p = 0.0010) with linear trends. Urban population showed a stronger relationship between blood Cd, Pb, and Hg levels and 10-year ASCVD risk score especially among men with multiple regression analysis. CONCLUSION: Blood Cd, Pb, and Hg levels are associated with ASCVD risk. Thus, they should be considered while developing preventive measures for ASCVD.

Mercury in aquatic fauna contamination: A systematic review on its dynamics and potential health risks.

Mercury is an important pollutant, released into aquatic ecosystems both naturally and by anthropogenic action. This element is transferred to aquatic organisms in different ways, causing potential health risks. In addition, mercury can be accumulated by humans, especially through the consumption of contaminated food. This systematic review aims to present mercury pathways, the major routes through which this element reaches the aquatic environment and its transformations until becoming available to living animals, leading to bioaccumulation and biomagnification phenomena. The key biotic and abiotic factors affecting such processes, the impact of mercury on animal and human health and the issue of seafood consumption as a source of chronic mercury contamination are also addressed. A total of 101 articles were retrieved from a standardized search on three databases (PubMed, Emabse, and Web of Science), in addition to 28 other studies not found on these databases but considered fundamental to this review (totaling 129 articles). Both biotic and abiotic factors display fundamental importance in mediating mercurial dynamics, i.e., muscle tropism, and salinity, respectively. Consequently, mercurial contamination in aquatic environments affects animal health, especially the risk of extinction species and also on human health, with methylmercury the main mercury species responsible for acute and chronic symptomatology.

[Hair Mercury Concentrations in Residents of Fuling and Zhongxian in the Three Gorges Reservoir Region and Their Influence Factors].

To evaluate the mercury (Hg) exposure risk for residents of the Three Gorges Reservoir Region (TGRR), hair samples were collected from 238 local residents within the central regions of the TGRR (Fuling District and Zhongxian County) in this study. Subsequently, total mercury (THg) and methylmercury (MeHg) concentrations were determined. The results obtained showed that the average THg and MeHg concentrations in hair samples of the residents within these two areas were (0.50±0.54) µg·g-1 and(0.35±0.25) µg·g-1, respectively. Specifically, the average THg and MeHg concentrations in hair samples of Fuling residents were(0.71±0.87) µg·g-1 and(0.53±0.46) µg·g-1, respectively. Both these values were higher than those in hair samples of Zhongxian County residents [THg(0.41±0.36) µg·g-1 and MeHg (0.28±0.26) µg·g-1]. It is noteworthy that the hair Hg levels in residents of these two areas are both well below the U.S. Environmental Protection Agency's reference dose (1 µg·g-1). Hair Hg levels varied slightly among different age groups; higher Hg levels were detected in residents in the age group of 40-50 years(P<0.05). However, there was no significant difference between the hair Hg levels among genders(P>0.05). Hair Hg levels in females were slightly above those in males. Hair Hg levels were significantly correlated with the frequency of fish consumption. Furthermore, hair Hg levels in non-fishermen were significantly lower than those in fishermen. An elevated mean value of (1.44±0.79) µg·g-1(P<0.01), which exceeds the RfD of 1 µg·g-1, was detected in fishermen. Moreover, hair Hg levels in smokers of Fuling and Zhongxian County[(0.55±0.24) µg·g-1 and (0.58±0.54) µg·g-1, respectively] were both markedly higher than those in non-smokers[(0.51±0.30) µg·g-1 and (0.36±0.26) µg·g-1respectively]. In conclusion, the risk of Hg exposure to residents of the TGRR was lower. However, in this study, it was determined that fishermen are at significant risk of Hg exposure.

The associations between blood mercury levels and shark meat intake among workers in Gyeongsangbuk-do.

BACKGROUND: Shark meat is used as sacrificial food in Gyeongsangbuk-do, and is a major source of dietary mercury. This study aimed to evaluate the effects of shark meat intake or the ritual of Jesa on blood mercury levels within workers living in Gyeongsangbuk-do. METHODS: This study was conducted from September 2016 to October 2016 in two cities of Gyeongsangbuk-do. To compare the differences between urban and rural areas, two workplaces each in Daegu as the urban area and Yeongcheon as the rural area were selected. General characteristics and characteristics related to shark meat consumption of the workers were acquired by personal interviews during their health examination. Blood mercury concentrations were analyzed by the gold amalgamation method using a direct mercury analyzer (DMA-80; Milestone Inc., Shelton, CT, USA). RESULTS: The shark consumption group had a higher blood mercury concentration than the non-consumption group. The levels of blood mercury increased with the frequency, annual intake, as well as most recent date of shark meat consumption. Moreover, the levels of mercury in blood increased according to the annual frequency of participation in Jesa (times per year) and the annual frequency of shark meat consumption during Jesa (times per year). CONCLUSIONS: Shark meat intake and the ritual of Jesa contributed to an increase in the blood mercury levels of workers in Gyeongsangbuk-do. Therefore, it is necessary to evaluate dietary exposure, occupational as well as other factors that may influence blood mercury concentrations in workers during their health examination, particularly in regions with high mercury exposures.

Seasonal Variations of Mercury Levels in Selected Medicinal Plants Originating from Poland.

The presence of mercury in the living cells may be caused by environmental pollution with this element, which is referred to as a toxic xenobiotic. Many literature reports have provided evidence for toxic effects of low levels of mercury in the human body. Therefore, it seems essential to investigate mercury content in food and in natural environment, particularly its seasonal variations. The objective of this study was to determine trace amounts of mercury in 45 samples of 20 medicinal plant species collected in northern Poland, in various seasons of the year, i.e., in autumn 2012 and then spring 2013. The results obtained showed that the levels of mercury in the herbs were lower in spring (3.66-34.89 ng/g) than in autumn (4.55-81.54 ng/g). The statistically significant correlation (p < 0.05) between the levels of mercury in herbs collected in spring and autumn indicates hazardous accumulation of the element in plants in autumn. The highest levels of mercury were found in leaves and plants growing in the vicinity of busy streets. Perennials plants have a significantly higher mercury levels as compared to those of monocarpic plants. Furthermore, commonly used herbal plants have a significantly higher mercury levels as compared to those less common.

The significance of cephalopod beaks in marine ecology studies: Can we use beaks for DNA analyses and mercury contamination assessment?

Cephalopod beaks found in the diet of predators have been a major source of scientific information. In this study, we evaluated the usefulness of DNA and contaminants analysis (total mercury - T-Hg) in cephalopod beaks in order to assess their applicability as tools in marine ecology studies. We concluded that, when applying DNA techniques to cephalopod beaks from Antarctic squid species, when using flesh attached to those beaks, it was possible to obtain DNA and to successfully identify cephalopod species; DNA was not found on the beaks themselves. This study also showed that it is possible to obtain information on T-Hg concentrations in beaks: the T-Hg concentrations found in the beaks were 6 to 46 times lower than in the flesh of the same cephalopod species. More research on the relationships of mercury concentrations in cephalopod beaks (and other tissues), intra- and inter-specifically, are needed in the future.

Relationship between Blood Mercury Level and Risk of Cardiovascular Diseases: Results from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV) 2008-2009.

Limited epidemiologic data is available regarding the cardiovascular effects of mercury exposure. The purpose of this study was to determine the relationship between mercury exposure from fish consumption and cardiovascular disease in a nationally representative sample of Korean adults using the Fourth Korea National Health and Nutrition Examination Survey (KNHANES IV 2008~2009). Survey logistic regression models accounting for the complex sampling were used to estimate the odds ratios (OR) adjusted for fish consumption frequency, age, education, individual annual income, household annual income, body mass index (BMI), waist circumference (WC), alcohol consumption status, and smoking status. The mean blood mercury level in the population was 5.44 µg/L. Trends toward increased blood mercury levels were seen for increased education level (P=0.0011), BMI (P<0.0001), WC (P<0.0001), and fish (i.e., anchovy) consumption frequency (P=0.0007). The unadjusted OR for hypertension in the highest blood mercury quartile was 1.450 [95% confidential interval (CI): 1.106~1.901] times higher than that of the lowest quartile. The fish consumption-adjusted OR for hypertension in the highest blood mercury quartile was 1.550 (95% CI: 1.131~2.123) times higher than that of the lowest quartile, and the OR for myocardial infarction or angina in the highest blood mercury quartile was 3.334 (95% CI: 1.338~8.308) times higher than that of the lowest quartile. No associations were observed between blood mercury levels and stroke. These findings suggest that mercury in the blood may be associated with an increased risk of hypertension and myocardial infarction or angina in the general Korean population.

Mercury exposure levels in children with dental amalgam fillings.

OBJECTIVES: Mercury combined with other metals to form solid amalgams has long been used in reconstructive dentistry but its use has been controversial since at least the middle of the 19th century. The exposure and body burden of mercury reviews have consistently stated that there is a deficiency of adequate epidemiological studies addressing this issue. Fish and dental amalgam are two major sources of human exposure to organic (MeHg) and inorganic Hg respectively. MATERIALS AND METHODS: A total of 150 subjects aged between 9 and 14 years were divided into two groups of 75 subjects each depending on their diet, i.e. seafood or nonseafood consuming. Each category was subdivided into three groups based on number of restorations. Scalp hair and urine samples were collected at baseline and 3 months later to assess the organic and inorganic levels of mercury respectively by atomic absorption spectrophotometer (AAS). RESULTS: The mean values of urinary mercury (inorganic mercury) in the group of children with restorations were 1.5915 µg/l as compared to 0.0130 µg/l in the groups with no amalgam restorations (p < 0.001) (Wilcoxon sign rank test and paired t-test). The hair mercury levels (organic mercury) varied signi-ficantly between the fsh-eating group and nonfsh-eating group, the average values being 1.03 µg/l and 0.84 µg/l respectively (p < 0.001) (Mann-Whitney U-test and paired t-test). CONCLUSION AND SIGNIFICANCE: The notion about the mercury being released from the amalgam restorations as a sole exposure source needs to be put to a rest, as environmental factors collectively overpower the exposure levels from restorations alone. How to cite this article: Varkey IM, Shetty R, Hegde A. Mercury Exposure Levels in Children with Dental Amalgam Fillings. Int J Clin Pediatr Dent 2014;7(3):180-185.