Exposure to mercury from dental amalgam: actual contribution for risk assessment.

OBJECTIVE: Mercury dental amalgam restorations are an important source of chronic exposure to mercury in the whole population and special attention should be paid not only to occupational exposure to mercury during the preparation and administration of amalgam. The authors' report is an up-to-date contribution to the health risk assessment of mercury use in dentistry, namely occupational exposure to mercury in dentists working with dental amalgam and exposure to mercury in persons treated with amalgam dental restorations. METHODS: Determination of total mercury in samples of biological material (urine, hair) was performed during 2017 and 2018 in 50 persons by the AAS method using the mercury vapour generation technique at 254.6 nm. RESULTS: Current dental exposures based on the most recent findings do not exceed acceptable risk levels and are below the biological limit of mercury in urine valid for occupationally exposed persons (100 µg.g-1 of creatinine), namely median value was 1.48 (min. < limit of detection (LOD), max. 17.14) µg.g-1 of creatinine (40 persons), total mercury content in hair of dental personnel expressed as median value was 0.340 (min. 0.060, max.1.628) µg.g-1. In controls (10 persons) was total mercury content in urine expressed as median value 0.36 (min. < LOD, max. 2.74) µg.g-1 of creatinine, in hair was median value 0.224 (min. 0.059, max. 0.453) µg.g-1. CONCLUSIONS: Authors support opinion that amalgam fillings in the oral cavity are a permanent source of mercury for the body itself.

Urinary Cadmium and Cotinine Levels and Hair Mercury Levels in Czech Children and Their Mothers Within the Framework of the COPHES/DEMOCOPHES Projects.

The COPHES/DEMOCOPHES twin project was performed in 2011-2012 in 17 European countries to harmonize all steps of the human biomonitoring survey. Urinary cadmium, cotinine, phthalate metabolites, and hair mercury were measured in children (N = 120, 6-11 years) and their mothers of reproductive age, living in urban or rural areas. Cadmium in mothers' and children's urine was detected at a geometric mean (GM) concentration 0.227 and 0.109 µg/L, respectively; 95th percentile (P95) was 0.655 and 0.280 µg/L in mothers and children, respectively. No age-related, education-related, or urban versus rural differences were observed within the frame of each population group. Cadmium urinary level in mothers was about twofold compared with children. Higher levels were obtained in all smoking mothers but not in occasionally smoking or mothers and children exposed to environmental tobacco smoke (ETS). Mercury values in mothers were significantly higher in urban than in rural populations but not in children. GM and P95 for mercury in children's hair were 0.098 and 0.439 µg/g and in mothers' hair were 0.155 and 0.570 µg/g. Concentrations for mercury in the Czech samples were lower than European average. Hair mercury increased significantly with consumption of fish or seafood and with number of amalgam tooth fillings (in children). A positive association was found with family educational level. No influence of age was observed. Urinary cadmium and hair mercury levels were lower than health-based guidelines with one exception. High levels of urinary cotinine were found in the 12 smoking mothers (GM approximately 500 µg/L); lower levels in occasionally smoking mothers, N = 11 (34.5 µg/L). The mean cotinine levels in nonsmoking mothers who reported daily exposure to ETS was 10.7 µg/L. A similar mean value (10.8 µg/L) was obtained in six children who had daily exposure to ETS. In children without exposure to ETS, the mean cotinine level was 1.39 µg/L urine. Cotinine in the urine of children demonstrates limited protection of the Czech children against exposure to ETS.

Blood levels of lead, cadmium, and mercury in the elderly living in institutionalized care in the Czech Republic.

BACKGROUND: There is limited research examining the chemical load of toxic metals in the elderly. The aim of the present study was two-fold: to determine the body burden of lead, cadmium and mercury in association with age, gender, locality, lifestyle factors and potential health impacts among this population and to compare the values with blood values from the general Czech population aged 18-64 years. METHODS: Lead, cadmium and mercury were examined in the blood of institutionalized senior citizens (46 males, 151 females aged 61-100 years) from two localities in the Czech Republic (Prague and Teplice) from 2009 through 2011. Measurements were made using inductively coupled plasma mass spectrometry (Pb, Cd) and a single purpose spectrometer AMA 254 (Hg). RESULTS: Geometric means (GM) of whole blood lead (B-Pb), cadmium (B-Cd) and mercury (B-Hg) levels were 25.3µg/l, 0.55µg/l and 0.21µg/l, respectively. No age-related differences were found for B-Pb and B-Cd levels but a negative correlation with age was observed for B-Hg levels (p=0.04). B-Pb levels in men were significantly higher than in women (GM 29.9µg/l vs. 24.1µg/l). B-Cd was significantly higher in women (GM 0.57µg/l) than in men (0.50µg/l) (p=0.007) and in smokers (GM 1.29µg/l) than in nonsmokers (GM 0.53µg/l) (p=<0.001) and in seniors from Prague (GM 0.60µg/l) compared to those from Teplice (GM 0.43µg/l) (p=<0.001). Seniors with a history of chronic kidney disease, stroke and those using psycho-pharmaceuticals had higher B-Pb levels (p=0.008, 0.04 and 0.05, resp.), seniors diagnosed with atherosclerosis had higher B-Cd levels (p=0.002) and seniors using psycho-pharmaceuticals had higher B-Hg levels (p=0.07). B-Hg levels were also positively correlated with blood albumin levels (p=0.015). CONCLUSIONS: This study provides data on levels of heavy metals in a group of elderly people. Such information is very scarce. Associations with diseases should be the subject of further investigation.

Economic benefits of methylmercury exposure control in Europe: monetary value of neurotoxicity prevention.

BACKGROUND: Due to global mercury pollution and the adverse health effects of prenatal exposure to methylmercury (MeHg), an assessment of the economic benefits of prevented developmental neurotoxicity is necessary for any cost-benefit analysis. METHODS: Distributions of hair-Hg concentrations among women of reproductive age were obtained from the DEMOCOPHES project (1,875 subjects in 17 countries) and literature data (6,820 subjects from 8 countries). The exposures were assumed to comply with log-normal distributions. Neurotoxicity effects were estimated from a linear dose-response function with a slope of 0.465 Intelligence Quotient (IQ) point reduction per µg/g increase in the maternal hair-Hg concentration during pregnancy, assuming no deficits below a hair-Hg limit of 0.58 µg/g thought to be safe. A logarithmic IQ response was used in sensitivity analyses. The estimated IQ benefit cost was based on lifetime income, adjusted for purchasing power parity. RESULTS: The hair-mercury concentrations were the highest in Southern Europe and lowest in Eastern Europe. The results suggest that, within the EU, more than 1.8 million children are born every year with MeHg exposures above the limit of 0.58 µg/g, and about 200,000 births exceed a higher limit of 2.5 µg/g proposed by the World Health Organization (WHO). The total annual benefits of exposure prevention within the EU were estimated at more than 600,000 IQ points per year, corresponding to a total economic benefit between €8,000 million and €9,000 million per year. About four-fold higher values were obtained when using the logarithmic response function, while adjustment for productivity resulted in slightly lower total benefits. These calculations do not include the less tangible advantages of protecting brain development against neurotoxicity or any other adverse effects. CONCLUSIONS: These estimates document that efforts to combat mercury pollution and to reduce MeHg exposures will have very substantial economic benefits in Europe, mainly in southern countries. Some data may not be entirely representative, some countries were not covered, and anticipated changes in mercury pollution all suggest a need for extended biomonitoring of human MeHg exposure.

Trace elements in the blood of institutionalized elderly in the Czech Republic.

Whole blood selenium, copper, zinc and manganese concentrations of 197 institutionalized senior citizens (46 males, 151 females) aged 61-100 years (mean age 83.6 years) were determined using atomic absorption spectrometry and inductively coupled plasma mass spectrometry from two localities in the Czech Republic (Prague and Teplice) from 2009 through 2011. Geometric means (GM) of whole blood selenium (B-Se), copper (B-Cu), zinc (B-Zn) and manganese (B-Mn) levels were 74.0 µg/l, 941.0 µg/l, 5898.0 µg/l and 10.9 µg/l, respectively. Gender-related differences were found with significantly higher B-Cu levels in women and significantly higher B-Zn levels in men. The percentage of seniors with B-Se levels lower than 56 µg/l (which is equivalent to the critical value of 45 µg/l of Se in serum (S-Se)) was 8.6%. A negative correlation between age and B-Se levels was found. B-Zn positively correlated with serum albumin and prealbumin whereas a negative correlation between age and B-Zn was observed. Seniors with diabetes mellitus and atherosclerosis had higher B-Cu and B-Mn levels, respectively, than those without these diagnoses. The elderly from Prague had significantly higher B-Mn concentrations than those from Teplice. We found no evidence of serious essential elements deficiencies or excesses in the seniors who participated in this study.

Human bio-monitoring study--toxic elements in blood of women.

The article describes bio-monitoring study concerning recent and long-term exposure of Czech women to toxic metals. Blood cadmium, mercury and lead levels were measured in groups of women with various life styles, etc., to have comparable results in the course of a long study period; a strong emphasis was laid on the quality control of the whole process during the study. Higher cadmium level was found in smokers compared to non-smokers, lower mercury level was found in the group of women who never eat fish. A slight increase of blood lead level with age was observed. No significant differences were found between localities in a given period. Our results do not differ from those gained in other European countries.

Human biomonitoring in the Czech Republic: an overview.

In the Czech Republic, the Human Biomonitoring Project (CZ-HBM) was launched in 1994 as an integral part of the nationwide Environmental Health Monitoring System (EHMS). Until now, the HBM covers two time periods: the first covered 1994-2003 and the second, 2005-2009. Altogether three population groups were included in the HBM: adults (blood donors aged 18-58 years), children aged 8-10 years, and breastfeeding primiparas. Sampling is organized on a yearly basis. Altogether three groups of biomarkers were analyzed: (a) selected heavy metals (Pb, Cd, Hg) and essential elements (Cu, Se, Zn) in blood and urine of adults and children, (b) indicator PCBs, DDT, DDE, HCB and HCHs in human milk and blood serum of adults and (c) cytogenetic changes in peripheral lymphocytes in blood of adults and children. This paper is focused on the general design of the CZ-HBM, the trends over time, and reference values. A significant downward time trend was observed for the blood lead levels in adults and children. Increased urinary cadmium levels were observed in Czech children compared to German children. The blood and urinary mercury levels were higher in women than in men. The levels of indicator PCB congeners in the Czech human milk samples were still higher than in most other European countries, because of existing hot spots. The levels of organochlorine pesticides showed a substantial continuous downward trend.

The mercury burden of the Czech population: An integrated approach.

In this paper an integrated approach in assessment of the population exposure from various sources of total mercury (THg) oral intake in the Czech Republic is presented. The information on total mercury levels in diet, drinking water, surface urban soil and body fluids and tissues stem from the Czech national Environmental Health Monitoring System (EHMS) operated since 1994. The THg concentration was determined by the special atomic absorption spectrophotometer AMA 254. The data on THg content in food from the sales network were collected in 12 cities. The estimated average dietary intake representing more than 95% of weight of usual diet composition ranged 1-2% of the JECFA/FAO WHO provisional tolerable weekly intake (PTWI) value for total mercury (5 microg/kg b.w./week). Data on drinking water quality stem from the nationwide monitoring database. The content of THg in drinking water is generally low; only 0.2% of the Czech population supplied with drinking water from the distribution networks (total of 92% of the population) has a mercury intake from drinking water higher than 1% PTWI and not exceeding 5% PTWI. The estimation of potential mercury intake by unintentional consumption of soil in small children was based on THg content in surface soil of a total of 324 nursery schools in 24 cities and towns. Median value was 0.16 mg/kg. Human biomonitoring was performed in 9 Czech cities. In 2007, the mercury median values in blood of adults (N=412) were 0.85 and 0.89 microg/l in males and in females, respectively; urine median value in adults was 1.10 microg/g creatinine. In 2008, the blood median value in children (N=324) amounted to 0.35 microg/l; urine median value is 0.16 microg/g creatinine. In children's hair the median THg value was 0.18 microg/g. The correlation between fish consumption and blood THg levels was observed in both adults and children. Also the biomonitoring outputs did not reveal a substantial burden of the population.

Mercury and methylmercury in hair of selected groups of Czech population.

As the concentration of methylmercury (MeHg) in the environment is insignificant, hair can be used as a suitable matrix to estimate endogenous MeHg exposure. Avalidated analytical method with AMA 254 spectrometer was used for the determination of inorganic mercury and methylmercury species in the hair of dentists, workers in fish industry and professionally non-exposed adults. ANOVA and QC Expert software was used for statistical evaluation. The number of amalgam fillings in oral cavity, consumption of fish, gender, smoking habits and age of the subjects were taken into account. A significantly higher level of inorganic bound mercury (Hg(in)) was found in the hair of dentists. The number of amalgam fillings had a slightly significant effect on Hg(in); fish consumption had a significant influence on MeHg and slightly also on Hg(in). Other parameters were not significant.

Determination of mercury and methylmercury in hair of the Czech children's population.

The developed method for mercury speciation analysis has been validated and used for the biomonitoring study of mercury species in human hair. Statistical evaluation proved the reliability of simplified determination of inorganic mercury (difference between total mercury and methylmercury). The results of the validation showed that the method is very well suitable for the determination of both species of mercury in hair for biomonitoring purposes. Non-exposed schoolchildren from three areas in the western and central part of the Czech Republic were chosen as the target group. Tenth of a microgram per gram of the total mercury were generally found in the analyzed hair; values higher than 1 microg g(-1) were detected only exceptionally. Comparable results were obtained for two western areas and differed significantly from those for the third area located in the central part of the Czech Republic. In the areas examined, the mean methylmercury contents amounted to 23-46% of the total mercury in the hair. The results confirm an assumption that exposure to mercury does not pose a significant risk to the population in the Czech Republic.

Human biomonitoring system in the Czech Republic.

The human biomonitoring (HBM) is an integral part of Environmental Health Monitoring System in the Czech Republic since 1994. Selected biomarkers of the internal dose (heavy metals, PCBs) and cytogenetic analysis of peripheral lymphocytes as a biomarker of the exposure/effect to/of environmental genotoxic factors are systematically followed up in the blood and urine of adults (blood donors), in children aged 8 to 10 years, and in the breast milk of nursing mothers. Selected outputs documented the declining trend of blood lead levels, with the recent reference value of 80 mg/l for men, and the rising trend of blood selenium levels in adults, but not in children. PCBs and chlorinated pesticides in human milk show a long-term downward trend, but still higher than in neighbouring countries. The frequency of aberrant cells revealed a downward trend, but the increase obtained in the last monitored period needs to be explained. Further HBM activities are required to demonstrate the corresponding trends and to reduce human exposure and health risks.

Blood and urine levels of Pb, Cd and Hg in the general population of the Czech Republic and proposed reference values.

The Human Biological Monitoring (HBM) project was launched in the Czech Republic in 1994 as a part of the nation-wide Environmental Health Monitoring System to assess the exposure of the Czech general population to a broad spectrum of environmental contaminants. Over the years 2001-2003, the concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) were determined in whole blood of 1188 adults (blood donors) and 333 children and in urine of 657 adults and 619 children. In adults, the median blood lead (B-Pb) level was 33microg/l. Men had higher B-Pb levels than women (medians 37microg/l vs. 25microg/l). Significantly higher B-Pb levels were observed in smokers compared to non-smokers (36microg/l vs. 31microg/l). In children, no sex-dependent differences were observed (median 31microg/l). In total, the median blood Cd level (B-Cd) in adults was 0.5microg/l. Smokers showed a median B-Cd level about 3 times as high as non-smokers (1.3microg/l vs. 0.40microg/l). Neither sex- nor age-related differences were observed in B-Cd levels. In 65% of children, B-Cd levels were below the limit of detection (LOD). The overall median urinary cadmium level (U-Cd) in adults was 0.31microg/g creatinine. Significantly higher U-Cd levels were found in women (median 0.39microg/g creatinine) compared to men (0.29microg/g creatinine). No significant differences were found between smokers and non-smokers. In more than 50% of children, the U-Cd level was below the LOD (=0.2microg/l). The median blood mercury (B-Hg) level in adults was 0.89microg/l. Significant differences were found between smokers (0.80microg/l) and non-smokers (0.92microg/l), and between men and women (0.86microg/l vs. 0.94microg/l). The median B-Hg level in children was 0.42microg/l and no sex-related differences were observed. The median urinary mercury (U-Hg) levels were 0.63microg/g creatinine in adults and 0.37microg/g creatinine in children. Significantly higher U-Hg levels were obtained in women and non-smokers compared to men and smokers, respectively. The B-Pb, B-Hg, U-Cd, and U-Hg levels significantly correlated with age. The following reference values were recommended for the period 2001-2003: 80, 65 and 55microg/l for B-Pb and 3.1, 4.0 and 1.5microg/l for B-Hg in men, women and children, respectively; 1.1microg/l and 1.2microg/g creatinine for B-Cd and U-Cd, respectively, in adult non-smokers; 5.4 and 12.0microg/g creatinine for U-Hg in men and women, respectively, and 3.7 and 5.5microg/g creatinine for U-Hg in boys and girls, respectively. The previous reference values for B-Pb and B-Cd needed revision and were reduced.

Whole blood selenium content in healthy adults in the Czech Republic.

Over a 5-year period, from 1996 to 2001, blood selenium levels were recorded in a set of 2414 healthy blood donors (1781 men and 633 women; 880 smokers and 1534 nonsmokers) living in four selected areas of the Czech Republic. About 100 blood samples per year and region were analyzed using the HGA method. The internal and external quality controls of this method were performed throughout the duration of the study. In general, blood selenium concentrations (81.9 and 106.7 microg/l for median and 90th percentile, respectively) did not reach optimum values; in approximately 10% of the population sample, values lower than 60 microg/l were detected. Nonetheless, the values obtained increased significantly, with median concentrations of 73.2 microg/l in 1996 and 91.5 microg/l in 2001. The percentage of subjects with a whole blood selenium level of less than 60 microg/l also decreased from nearly 20% in 1996 to 0.2% in 2001. No substantial regional or gender-related differences were observed, but significantly lower blood selenium levels were found in smokers as opposed to nonsmokers. Although mild selenium deficiency continues to be observed, the data presented do not indicate extremely low selenium levels in the population sample.

Sampling procedure and a radio-indicator study of mercury determination in whole blood by using an AMA 254 atomic absorption spectrometer.

A sampling procedure appropriate for the determination of mercury in whole blood was tested by using both inactive controls and a 197Hg mercury radio-indicator. To exclude the influence of the instrumental device (an AMA 254 single-purpose mercury atomic absorption spectrometer) on the determination of mercury in whole blood, the function of the instrument was checked by using rat blood with metabolised 197Hg. The measurement procedure was found to be free of errors. However, the study showed that the material used for the sampling vessels is a crucial parameter for obtaining accurate analytical results. The stability of solutions and samples was tested towards polyethylene (PE) and polypropylene (PP) vessels. PE displayed a time-dependent increase in the mercury content both in the samples and in the blood control material. The probable cause of this increase was direct contamination from the material of the vessel and/or diffusion of mercury from the environment through the vessel walls related to a strong complexing affinity of the sample matrix. This assumption was confirmed by supplying the vessels with the complexing agent Na2EDTA (0.05 mol L(-1)). Commercial PP vessels for blood sampling (Sarstedt S-Monovette Metall Analytik) did not give rise to statistically significant variations in mercury content in the samples and blood control material over a 30-day period.

Population-based biomonitoring in the Czech Republic: urinary arsenic.

The method of Guo et aL (AnaL Chim. Acta, 1997, 349, 313-318) for the determination of the toxicologically relevant arsenic in urine was verified and then used for the determination of arsenic in urine of the Czech population for monitoring purposes. Statistical evaluation at the level alpha = 0.05 did not prove any significant differences between industrial and agricultural regions, between males and females and smokers and nonsmokers. Likewise no differences were found among children in all the regions monitored. In the adult population small differences were found between some regions but these differences were not dependent on industrial pollution. The values of toxicologically relevant arsenic are low for all regions. The summarised value of the median for all groups together is 3.5 microg (g creatinine)(-1).