Lead, cadmium, mercury, and chromium in urine and blood of children and adolescents in Germany - Human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V).

Metals reach humans through food and drinking water intake and inhalation of airborne particles and can have detrimental health effects in particular for children. The metals presented here (lead, cadmium, chromium, and mercury) could lead to toxic effects such as neurotoxicity, mutagenicity, and have been classified as (possible) carcinogens. Using population representative data from the German Environmental Survey 2014-2017 (GerES V) from 3- to 17-year-old children on lead and cadmium in blood (n = 720) and on cadmium, chromium, and mercury in urine (n = 2250) we describe current internal exposure levels, and socio-demographic and substance-specific exposure determinants. Average internal exposure (geometric means) in blood was 9.47 µg/L for lead and below 0.06 µg/L (limit of quantification) for cadmium, and in urine 0.072 µg/L for cadmium, 0.067 µg/L for mercury, and 0.393 µg/L for chromium, respectively. Younger children have higher concentrations of lead and chromium compared to 14-17-year-old adolescents, and boys have slightly higher mercury concentrations than girls. With respect to substance specific determinants, higher lead concentrations emerged in participants with domestic fuel and in non-smoking children with smokers in the household, higher levels of cadmium were associated with smoking and vegetarian diet and higher levels of mercury with the consumption of seafood and amalgam teeth fillings. No specific exposure determinants emerged for chromium. The health based guidance value HBM-I was not exceeded for mercury and for cadmium in urine it was exceeded by 0.6% of the study population. None of the exceedances was related to substantial tobacco smoke exposure. Comparisons to previous GerES cycles (GerES II, 1990-1992; GerES IV, 2003-2006) indicate continuously lower levels.

Instability of urinary excreted methyl-2-acetamido-2-deoxy-1-seleno-ß-d-galactopyranoside (selenosugar 1), the main elimination product of human selenium metabolism, and measures for its stabilization.

BACKGROUND: The urinary excreted selenium species selenosugar 1 (SeSug1) plays a key role for monitoring of supplemental selenium exposure, e.g. by occupational exposure. In order to reproduce its contents in the long term, the integrity of SeSug1 in the urine is essential. Studies on the stability of SeSug1 in urine samples stored at -20 °C have shown that degradation of SeSug 1 occurs, requiring adequate countermeasures. METHODS: Here, we explored the long-term stability of SeSug1 under usual storage conditions at -20 °C. For this purpose, the simultaneous determination of selenosugar 1 and methylselenic acid (MeSeA) was used to explore the stabilizing of the SeSug1 content by applying sodium azide (NaN3) as a bactericide or/and 5 M ammonium acetate buffer for pH control. RESULTS: In untreated urine, conversion of SeSug1 to MeSeA was evident within days. Differences in urine matrices clearly showed different impact, which could be attributed to different buffer strengths by the urine itself. For durability, various concentrations of sodium azide were first applied, followed by pH buffering. A combination of 0.1% NaN3 and pH of 5.5 kept the SeSug1 content stable for over 3 months. CONCLUSION: The formation of MeSeA as degradation product of SeSug1 could be confirmed. Based on the proportions, an oxidation-based decomposition pathway was proposed. The investigations revealed that the complex interaction of pH buffering and bactericidal activity must be taken into account in order to stabilize SeSug1 in the urine. The main effect was the addition of NaN3. However, the alkaline nature of NaN3 required a sufficient buffering of the urinary matrix at a pH of 5.5.

Determination of eleven small selenium species in human urine by chromatographic-coupled ICP-MS methods.

BACKGROUND: The determination of various selenium species in urine enables a specific biomonitoring of the exposure to different selenium compounds. METHODS: For this task a coupling of three chromatographic techniques with ICP-MS was developed for the separate quantification of eleven species in urine. The first procedure was based on reverse phase chromatography and was designed for the separate determination of methyl-2-acetamido-2-deoxy-1-seleno-b-d-galactopyranoside (SeSug1), methyl-2-acetamido-2-deoxy-1-seleno-b-d-glucopyranoside (SeSug2), selenomethionine (SeMet), methylselenocysteine (MeSeC), seleno-D,L-ethionine (SeEt), methylselenic acid (MeSeA) and methylselenoglutathione (MeSeG); the second procedure was based on anion exchange chromatography and measured selenate (Se (VI)) and selenite (Se (IV)); the third procedure was based on cationic exchange chromatography and determined methyl-2-amino-2-deoxy-1-seleno-b-d-galactopyranoside (SeSug3) and the trimethylselenium ion (TMSe). A fourth method for the more sensitive determination of TMSe was upgraded by an on-line after-column reaction process. RESULTS: The validation of the methods yielded sensitive detection limits of the species between 0.03 and 0.10 µg Se/L. For TMSe a detection limit of 0.02 µg Se/L resulted by the fourth method. An intra-day precision of 2.7-10.6% and a relative recovery between 87 % and 108 % confirm the robustness of the methods. CONCLUSION: The developed procedures enable a separate and sensitive determination of eleven selenium species in urine and thus permit the exploring of metabolic factors in the general population and particularly exposed individuals.

Low internal exposure and absence of adverse effects in workers exposed to high air levels of inorganic selenium.

Selenium is an essential trace element for humans, but adverse health effects may occur after elevated intake. The margin between it is small. This study aimed to assess external and internal exposure in workers of a selenium-processing plant, in which elemental and inorganic selenium occurred. Selenium was analyzed in the form of the selenium concentration in plasma (Se-P), in erythrocytes (Se-RBC) and in personal air samples (Setotal-Air) of 17 exposed workers. Internal exposure was compared to 20 controls without occupational selenium exposure. For potential effects, glucose, HbA1c, proinsulin, prothrombin time and GPX were determined. Setotal-Air had a maximum of 2394 µg/m3 (median 319 µg/m3), containing a small water-soluble fraction (median 12.7 µg/m3, range 0.07-975 µg/m3). Se-P of the exposed ranged from 62 to 123 µg/L (median 105 µg/L), whereas the median of Se-RBC was 63.4 µg/L blood (range 51.9-92.7 µg/L). Both were significantly higher than the controls. No significant difference was found for the effect parameters. Biological effect monitoring of employees occupationally exposed to very high levels of selenium and inorganic selenium compounds did not show any indication of adverse health effects. The moderate increase of the internal selenium exposure compared to the high ambient exposure to selenium and its compounds suggests an efficient air protection or an extremely low resorption of elemental and inorganic species of selenium via inhalation.

Discovering time-trends of the German populations exposure to contaminants by analysis of human samples of the German Environmental Specimen Bank (ESB).

The German Environmental Specimen Bank (ESB) is a monitoring instrument of the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The permanent biobank facility is run since 1981 containing environmental and human samples from Germany. All samples are collected according to standard operating procedures (SOP). An standardized annual collection of human samples at four different regional sites of the country has been established since 1997. Routine sampling is done once a year, recruiting healthy non occupationally exposed students aged 20-29 years, in an equal gender distribution. The number of participants recruited is approximately 120 students per site and year. Directly after the annual sampling process, the human samples are analyzed for selected environmental chemicals. The time-trends of lead in blood, mercury and pentachlorophenol in 24 h-urine and polychlorinated biphenyls in plasma demonstrated a decrease of exposure during the last two decades by about 40-90 percent. In parallel retrospective studies using cryo-archived samples revealed increasing time trends of emerging chemicals used as substitutes for regulated toxicants. The data demonstrates the great relevance of the ESB for the health related environmental monitoring and shows the importance of human biomonitoring as a tool in information based policy making.

Human biomonitoring pilot study DEMOCOPHES in Germany: Contribution to a harmonized European approach.

Human biomonitoring (HBM) is an effective tool to assess human exposure to environmental pollutants, but comparable HBM data in Europe are lacking. In order to expedite harmonization of HBM studies on a European scale, the twin projects COPHES (Consortium to Perform Human Biomonitoring on a European Scale) and DEMOCOPHES (Demonstration of a study to Coordinate and Perform Human Biomonitoring on a European Scale) were formed, comprising 35 partners from 27 European countries. In COPHES a research scheme and guidelines were developed to exemplarily measure in a pilot study mercury in hair, cadmium, cotinine and several phthalate metabolites in urine of 6-11year old children and their mothers in an urban and a rural region. Seventeen European countries simultaneously conducted this cross-sectional DEMOCOPHES feasibility study. The German study population was taken in the city of Bochum and in the Higher Sauerland District, comprising 120 mother-child pairs. In the present paper features of the study implementation are presented. German exposure concentrations of the pollutants are reported and compared with European average concentrations from DEMOCOPHES and with those measured in the representative German Environmental Survey (GerES IV). German DEMOCOPHES concentrations for mercury and cotinine were lower than the European average. However, 47% of the children were still exposed to environmental tobacco smoke (ETS) outside their home, which gives further potential for enhancing protection of children from ETS. Compared with samples from the other European countries German participating children had lower concentrations of the phthalate metabolites MEP and of the sum of 3 DEHP-metabolites (MEHP, 5OH-MEHP and 5oxo-MEHP), about the same concentrations of the phthalate metabolites MBzP and MiBP and higher concentrations of the phthalate metabolite MnBP. 2.5% of the German children had concentrations of the sum of 4 DEHP-metabolites and 4.2% had concentrations of MnBP that exceeded health based guidance values, indicating reasons for concern. Continuous HBM is necessary to track changes of pollutant exposure over time. Therefore Germany will continue to cooperate on the harmonisation of European human biomonitoring to support the chemicals regulation with the best possible exposure data to protect Europe's people against environmental health risks.