Environmental surveys, specimen bank and health related environmental monitoring in Germany

Assessing background contamination of sample tubes used in human biomonitoring by non-targeted liquid chromatography-high resolution mass spectrometry

Controlling and minimising background contamination is crucial for maintaining a high quality of samples in human biomonitoring targeting organic chemicals. We assessed the contamination of three previous types and one newly introduced medical-grade type of sample tubes used for storing human body fluids at the German Environmental Specimen Bank. Aqueous extracts from these tubes were analysed by non-targeted liquid chromatography-high resolution mass spectrometry (LC-HRMS) before and after a dedicated cleaning procedure. After peak detection using MZmine, Bayesian hypothesis testing was used to group peaks into those originating either from instrumental and laboratory background contamination, or actual tube contaminants, based on if their peak height was reduced, increased or not affected by the cleaning procedure. For all four tube types 80-90% of the 2475 peaks (1549 in positive and 926 in negative mode) were assigned to laboratory/instrumental background, which we have to consider as potential sample tube contaminants. Among the tube contaminants, results suggest a considerable difference in the contaminant peak inventory and the absolute level of contamination among the different sample tube types. The cleaning procedure did not affect the largest fraction of peaks (50-70%). For the medical grade tubes, the removal of contaminants by the cleaning procedure was strongest compared to the previous tubes, but in all cases a small fraction increased in intensity after cleaning, probably due to a release of oligomers or additives. The identified laboratory background contaminants were mainly semi-volatile polymer additives such as phthalates and phosphate esters. A few compounds could be assigned solely as tube-specific contaminants, such as N,N-dibutylformamide and several constituents of the oligomeric light stabiliser Tinuvin-622. A cleaning procedure before use is an effective way to standardise the used sample tubes and minimises the background contamination, and therefore increases sample quality and therewith analytical results.

Increasing exposure to the UV filters octocrylene and 2-ethylhexyl salicylate in Germany from 1996 to 2020: Human biomonitoring in 24-h urine samples of the German Environmental Specimen Bank (ESB)

The UV filters octocrylene (OC) and 2-ethylhexyl salicylate (EHS) are commonly used in sunscreens and frequently detected in environmental media. However, knowledge on human exposures is scarce. In this human biomonitoring (HBM) study, we analyzed concentrations of exposure biomarkers specific to OC (CPAA, DOCCA, 5OH-OC) and EHS (5OH-EHS, 5oxo-EHS, 5cx-EPS) in 24-h urine samples (n = 420) from the German Environmental Specimen Bank (ESB). These samples were collected from German students (20-29 years; 30 males/30 females per year) between 1996 and 2020 (4-year intervals; collection in winter). We found continuously increasing OC and EHS exposures (Jonckheere-Terpstra; p < 0.001) documented by very few to no samples with concentrations of the most sensitive biomarkers CPAA and 5cx-EPS above the limit of quantification (LOQ) in 1996 (5 % and 0 %, respectively) and reaching 100 % and 93 % above the LOQ in 2016, with median concentrations of 4.79 and 0.071 µg/L, respectively. In 2020, biomarker concentrations slightly decreased to 3.12 µg/L CPAA (97 %>LOQ) and 0.060 µg/L 5cx-EPS (88 %>LOQ). This general trend was confirmed by the other biomarkers, however at lower detection rates. Based on metabolite excretion in the 24-h urine samples and human toxicokinetic data, we calculated maximum daily intakes (DI) of 17 µg/(kg bw * d) OC and 59 µg/(kg bw * d) EHS. Based on a derived no-effect level (DNEL) of 0.8 mg/(kg bw * d), the OC exposures of individuals in our study did not indicate any health risk. Similarly, for EHS all biomarker concentrations were well below the HBM-I values of 12 µg/L 5OH-EHS and 11 µg/L 5cx-EPS. Our data proves the general applicability of specific OC and EHS metabolites for HBM in the general population and shows clearly increasing exposures. Higher (co-)exposures must be expected in populations with increased sunscreen use such as (summer) vacationers, children and outdoor workers.

National blood bank services as a platform for national human biomonitoring - A proof-of-concept study

BACKGROUND

Human biomonitoring (HBM) is crucial for identifying potential risks to human health from exposure to environmental hazards. However, it is an expensive and labor-intensive endeavor. To save on samples' collection process we suggested using a national blood banking system as a platform for a national HBM program. For the case study, we used a comparison of blood donors from heavily industrialized Haifa Bay region, northern Israel, with donors from the rest of the country.

METHODS

The study population comprised a random sample of blood donors donating blood all over Israel. Samples of whole blood were tested for arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb). Donors' donations sites and residential locations were geocoded. Smoking status was verified based on Cd levels, after calibrating their concentrations vs Cotinine in a sub-sample of 45 subjects. Metal concentrations were compared between regions using a lognormal regression, while controlling for age, gender, and predicted probability of smoking.

RESULTS

During Mar 2020-Feb 2022, we collected 6230 and tested 911 samples. Concentrations of most of the metals were modified by age, gender, and smoking. Cr and Pb appeared to be 1.08-1.10 times higher among Haifa Bay residents than in the rest of the country (although with borderline significance of 0.069 for Cr). Cr and Pb were 1.13-1.15 times higher for those who donated blood in the Haifa Bay region, but not necessarily resided in the area. Donors from Haifa Bay had lower levels of As and Cd as compared to other donors in Israel.

CONCLUSIONS

Using a national blood banking system for HBM proved to be feasible and efficient. Blood donors from Haifa Bay area were characterized by elevated levels of Cr and Pb and lower levels of As and Cd. An extensive investigation of industries in the area is warranted.

Human biomonitoring of deoxynivalenol (DON) - Assessment of the exposure of young German adults from 1996 - 2021

The mycotoxin deoxynivalenol (DON) is a frequently found contaminant in cereals and cereal-based products. As a German contribution to the European Joint Programme HBM4EU, we analysed the total DON concentration (tDON) in 24-h urine samples from the German Environmental Specimen Bank (ESB). In total, 360 samples collected in 1996, 2001, 2006, 2011, 2016, and 2021 from young adults in Muenster (Germany), were measured by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) after enzymatic deconjugation of the glucuronide metabolites. tDON was found in concentrations above the lower limit of quantification (0.3 μg/L) in 99% of the samples. Medians of the measured concentrations and the daily excretion were 4.3 μg/L and 7.9 μg/24 h, respectively. For only nine participants, urinary tDON concentrations exceeded the provisional Human biomonitoring guidance value (HBM GV) of 23 μg/L. Urinary tDON concentrations were significantly higher for male participants. However, 24-h excretion values normalized to the participant's body weight did not exhibit any significant difference between males and females and the magnitude remained unchanged over the sampling years with exception of the sampling year 2001. Daily intakes were estimated from excretion values. Exceedance of the tolerable daily intake (TDI) of 1 μg/kg bw per day was observed for less than 1% of all participants. TDI exceedances were only present in the sampling year 2001 and not in more recent sampling years while exceedance of the HBM guidance value was also observed in 2011 and 2021.

A time trend of urinary 4-methylbenzylidene camphor metabolites in young adults from Germany

4-methylbenzylidene camphor (4-MBC) is used as a UV-B filter in cosmetics. Two oxidized metabolites of 4-MBC - 3-(4-carboxybenzylidene)camphor (cx-MBC) and 3-(4-carboxybenzylidene)-6-hydroxycamphor (cx-MBC-OH) - were analyzed in 250 24-h urine samples from young adults in Germany. The samples were from the German Environmental Specimen Bank (ESB) and represented exposure in the years 1995, 2005, 2010, 2015 and 2019. A UHPLC-MS/MS method enabled the sensitive determination of both metabolites, with limits of quantification at 0.15 μg L^-1 (cx-MBC) and 0.30 μg L^-1 (cx-MBC-OH), respectively. A temporal trend of the internal exposure to 4-MBC was clearly noticeable. The metabolite cx-MBC was frequently quantifiable at the beginning of the period: in 70% of the samples in 1995, and 56% in 2005. After 2005, urinary concentrations and detection rates of cx-MBC dropped to reach very low levels. In 2015 and 2019, the detection rate was only 2% and 0%, respectively. A similar trend was observed for cx-MBC-OH, though overall, this metabolite was detected less often and at lower concentration levels than cx-MBC. Nowadays, measurable levels of urinary 4-MBC metabolites are an extremely rare occurrence in Germany. These trends are consistent with the history of 4-MBC use by the cosmetic industry. The highest measured individual concentration of 16.20 μg L^-1 (in a sample of the year 2005) was still more than 30 times below the health-based guidance value (HBM-I). An investigation of the ratios between both metabolites uncovered several features of the 4-MBC metabolism which have been essentially overlooked until now. In particular, stereochemical aspects should be explored in future studies. As urine was collected in autumn/winter in Northwestern Germany, the 4-MBC metabolites measured probably do not arise from sunscreen products in a narrow sense. They rather may reveal the use of other skin care products containing 4-MBC for UV protection as an added feature.

Application of human biomonitoring data to support policy development, raise awareness and environmental public health protection among countries within the HBM4EU project

Most countries have acknowledged the importance of assessing and quantifying their population's internal exposure from chemicals in air, water, soil, food and other consumer products due to the potential health and economic impact. Human biomonitoring (HBM) is a valuable tool which can be used to quantify such exposures and effects. Results from HBM studies can also contribute to improving public health by providing evidence of individuals' internal chemical exposure as well as data to understand the burden of disease and associated costs thereby stimulating the development and implementation of evidence-based policy. To have a holistic view on HBM data utilisation, a multi-case research approach was used to explore the use of HBM data to support national chemical regulations, protect public health and raise awareness among countries participating in the HBM4EU project. The Human Biomonitoring for Europe (HBM4EU) Initiative (https://www.hbm4eu.eu/) is a collaborative effort involving 30 countries, the European Environment Agency (EEA) and the European Commission (contracting authority) to harmonise procedures across Europe and advance research into the understanding of the health impacts of environmental chemical exposure. One of the aims of the project was to use HBM data to support evidence based chemical policy and make this information timely and directly available for policy makers and all partners. The main data source for this article was the narratives collected from 27 countries within the HBM4EU project. The countries (self-selection) were grouped into 3 categories in terms of HBM data usage either for public awareness, policy support or for the establishment HBM programme. Narratives were analysed/summarised using guidelines and templates that focused on ministries involved in or advocating for HBM; steps required to engage policy makers; barriers, drivers and opportunities in developing a HBM programme. The narratives reported the use of HBM data either for raising awareness or addressing environmental/public health issues and policy development. The ministries of Health and Environment were reported to be the most prominent entities advocating for HBM, the involvement of several authorities/institutions in the national hubs was also cited to create an avenue to interact, discuss and gain the attention of policy makers. Participating in European projects and the general population interest in HBM studies were seen as drivers and opportunities in developing HBM programmes. A key barrier that was cited by countries for establishing and sustaining national HBM programmes was funding which is mainly due to the high costs associated with the collection and chemical analysis of human samples. Although challenges and barriers still exist, most countries within Europe were already conversant with the benefits and opportunities of HBM. This article offers important insights into factors associated with the utilisation of HBM data for policy support and public awareness.

Coordination of chemical analyses under the European Human Biomonitoring Initiative (HBM4EU): Concepts, procedures and lessons learnt

The European Human Biomonitoring Initiative (HBM4EU) ran from 2017 to 2022 with the aim of advancing and harmonizing human biomonitoring in Europe. More than 40,000 analyses were performed on human samples in different human biomonitoring studies in HBM4EU, addressing the chemical exposure of the general population, temporal developments, occupational exposure and a public health intervention on mercury in populations with high fish consumption. The analyses covered 15 priority groups of organic chemicals and metals and were carried out by a network of laboratories meeting the requirements of a comprehensive quality assurance and control system. The coordination of the chemical analyses included establishing contacts between sample owners and qualified laboratories and monitoring the progress of the chemical analyses during the analytical phase, also addressing status and consequences of Covid-19 measures. Other challenges were related to the novelty and complexity of HBM4EU, including administrative and financial matters and implementation of standardized procedures. Many individual contacts were necessary in the initial phase of HBM4EU. However, there is a potential to develop more streamlined and standardized communication and coordination in the analytical phase of a consolidated European HBM programme.

A step towards harmonising human biomonitoring study setup on European level: Materials provided and lessons learnt in HBM4EU

Internal exposure of the human body to potentially harmful chemical substances can be assessed by Human Biomonitoring (HBM). HBM can be used to generate conclusive data that may provide an overview of exposure levels in entire or specific population groups. This knowledge can promote the understanding of potential risks of the substances of interest or help monitoring the success of regulatory measures taken on the political level. Study planning and design are key elements of any epidemiologic study to generate reliable data. In the field of HBM, this has been done using differing approaches on various levels of population coverage so far. Comparison and combined usage of the resulting data would contribute to understanding exposure and its factors on a larger scale, however, the differences between studies make this a challenging and somewhat limited endeavour. This article presents templates for documents that are required to set up an HBM study, thus facilitating the generation of harmonised HBM data as a step towards standardisation of HBM in Europe. They are designed to be modular and adaptable to the specific needs of a single study while emphasising minimum requirements to ensure comparability. It further elaborates on the challenges encountered during the process of creating these documents during the runtime of the European Joint Programme HBM4EU in a multi-national expert team and draws up lessons learnt in the context of knowledge management.

How to use human biomonitoring in chemical risk assessment: Methodological aspects, recommendations, and lessons learned from HBM4EU

One of the aims of the European Human Biomonitoring Initiative, HBM4EU, was to provide examples of and good practices for the effective use of human biomonitoring (HBM) data in human health risk assessment (RA). The need for such information is pressing, as previous research has indicated that regulatory risk assessors generally lack knowledge and experience of the use of HBM data in RA. By recognising this gap in expertise, as well as the added value of incorporating HBM data into RA, this paper aims to support the integration of HBM into regulatory RA. Based on the work of the HBM4EU, we provide examples of different approaches to including HBM in RA and in estimations of the environmental burden of disease (EBoD), the benefits and pitfalls involved, information on the important methodological aspects to consider, and recommendations on how to overcome obstacles. The examples are derived from RAs or EBoD estimations made under the HBM4EU for the following HBM4EU priority substances: acrylamide, o-toluidine of the aniline family, aprotic solvents, arsenic, bisphenols, cadmium, diisocyanates, flame retardants, hexavalent chromium [Cr(VI)], lead, mercury, mixture of per-/poly-fluorinated compounds, mixture of pesticides, mixture of phthalates, mycotoxins, polycyclic aromatic hydrocarbons (PAHs), and the UV-filter benzophenone-3. Although the RA and EBoD work presented here is not intended to have direct regulatory implications, the results can be useful for raising awareness of possibly needed policy actions, as newly generated HBM data from HBM4EU on the current exposure of the EU population has been used in many RAs and EBoD estimations.

Urinary excretion of phthalates and the substitutes DINCH and DEHTP in Danish young men and German young adults between 2000 and 2017 - A time trend analysis

Over the last twenty-five years it has become evident that exposure to several phthalates can have adverse effects on human health, such as endocrine disruption. This led to a series of EU regulations that resulted in a decrease in the production volumes of the restricted phthalates and an increased production of substitutes. The current study describes the impact of regulations and changes in production and use of phthalates and their substitutes on internal exposure patterns in two European populations since the beginning of the 2000'ies. Using harmonised data from young adults in Denmark (Danish Young Men Study, n = 1,063, spot urine) and Germany (Environmental Specimen Bank, n = 878, 24-h urine) with repeated cross-sectional design (3-11 cycles per biomarker) we applied Locally Estimated Scatterplot Smoothing (LOESS) and Generalized Linear Models (GLMs) to estimate time trends and the role of covariates on the trend (e.g. age, BMI). Time trends of daily excretion (μg/24h) are comparable between the two samples for the regulated (DEHP, BBzP, DiNP, DnBP, DiBP, DiDP/DPHP) as well as the non-regulated substances (DMP, DEP, DINCH, DEHTP) although the rate of change differ for some of the compounds. GLM results indicate that the daily excretion of the most regulated phthalates has decreased over time (DEHP yearly about 12-16%, BBzP 5%, DnBP 0.3-17%, and DiBP 4-12%). Interestingly, also the non-regulated phthalates DMP and DEP decreased by 6-18% per year. In sharp contrast, the phthalate substitutes DINCH and DEHTP show very steep annual increases (∼10-68% and ∼100%, respectively) between 2009 and 2017. We did not find an effect of age, sex, BMI, or education on the time trend. The present study provides comparable insights into how exposure to phthalates and two of their substitutes have changed over the last two decades in Germany and Denmark.

Time trend of exposure to secondhand tobacco smoke and polycyclic aromatic hydrocarbons between 1995 and 2019 in Germany - Showcases for successful European legislation

Starting in 2002, regulations and legislative amendments in Germany focused on the non-smoker protection with several measures to reduce exposure to secondhand tobacco smoke (SHS). The present work aimed to evaluate the relationship between polycyclic aromatic hydrocarbons (PAHs) and SHS exposure and to determine to which extent enforced non-smoking regulations and smoking bans affected the exposure of the non-smoking population in Germany since their implementation in the early 2000s until today. For this purpose, cotinine and selected monohydroxylated PAHs (OH-PAHs) were analyzed by means of (UP)LC-MS/MS in 510 24-h-urine samples of the Environmental Specimen Bank collected over a time span of 24 years from 1995 to 2019. Median urinary cotinine levels were found to steadily and significantly decline by 82% from 1995 to 2019. A significant decrease of urinary 3-hydroxybenzo[a]pyrene (19%), 1-OH-pyrene (39%), 1-naphthol (66%), 1- (17%), 2- (25%), and 3-OH-phenanthrene (22%) was also observed throughout the same time span. The decline in urinary levels of cotinine and several OH-PAHs can most likely be attributed to smoking bans and regulations limiting SHS and PAH exposure. This study therefore emphasizes the relevance of human biomonitoring to investigate the exposure of humans to chemicals of concern, assess the effectiveness of regulatory measures, and help policies to enforce provisions to protect public health.

Developing human biomonitoring as a 21st century toolbox within the European exposure science strategy 2020-2030

Human biomonitoring (HBM) is a crucial approach for exposure assessment, as emphasised in the European Commission's Chemicals Strategy for Sustainability (CSS). HBM can help to improve chemical policies in five major key areas: (1) assessing internal and aggregate exposure in different target populations; 2) assessing exposure to chemicals across life stages; (3) assessing combined exposure to multiple chemicals (mixtures); (4) bridging regulatory silos on aggregate exposure; and (5) enhancing the effectiveness of risk management measures. In this strategy paper we propose a vision and a strategy for the use of HBM in chemical regulations and public health policy in Europe and beyond. We outline six strategic objectives and a roadmap to further strengthen HBM approaches and increase their implementation in the regulatory risk assessment of chemicals to enhance our understanding of exposure and health impacts, enabling timely and targeted policy interventions and risk management. These strategic objectives are: 1) further development of sampling strategies and sample preparation; 2) further development of chemical-analytical HBM methods; 3) improving harmonisation throughout the HBM research life cycle; 4) further development of quality control / quality assurance throughout the HBM research life cycle; 5) obtain sustained funding and reinforcement by legislation; and 6) extend target-specific communication with scientists, policymakers, citizens and other stakeholders. HBM approaches are essential in risk assessment to address scientific, regulatory and societal challenges. HBM requires full and strong support from the scientific and regulatory domain to reach its full potential in public and occupational health assessment and in regulatory decision-making.

Harmonization of Human Biomonitoring Studies in Europe: Characteristics of the HBM4EU-Aligned Studies Participants

Human biomonitoring has become a pivotal tool for supporting chemicals’ policies. It provides information on real-life human exposures and is increasingly used to prioritize chemicals of health concern and to evaluate the success of chemical policies. Europe has launched the ambitious REACH program in 2007 to improve the protection of human health and the environment. In October 2020 the EU commission published its new chemicals strategy for sustainability towards a toxic-free environment. The European Parliament called upon the commission to collect human biomonitoring data to support chemical’s risk assessment and risk management. This manuscript describes the organization of the first HBM4EU-aligned studies that obtain comparable human biomonitoring (HBM) data of European citizens to monitor their internal exposure to environmental chemicals. The HBM4EU-aligned studies build on existing HBM capacity in Europe by aligning national or regional HBM studies. The HBM4EU-aligned studies focus on three age groups: children, teenagers, and adults. The participants are recruited between 2014 and 2021 in 11 to 12 primary sampling units that are geographically distributed across Europe. Urine samples are collected in all age groups, and blood samples are collected in children and teenagers. Auxiliary information on socio-demographics, lifestyle, health status, environment, and diet is collected using questionnaires. In total, biological samples from 3137 children aged 6–12 years are collected for the analysis of biomarkers for phthalates, HEXAMOLL^® DINCH, and flame retardants. Samples from 2950 teenagers aged 12–18 years are collected for the analysis of biomarkers for phthalates, Hexamoll^® DINCH, and per- and polyfluoroalkyl substances (PFASs), and samples from 3522 adults aged 20–39 years are collected for the analysis of cadmium, bisphenols, and metabolites of polyaromatic hydrocarbons (PAHs). The children’s group consists of 50.4% boys and 49.5% girls, of which 44.1% live in cities, 29.0% live in towns/suburbs, and 26.8% live in rural areas. The teenagers’ group includes 50.6% girls and 49.4% boys, with 37.7% of residents in cities, 31.2% in towns/suburbs, and 30.2% in rural areas. The adult group consists of 52.6% women and 47.4% men, 71.9% live in cities, 14.2% in towns/suburbs, and only 13.4% live in rural areas. The study population approaches the characteristics of the general European population based on age-matched EUROSTAT EU-28, 2017 data; however, individuals who obtained no to lower educational level (ISCED 0–2) are underrepresented. The data on internal human exposure to priority chemicals from this unique cohort will provide a baseline for Europe’s strategy towards a non-toxic environment and challenges and recommendations to improve the sampling frame for future EU-wide HBM surveys are discussed.

Long-term monitoring of mercury in young German adults: Time trend analyses from the German Environmental Specimen Bank, 1995-2018

As highlighted in the Minamata Convention, Mercury (Hg) in its various forms poses a substantial risk to human health and the environment. The health relevance of Hg is also recognized by the European Human Biomonitoring Initiative (HBM4EU), which classifies Hg as a priority substance, since considerable knowledge and data gaps on Hg exposure levels and their changes over time still exist in Europe. The German Environmental Specimen Bank (German ESB) provides valuable policy relevant data and long-term trends of substance exposure on a national level for international comparison and evaluation. In this study we analysed data of the German ESB on Hg exposure of young adults aged 20 to 29 including data on urinary Hg levels from 1995 to 2018 and whole blood Hg levels from 2001 to 2010. Results show a clear decrease in both, about 86% in urine total daily Hg excretion from 1995 (0.76 μg/L) to 2018 (0.11 μg/L) (n = 10,069) and about 57% in blood concentrations of Hg from 2001 (1.76 μg/L) to 2010 (0.77 μg/L) (n = 4085). Over the investigated timeframe only a few values exceeded the toxicologically derived health based guidance value HBM I for blood and urine, with these exceedances decreasing over time in line with the general trend. The factors mostly influencing Hg excretion identified in this study are dental amalgam as well as fish and seafood consumption. Besides other factors (e.g. age and sex), also airborne Hg exposure appears to be a low but evident influencing factor in Germany. Although a considerable decrease in internal Hg exposure is recognized in the last decades, the current low-level exposure may cause adverse health effects especially to vulnerable groups such as pregnant women and children. To further elucidate and evaluate current exposure sources and to reduce human exposure to Hg, continuous environmental and human biomonitoring is needed.

The questionnaire design process in the European Human Biomonitoring Initiative (HBM4EU)

BACKGROUND

Designing questionnaires is a key point of epidemiological studies assessing human exposure to chemicals. The lack of validated questionnaires can lead to the use of previously developed and sub-optimally adapted questionnaires, which may result in information biases that affect the study's validity. On this ground, a multidisciplinary group of researchers developed a series of tools to support data collection within the HBM4EU initiative. The objective of this paper is to share the process of developing HBM4EU questionnaires, as well as to provide researchers with harmonized procedures that could help them to design future questionnaires to assess environmental exposures.

METHODS

In the frame of the work package on survey design and fieldwork of the HBM4EU, researchers carried out procedures necessary for the development of quality questionnaires and related data collection tools. These procedures consisted of a systematic search to identify questionnaires used in previous human biomonitoring (HBM) studies, as well as the development of a checklist and evaluation sheet to assess the questionnaires identified. The results of these evaluations were taken into consideration for the development of the final questionnaires.

RESULTS

The main points covered by each of the sections included in HBM4EU questionnaires are described and discussed in detail. Additional tools developed for data collection in the HBM4EU (e.g. non-responder questionnaire, satisfaction questionnaire, matrix-specific questionnaire) are also addressed. Special attention is paid to the limitations faced and hurdles overcome during the process of questionnaire development.

CONCLUSIONS

Designing questionnaires for use in HBM studies requires substantial effort by a multidisciplinary team to guarantee that the quality of the information collected meets the study's objectives. The process of questionnaire development described herein will contribute to improve the harmonization of HBM studies within the social and environmental context of the EU countries.

Formaldehyde, aliphatic aldehydes (C2 -C11 ), furfural, and benzaldehyde in the residential indoor air of children and adolescents during the German Environmental Survey 2014-2017 (GerES V)

Indoor air concentrations of formaldehyde, furfural, benzaldehyde, and 11 aliphatic aldehydes (C₂ -C₁₁ ) were measured in residences of 639 participants in the German Environmental Survey for Children and Adolescents 2014-2017 (GerES V). Sampling was conducted using passive samplers over periods of approximately seven days for each participant. The most abundant compounds were formaldehyde and hexanal with median concentrations of 24.9 µg m^-3 and 10.9 µg m^-3 , respectively. Formaldehyde concentrations exceeded the Guide Value I recommended by the German Committee on Indoor Guide Values (Ausschuss für Innenraumrichtwerte - AIR) (0.10 mg m^-3 ) for 0.3% of the participating residences. The sum of aliphatic n-aldehydes between C₄ (butanal) and C₁₁ (undecanal) exceeded their Guide Value (0.10 mg m^-3 ) for 2.0% of the residences. The geometric mean concentrations of most aldehydes were lower than in the earlier GerES IV (2003-2006) study. Formaldehyde and hexanal concentrations, however, were comparable in both studies and showed no significant difference. Indoor aldehyde concentrations did not exhibit significant correlations with factors collected in questionnaires, such as the age of the participants, their socio-economic status, the location of the residence (former East/West Germany), migration background, tobacco exposure, and the type of furniture used. The validity of the passive sampler measurements was verified against active sampling techniques in a test chamber experiment.

Determination of trace elements in urine by inductively coupled plasma-tandem mass spectrometry - Biomonitoring of adults in the German capital region

A method was developed and validated for multi-element analyses of human urine samples using inductively coupled plasma-tandem mass spectrometry. The combination of a simple sample preparation and the state-of-the-art technique allows high-throughput and lowest limits of quantification up to 1 ng/L. Thereby coefficients of variation ranges from 0.4% (V) to 3.7% (Be), and 0.9% (Cd) to 4.8% (Ni) for intraday and interday precision, respectively. The method's performance is demonstrated by successful participation in international interlaboratory comparison programs as external quality assurance. Moreover, the method was applied for the analysis of first-morning void urine samples of adults (N = 77) living in the German capital region. 15 metals and metalloids (As_total, Be, Bi, Cd, Co, Cr, In, Mn, Mo, Ni, Pb, Sn, Tl, V, and Zn) were determined. With exception of indium, all elements were found in urine samples above the limit of quantification, demonstrating the suitability to measure the general population's exposure to these metals and metalloids. The method presented here shall be used for analysis of urine samples collected in the upcoming German Environmental Survey, GerES VI, a cross-sectional, population-representative study.

Time trend of the exposure to geraniol in 24-h urine samples derived from the German Environmental Specimen Bank from 2004 to 2018

Geraniol (trans-3,7-dimethyl-2,6-octadiene-1-ol) is an acyclic isoprenoid monoterpene with a widespread use as fragrance in consumer products, agrochemicals and pharmaceuticals. The class of terpene chemicals has been associated with varying sensitizing potencies. A recently developed sensitive LC- MS/MS method for the analysis of geraniol metabolites was further improved and validated for the two metabolites, 8-carboxygeraniol and Hildebrandt acid. The successfully validated method was applied to 250 urine samples derived from the Environmental Specimen Bank (ESB) collected between 2004 and 2018. Both metabolites of this allergen of special concern were quantified in all urine samples of this study. Correlation analysis revealed that 8-carboxygeraniol appears to be the sole specific biomarker in urine for geraniol exposure. Overall, the excreted amounts of 8-carboxygeraniol remained unchanged in urine samples collected from 2004 to 2018. However, a significantly higher 8-carboxygeraniol excretion per 24 h was observed in females compared to males across the sampling years from 2004 to 2012. This trend equalized in the years 2015 and 2018. We could demonstrate that 8-carboxygeraniol may be a suited biomarker for assessing the geraniol exposure in the general population. Regardless of the fact that additional, preferably population representative studies combining HBM and health examination were helpful to further elucidate the risks of a geraniol exposure, the current study adds important data for identifying time trends and body burden of geraniol in the environment and shows the ubiquitous exposure towards mixtures of sensitizing chemicals.

Glyphosate and aminomethylphosphonic acid (AMPA) in urine of children and adolescents in Germany - Human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Since the 1970s, glyphosate has become the most used herbicide of the world. The general population is ubiquitously exposed to glyphosate. Its long-term toxicity, carcinogenic potential and other health effects are controversially discussed. Even though the possible health impacts of glyphosate are of global concern, no population-wide monitoring of glyphosate was done yet. This study presents the worldwide first population-representative data on glyphosate and its metabolite aminomethylphosphonic acid (AMPA) for children and adolescents. 2144 first-morning void urine samples of 3-17-year-old children and adolescents living in Germany were analysed for concentrations of glyphosate and AMPA in the German Environmental Survey for Children and Adolescents 2014-2017 (GerESV). In 52 % of the samples (46 % for AMPA) the urinary glyphosate concentrations were above the limit of quantification of 0.1 µg/L. The geometric mean concentrations were 0.107 µg/L (0.090 µg/gcreatinine) for glyphosate and 0.100 µg/L (0.085 µg/gcreatinine) for AMPA. No clear association between exposure to glyphosate or AMPA and vegetarian diet or consumption of cereals, pulses, or vegetables could be identified. The low quantification rate and the 95th percentiles for glyphosate and AMPA of around 0.5 µg/L demonstrate an overall low exposure of the young population in Germany.

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.

Substitutes mimic the exposure behaviour of REACH regulated phthalates - A review of the German HBM system on the example of plasticizers

The population is constantly exposed to potentially harmful substances present in the environment, including inter alia food and drinking water, consumer products, and indoor air. Human biomonitoring (HBM) is a valuable tool to determine the integral, internal exposure of the general population, including vulnerable subgroups, to provide the basis for risk assessment and policy advice. The German HBM system comprises of five pillars: (1) the development of suitable analytical methods for new substances of concern, (2) cross-sectional population-representative German Environmental Surveys (GerES), (3) time trend analyses using archived samples from the Environmental Specimen Bank (ESB), (4) the derivation of health-based guidance values as a risk assessment tool, and (5) transfer of data into the European cooperation network HBM4EU. The goal of this paper is to present the complementary elements of the German HBM system and to show its strengths and limitations on the example of plasticizers. Plasticizers have been identified by EU services and HBM4EU partners as priority substances for chemical policy at EU level. Using the complementary elements of the German HBM system, the internal exposure to classical phthalates and novel alternative plasticizers can be reliably monitored. It is shown that market changes, due to regulation of certain phthalates and the rise of substitutes, are rapidly reflected in the internal exposure of the population. It was shown that exposure to DEHP, DiBP, DnBP, and BBzP decreased considerably, whereas exposure to the novel substitutes such as DPHP, DEHTP, and Hexamoll®DINCH has increased significantly. While health-based guidance values for several phthalates (esp. DnBP, DiBP, DEHP) were exceeded quite often at the turn of the millennium, exceedances today have become rarer. Still, also the latest GerES reveals the ubiquitous and concurrent exposures to many plasticizers. Of concern is that the youngest children showed the highest exposures to most of the investigated plasticizers and in some cases their levels of DiBP and DnBP still exceeded health-based guidance values. Over the last years, mixture exposures are increasingly recognized as relevant, especially if the toxicological modes of action are similar. This is supported by a cumulative risk assessment for four endocrine active phthalates which confirms the still concerning cumulative exposure in many young children. Given the adverse health effects of some phthalates and the limited toxicological knowledge of substitutes, exposure reduction and surveillance are needed on German and EU-level. Substitutes need to be monitored, to intervene if exposures are threatening to exceed acceptable levels, or if new toxicological data question their appropriateness. It is strongly recommended to reconsider the use of plastics and plasticizers.

Chemical prioritisation strategy in the European Human Biomonitoring Initiative (HBM4EU) - Development and results

The European Human Biomonitoring Initiative (HBM4EU¹) has established a European Union-wide human biomonitoring (HBM) programme to generate knowledge on human internal exposure to chemical pollutants and their potential health impacts in Europe, in order to support policy makers' efforts to ensure chemical safety and improve health in Europe. A prioritisation strategy was necessary to determine and meet the most important needs of both policy makers and risk assessors, as well as common national needs of participating countries and a broad range of stakeholders. This strategy consisted of three mains steps: 1) mapping of knowledge gaps identified by policy makers, 2) prioritisation of substances using a scoring system, and 3) generation of a list of priority substances reflective of the scoring, as well as of public policy priorities and available resources. For the first step, relevant ministries and agencies at EU and national levels, as well as members of the Stakeholder Forum each nominated up to 5 substances/substance groups of concern for policy-makers. These nominations were collated into a preliminary list of 48 substances/substance groups, which was subsequently shortened to a list of 23 after considering the total number of nominations each substance/substance group received and the nature of the nominating entities. For the second step, a panel of 11 experts in epidemiology, toxicology, exposure sciences, and occupational and environmental health scored each of the substances/substance groups using prioritisation criteria including hazardous properties, exposure characteristics, and societal concern. The scores were used to rank the 23 substances/substance groups. In addition, substances were categorised according to the level of current knowledge about their hazards, extent of human exposure (through the availability of HBM data), regulatory status and availability of analytical methods for biomarker measurement. Finally, in addition to the ranking and categorisation of the substances, the resources available for the project and the alignment with the policy priorities at European level were considered to produce a final priority list of 9 substances/substance groups for research activities and surveys within the framework of the HBM4EU project.

Pentachlorophenol and nine other chlorophenols in urine of children and adolescents in Germany - Human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Chlorophenols comprise of a large group of chemicals used inter alia for the production of biocides, pharmaceuticals, other industrial products and are used e.g. as antiseptics or wood preservatives due to their biocidal properties. Several of them are classified as toxic to aquatic life and harmful to humans by ingestion, inhalation, or dermal contact, causing skin and eye irritation. Moreover, chlorophenols are possibly carcinogenic to humans. The most prominent chlorophenol - pentachlorophenol - is carcinogenic to humans, was banned in Germany in 1989 and further regulated by the European Commission in 2006 and included in the Stockholm Convention in 2017. Some chlorophenols are persistent in the environment and are also biodegradation products of precursor substances. To evaluate the health-relevance of recent exposure and monitor the effectiveness of regulatory measures, chlorophenols were analysed in the population-representative German Environmental Survey on Children and Adolescents 2014-2017 (GerES V). First-morning void urine samples of 485 3-17-year-old children and adolescents were analysed for ten chlorophenols. Pentachlorophenol was still quantified in 87% of the children and adolescents with a geometric mean (GM) concentration of 0.19 μg/L (0.16 μg/g_crea) and a maximum concentration of 6.7 μg/L (5.4 μg/g_crea). The maximum concentration was well below the health-based guidance value HBM-I of 25 μg/L (20 μg/g_crea). 4-Monochlorophenol was quantified in all samples with a GM concentration of 1.38 μg/L (1.14 μg/g_crea). 2-Monochlorophenol, 2,4-dichlorophenol, and 2,5-dichlorophenol were quantified in 97%, 98%, and 95% of the samples, with GMs of 0.26 μg/L (0.21 μg/g_crea), 0.24 μg/L (0.20 μg/g_crea), and 0.26 μg/L (0.21 μg/g_crea). 2,6-dichlorophenol, 2,3,4-trichlorophenol, and 2,4,5-trichlorophenol were quantified in 17-25% of the samples with GMs below the limit of quantification (LOQ) of 0.1 μg/L 2,4,6-trichlorophenol was quantified in 72% of the samples (GM: 0.13 μg/L, 0.11 μg/g_crea), 2,3,4,6-tetrachlorophenol in 44% of the samples (GM < LOQ). Comparison to previous cycles of GerES revealed substantially lower exposure to most of the chlorophenols in GerES V. Exposure levels found in Germany were comparatively low in contrast to North American results.

Bisphenol A and six other environmental phenols in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Exposure to environmental phenols such as bisphenol A, benzophenones, 2-phenylphenol, triclosan, and triclocarban is of concern, because of their endocrine disrupting properties and broad application in consumer products. The current body burden of the 3-17-year-old population in Germany to these substances was assessed in first-morning void urine samples (N = 515-516) collected within the population-representative German Environmental Survey for Children and Adolescents 2014-2017 (GerES V). Bisphenol A was the most prominent phenol analysed here, ubiquitously found in almost all samples with a geometric mean (GM) concentration of 1.905 μg/L (1.669 μg/g_creatinine) and a maximum (MAX) urinary concentration of 399 μg/L. Benzophenone-3 and benzophenone-1 were quantified in 35% and 41% of the samples. GM was below the limit of quantification (LOQ) for benzophenone-3 and 0.559 μg/L (0.489 μg/g_crea) for benzophenone-1, MAX concentrations were 845 μg/L and 202 μg/L, respectively. In 16% of the samples triclosan was found in quantifiable amounts resulting in a GM below LOQ and a MAX concentration of 801 μg/L. Benzophenone-8, 2-phenylphenol and triclocarban were quantified in none or only 1% of the samples. Benzophenone-1 and -3 concentrations were found to be associated with frequent application of personal care products. A comparison with the previous cycle of the survey, GerES IV (2003-2006), showed a decrease of urinary bisphenol A concentrations, mainly in young children. Despite this decrease, the concentration of bisphenol A exceeded the human biomonitoring (HBM) value HBM-I of 0.1 mg/L in 0.11% of the samples. For triclosan, all urinary concentrations were well below the HBM-I value of 2 mg/L. To minimise environmental health risks, it is therefore necessary to maintain a further declining trend for bisphenol A and continue monitoring the exposure to environmental phenols, as well as to monitor substitutes such as bisphenol F and S.

The European human biomonitoring platform - Design and implementation of a laboratory quality assurance/quality control (QA/QC) programme for selected priority chemicals

A fundamental objective of the human biomonitoring for Europe initiative (HBM4EU) is to progress toward comparable and robust exposure data for a wide variety of prioritized chemicals in human samples. A programme for Quality Assurance/Quality Control (QA/QC) was designed in HBM4EU with the purpose of creating a network of European laboratories providing comparable analytical data of high quality. Two approaches were chosen for two sets of prioritized chemicals with different timelines: (i) Scheme 1, where interested candidate laboratories participated in multiple rounds of proficiency tests (ii) Scheme 2, where selected expert laboratories participated in three rounds of interlaboratory comparison investigations. In both cases, the results were used to identify laboratories capable of generating consistent and comparable results for sample analysis in the frame of HBM4EU. In total, 84 laboratories from 26 countries were invited to participate in Scheme 1 that covered up to 73 biomarkers from Hexamoll® DINCH, phthalates, bisphenols, per- and polyfluoroalkyl substances, halogenated flame retardants (HFRs), organophosporous flame retardants (OPFRs), polycyclic aromatic hydrocarbons (PAH), cadmium, chromium and aromatic amines. 74 of the participants were successful for at least one biomarker in Scheme 1. Scheme 2 involved 22 biomarkers and successful results were obtained by 2 expert laboratories for arsenic, 5 for acrylamide, 4 for mycotoxins, 2 for pesticides and 2 for UV-filters in skin care products. The QA/QC programme allowed the identification of major difficulties and needs in HBM analysis as well of gaining insight in the analytical capacities of European laboratories. Furthermore, it is the first step towards the establishment of a sustainable European network of HBM laboratories.

Parabens in urine of children and adolescents in Germany - human biomonitoring results of the german environmental survey 2014-2017 (GerES V)

Parabens are antimicrobial preservatives used in a wide range of consumer products such as personal care products, cosmetics, pharmaceuticals, and food. Consequently, the general population is ubiquitously exposed to these substances via dermal absorption, ingestion, and inhalation. Parabens promote estrogenic activity and are hence under assessment as endocrine disrupting substances. Urine samples from 3- to 17-year-old children and adolescents (N = 516) living in Germany were analysed for concentrations of nine parabens in the population representative German Environmental Survey for Children and Adolescents 2014-2017 (GerES V). Detection rates and urinary concentrations of the parabens decreased with increasing length of the alkyl chain. Methyl paraben was quantified in 97% of the samples with a geometric mean (GM) concentration of 7.724 μg/L (6.714 μg/g_creatinine), ethyl paraben was quantified in 69% (GM: 0.943 μg/L and 0.825 μg/g_crea), and n-propyl paraben in 31% (GM: 0.563 μg/L and 0.493 μg/g_crea). Concentrations of iso-propyl paraben, butyl paraben, iso-butyl paraben, and benzyl paraben were below the limit of quantification in most samples. Pentyl paraben and heptyl paraben were not detected in any of the samples. Paraben concentrations in urine were found to be associated with frequent usage of leave-on personal care products and cosmetics. Cumulative exposure to parabens (back-calculated daily intakes, expressed as hazard index) was found to be on a level raising concern in up to 14% of the population, mainly driven by n-propyl paraben, and depending on the level of conservativeness and point-of departures used for calculation.

Human biomonitoring in urine samples from the Environmental Specimen Bank reveals a decreasing trend over time in the exposure to the fragrance chemical lysmeral from 2000 to 2018

2-(4-tert-butylbenzyl)propionaldehyde (trade names, e.g. lysmeral or lilial) is a fragrance chemical frequently used in cosmetic products where it is labelled as Butylphenyl methylpropional. A recently developed LC-MS/MS method for the analysis of four lysmeral metabolites (tert-butylbenzoic acid (TBBA), lysmerol, lysmerylic acid, and hydroxy-lysmerylic acid) was applied to 329 urine samples from the Environmental Specimen Bank collected between 2000 and 2018. The two major metabolites TBBA and lysmerol were found in quantifiable concentrations in almost all samples in this study and correlated significantly. Hence, both analytes proved to be specific biomarkers indicating the broad exposure to lysmeral. A significant decline was found for TBBA and lysmerol for the monitored years with the most pronounced decrease from 2012 to 2015. The daily intake (DI) was used to evaluate potential health risks with respect to the derived no-effect level (DNEL) as a threshold for exposure of the general population. The median DI (1.63 μg/kg bw/d) and the 95th percentile (4.69 μg/kg bw/d) corresponded to 2.6% and 7.5% of the lowest DNEL (62.5 μg/kg bw/d for oral administration), respectively. Even though a decreasing trend in exposure was observed the data still calls for efforts to reduce the exposure towards lysmeral since metabolites of lysmeral were detected in nearly all samples and adverse effects cannot be excluded. Clearly, these results need to be substantiated by HBM campaigns in population representative samples like the German Environmental Survey in adults (GerES VI) to provide more robust data for the adult population.

Biomarkers, matrices and analytical methods targeting human exposure to chemicals selected for a European human biomonitoring initiative

The major purpose of human biomonitoring is the mapping and assessment of human exposure to chemicals. The European initiative HBM4EU has prioritized seven substance groups and two metals relevant for human exposure: Phthalates and substitutes (1,2-cyclohexane dicarboxylic acid diisononyl ester, DINCH), bisphenols, per- and polyfluoroalkyl substances (PFASs), halogenated and organophosphorous flame retardants (HFRs and OPFRs), polycyclic aromatic hydrocarbons (PAHs), arylamines, cadmium and chromium. As a first step towards comparable European-wide data, the most suitable biomarkers, human matrices and analytical methods for each substance group or metal were selected from the scientific literature, based on a set of selection criteria. The biomarkers included parent compounds of PFASs and HFRs in serum, of bisphenols and arylamines in urine, metabolites of phthalates, DINCH, OPFRs and PAHs in urine as well as metals in blood and urine, with a preference to measure Cr in erythrocytes representing Cr (VI) exposure. High performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was the method of choice for bisphenols, PFASs, the HFR hexabromocyclododecane (HBCDD), phenolic HFRs as well as the metabolites of phthalates, DINCH, OPFRs and PAHs in urine. Gas chromatographic (GC) methods were selected for the remaining compounds, e.g. GC-low resolution MS with electron capture negative ionization (ECNI) for HFRs. Both GC-MS and LC-MS/MS were suitable for arylamines. New developments towards increased applications of GC-MS/MS may offer alternatives to GC-MS or LC-MS/MS approaches, e.g. for bisphenols. The metals were best determined by inductively coupled plasma (ICP)-MS, with the particular challenge of avoiding interferences in the Cd determination in urine. The evaluation process revealed research needs towards higher sensitivity and non-invasive sampling as well as a need for more stringent quality assurance/quality control applications and assessments.

Alkyl pyrrolidone solvents N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerESV)

N-methyl-2-pyrrolidone (NMP) and its substitute N-ethyl-2-pyrrolidone (NEP) are aprotic solvents used in many technical applications, but also in carpets, and consumer products such as cleaning agents, and cosmetics. NMP and NEP are classified as reproductive toxicants. As a substance of very high concern (SVHC), NMP is included in the European REACH (Registration, Evaluation, Authorisation of Chemicals) candidate listfor authorisation. NMP and NEP metabolites were measured in more than 2100 urine samples of 3- to 17-year-old children and adolescents, participating in the population-representative German Environmental Survey for Children and Adolescents 2014-2017 (GerESV). The two NMP metabolites 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP) and 2-hydroxy-N-methylsuccinimide (2-HMSI) could be detected and quantified in all urine samples, and the two NEP metabolites 5-hydroxy-N-ethylpyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI) in 32% and 87% of the urine samples. Geometric mean concentrations were 103.1 µg/L (88.21 µg/g_creatinine) for the sum of NMP metabolites and 11.86 µg/L (10.15 µg/g_creatinine) for the sum of NEP metabolites, thus remaining below the current health-based human biomonitoring values. For NMP, highest exposure was found in young children, but exposure pathways could not be revealed. Exposure to NEP was highest in adolescents and participants with low socio-economic status or migration background. Associations to usage of personal care products suggested the choice of products to have a distinct impact on NEP exposure. The presented data can be used by the German Human Biomonitoring Commission to derive new reference values (RV95) for NMP and NEP for children and adolescents in Germany. This will facilitate to recognise changing exposure levels in this population group in Germany.

Benzene metabolite SPMA and acrylamide metabolites AAMA and GAMA in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Benzene and acrylamide are carcinogenic substances contained inter alia in tobacco smoke. The mercapturic acid metabolites of benzene, N-acetyl-S-phenyl-L-cysteine (SPMA), and of acrylamide, N-acetyl-S-(3-amino-3-oxopropyl)-cysteine (AAMA) and N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)-cysteine (GAMA), were analysed in 2260 first-morning void urine samples from children and adolescents aged 3-17 years, participating in the population-representative German Environmental Survey on Children and Adolescents, GerES V 2014-2017. SPMA was detected in 98% of the participants with a geometric mean (GM) of 0.097 μg/L urine. Smokers had about 10-fold higher levels of the benzene metabolite SPMA than non-smokers. The sample comprises of 48 self-reported smokers, mainly in the oldest age group (14-17-year-olds). Second-hand smoke exposure, living near busy or very busy roads, and using domestic fuels for heating were additionally associated with higher benzene metabolite levels. SPMA levels in GerES V were lower compared to levels found in other countries, which in part however may reflect different proportions of smokers. The acrylamide metabolites AAMA and GAMA were detected in 100% of the participants with a GM of 72.6 μg/L urine for AAMA and 15.0 μg/L urine for GAMA. Smoking children and adolescents had about 2.5-fold higher AAMA levels than non-smoking ones. The frequency of consumption of french-fried potatoes and potato crisps consumption was also positively associated with urinary AAMA and GAMA levels. Compared to the urinary AAMA and GAMA levels in Germany and other countries, levels in GerES V tended to be higher than in the few studies reported. The urinary levels of the benzene biomarker SPMA, and the acrylamide biomarkers AAMA and GAMA build the basis to derive reference values for the exposure of children and adolescents in Germany. The results reveal options for exposure reduction mainly in personal choices regarding smoking and diet, but also requiring policy to maintain efforts in non-smoking regulations and improving ambient air quality. Providing these results also to the European HBM Initiative HBM4EU will contribute to gain knowledge on the exposure of the European population, the health impact of carcinogens and thus providing support for substantiated exposure assessment.

Metabolites of 4-methylbenzylidene camphor (4-MBC), butylated hydroxytoluene (BHT), and tris(2-ethylhexyl) trimellitate (TOTM) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey GerES V (2014-2017)

The UV filter 4-methylbenzylidene camphor (4-MBC), used in cosmetics, the antioxidant butylated hydroxytoluene (BHT), used inter alia as a food additive and in cosmetics, and the plasticizer tris(2-ethylhexyl) trimellitate (TOTM), used mainly in medical devices as substitute for di-(2-ethylhexyl) phthalate (DEHP), are suspected to have endocrine disrupting effects. Human biomonitoring methods that allow for assessing the internal exposure of the general population to these substances were recently developed in a German cooperation to enhance the use of human biomonitoring. First-morning void urine samples from 3- to 17-year-old children and adolescents living in Germany were analysed for metabolites of 4-MBC (N = 447), BHT (N = 2091), and TOTM (N = 431) in the population-representative German Environmental Survey on Children and Adolescents 2014-2017 (GerES V). 4-MBC metabolites were found in quantifiable amounts only in single cases and exposure levels remained well below health-based guidance values. In contrast, ubiquitous exposure to BHT became evident with a geometric mean (GM) urinary concentration of the metabolite BHT acid of 2.346 μg/L (1.989 μg/g_creatinine) and a maximum concentration of 248 μg/L (269 μg/g_crea). The highest GM concentration was found in young children aged 3-5 years, yet no specific sources of exposure could be identified. Also, TOTM metabolites were found in quantifiable amounts only in very few samples. None of these findings could be related to previous hospital treatment or exposure via house dust. The presented results will be the basis to derive reference values for exposure of children and adolescents in Germany to BHT and will facilitate to identify changing exposure levels in the general population.

A Phased Approach for preparation and organization of human biomonitoring studies

BACKGROUND

Human biomonitoring (HBM) studies like other epidemiological studies are costly and time-consuming. They require the administration of questionnaires and collection of biological samples, putting substantial burden on the participants which may result in low participation rates. The growing importance of HBM studies in epidemiology, exposure assessment and risk assessment underline the importance of optimizing study planning, designing and implementation thus minimizing the above-mentioned difficulties.

METHODS

Based on frameworks from survey design and fieldwork preparation of the European Joint Program HBM4EU, the German Environment Surveys and the COPHES/DEMOCOPHES twin projects combined with elements of project management strategies, a Phased Approach has been developed, introducing a step-by-step guideline for the development of epidemiological studies.

RESULTS

The Phased Approach splits the process of developing a study into six phases: Phase 0 (Scoping and Planning): All aspects that are necessary to conduct a study are compiled and put on the agenda for decision-making. Phase 1 (Preparation and Testing): Instruments (e.g. questionnaires), materials (e.g. guidelines, information), and ethics and data management issues, needing thorough preparation and testing before a study can start. Phase 2 (Initiation): Organization and acquisition of necessary equipment and engaging and training personnel. Phase 3 (Implementation): All procedures that require temporal proximity to the start date of fieldwork, such as obtaining contact information of invitees. Phase 4 (Fieldwork and Analysis): Involvement of participants and chemical analysis of the collected samples. Phase 5 (Results and Evaluation): Final procedures leading to closure of the project, such as providing and communicating results.

CONCLUSIONS

The separation of the planning and conduct of human biomonitoring studies into different phases creates the basis for a structured procedure and facilitates a step-by-step approach reducing costs, warranting high participation rates and increasing quality of conduct. Emphasis is put on a comprehensive scoping phase ensuring high quality of the study design, which is indispensable for reliable results.

Long-term time trend of lead exposure in young German adults - Evaluation of more than 35 Years of data of the German Environmental Specimen Bank

Lead is a ubiquitous pollutant with well-known effects on human health. As there is no lower toxicological threshold for lead in blood and since data gaps on lead exposure still exist in many European countries, HBM data on lead is of high importance. To address this, the European Human Biomonitoring Initiative HBM4EU classified lead as a priority substance. The German Environmental Specimen Bank (German ESB) has monitored lead exposure since more than 35 years. Using data from the early 1980s to 2019 we reveal and discuss long-term trends in blood lead levels (BLLs) and current internal exposure of young adults in Germany. BLLs in young adults decreased substantially in the investigated period. As results from the ESB sampling site Muenster demonstrate, the geometric mean of BLLs of young adults decreased from 1981 (78,7 μg/L) to 2019 (10.4 μg/L) by about 87%. Trends in human exposure closely correlate with air lead levels (ALLs) provided by the European Monitoring and Evaluation Programme (EMEP). Hence, the decrease of BLLs largely reflects the drop in air lead pollution. Known associations of sex, smoking, alcohol consumption, and housing situation with BLLs are confirmed with data of the German ESB. Although internal lead exposure in Germany decreased substantially, the situation might be different in other European countries. Since 2010, BLLs of young adults in Germany levelled out at approximately 10 μg/L. The toxicity of lead even at low levels is known to cause adverse health effects especially in children following exposure of the child or the mother during pregnancy. To identify current exposure sources and to minimize future lead exposure, continuous monitoring of lead intake and exposure levels is needed.

Biomonitoring of PFOA, PFOS and PFNA in human milk from Czech Republic, time trends and estimation of infant's daily intake

BACKGROUND

Perfluoralkylated substances (PFASs) are persistent and bioaccumulative environmental contaminants. They are included on the list of emergent compounds monitored in the frame of HBM4EU project.

OBJECTIVES

To analyze PFASs levels in human milk samples collected in the period 2006 through 2017, to follow their time trends, to assess the PFASs exposure in breastfed infants, to calculate the daily intake of PFASs and to compare it with the tolerable daily/weekly) intakes and to quantify risk from exposure using the hazard quotient and hazard index approach.

MATERIAL AND METHODS

A broad spectrum of PFASs were analyzed by means of UHPLC-MS/MS in primipara human milk samples collected in four consecutive time periods 2006, 2010/11, 2014, and 2017; N = 46, 183, 164 and 232, respectively. Mothers living in urban and suburban residences were recruited after their delivery at maternity hospitals, and milk samples were taken within 2 and 8 weeks after delivery. The questionnaire was focused on possible sources of exposure, dietary habits and lifestyle.

RESULTS

Only perfluorooctane sulfonate (PFOS) and perfluorooctanoid acid PFOA (in 2017, also perfluorononanoic acid (PFNA)) were quantified in more than 90% of analyzed human milk samples. In all sampling periods, the levels of PFOA were higher than those of PFOS (p < 0.05). A significant downward temporal trend (p < 0.001) was observed for both PFOA and PFOS levels. The median concentrations in sampling years 2006, 2010/11, 2014, and 2017 were 0.075, 0.059, 0.035, and 0.023 ng/mL for PFOA and 0.045, 0.031, 0.029, and 0.020 ng/mL for PFOS, respectively. In 2017, PFNA was also quantified in 99% of samples with the median concentration of 0.007 ng/mL. The levels of PFASs correlated with maternal sea fish consumption. No maternal age-related relationship was observed. Using the tolerably daily intake (TDI) values for PFOS and PFOA set by the European Food Safety Authority (EFSA) in 2008, the calculated daily intakes from breastfeeding were clearly below these limits. Using the new, more conservative EFSA Provisional Tolerably Weekly Intake (PTWI) values set in 2018, we demonstrated a considerable exceedance of PTWI, with a hazard index above 1.

CONCLUSION

Significant time-related decreasing trends in the PFOS and PFOA levels in human milk were observed. Nevertheless, the body burden of infants from breastfeeding might pose an enhanced health risk to infants when the current PTWI values are applied. These findings strongly support the present EU efforts to phase out PFOA, its salts and PFOA related compounds. Since PFOS exposure there has still been widely detected despite PFOS usage reduction measures, the major exposure routes should be further monitored and, if possible, eliminated.

Impact of the Pandemic on NonInfected Cardiometabolic Patients: A Survey in Countries of Latin America-Rationale and Design of the CorCOVID LATAM Study

Background

The first case of coronavirus 2019 (COVID-19) in Latin America was detected on February 26th, 2020, in Brazil. Later, in June, the World Health Organization announced that the focus of the outbreak had shifted to Latin America, where countries already had poor control of indicators of noncommunicable diseases (NCDs). Concerns about coronavirus infection led to a reduced number of visits and hospitalizations in patients with NCDs, such as cardiovascular disease, diabetes, and cancer. There is a need to determine the impact of the COVID-19 pandemic on patients who have cardiometabolic diseases but do not have clinical evidence of COVID-19 infection.

Methods

The CorCOVID LATAM is a cross-sectional survey of ambulatory cardiometabolic patients with no history or evidence of COVID-19 infection. The study will be conducted by the Interamerican Society of Cardiology. An online survey composed of 38 questions using Google Forms will be distributed to patients of 13 Latin American Spanish-speaking countries from June 15th to July 15th, 2020. Data will be analyzed by country and regions. Seven clusters of questions will be analyzed: demographics, socioeconomic and educational level, cardiometabolic profile, lifestyle and habits, body-weight perception, medical follow-up and treatments, and psychological symptoms.

Results

Final results will be available upon completion of the study.

Conclusions

The present study will provide answers regarding the impact of the COVID-19 pandemic on noninfected cardiometabolic patients. Data on this topic are scarce, as it is an unprecedented threat, without short-term solutions.

Time trend of exposure to dechloranes: Plasma samples of German young adults from the environmental specimen bank collected from 1995 to 2017

Dechloranes, like Dechlorane Plus® are commonly used flame retardants identified by the EU as substances of very high concern (SVHC) because of their persistence and bioaccumulation potential. To characterize the dechlorane exposure of Germans in the last two decades, 180 archived blood plasma samples of the German Environmental Specimen Bank (students aged 20-29 years) collected at six time points between 1995 and 2017 were analyzed for four dechloranes; namely Dechlorane Plus® (syn- and anti-DDC-CO), dechlorane 602 (DDC-DBF), and dechlorane 603 (DDC-Ant). These were quantified using a GC-MS/MS method. Overall, anti- and syn-DDC-CO were detected in 88% and 98% of the samples, whereas DDC-DBF and DDC-Ant were found in 40% and 37% of the samples, respectively. The median (95th percentile) values were 1.0 ng/g lipid weight (l.w.) (3.0 ng/g l.w.). for anti-DDC-CO, 0.6 ng/g l.w (1.9 ng/g l.w.). for syn-DDC-CO, 0.1 ng/g l.w (0.6 ng/g l.w.). for DDC-DBF, and 0.1 ng/g l.w (0.2 ng/g l.w.). for DDC-Ant. The 95th percentile concentrations of the sum of syn- and anti-DDC-CO decreased from 4.2 ng/g l.w. in 1995, to 2.9 ng/g l.w. in 1999, and subsequently increased to 3.7 ng/g l.w. in 2008, and up to 5.9 ng/g l.w. in 2017. A statistically significant decrease with time was observed for DDC-DBF and DDC-Ant, but not for DDC-CO. Our medians found in blood samples in 2017 are similar to those observed in Germany in 2013/14, but higher compared to values reported in other European countries. Overall, more toxicological and monitoring data is needed to better characterize the potential impact on health.

N-methylmalonamic acid (NMMA) as metabolite of methylisothiazolinone and methylchloroisothiazolinone in 24-h urine samples of the German Environmental Specimen Bank from 2000 to 2017 - exposure and time trends

Methylisothiazolinone (MI) and the mixture of methylchloroisothiazo¬linone/methylisothiazolinone (MCI/MI, 3:1) are widespread biocides used in cosmetics, household products, paints or as disinfectant in air-conditioning systems. Exposure to these compounds has raised concerns due to their sensitizing potential, as rates of skin sensitization were reported to increase in the last decade. We have analyzed N-methylmalonamic acid (NMMA), a common metabolite of MI and MCI in 24-h urine samples of the German Environmental Specimen Bank collected from 480 participants (240 male/240 female) between the years 2000 and 2017. Using these data, we were able to calculate the overall daily intake of MI and/or MCI/MI (3:1) of the study participants and point out time trends. NMMA was determined in all urine samples investigated above the LOQ of 0.5 μg/L urine. Median and 95th percentile level of NMMA in all 24-h urine samples was 4.1 μg/g creatinine and 8.5 μg/g creatinine, respectively. This would correspond to a median and 95th percentile daily intake of 0.35 μg/kg bw and 0.71 μg/kg bw for exclusive uptake of MI and 0.64 μg/kg bw and 1.28 μg/kg bw for exclusive uptake of MCI/MI (3:1). We noted only slight variations over time for median exposures, but an increasing time trend in the 95th percentile exposure between 2006 and 2011 with a decrease in recent years, probably reflecting regulatory measures on MI and MCI/MI (3:1) in cosmetic products. Increasing knowledge on determinants of exposure to MI and/or MCI/MI (3:1) would be necessary to further lower exposure to these sensitizing compounds.

Time course of phthalate cumulative risks to male developmental health over a 27-year period: Biomonitoring samples of the German Environmental Specimen Bank

In several human biomonitoring surveys, changes in the usage patterns of phthalates have come to light, but their influence on the risks associated with combined exposures is insufficiently understood. Based on the largest study to date, the 27-year survey of urinary phthalate metabolite levels in 24-hour urine samples from the German Environmental Specimen Bank, we present a deep analysis of changing phthalate exposures on mixture risks. This analysis adopts the Hazard Index (HI) approach based on the five phthalates DBP, DIBP, BBP, DEHP and DINP. Calculations of the hazard index for each study participant included updated phthalate reference doses for anti-androgenicity (RfD_AAs) that take account of new evidence of phthalates' developmental toxicity. The Maximum Cumulative Ratio (MCR) approach was used to establish whether a subject's combined exposure was dominated by one phthalate or was influenced by several phthalates simultaneously. Generally, over the years there was a shift towards lower HIs and higher MCRs, reflecting an increased complexity of the combined exposures. The decade from 1988 to about 1999 was characterised by rather high HIs of between 3 and 7 (95th percentile) which were driven by exposure to DBP and DEHP, often exceeding their single acceptable exposures. Traditional single phthalate risk assessments would have underestimated these risks by up to 50%. From 2006 onwards, no study participant experienced exposures above acceptable levels for a single phthalate, but combined exposures were still in excess of HI = 1. From 2011 onwards most individuals stayed below HI = 1. In interpreting these results, we caution against the use of HI = 1 as an acceptable limit and develop proposals for improved and more realistic mixture risk assessments that take account of co-exposures to other anti-androgenic substances also capable of disrupting the male reproductive system. From this perspective, we regard HIs between 0.1 and 0.2 as more appropriate for evaluating combined phthalate exposures. Assessed against lowered HIs of 0.1 - 0.2, the combined phthalate exposures of most study participants exceeded acceptable levels in all study years, including 2015. Continued monitoring efforts for phthalate combinations are required to provide the basis for appropriate risk management measures.

Biomonitoring data on young adults from the Environmental Specimen Bank suggest a decrease in the exposure to the fragrance chemical 7-hydroxycitronellal in Germany from 2000 to 2018

7-Hydroxy-3,7-dimethyl-1-octanal, also known as 7-hydroxycitronellal (7-HC, CAS No. 107-75-5) is a synthetic fragrance widely used in cosmetic and hygiene products. Because of its wide spread use and its known sensitizing properties, 7-HC was selected as one of 50 chemicals within the frame of the cooperation project between the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) and the German Chemical Industry Association (VCI) to develop a suitable human biomonitoring (HBM) method in order to assess the exposure of the general population in Germany. Within this scope, the recently published analytical method for urinary 7-hydroxycitronellylic acid (7-HCA), the major metabolite of 7-HC, was applied to 329 24h-urine samples of young adults (20 to 29 years) collected between 2000 and 2018 and stored in the Environmental Specimen Bank (ESB). The widespread exposure to 7-HC as already observed in a pilot study with 40 volunteers could be confirmed with quantifiable concentrations of 7-HCA in all 329 study samples (mean: 14.9 ng/mL; median: 8.1 ng/mL). A significant, chronological decrease in 7-HCA levels was found for the monitored years (2000, 2004, 2008, 2012, 2015, 2018). The most pronounced decline occurred between 2000 and 2004 (means: 34.37 versus 23.31, medians: 20.97 versus 12.49 μg/24h; p < 0.01). On average, females exhibited higher levels of urinary 7-HCA compared to males (29.34 versus 17.21 μg/24h, p < 0.05). Based on the urinary 7-HCA excretion, the daily intake (DI) of 7-HC normalized for body weight (bw) was estimated. Over all sampling years, average DI in females was significantly higher compared to males (0.99 versus 0.46 μg/kg bw/d). Assuming dermal exposure as the main route of 7-HC intake, the mean DIs correspond to <0.1% of the derived no effect level (DNEL) of 1,100 μg/kg bw/d defined by the European Chemical Agency (ECHA). The presented results for the exposure to the widely used fragrance 7-HC in Germany can be substantiated by applying the described methodology to the representative cohort of the launched German Environmental Survey in adults (GerES VI).

Polycyclic aromatic hydrocarbons (PAH) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey 2014-2017 (GerES V)

Polycyclic aromatic hydrocarbons (PAH) mainly originate from incomplete combustion of organic materials and are, among other sources, found in traffic emissions, smoked or barbecued food, leafy vegetables, and tobacco smoke. Some PAH or their metabolites are hazardous for health and classified as carcinogenic, mutagenic, or toxic to reproduction. Urine samples from 3- to 17-year-old children and adolescents living in Germany were analysed for concentrations of metabolites of the PAH fluorene, naphthalene, phenanthrene, and pyrene in the population-representative German Environmental Survey for Children and Adolescents GerES V (2014-2017). PAH metabolites were analysed in urine samples of 516 participants and could be quantified in 88-100% of the samples. Geometric mean concentrations were: 0.785 μg/L (0.688 μg/g_creatinine) for 1-OH-naphthalene, 4.233 μg/L (3.706 μg/g_crea) for 2-OH-naphthalene, 0.139 μg/L (0.122 μg/g_crea) for 1-OH-phenanthrene, 0.085 μg/L (0.075 μg/g_crea) for 2-OH-phenanthrene, 0.131 μg/L (0.115 μg/g_crea) for 3-OH-phenanthrene, 0.045 μg/L (0.040 μg/g_crea) for 4-OH-phenanthrene, 0.058 μg/L (0.050 μg/g_crea) for 9-OH-phenanthrene, 0.511 μg/L (0.448 μg/g_crea) for Σ-OH-phenanthrene, and 0.099 μg/L (0.087 μg/g_crea) for 1-OH-pyrene. Analyses of subgroups revealed higher PAH metabolite concentrations in young children compared to adolescents, and also in residents of former East Germany compared to those living in former West Germany. Increased urinary PAH metabolite concentrations were found in participants using domestic fuel for heating or gas for cooking. Plastic objects were identified as another potential source of exposure. Urinary concentrations of naphthalene and fluorene metabolites were elevated in active smokers and to the same extent in non-smokers exposed to passive smoking. Comparison with previous cycles of GerES revealed a decrease over time and a further decline in the still significant differences in urinary PAH metabolite concentrations of participants living in former East versus West Germany.

Phthalate metabolites in urine of children and adolescents in Germany. Human biomonitoring results of the German Environmental Survey GerES V, 2014-2017

During the population representative German Environmental Survey of Children and Adolescents (GerES V, 2014-2017) 2256 first-morning void urine samples from 3 to 17 years old children and adolescents were analysed for 21 metabolites of 11 different phthalates (di-methyl phthalate (DMP), di-ethyl phthalate (DEP), butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), di-cyclohexyl phthalate (DCHP), di-n-pentyl phthalate (DnPeP), di-(2-ethylhexyl) phthalate (DEHP), di-iso-nonyl phthalate (DiNP), di-iso-decyl phthalate (DiDP) and di-n-octyl phthalate (DnOP)). Metabolites of DMP, DEP, BBzP, DiBP, DnBP, DEHP, DiNP and DiDP were found in 97%-100% of the participants, DCHP and DnPeP in 6%, and DnOP in none of the urine samples. Geometric means (GM) were highest for metabolites of DiBP (MiBP: 26.1 μg/L), DEP (MEP: 25.8 μg/L), DnBP (MnBP: 20.9 μg/L), and DEHP (cx-MEPP: 11.9 μg/L). For all phthalates but DEP, GMs were consistently higher in the 3-5 years old children than in the 14-17 years old adolescents. For DEHP, the age differences were most pronounced. All detectable phthalate biomarker concentrations were positively associated with the levels of the respective phthalate in house dust. In GerES V we found considerably lower phthalate biomarker levels than in the preceding GerES IV (2003-2006). GMs of biomarker levels in GerES V were only 18% (BBzP), 23% (MnBP), 23% (DEHP), 29% (MiBP) and 57% (DiNP) of those measured a decade earlier in GerES IV. However, some children and adolescents still exceeded health-based guidance values in the current GerES V. 0.38% of the participants had levels of DnBP, 0.08% levels of DEHP and 0.007% levels of DiNP which were higher than the respective health-based guidance values. Accordingly, for these persons an impact on health cannot be excluded with sufficient certainty. The ongoing and substantial exposure of vulnerable children and adolescents to many phthalates confirms the need of a continued monitoring of established phthalates, whether regulated or not, as well as of potential substitutes. With this biomonitoring approach we provide a picture of current individual and cumulative exposure developments and body burdens to phthalates, thus providing support for timely and effective chemicals policies and legislation.

Blood lead levels among Chinese children: The shifting influence of industry, traffic, and e-waste over three decades

In China, data relating to the historic prevalence of childhood lead poisoning suggest its pervasiveness. This review analysed published epidemiological data on blood lead levels (BLLs) of 735,271 Chinese children aged 0-6 between 1987 and 2017. Among these children, the geometric mean (GM) BLL was 95.1 μg/L (geometric SD = 1.62), and 24.1% suffered lead poisoning (BLL ≥ 100 μg/L). Importantly, there was a temporal decrease in the GM BLL value, from 182.9 μg/L in 1987-1991 to 42.4 μg/L in 2012-2017. However, a rebound was seen in the most recent two years (2016 and 2017). Moreover, the GM BLL among Chinese children has not fallen as low as U.S. children. This indicates that either (1) leaded petrol or lead based-paint exposure sources have not been adequately controlled in China, or (2) other pollution sources, such as industry, traffic, and e-waste, are impacting Chinese children. Drivers behind spatio-temporal variations were explored to provide scientific evidence regarding the prevention of childhood lead poisoning. We found that BLLs among children in the central and eastern areas of China have dropped lower than those in the western area, and that the GM BLL of children living in rural areas now exceeds children in urban areas. These reversals may be associated with the industrial decentralization policy of the late 1980s, when many heavily polluting industries and manufacturers moved away from cities on the east coast. It was discovered that the BLLs of children living in areas associated with mining have remained high (GM BLL = 155.0 μg/L for 2007-2017), and that the lead poisoning rate (LPR) has become exceptionally high in areas associated with e-waste. Finally, the review offers a data comparison with other countries, an overview of potentially influencing factors and sources, as well as some suggested prevention strategies to reduce childhood lead exposure.