Polychlorinated biphenyls (PCB) and organochlorine pesticides (OCP) in blood plasma - Results of the German environmental survey for children and adolescents 2014-2017 (GerES V)

Systematic investigation of organochlorine pesticides and polychlorinated biphenyls blood levels in Greek children from the Rhea birth cohort suggests historical exposure to DDT and through diet to DDE

The blood levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been thoroughly investigated in Greek children from the Rhea birth cohort study. This investigation aimed to assess exposure levels, explore their possible relationship with children's age and sex, and indicate potential sources of exposure. Exposure patterns and common sources of PCBs and OCPs were analyzed using bivariate and multivariate statistics. A total of 947 blood samples from study participants were analyzed for OCP and PCB exposure, with 375 samples collected at 4 years old, 239 at 6.5 years old, and 333 at 11 years old. Elevated levels of DDE were observed in 6.5-year-old children compared to corresponding levels in other European countries. Higher levels of DDE were found in 4-year-old children, with the lowest concentrations in the 11-year-old group. The DDT/DDE ratio was consistently less than 1 among all the examined subjects. These results indicate exposure to DDT and DDE both in utero and through breastfeeding and dietary intake. For the entire cohort population, the highest concentration was determined for PCB 28, followed by PCBs 138, 153, and 180. The sum of the six indicator PCBs implied low exposure levels for the majority of the cohort population. Spearman correlations revealed strong associations between PCBs and OCPs, while principal component analysis identified two different groupings of exposure. DDE exhibited a correlation with a series of PCBs (153, 156, 163, 180), indicating a combined OCP-PCB source, and an anticorrelation with others (52, 28, 101), implying a separate and competing source.

Socio-demographic inequalities influence differences in the chemical exposome among Swedish adolescents

Relatively little is known about the relationship between socio-demographic factors and the chemical exposome in adolescent populations. This knowledge gap hampers global efforts to meet certain UN sustainability goals. The present work addresses this problem in Swedish adolescents by discerning patterns within the chemical exposome and identify demographic groups susceptible to heightened exposures. Enlisting the Riksmaten Adolescents 2016-17 (RMA) study population (N = 1082) in human-biomonitoring, and using proportional odds ordinal logistic regression models, we examined the associations between concentrations of a diverse array of substances (N = 63) with the determinants: gender, age, participant/maternal birth country income per capita level, parental education levels, and geographic place of living (longitude/latitude). Participant/maternal birth country exhibited a significant association with the concentrations of 46 substances, followed by gender (N = 41), and longitude (N = 37). Notably, individuals born in high-income countries by high-income country mothers demonstrated substantially higher estimated adjusted means (EAM) concentrations of polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs) and per- and polyfluoroalkyl substances (PFASs) compared to those born in low-income countries by low-income country mothers. A reverse trend was observed for cobalt (Co), cadmium (Cd), lead (Pb), aluminium (Al), chlorinated pesticides, and phthalate metabolites. Males exhibited higher EAM concentrations of chromium (Cr), mercury (Hg), Pb, PCBs, chlorinated pesticides, BFRs and PFASs than females. In contrast, females displayed higher EAM concentrations of Mn, Co, Cd and metabolites of phthalates and phosphorous flame retardants, and phenolic substances. Geographical disparities, indicative of north-to-south or west-to-east substance concentrations gradients, were identified in Sweden. Only a limited number of lifestyle, physiological and dietary factors were identified as possible drivers of demographic inequalities for specific substances. This research underscores birth country, gender, and geographical disparities as contributors to exposure differences among Swedish adolescents. Identifying underlying drivers is crucial to addressing societal inequalities associated with chemical exposure and aligning with UN sustainability goals.

Chemical contaminants in blood and their implications in chronic diseases

Artificial chemical products are widely used and ubiquitous worldwide and pose a threat to the environment and human health. Accumulating epidemiological and toxicological evidence has elucidated the contributions of environmental chemical contaminants to the incidence and development of chronic diseases that have a negative impact on quality of life or may be life-threatening. However, the pathways of exposure to these chemicals and their involvements in chronic diseases remain unclear. We comprehensively reviewed the research progress on the exposure risks of humans to environmental contaminants, their body burden as indicated by blood monitoring, and the correlation of blood chemical contaminants with chronic diseases. After entering the human body through various routes of exposure, environmental contaminants are transported to target organs through blood circulation. The application of the modern analytical techniques based on human plasma or serum specimens is promising for determining the body burden of environmental contaminants, including legacy persistent organic pollutants, emerging pollutants, and inorganic elements. Furthermore, their body burden, as indicated by blood monitoring correlates with the incidence and development of metabolic syndromes, cancers, chronic nervous system diseases, cardiovascular diseases, and reproductive disorders. On this basis, we highlight the urgent need for further research on environmental pollution causing health problems in humans.

Development and evaluation of a comprehensive workflow for suspect screening of exposome-related xenobiotics and phase II metabolites in diverse human biofluids

Suspect and non-target screening (SNTS) methods are being promoted in order to decode the human exposome since a wide chemical space can be analysed in a diversity of human biofluids. However, SNTS approaches in the exposomics field are infra-studied in comparison to environmental or food monitoring studies. In this work, a comprehensive suspect screening workflow was developed to annotate exposome-related xenobiotics and phase II metabolites in diverse human biofluids. Precisely, human urine, breast milk, saliva and ovarian follicular fluid were employed as samples and analysed by means of ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometry (UHPLC-HRMS/MS). To automate the workflow, the "peak rating" parameter implemented in Compound Discoverer 3.3.2 was optimized to avoid time-consuming manual revision of chromatographic peaks. In addition, the presence of endogenous molecules that might interfere with the annotation of xenobiotics was carefully studied as the employment of inclusion and exclusion suspect lists. To evaluate the workflow, limits of identification (LOIs) and type I and II errors (i.e., false positives and negatives, respectively) were calculated in both standard solutions and spiked biofluids using 161 xenobiotics and 22 metabolites. For 80.3 % of the suspects, LOIs below 15 ng/mL were achieved. In terms of type I errors, only two cases were identified in standards and spiked samples. Regarding type II errors, the 7.7 % errors accounted in standards increased to 17.4 % in real samples. Lastly, the use of an inclusion list for endogens was favoured since it avoided 18.7 % of potential type I errors, while the exclusion list caused 7.2 % of type II errors despite making the annotation workflow less time-consuming.

Review of scientific literature on available methods of assessing organochlorine pesticides in the environment

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) widely used in agriculture and industry, causing serious health and ecological consequences upon exposure. This review offers a thorough overview of OCPs analysis emphasizing the necessity of ongoing work to enhance the identification and monitoring of these POPs in environmental and human samples. The benefits and drawbacks of the various OCPs analysis techniques including gas chromatography-mass spectrometry (GC-MS), gas chromatography-electron capture detector (GC-ECD), and liquid chromatography-mass spectrometry (LC-MS) are discussed. Challenges associated with validation and optimization criteria, including accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ), must be met for a method to be regarded as accurate and reliable. Suitable quality control measures, such as method blanks and procedural blanks, are emphasized. The LOD and LOQ are critical quality control measure for efficient quantification of these compounds, and researchers have explored various techniques for their calculation. Matrix interference, solubility, volatility, and partition coefficient influence OCPs occurrences and are discussed in this review. Validation experiments, as stated by European Commission in document SANTE/11813/2017, showed that the acceptance criteria for method validation of OCP analytes include ≤20 % for high precision, and 70-120 % for recovery. This may ultimately be vital for determining the human health risk effects of exposure to OCP and for formulating sensible environmental and public health regulations.

Exposure of the general French population to herbicides, pyrethroids, organophosphates, organochlorines, and carbamate pesticides in 2014-2016: Results from the Esteban study

Esteban is a nationwide cross-sectional study conducted in France in 2014-2016, including 2503 adults aged 18-74 years old and 1104 children aged 6-17 years old, as part of the French Human Biomonitoring programme. The present paper describes the biological levels of five families of pesticides analysed on random sub-samples of 900 adults and 500 children for urine concentrations, and 759 adults and 255 children for serum concentrations, and the determinants of exposure. Organophosphates, carbamates and herbicides were measured in urine by UPLC-MS/MS; chlorophenols and pyrethroids were measured in urine by GC-MS/MS; specific organochlorines were measured in serum by GC-HRMS. Multivariate analyses were performed to identify the determinants of exposure using a generalized linear model. Pyrethroid metabolites were quantified in 99% of adults and children, with the exeption of F-PBA, which was quantified in 31% of adults and 27% of children, respectively. Carbamates and some specific organophosphates were barely or not quantified. DMTP was quantified in 82% of adults and 93% of children, and γ-HCH (lindane) was quantified in almost 50% of adults and children. Concentration levels of pesticide biomarkers were consistent with comparable international studies, except for β-HCH, DMTP, and the deltamethrin metabolite Br2CA, whose levels were sometimes higher in France. Household insecticide use and smoking were also associated with higher levels of pyrethroids. All pyrethroids concentration levels were below existing health-based HBM guidance values, HBM-GVsGenPop, except for 3-PBA, for which approximately 1% and 10% of children were above the lower and upper urine threshold values of 22 μg/L and 6.4 μg/L, respectively. Esteban provides a French nationwide description of 70 pesticide biomarkers for the first time in children. It also describes some pesticide biomarkers for the first time in adults, including glyphosate and AMPA. For the latter, urine concentration levels were overall higher in children than in adults. Our results highlight a possible beneficial impact of existing regulations on adult exposure to organochlorine and organophosphate pesticides between 2006 and 2016, as concentration levels decreased over this period.

Dilute-and-shoot coupled to mixed mode liquid chromatography-tandem mass spectrometry for the analysis of persistent and mobile organic compounds in human urine

In this work, a comprehensive method for the simultaneous determination of 33 diverse persistent and mobile organic compounds (PMOCs) in human urine was developed by dilute-and-shoot (DS) followed by mixed-mode liquid chromatography coupled with tandem mass spectrometry (MMLC-MS/MS). In the sample preparation step, DS was chosen since it allowed the quantification of all targets in comparison to lyophilization. For the chromatographic separation, Acclaim Trinity P1 and P2 trimodal columns provided greater capacity for retaining PMOCs than reverse phase and hydrophilic interaction liquid chromatography. Therefore, DS was validated at 5 and 50 ng/mL in urine with both mixed mode columns at pH = 3 and 7. Regarding figures of merit, linear calibration curves (r2 > 0.999) built between instrumental quantification limits (mostly below 5 ng/mL) and 500 ng/mL were achieved. Despite only 60% of the targets were recovered at 5 ng/mL because of the dilution, all PMOCs were quantified at 50 ng/mL. Using surrogate correction, apparent recoveries in the 70-130% range were obtained for 91% of the targets. To analyse human urine samples, the Acclaim Trinity P1 column at pH = 3 and 7 was selected as a consensus between analytical coverage (i.e. 94% of the targets) and chromatographic runs. In a pooled urine sample, industrial chemicals (acrylamide and bisphenol S), biocides and their metabolites (2-methyl-4-isothiazolin-3-one, dimethyl phosphate, 6-chloropyridine-3-carboxylic acid, and ammonium glufosinate) and an artificial sweetener (aspartame) were determined at ng/mL levels. The outcomes of this work showed that humans are also exposed to PMOCs due to their persistence and mobility, and therefore, further human risk assessment is needed.

A revised concept for deriving reference values for internal exposures to chemical substances and its application to population-representative biomonitoring data in German children and adolescents 2014-2017 (GerES V)

HBM reference values, in contrast to toxicologically derived values, are statistically derived values that provide information on the exposure of the population. The exceedance frequency (if applicable for individual population groups) is often a first assessment standard for the local exposure situation for municipalities. More than 25 years have passed since the German Human Biomonitoring Commission (HBMC) formulated the first recommendations for the derivation of population-based reference values (HBM reference values, RV95) for substance concentrations based on HBM studies. A fundamental revision is timely, for several reasons. There have been considerable advances in relevant statistical methods, which meant that previously time-consuming and inaccessible procedures and calculations are now widely available. Furthermore, not all steps for the derivation of HBM reference values were clearly elaborated in the first recommendations. With this revision we intended to achieve a rigorous standardization of the entire process of deriving HBM reference values, also to realise a higher degree of transparency. In accordance with established international practice, it is recommended to use the 95th percentile of the reference distribution as the HBM reference value. To this end, the empirical 95th percentile of a suitable sample should be rounded, ensuring that the rounded value is within the two-sided 95% confidence interval of the percentile. All estimates should be based on distribution-free methods, and the confidence interval should be estimated using a bootstrap approach, if possible, according to the BCa ("bias-corrected and accelerated bootstrap"). A minimum sample size of 80 observations is considered necessary. The entire procedure ensures that the derived HBM reference value is robust against at least two extreme values and can also be used for underlying mixed distributions. If it is known in advance that certain subgroups (different age groups, smokers, etc.) show differing internal exposures, it is recommended that group-specific HBM reference values should be derived. Especially when the sample sizes for individual subgroups are too small, individual datasets with potential outliers can be excluded in advance to homogenize the reference value population. In the second part, new HBM reference values based on data of the German Environmental Survey for Children and Adolescents (GerES V, 2014-2017) were derived in accordance with the revised recommendations. The GerES V is the most recent population-representative monitoring of human exposure to pollutants in Germany on children and adolescents aged 3-17 years (N = 2294). RV95 for GerES V are reported for four subgroups (males/females and 3-11/12-17 years) for 108 different substances including phthalates and alternative plasticisers, metals, organochlorine pesticides, polychlorinated biphenyls (PCB), per- and polyfluoroalkyl substances (PFAS), parabens, aprotic solvents, chlorophenols, polycyclic aromatic hydrocarbons (PAH) and UV filter, in total 135 biomarkers. Algorithms implemented in R were used for the statistics and the determination of the HBM reference values. To facilitate a quality control of the study data, the corresponding R source code is given, together with graphical representations of results. The HBM reference values listed in this article replace earlier RV95 values derived by the HBMC for children and adolescents from data of precedent GerES studies (e.g. published in Apel et al., 2017).

Environmental and biological monitoring of organochlorine pesticides in the city of Salamanca, Mexico

The former Tekchem Industrial Unit located in the city of Salamanca, Mexico, constitutes an environmental liability in which the presence of high levels of organochlorine pesticides (OCPs) has been reported. In the present study, levels of OCPs were quantified using gas chromatography-mass spectrometry in 52 soil samples and in 88 blood samples from school-age children in the city of Salamanca. A median concentration of 70.6 ng/g (6.93-3299) was obtained for total OCPs in soil, while for the total sum of dichlorodiphenyltrichloroethane (DDT) the value was 49.6 ng/g (6.93-3276). In children, the median level of the total sum of OCPs was 390 ng/g lipid (7.34-14,895), and for the total sum of DDT was 175 ng/g lipid (< LOD-14,802). The OCPs that resulted in highest concentrations in soil were DDT and its metabolites, as well as aldrin and heptachlor epoxide, while in blood the highest levels corresponded to 4,4'-dichlorodiphenyltrichloroethane (4,4'-DDT) and its metabolites, followed by heptachlor and heptachlor epoxide. The spatial distribution of the concentrations of OCPs in soil shows that the facilities of Tekchem may be a significant potential source for the dispersion of these compounds toward the metropolitan area of Salamanca. The results obtained in the present study demonstrate the presence of OCPs in soil and in child population, providing important bases to study the problem from a broader perspective, while reiterating the importance of continuing efforts to generate resolute and precautionary measures with respect to the environmental liability of Tekchem.

Lysmeral Exposure in Children and Adolescences Participating in the German Environmental Survey (2012-2015): Integrating Sex/Gender into Analysis

Comprehensive consideration of the biological and social diversities of sex and gender as well as their interdependencies is mostly missing in human biomonitoring (HBM) studies. Using the INGER sex/gender concept as theoretical background, we analyzed differences in exposure to lysmeral, a compound commonly found as a fragrance in cosmetics, personal care, and household products, in 2294 children and adolescents in Germany using decision tree, regression, and mediation analysis. The variables "sex assigned at birth" and "age", as well as well as use of personal care products and fabric conditioner proved to have the highest explanatory value. Mediating effects of behaviour associated with societal gender expectations were observed, as the use of cosmetics correlated highly with lysmeral metabolites concentrations in girls between 6 and 17 years, with the strongest effect in adolescents between 14 and 17 years old. In the youngest age group (3-5 years) boys showed higher concentration of the metabolite tert-butylbenzoic acid (TBBA) compared to girls of the same age but only if TBBA urine concentrations were normalized on creatinine. Our study offers the first retrospective sex/gender assessment of HBM data. It demonstrates the possibilities to rethink and broaden sex/gender analysis in existing HBM-studies and highlights the need for inclusion of new sex/gender concepts in the design of new studies.

Persistent Organic Pollutant Exposure and Thyroid Function among 12-Year-Old Children

INTRODUCTION

Polychlorobiphenyls (PCBs), organochlorine pesticides (OCPs), and per- and polyfluoroalkyl substances (PFASs) are persistent organic pollutants (POPs) having numerous toxicological properties, including thyroid endocrine disruption. Our aim was to assess the impact of POPs on thyroid hormones among 12-year-old children, while taking puberty into consideration.

METHODS

Exposure to 7 PCBs, 4 OCPs, and 6 PFASs (in µg/L), and free tri-iodothyronine (fT3, pg/mL), free thyroxine (fT4, ng/dL), and thyroid-stimulating hormones (TSH, mIU/L) were assessed through blood-serum measurements at age 12 years in 249 boys and 227 girls of the PELAGIE mother-child cohort (France). Pubertal status was clinically rated using the Tanner stages. For each POP, associations were estimated using linear regression, adjusted for potential confounders.

RESULTS

Among boys, hexachlorobenzene and perfluorodecanoic acid were associated with decreased fT3 (log-scale; β [95% confidence interval] = -0.07 [-0.12,-0.02] and β = -0.03 [-0.06,-0.00], respectively). Intermediate levels of perfluorohexanesulfonic acid (PFHxS) and PCB180 were associated, respectively, with increased and decreased fT4. After stratification on pubertal status, PCBs and OCPs were associated with decreased TSH only in the more advanced Tanner stages (3-5) and with decreased fT3 among early Tanner stages (1-2). Among girls, PFHxS was associated with decreased TSH (log-scale; β = -0.15 [-0.29,-0.00]), and perfluorooctanoic acid was associated with decreased fT3 (β2nd_tercile = -0.06 [-0.10,-0.03] and β3rd_tercile = -0.04 [-0.08,-0.00], versus. 1st tercile).

DISCUSSION

This cross-sectional study highlights associations between some POPs and thyroid function disruption, which appears consistent with the literature. Considering that the associations were sex-specific and moderated by pubertal status in boys, complex endocrine interactions are likely involved.

Chemical Mixtures in the EU Population: Composition and Potential Risks

Regulating chemical mixtures is a complex scientific and policy task. The aim of this study was to investigate typical mixtures and their potential risks based on internal exposure levels in the European population. Based on human biomonitoring (HBM) data made available via the HBM4EU project, we derived generic mixtures representative of a median (P50) and a worst-case scenario (P95) for adults and children. We performed a mixture risk assessment based on HBM concentrations, health-based guidance values (HBGVs) as internal thresholds of concern, and the conservative assumption of concentration addition applied across different toxicological endpoints. Maximum cumulative ratios (MCRs) were calculated to characterize the mixture risk. The mixtures comprise 136 biomarkers for adults and 84 for children, although concentration levels could be quantified only for a fraction of these. Due to limited availability of HBGVs, the mixture risk was assessed for a subset of 20 substance-biomarker pairs for adults and 17 for children. The mixture hazard index ranged from 2.8 (P50, children) to 9.2 (P95, adults). Six to seven substances contributed to over 95% of the total risk. MCR values ranged between 2.6 and 5.5, which is in a similar range as in previous studies based on human external exposures assessments. The limited coverage of substances included in the calculations and the application of a hazard index across toxicological endpoints argue for caution in the interpretation of the results. Nonetheless the analyses of MCR and MAF_ceiling can help inform a possible mixture assessment factor (MAF) applicable to single substance risk assessment to account for exposure to unintentional mixtures.

Internal exposure of Flemish teenagers to environmental pollutants: Results of the Flemish Environment and Health Study 2016-2020 (FLEHS IV)

The Flemish Environment and Health Study (FLEHS) collects information on internal exposure to a broad range of environmental chemicals in the general population in Flanders, the Northern region of Belgium. The aim is to establish biomonitoring exposure distributions for the general population in support of public health and environmental policy, environmental risk assessment and risk management decisions. In 2017-2018, urine and blood samples were collected from 428 teenagers by a stratified clustered two stage randomized design. Samples were analyzed for a broad range of biomarkers related to exposure to chlorinated and newer pesticides, brominated and organophosphate flame retardants (BFR/OPFR), polychlorinated biphenyls (PCBs), bisphenols, phthalates and alternative plasticizers, per-and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), benzene, metals and trace elements. The geometric mean levels and percentiles of the distribution were estimated for each biomarker, for the whole study population and following stratification for sex, the household educational attainment and the residence area's urbanicity. Geometric means of biomarkers of lead, dichlorodiphenyltrichloroethane (DDT), PCBs, PAHs, regulated phthalates and bisphenol A (BPA) were lower than in the previous FLEHS cycles. Most biomarker levels were below health-based guidance values (HB-GVs). However, HB-GVs of urinary arsenic, blood lead, blood cadmium, sum of serum perfluorooctane sulfonate (PFOS) and perfluoro-1-hexanesulfonate (PFHxS) and the urinary pyrethroid metabolite (3-PBA) were exceeded in respectively 25%, 12%, 39.5%, 10% and 22% of the teenagers. These results suggest that the levels of exposure in the Flemish population to some environmental chemicals might be of concern. At the same time, we noticed that biomarkers for BPA substitutes, metabolites of OPFRs, an expanded list of PFAS, glyphosate and its metabolite could be measured in substantial proportions of participants. Interpretation of these levels in a health-risk context remains uncertain as HB-GVs are lacking. Household educational attainment and residential urbanicity were significant exposure determinants for many biomarkers and could influence specific biomarker levels up to 70% as shown by multiple regression analysis. The research consortium also took care of the broader external communication of results with participants, policy makers, professional groups and civil society organizations. Our study demonstrated that teenagers are exposed to a wide range of chemicals, it demonstrates the success of public policies to reduce exposure but also points to concern and further priorities and needs for follow up.

Plasma levels of unintentionally produced non-Aroclor polychlorinated biphenyl (PCB) congeners in workers from the silicone rubber industry

The unintentional release of non-Aroclor-PCBs 47, PCB 68 and PCB 51 by a silicone manufacturing company in North Rhine-Westphalia, Germany, due to the use of bis-(2,4-dichlorobenzoyl)peroxide (2,4-DCBP) as an initiator has raised serious concerns about the possible uptake of these congeners by workers in silicone rubber production. We have conducted a pilot study in Germany to quantify these congeners in plasma samples of employees working in and handling silicone rubber during production and electrical cable manufacturing. A total of 117 plasma samples were collected from workers in 7 companies and 84 plasma samples from control subjects not working in silicone industry. PCB 47 and PCB 68 were detected in plasma above the limit of quantification (0.01 μg/L) in 84% and 66% of the silicone industry workers, respectively, whereas both congeners were undetectable in plasma of the control group. The maximum levels for PCB 47 were 2.56 μg/L and for PCB 68 were 0.42 μg/L. PCB 51 could not be determined in any plasma sample. Plasma samples of workers making electric cables had in general lower levels than those from workers making silicone rubber. Due to the high persistence of PCBs and the poorly defined toxicological properties of PCB 47 and PCB 68, a replacement of 2,4-DCBP as initiator in silicone rubber production should be considered. Given the large market for silicone products, our results might have a global impact on silicone industry.

Identifying emerging environmental concerns from long-chain chlorinated paraffins towards German ecosystems

Germany is one of several major European producers of chlorinated paraffins (CPs). This study showed that not only the legacy short-chain products (SCCPs, C_10-13), but also the current-use medium- and long-chain products (MCCPs, C_14-17; LCCPs, C_>17) as well as the very-short-chain impurities (vSCCPs, C_<10) are ubiquitous in the 72 samples collected from the coastal, terrestrial, and freshwater ecosystems across the country. The concentrations of LCCPs surpassed those of the other CPs in 40% of the biota samples. Archived bream samples collected downstream of a CP-manufacturing factory showed decreasing temporal trends of (v)SCCPs and relatively constant levels of MCCPs from 1995 to 2019; however, the overall levels of LCCPs have increased by 290%, reflecting the impact of chemical regulation policies on changes in CP production. A visualization algorithm was developed for integrating CP results from various matrices to illustrate spatial tendencies of CP pollution. Higher levels of (v)SCCPs were indicated in the former West Germany region, while MCCP and LCCP concentrations did not seem to differ between former East and West Germany, suggesting relatively equal production and use of these chemicals after the German Reunification. The results provide an early warning signal of environmental concerns from LCCPs on the eve of their booming global production and use.

Mixed Exposure of Persistent Organic Pollutants Alters Oxidative Stress Markers and Mitochondrial Function in the Tail of Zebrafish Depending on Sex

Persistent organic pollutants (POPs) are lipid-soluble toxins that are not easily degraded; therefore, they accumulate in the environment and the human body. Several studies have indicated a correlation between POPs and metabolic diseases; however, their effects on mitochondria as a central organelle in cellular metabolism and the usage of mitochondria as functional markers for metabolic disease are barely understood. In this study, a zebrafish model system was exposed to two subclasses of POPs, organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), under two different conditions (solitary OCPs or OCPs with PCBs (Aroclor 1254)), and changes in the oxidative stress marker levels and mitochondrial enzyme activities in the electron transport chain of the tail were measured to observe the correlation between POPs and representative biomarkers for metabolic disease. The results indicated different responses upon exposure to OCPs and OCPs with Aroclor 1254, and accelerated toxicity was observed following exposure to mixed POPs (OCPs with Aroclor 1254). Males were more sensitive to changes in the levels of oxidative stress markers induced by POP exposure, whereas females were more susceptible to the toxic effects of POPs on the levels of mitochondrial activity markers. These results demonstrate that the study reflects real environmental conditions, with low-dose and multiple-toxin exposure for a long period, and that POPs alter major mitochondrial enzymes’ functions with an imbalance of redox homeostasis in a sex-dependent manner.

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.

The German Environmental Survey for Children and Adolescents 2014-2017 (GerES V) - Study population, response rates and representativeness

The German Environmental Survey (GerES) is a population-representative, cross-sectional study on environmental exposures of the general population of Germany. GerES has repeatedly been conducted since 1985 by the German Environment Agency (UBA) in close collaboration with the Health Interview and Examination Surveys of the Robert Koch Institute (RKI). In the German Environmental Survey for Children and adolescents 2014-2017 (GerES V) pollutants and other environmental stressors were measured in human samples as well as in the homes of 3- to 17-year-old children and adolescents. Interviews were conducted about health-related behaviors and living conditions. The GerES V basic program encompassed examinations of whole blood, blood plasma, morning urine and drinking water samples, measurements of ultrafine particles and noise levels, comprehensive standardized interviews, and self-administrated questionnaires. Additional modules on volatile organic compounds and aldehydes, particulate matter (PM_2.5) in indoor air, organic compounds in drinking water and pollutants in house dust were conducted in subsamples. Potential GerES V participants were identified and attained by the RKI from those participants who were examined and interviewed for the cross-sectional component of the second follow-up to the German Health Interview and Examination Survey for Children and Adolescents (KiGGS Wave 2). The gross sample of GerES V comprised 3031 children and adolescents of which 2294 finally took part in the survey. This equals a total response rate of 75.7 %. Response rates varied, depending on region, type of municipality, age and sex, from 66.0 % to 78.3 %. By calculating individual case weights, discrepancies due to sample design and non-response between the GerES V sample and the whole population could be considered in statistical analysis. Therefore, the representativeness of the GerES V results with regard to age, sex, community size and region was assured.

Characterization of the Metabolic Pathways of 4-Chlorobiphenyl (PCB3) in HepG2 Cells Using the Metabolite Profiles of Its Hydroxylated Metabolites

The characterization of the metabolism of lower chlorinated PCB, such as 4-chlorobiphenyl (PCB3), is challenging because of the complex metabolite mixtures formed in vitro and in vivo. We performed parallel metabolism studies with PCB3 and its hydroxylated metabolites to characterize the metabolism of PCB3 in HepG2 cells using nontarget high-resolution mass spectrometry (Nt-HRMS). Briefly, HepG2 cells were exposed for 24 h to 10 μM PCB3 or its seven hydroxylated metabolites in DMSO or DMSO alone. Six classes of metabolites were identified with Nt-HRMS in the culture medium exposed to PCB3, including monosubstituted metabolites at the 3'-, 4'-, 3-, and 4- (1,2-shift product) positions and disubstituted metabolites at the 3',4'-position. 3',4'-Di-OH-3 (4'-chloro-3,4-dihydroxybiphenyl), which can be oxidized to a reactive and toxic PCB3 quinone, was a central metabolite that was rapidly methylated. The resulting hydroxylated-methoxylated metabolites underwent further sulfation and, to a lesser extent, glucuronidation. Metabolomic analyses revealed an altered tryptophan metabolism in HepG2 cells following PCB3 exposure. Some PCB3 metabolites were associated with alterations of endogenous metabolic pathways, including amino acid metabolism, vitamin A (retinol) metabolism, and bile acid biosynthesis. In-depth studies are needed to investigate the toxicities of PCB3 metabolites, especially the 3',4'-di-OH-3 derivatives identified in this study.

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.

Polychlorinated biphenyl congener 180 (PCB 180) regulates mitotic clonal expansion and enhances adipogenesis through modulation of C/EBPβ SUMOylation in preadipocytes

PCB 180 is a typical non-dioxin-like polychlorinated biphenyl (NDL-PCB). It is one of the most prevalent PCB-congeners found in human adipose tissue. However, the role of PCB 180 in obesity remains poorly understood. The aim of this study was to explore the adipogenic effect and mechanism of PCB 180. Significant enhancement in adipogenesis was observed when differentiating murine 3T3-L1 preadipocytes or human preadipocytes-visceral (HPA-v) that were exposed to PCB 180. Furthermore, exposure to PCB 180 during the first two days was critical to the adipogenic effect. According to results from sequential cell cycle analyses, cell counting, BrdU incorporation, and cyclin D1, cyclin B1, and p27 protein quantification, PCB 180 was found to enhance mitotic clonal expansion (MCE) during early adipogenic differentiation. Molecular mechanistic investigation revealed that PCB 180 promoted accumulation of the C/EBPβ protein, a key regulator that controls MCE. Finally, it was found that PCB 180 mitigated degradation of the C/EBPβ protein by repressing the SUMOylation and subsequent ubiquitination of C/EBPβ by the upregulation of SENP2. In summary, it was shown for the first time that PCB 180 facilitated adipogenesis by alleviating C/EBPβ protein SUMOylation. This result provides novel evidence regarding obesogenic effect of PCB 180.

Spatial, temporal, and inter-compartmental environmental monitoring of lipophilic pollutants by virtual organisms

Sampling points belonging to the Harz National Park river system, Germany, were selected between the period of 2014 and 2017 for monitoring polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in water, air, and sediment. Triolein-containing Virtual Organisms (VO) were employed to assess the levels of chemicals in water, air and triolein as surrogate for natural fat. To avoid overestimation of the concentrations 20 performance reference compounds (PRCs)-16 PRCs-PAHs and 4 PRCs-PCBs were covering the range of properties of native compounds. Results manifested the highest concentration of individual PAH as follows: 31 ng fluoranthene/L water, 3600 ng pyrene/g fat, 62 ng phenanthrene/m³ air and 2800 ng fluoranthene/g dw sediment. All PCBs and OCPs values were below above mentioned PAH concentrations and far below EU-limit levels. Environmental partition of chemicals was investigated by calculating fugacity, suggesting a mass transport from water to air. Only quite volatile compounds such as hexachlorobutadiene showed higher fugacity in air. Ratios of sediment/water concentrations and log Kow within individual sampling periods at Holtemme River exhibited strong linear relationships. Interestingly, during summer months of the years water and fat contents well correlate to the flow rates of Holtemme River. Our results show that VO can be successfully used as a tool for ongoing exposure assessment studies and predictions of worst case levels in food and nutrition.

A new proposal for the determination of polychlorinated biphenyls in environmental water by using host-guest adsorption

Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants whose wide industrial use has been banned over the years in most countries due to their persistence and bioaccumulation. In fact, the International Agency for Research on Cancer defined them in 2016 as carcinogenic to humans based on sufficient evidence of an increased risk of cancer, being children and pregnant or lactating women the most vulnerable population subgroups. In this work, a new alternative for the determination of polychlorinated biphenyls (PCB28, PCB52, PCB101, PCB138, PCB153, and PCB180) in water samples has been developed by using a cyclodextrin-containing silica microparticulated material as an adsorbent in solid-phase extraction. Gas chromatography coupled to an electron capture detector has been used in the quantification step. The methodology allows quantifying polychlorinated biphenyls at very trace levels, with limits of detection between 0.2 and 1.7 ng L^-1. Other parameters such as the repeatability, with coefficients of variation lower than 11%, were likewise established. To end, real water samples were analyzed, and the results were comparable with those obtained with a reference method. The proposed methodology can be utilized for assessing the presence of these compounds in the environment and can come in handy for evaluation and remediation purposes.