A proposal for assessing study quality: Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument

Biomonitoring of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide: A global view

We conducted a literature review of urinary 2,4-D in populations not associated with a herbicide application. Of the 33 studies identified, the median/mean concentrations were similar for children, adults, and pregnant women regardless of geography. Individuals with highest concentrations may have had opportunities to directly contact 2,4-D outside of an application. Most studies were conducted in populations in North America and did not examine potential sources of 2,4-D, or what factors might influence higher or lower urinary 2,4-D concentrations. In the future, prioritizing the examination of 2,4-D biomonitoring in other regions and collecting information on sources and factors influencing exposures would better our understanding of 2,4-D exposures globally. In all the studies reviewed the concentrations of urinary 2,4-D observed were orders of magnitude below the US regulatory endpoints, suggesting that people are not being exposed to 2,4-D at levels high enough to result in adverse health effects.

A Comparison of In Vitro Points of Departure with Human Blood Levels for Per- and Polyfluoroalkyl Substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are widely used, and their fluorinated state contributes to unique uses and stability but also long half-lives in the environment and humans. PFAS have been shown to be toxic, leading to immunosuppression, cancer, and other adverse health outcomes. Only a small fraction of the PFAS in commerce have been evaluated for toxicity using in vivo tests, which leads to a need to prioritize which compounds to examine further. Here, we demonstrate a prioritization approach that combines human biomonitoring data (blood concentrations) with bioactivity data (concentrations at which bioactivity is observed in vitro) for 31 PFAS. The in vitro data are taken from a battery of cell-based assays, mostly run on human cells. The result is a Bioactive Concentration to Blood Concentration Ratio (BCBCR), similar to a margin of exposure (MoE). Chemicals with low BCBCR values could then be prioritized for further risk assessment. Using this method, two of the PFAS, PFOA (Perfluorooctanoic Acid) and PFOS (Perfluorooctane Sulfonic Acid), have BCBCR values < 1 for some populations. An additional 9 PFAS have BCBCR values < 100 for some populations. This study shows a promising approach to screening level risk assessments of compounds such as PFAS that are long-lived in humans and other species.

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.

Interpreting biomonitoring data: Introducing the international human biomonitoring (i-HBM) working group's health-based guidance value (HB2GV) dashboard

Human biomonitoring (HBM) data measured in specific contexts or populations provide information for comparing population exposures. There are numerous health-based biomonitoring guidance values, but to locate these values, interested parties need to seek them out individually from publications, governmental reports, websites and other sources. Until now, there has been no central, international repository for this information. Thus, a tool is needed to help researchers, public health professionals, risk assessors, and regulatory decision makers to quickly locate relevant values on numerous environmental chemicals. A free, on-line repository for international health-based guidance values to facilitate the interpretation of HBM data is now available. The repository is referred to as the "Human Biomonitoring Health-Based Guidance Value (HB2GV) Dashboard". The Dashboard represents the efforts of the International Human Biomonitoring Working Group (i-HBM), affiliated with the International Society of Exposure Science. The i-HBM's mission is to promote the use of population-level HBM data to inform public health decision-making by developing harmonized resources to facilitate the interpretation of HBM data in a health-based context. This paper describes the methods used to compile the human biomonitoring health-based guidance values, how the values can be accessed and used, and caveats with using the Dashboard for interpreting HBM data. To our knowledge, the HB2GV Dashboard is the first open-access, curated database of HBM guidance values developed for use in interpreting HBM data. This new resource can assist global HBM data users such as risk assessors, risk managers and biomonitoring programs with a readily available compilation of guidance values.

Considerations towards the better integration of epidemiology into quantitative risk assessment

Environmental epidemiology has proven critical to study various associations between environmental exposures and adverse human health effects. However, there is a perception that it often does not sufficiently inform quantitative risk assessment. To help address this concern, in 2017, the Health and Environmental Sciences Institute initiated a project engaging the epidemiology, exposure science, and risk assessment communities with tripartite representation from government agencies, industry, and academia, in a dialogue on the use of environmental epidemiology for quantitative risk assessment and public health decision making. As part of this project, four meetings attended by experts in epidemiology, exposure science, toxicology, statistics, and risk assessment, as well as one additional meeting engaging funding agencies, were organized to explore incentives and barriers to realizing the full potential of epidemiological data in quantitative risk assessment. A set of questions was shared with workshop participants prior to the meetings, and two case studies were used to support the discussion. Five key ideas emerged from these meetings as areas of desired improvement to ensure that human data can more consistently become an integral part of quantitative risk assessment: 1) reducing confirmation and publication bias, 2) increasing communication with funding agencies to raise awareness of research needs, 3) developing alternative funding channels targeted to support quantitative risk assessment, 4) making data available for reuse and analysis, and 5) developing cross-disciplinary and cross-sectoral interactions, collaborations, and training. We explored and integrated these themes into a roadmap illustrating the need for a multi-stakeholder effort to ensure that epidemiological data can fully contribute to the quantitative evaluation of human health risks, and to build confidence in a reliable decision-making process that leverages the totality of scientific evidence.

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.

Reproducibility of the Blood and Urine Exposome: A Systematic Literature Review and Meta-Analysis

Endogenous and exogenous metabolite concentrations may be susceptible to variation over time. This variability can lead to misclassification of exposure levels and in turn to biased results. To assess the reproducibility of metabolites, the intraclass correlation coefficient (ICC) is computed. A literature search in three databases from 2000 to May 2021 was conducted to identify studies reporting ICCs for blood and urine metabolites. This review includes 192 studies, of which 31 studies are included in the meta-analyses. The ICCs of 359 single metabolites are reported, and the ICCs of 10 metabolites were meta-analyzed. The reproducibility of the single metabolites ranges from poor to excellent and is highly compound-dependent. The reproducibility of bisphenol A (BPA), mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-2-ethylhexyl phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-benzyl phthalate (MBzP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), methylparaben, and propylparaben is poor to moderate (ICC median: 0.32; range: 0.15-0.49), and for 25-hydroxyvitamin D [25(OH)D], it is excellent (ICC: 0.95; 95% CI, 0.90-0.99). Pharmacokinetics, mainly the half-life of elimination and exposure patterns, can explain reproducibility. This review describes the reproducibility of the blood and urine exposome, provides a vast dataset of ICC estimates, and hence constitutes a valuable resource for future reproducibility and clinical epidemiologic studies.

The Use of Human Biomonitoring to Assess Occupational Exposure to PAHs in Europe: A Comprehensive Review

Polycyclic aromatic hydrocarbons (PAHs) are among the chemicals with proven impact on workers' health. The use of human biomonitoring (HBM) to assess occupational exposure to PAHs has become more common in recent years, but the data generated need an overall view to make them more usable by regulators and policymakers. This comprehensive review, developed under the Human Biomonitoring for Europe (HBM4EU) Initiative, was based on the literature available from 2008-2022, aiming to present and discuss the information on occupational exposure to PAHs, in order to identify the strengths and limitations of exposure and effect biomarkers and the knowledge needs for regulation in the workplace. The most frequently used exposure biomarker is urinary 1-hydroxypyrene (1-OH-PYR), a metabolite of pyrene. As effect biomarkers, those based on the measurement of oxidative stress (urinary 8-oxo-dG adducts) and genotoxicity (blood DNA strand-breaks) are the most common. Overall, a need to advance new harmonized approaches both in data and sample collection and in the use of appropriate biomarkers in occupational studies to obtain reliable and comparable data on PAH exposure in different industrial sectors, was noted. Moreover, the use of effect biomarkers can assist to identify work environments or activities of high risk, thus enabling preventive risk mitigation and management measures.

CpG site-specific methylation as epi-biomarkers for the prediction of health risk in PAHs-exposed populations

Environmental insults can lead to alteration in DNA methylation of specific genes. To address the role of altered DNA methylation in prediction of polycyclic aromatic hydrocarbons (PAHs) exposure-induced genetic damage, we recruited two populations, including diesel engine exhausts (low-level) and coke oven emissions (high-level) exposed subjects. The positive correlation was observed between the internal exposure marker (1-hydroxypyrene) and the extents of DNA damage (P < 0.05). The methylation of representative genes, including TRIM36, RASSF1a, and MGMT in peripheral blood lymphocytes was quantitatively examined by bisulfite-pyrosequencing assay. The DNA methylation of these three genes in response to PAHs exposure were changed in a CpG-site-specific manner. The identified hot CpG site-specific methylation of three genes exhibited higher predictive power for DNA damage than the respective single genes in both populations. Furthermore, the dose-response relationship analysis revealed a nonlinear U-shape curve of TRIM36 or RASSF1a methylation in combined population, which led to determination of the threshold of health risk. Furthermore, we established a prediction model for genetic damage based on the unidirectional-alteration MGMT methylation levels. In conclusion, this study provides new insight into the application of multiple epi-biomarkers for health risk assessment upon PAHs exposure.

Urinary levels of phthalate, bisphenol, and paraben and allergic outcomes in children: Korean National Environmental Health Survey 2015-2017

BACKGROUND

Phthalates, bisphenols and parabens have been widely used in household and personal-care products. Their endocrine disrupting, sensitizing and antimicrobial properties might play a role in the occurrence of allergic diseases. However, the effects of these chemicals, particularly on humans, are relatively underexplored.

OBJECTIVES

This study aimed to report the concentrations of phthalate, bisphenol and paraben in urine of Korean children, and assess their relationship with allergic outcomes.

METHODS

Data obtained from nationally representative Korean children, a total of 1458 children between 3 and 11 years of age recruited in the Korean National Environmental Health Survey (3 rd round of KoNEHS 2015-2017), were analyzed. Associations of urinary phthalate metabolites, bisphenols, and parabens levels with atopic dermatitis and allergic rhinitis was examined by grouped into preschool (aged 3-5 years) and school children (aged 6-11 years). Allergic outcomes were obtained through questionnaires answered by their caregivers.

RESULTS

Atopic dermatitis was associated with urinary metabolites of DEHP, BzBP, DINP, and DIDP, and MeP and PrP in preschool children, BPA and PrP in school children. Allergic rhinitis was associated with MeP and PrP in preschool children, and metabolites of DEHP, MeP and PrP in school children. The association of urinary chemicals with atopic dermatitis and allergic rhinitis were different by gender, especially in preschool children.

CONCLUSION

Urinary phthalates, BPA and parabens levels in the Korean children were related with atopic dermatitis and allergic rhinitis. Considering the importance of allergic diseases in children, the public health implications of exposure to these chemicals warrant further studies. Given the cross-sectional design and confounding variables, the results of this study should be interpreted with caution.

Providing Biological Plausibility for Exposure-Health Relationships for the Mycotoxins Deoxynivalenol (DON) and Fumonisin B1 (FB1) in Humans Using the AOP Framework

Humans are chronically exposed to the mycotoxins deoxynivalenol (DON) and fumonisin B1 (FB1), as indicated by their widespread presence in foods and occasional exposure in the workplace. This exposure is confirmed by human biomonitoring (HBM) studies on (metabolites of) these mycotoxins in human matrices. We evaluated the exposure-health relationship of the mycotoxins in humans by reviewing the available literature. Since human studies did not allow the identification of unequivocal chronic health effects upon exposure to DON and FB1, the adverse outcome pathway (AOP) framework was used to structure additional mechanistic evidence from in vitro and animal studies on the identified adverse effects. In addition to a preliminary AOP for DON resulting in the adverse outcome (AO) 'reduced body weight gain', we developed a more elaborated AOP for FB1, from the molecular initiating event (MIE) 'inhibition of ceramide synthases' leading to the AO 'neural tube defects'. The mechanistic evidence from AOPs can be used to support the limited evidence from human studies, to focus FB1- and DON-related research in humans to identify related early biomarkers of effect. In order to establish additional human exposure-health relationships in the future, recommendations are given to maximize the information that can be obtained from HBM.

Elements to increase translation in pyrethroid epidemiology research: A review

Pyrethroid insecticides have been the subject of numerous epidemiology studies in the past two decades. We examined the pyrethroids epidemiology literature published between 2016 and 2021. Our objective with this exercise was to inform interested readers regarding information on methodological elements that strengthen a study's use for translation (i.e., use in risk assessment) and to describe aspects of future research methods that could improve utility for decision-making. We focused on the following elements: (i) study design that provided evidence that pyrethroid exposure preceded the outcome, (ii) evidence that the method used for exposure characterization was reliable and sufficiently accurate for the intended purpose, and (iii) use of a robust approach for outcome ascertainment. For each of the 74 studies identified via the literature search, we categorized the methodological elements as Acceptable or Supplemental. A study with three Acceptable elements was considered Relevant for risk assessment purposes. Based on our evaluative approach, 18 (24%) of the 74 publications were considered to be Relevant. These publications were categorized as Acceptable for all three elements assessed: confirmed exposure (N = 24), confirmed outcome (N = 64), exposure preceded the outcome (N = 44). Three of these studies were birth cohorts. There were 15 Relevant publications of adults which included 10 Agricultural Health Study cohort publications of self-reported permethrin. Overall, the majority of the reviewed studies used methods that did not permit a determination that pyrethroid exposure preceded the outcome, and/or did not utilize robust methods for exposure assessment and outcome ascertainment. There is an opportunity for investigators and research sponsors to build on the studies reviewed here and to incorporate more translational approaches to studying exposure/outcome associations related to pesticides and other chemicals.

Endocrine disruptors: Challenges and future directions in epidemiologic research

Public concern about the impact of endocrine disrupting chemicals (EDCs) on both humans and the environment is growing steadily. Epidemiologic research provides key information towards our understanding of the relationship between environmental exposures like EDCs and human health outcomes. Intended for researchers in disciplines complementary to epidemiology, this paper highlights the importance and challenges of epidemiologic research in order to present the key elements pertaining to the design and interpretation of an epidemiologic study on EDCs. The conduct of observational studies on EDCs derives from a thoughtful research question, which will help determine the subsequent methodological choices surrounding the careful selection of the study population (including the comparison group), the adequate ascertainment of exposure(s) and outcome(s) of interest, and the application of methodological and statistical concepts more specific to epidemiology. The interpretation of epidemiologic results may be arduous due to the latency occurring between EDC exposure and certain outcome(s), the complexity in capturing EDC exposure(s), and traditional methodological and statistical issues that also deserve consideration (e.g., confounding, effect modification, non-monotonic responses). Moving forward, we strongly advocate for an integrative approach of expertise in the fields of epidemiology, exposure science, risk assessment and toxicology to adequately study the health risks associated with EDCs while tackling their challenges.

Environmental epidemiology and risk assessment: Exploring a path to increased confidence in public health decision-making

Throughout history, environmental epidemiology has proven crucial to identify certain threats to human health and to provide a basis for the development of life-saving public health policies. However, epidemiologists are facing challenges when studying tenuous threats such as environmental exposure to chemicals, whose association with adverse health effects may be difficult to characterize. As a result, epidemiological data can seldom be fully leveraged for quantitative risk assessment and decision-making. Despite two decades of efforts to improve a more systematic integration of human data to evaluate human health risks, assessors still heavily rely on animal data to do so, while epidemiology plays more of a secondary role. Although the need for more and better collaboration between risk assessors and epidemiologists is widely recognized, both fields tend to remain siloed. In 2017, the Health and Environmental Sciences Institute initiated a project engaging the epidemiology, exposure science, and regulatory communities with tripartite representation from regulators, industry, and academia in a dialogue on the use of environmental epidemiology for regulatory decision-making. Several focus groups attended by epidemiology, exposure science, and risk assessment experts were organized to explore incentives and barriers to collaboration, to ultimately bridge the gap between the various disciplines, and to realize the full potential of epidemiological data in risk assessment. Various ideas that have emerged from these meetings could help ensure the better integration of epidemiological data in quantitative risk assessment and contribute to building confidence in a robust and science-based regulatory decision-making process.

Trends in environmental chemical concentrations in the Canadian population: Biomonitoring data from the Canadian Health Measures Survey 2007-2017

Ten years of nationally representative biomonitoring data collected between 2007 and 2017 are available from the Canadian Health Measures Survey (CHMS). These data establish baseline environmental chemical concentrations in the general population. Here we sought to evaluate temporal trends in environmental chemical exposures in the Canadian population by quantifying changes in biomarker concentrations measured in the first five two-year cycles of the CHMS. We identified 39 chemicals that were measured in blood or urine in at least three cycles and had detection rates over 50% in the Canadian population. We calculated geometric mean concentrations for each cycle using the survey weights provided. We then conducted analyses of variance to test for linear trends over all cycles. We also calculated the percent difference in geometric means between the first and most recent cycle measured. Of the 39 chemicals examined, we found statistically significant trends across cycles for 21 chemicals. Trends were decreasing for 19 chemicals from diverse chemical groups, including metals and trace elements, phenols and parabens, organophosphate pesticides, per- and polyfluoroalkyl substances, and plasticizers. Significant reductions in chemical concentrations included di-2-ethylhexyl phthalate (DEHP; 75% decrease), perfluorooctane sulfate (PFOS; 61% decrease), perfluorooctanoic acid (PFOA; 58% decrease), dimethylphosphate (DMP; 40% decrease), lead (33% decrease), and bisphenol A (BPA; 32% decrease). Trends were increasing for two pyrethroid pesticide metabolites, including a 110% increase between 2007 and 2017 for 3-phenoxybenzoic acid (3-PBA). No significant trends were observed for the remaining 18 chemicals that included arsenic, mercury, fluoride, acrylamide, volatile organic compounds, and polycyclic aromatic hydrocarbons. National biomonitoring data indicate that concentrations, and therefore exposures, have decreased for many priority chemicals in the Canadian population. Concentrations for other chemical groups have not changed or have increased, although average concentrations remain below thresholds of concern derived from human exposure guidance values. Continued collection of national biomonitoring data is necessary to monitor trends in exposures over time.

Does ozone inhalation cause adverse metabolic effects in humans? A systematic review

We utilized a practical, transparent approach for systematically reviewing a chemical-specific evidence base. This approach was used for a case study of ozone inhalation exposure and adverse metabolic effects (overweight/obesity, Type 1 diabetes [T1D], Type 2 diabetes [T2D], and metabolic syndrome). We followed the basic principles of systematic review. Studies were defined as "Suitable" or "Supplemental." The evidence for Suitable studies was characterized as strong or weak. An overall causality judgment for each outcome was then determined as either causal, suggestive, insufficient, or not likely. Fifteen epidemiologic and 33 toxicologic studies were Suitable for evidence synthesis. The strength of the human evidence was weak for all outcomes. The toxicologic evidence was weak for all outcomes except two: body weight, and impaired glucose tolerance/homeostasis and fasting/baseline hyperglycemia. The combined epidemiologic and toxicologic evidence was categorized as weak for overweight/obesity, T1D, and metabolic syndrome,. The association between ozone exposure and T2D was determined to be insufficient or suggestive. The streamlined approach described in this paper is transparent and focuses on key elements. As systematic review guidelines are becoming increasingly complex, it is worth exploring the extent to which related health outcomes should be combined or kept distinct, and the merits of focusing on critical elements to select studies suitable for causal inference. We recommend that systematic review results be used to target discussions around specific research needs for advancing causal determinations.

Biomonitoring of occupational exposure to bisphenol A, bisphenol S and bisphenol F: A systematic review

Bisphenol A (BPA) and its substitutes bisphenol S (BPS) and bisphenol F (BPF) are endocrine disrupting chemicals widely used in the production of polycarbonate plastics, epoxy resins and thermal papers. The aim of the review was to identify occupational studies using human biomonitoring (HBM) as a tool for bisphenol exposure assessment and to characterize research gaps on the topic as part of the HBM4EU project. Hence, a systematic literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology was conducted for articles published between 2000 and 27th March 2020 across three databases (PubMed, Scopus and Web of Science). Thirty studies on the occupational HBM of BPA met the inclusion criteria. Regarding BPS and BPF, only 4 and 2 publications were retrieved, respectively. Fifty-seven percent (57%) of the studies selected for BPA were conducted in Asia whereas half of BPS and BPF studies were undertaken in Europe. Studies on BPA in plastic and epoxy resin sectors were infrequent in Europe while Asian data showed higher exposure when the substance is employed as raw material. The main data on BPS were among cashiers while BPF data were available from incinerator workers. Several research gaps have been identified: (i) shortage of HBM studies on occupational exposure, especially to BPS and BPF; (ii) different methodological designs making suitable comparisons between studies difficult; and (iii) only few studies conducted on the industrial applications of bisphenols outside Asia. This review highlights the lack of recent occupational HBM studies on bisphenols and the need for a harmonized approach to acquire reliable data. Considering the increasing replacement of BPA by BPS and BPF, it is of relevance to evaluate the exposure to these substances and the impact of the available risk management measures on workers exposure and possible health risk.

Bisphenol-A exposure and risk of breast and prostate cancer in the Spanish European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Bisphenol A (BPA) is an endocrine disruptor that it is present in numerous products of daily use. The aim of this study was to assess the potential association of serum BPA concentrations and the risk of incident breast and prostate cancer in a sub-cohort of the Spanish European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

We designed a case-cohort study within the EPIC-Spain cohort. Study population consisted on 4812 participants from 4 EPIC-Spain centers (547 breast cancer cases, 575 prostate cancer cases and 3690 sub-cohort participants). BPA exposure was assessed by means of chemical analyses of serum samples collected at recruitment. Borgan II weighted Cox regression was used to estimate hazard ratios.

RESULTS

Median follow-up time in our study was 16.9 years. BPA geometric mean serum values of cases and sub-cohort were 1.12 ng/ml vs 1.10 ng/ml respectively for breast cancer and 1.33 ng/ml vs 1.29 ng/ml respectively for prostate cancer. When categorizing BPA into tertiles, a 40% increase in risk of prostate cancer for tertile 1 (p = 0.022), 37% increase for tertile 2 (p = 0.034) and 31% increase for tertile 3 (p = 0.072) was observed with respect to values bellow the limit of detection. No significant association was observed between BPA levels and breast cancer risk.

CONCLUSIONS

We found a similar percentage of detection of BPA among cases and sub-cohort from our population, and no association with breast cancer risk was observed. However, we found a higher risk of prostate cancer for the increase in serum BPA levels. Further investigation is needed to understand the influence of BPA in prostate cancer risk.

Systematic review of biomonitoring data on occupational exposure to hexavalent chromium

Occupational exposure to hexavalent chromium (Cr(VI)) can cause serious adverse health effects such as lung cancer and irritation of the skin and airways. Although assessment of chromium (Cr) in urine is not specific for Cr(VI) exposure, the total amount of Cr in urine is the most used marker of exposure for biomonitoring of Cr(VI). The purpose of this systematic review was fourfold: (1) to assess current and recent biomonitoring levels in subjects occupationally exposed to Cr(VI), with a focus on urinary Cr levels at the end of a working week, (2) to identify variables influencing these biomonitoring levels, (3) to identify how urinary Cr levels correlate with other Cr(VI) exposure markers and (4) to identify gaps in the current research. To address these purposes, unpublished and published biomonitoring data were consulted: (i) unpublished biomonitoring data comprised urinary Cr levels (n = 3799) of workers from different industries in Belgium collected during 1998-2018, in combination with expert scores indicating jobs with Cr exposure and (ii) published biomonitoring data was extracted by conducting a systematic literature review. A linear mixed effect model was applied on the unpublished biomonitoring data, showing a decreasing time trend of 30% in urinary Cr levels. Considering the observed decreasing time trend, only articles published between January 1, 2010 and September 30, 2020 were included in the systematic literature search to assess current and recent biomonitoring levels. Twenty-five studies focusing on human biomonitoring of exposure to Cr(VI) in occupational settings were included. Overall, the results showed a decreasing time trend in urinary Cr levels and the need for more specific Cr(VI) biomarkers. Furthermore, this review indicated the importance of improved working conditions, efficient use of personal protective equipment, better exposure control and increased risk awareness to reduce Cr levels in biological matrices. Further investigation of the contribution of the different exposure routes is needed, so that better guidance on the use of control measures can be provided. In addition, this review support the call for more harmonization of human biomonitoring.

Cytokinesis-block micronucleus cytome (CBMN-CYT) assay biomarkers and telomere length analysis in relation to inorganic elements in individuals exposed to welding fumes

During the welding activities many compounds are released, several of these cause oxidative stress and inflammation and some are considered carcinogenic, in fact the International Agency for Research on Cancer established that welding fumes are carcinogenic to humans. The aim of the present study was to analyze the cytotoxic and genotoxic potential of exposure to welding fumes and to determine concentrations of metals in blood and urine of occupationally exposed workers. We included 98 welders and 100 non-exposed individuals. Our results show significant increase in the frequency of micronuclei (MN), nucleoplasmic bridges (NPB), nuclear buds (NBUD) and necrotic cells (NECR) in cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, as well as in the telomere length (TL) of the exposed individuals with respect to the non-exposed group. In the analysis of the concentrations of inorganic elements using PIXE method, were found higher concentrations of Cr, Fe and Cu in the urine, and Cr, Fe, Mg, Al, S, and Mn in the blood in the exposed group compared to the non-exposed group. A significant correlation was observed between MN and age and between NPB and years of exposure. Additionally, we found a significant correlation for TL in relation to MN, NPB, age and years of exposure in the exposed group. Interestingly, a significant correlation between MN and the increase in the concentration of Mg, S, Fe and Cu in blood samples of the exposed group, and between MN and Cr, Fe, Ni and Cu in urine. Thus, our findings may be associated with oxidative and inflammatory damage processes generated by the components contained in welding fumes, suggesting a high occupational risk in welding workers.

The role of epidemiology studies in human health risk assessment of polychlorinated biphenyls

Polychlorinated biphenyls (PCBs) are a public health concern given evidence that they persist and accumulate in the environment and can cause toxic effects in animals and humans. However, evaluating adverse effects of PCBs in epidemiologic studies is complicated by the characteristics of PCB exposure. PCBs exist as mixtures in the environment; the mixture changes over time due to degradation, and given physicochemical differences between specific PCB congeners, the mixture that an individual is exposed to (via food, air, or other sources) is likely different from that which can be measured in biological tissues. This is particularly problematic when evaluating toxicity of shorter-lived congeners that may not be measurable by the time biological samples are collected. We review these and other issues that arise when evaluating epidemiologic studies of PCBs and discuss how epidemiology data can still be used to inform both hazard identification and dose-response evaluation.

Biomonitoring as an Underused Exposure Assessment Tool in Occupational Safety and Health Context-Challenges and Way Forward

Recent advances in analytical chemistry have allowed a greater possibility of using quantitative approaches for measuring human exposure to chemicals. One of these approaches is biomonitoring (BM), which provides unequivocal evidence that both exposure and uptake of a chemical have taken place. BM has been a longstanding practice in occupational health for several reasons. BM integrates exposure from all routes. It can help identify unintentional and unexpected exposures and assess the effectiveness of existing risk-management measures. BM also provides relevant information to support policy development by delivering better evidence of workers’ exposure to chemical substances, even within the framework of the present regulations. Thus, BM can allow for both the evaluation of the impact of regulation and identification of further needs for new or improved regulation. However, despite all these well-recognized advantages, BM is currently an underused exposure assessment tool. This paper provides an overview of the key aspects to be considered when using BM in the context of occupational health interventions. Additionally, this paper describes the potential of BM as an exposure assessment tool, distinguishing the role of BM in exposure assessment and health surveillance and clarifies ethical and communication aspects to guarantee that general data protection regulations are followed. In addition, actions and research needs are identified (particularly with reference to the European situation), which aim to encourage the increased use of BM as an exposure assessment tool.

The association between environmental endocrine disruptors and cardiovascular diseases: A systematic review and meta-analysis

BACKGROUND

Except for known cardiovascular risk factors, long-term exposure to environmental endocrine disruptors (EEDs) - a class of exogenous chemicals, or a mixture of chemicals, that can interfere with any aspect of hormone action - has been shown to increase the risk of cardiovascular diseases (CVDs), which are still controversial.

OBJECTIVE

To conduct a comprehensive systematic review and meta-analysis to estimate the association between EEDs, including nonylphenol (NP), bisphenol A (BPA), polychlorinated biphenyl (PCB), organo-chlorine pesticide (OCP) and phthalate (PAE) exposure and CVD risk.

METHODS

The heterogeneity between different studies was qualitatively and quantitatively evaluated using Q test and I² statistical magnitude, respectively. Subgroup analysis was performed using chemical homologs - a previously unused grouping method - to extract data and perform meta-analysis to assess their exposure to CVD.

RESULTS

Twenty-nine literatures were enrolled with a total sample size of 88891. The results indicated that exposure to PCB138 and PCB153 were the risk factors for CVD morbidity (odds ratio (OR) = 1.35, 95% confidence interval (CI): 1.10-1.66; OR = 1.35, 95% CI: 1.13-1.62). Exposure to organo-chlorine pesticide (OCP) (OR = 1.12, 95% CI: 1.00-1.24), as well as with phthalate (PAE) (OR = 1.11, 95% CI: 1.06-1.17) and BPA (OR = 1.19, 95% CI: 1.03-1.37) were positively associated with CVD risk, respectively. BPA exposure concentration had no correlation with total cholesterol (TC), or low-density lipoprotein (LDL), but exhibited a correlation with gender, waist circumference (WC), high-density lipoprotein (HDL), age, and body mass index (BMI) (standardized mean difference (SMD)) = 1.51; 95% CI: =(1.01-2.25); SMD = 0.16; 95% CI: (0.08-0.23); SMD = -0.19; 95% CI: (-0.27-0.12); SMD = -0.78; 95% CI: (-1.42-0.14); SMD = 0.08; 95% CI: (0.00-0.16).

CONCLUSIONS

EED exposure is a risk factor for CVD. Long-term exposure to EEDs can influence cardiovascular health in humans. A possible synergistic effect may exist between the homologs. The mechanism of which needs to be further explored and demonstrated by additional prospective cohort studies, results of in vitro and in vivo analyses, as well as indices affecting CVD.

"Good Epidemiology Practice" Guidelines for Pesticide Exposure Assessment

Both toxicology and epidemiology are used to inform hazard and risk assessment in regulatory settings, particularly for pesticides. While toxicology studies involve controlled, quantifiable exposures that are often administered according to standardized protocols, estimating exposure in observational epidemiology studies is challenging, and there is no established guidance for doing so. However, there are several frameworks for evaluating the quality of published epidemiology studies. We previously developed a preliminary list of methodology and reporting standards for epidemiology studies, called Good Epidemiology Practice (GEP) guidelines, based on a critical review of standardized toxicology protocols and available frameworks for evaluating epidemiology study quality. We determined that exposure characterization is one of the most critical areas for which standards are needed. Here, we propose GEP guidelines for pesticide exposure assessment based on the source of exposure data (i.e., biomonitoring and environmental samples, questionnaire/interview/expert record review, and dietary exposures based on measurements of residues in food and food consumption). It is expected that these GEP guidelines will facilitate the conduct of higher-quality epidemiology studies that can be used as a basis for more scientifically sound regulatory risk assessment and policy making.

Biomonitoring of occupational exposure to phthalates: A systematic review

INTRODUCTION

Phthalates, a group of ubiquitous industrial chemicals, have been widely used in occupational settings, mainly as plasticizers in a variety of applications. Occupational exposure to different phthalates has been studied in several occupational settings using human biomonitoring (HBM).

AIM

To provide a comprehensive review of the available literature on occupational exposure to phthalates assessed using HBM and to determine future data needs on the topic as part of the HBM4EU project.

METHODS

A systematic search was carried out in the databases of Pubmed, Scopus, and Web of Science for articles published between 2000 and September 4, 2019 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 22 studies on the occupational HBM of phthalates was considered suitable for review.

RESULTS AND DISCUSSION

Among the reviewed studies, 19 (86%) focused on DEHP, an old phthalate that is now subject to authorization and planned to be restricted in the EU. Concentrations of MEHHP, one of its metabolites, varied up to 13-fold between studies and across sectors when comparing extreme geometric means, ranging from 11.6 (similar to the general populations) to 151 μg/g creatinine. Only 2 studies focused on newer phthalates such as DiNP and DPHP. Concerning the geographical distribution, 10 studies were performed in Europe (including 6 in Slovakia), 8 in Asia, and 4 in North America, but this distribution is not a good reflection of phthalate production and usage levels worldwide. Most HBM studies were performed in the context of PVC product manufacturing. Future studies should focus on: i) a more uniform approach to sampling timing to facilitate comparisons between studies; ii) newer phthalates; and iii) old phthalates in waste management or recycling.

CONCLUSION

Our findings highlight the lack of recent occupational HBM studies on both old and new phthalate exposure in European countries and the need for a harmonized approach. Considering the important policy actions taken in Europe regarding phthalates, it seems relevant to evaluate the impact of these actions on exposure levels and health risks for workers.

Biomonitoring for Occupational Exposure to Diisocyanates: A Systematic Review

Diisocyanates are a group of chemicals that are widely used in occupational settings. They are known to induce various health effects, including skin- and respiratory tract sensitization resulting in allergic dermatitis and asthma. Exposure to diisocyanates has been studied in the past decades by using different types of biomonitoring markers and matrices. The aim of this review as part of the HBM4EU project was to assess: (i) which biomarkers and matrices have been used for biomonitoring diisocyanates and what are their strengths and limitations; (ii) what are (current) biomonitoring levels of the major diisocyanates (and metabolites) in workers; and (iii) to characterize potential research gaps. For this purpose we conducted a systematic literature search for the time period 2000-end 2018, thereby focussing on three types of diisocyanates which account for the vast majority of the total isocyanate market volume: hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI), and 4,4'-methylenediphenyl diisocyanate (MDI). A total of 28 publications were identified which fulfilled the review inclusion criteria. The majority of these studies (93%) investigated the corresponding diamines in either urine or plasma, but adducts have also been investigated by several research groups. Studies on HDI were mostly in the motor vehicle repair industry [with urinary hexamethylene diamine result ranging from 0.03 to 146.5 µmol mol-1 creatinine]. For TDI, there is mostly data on foam production [results for urinary toluene diamine ranging from ~0.01 to 97 µmol mol-1 creatinine] whereas the available MDI data are mainly from the polyurethane industry (results for methylenediphenyl diamine range from 0.01 to 32.7 µmol mol-1 creatinine). About half of the studies published were prior to 2010 hence might not reflect current workplace exposure. There is large variability within and between studies and across sectors which could be potentially explained by several factors including worker or workplace variability, short half-lives of biomarkers, and differences in sampling strategies and analytical techniques. We identified several research gaps which could further be taken into account when studying diisocyanates biomonitoring levels: (i) the development of specific biomarkers is promising (e.g. to study oligomers of HDI which have been largely neglected to date) but needs more research before they can be widely applied, (ii) since analytical methods differ between studies a more uniform approach would make comparisons between studies easier, and (iii) dermal absorption seems a possible exposure route and needs to be further investigated. The use of MDI, TDI, and HDI has been recently proposed to be restricted in the European Union unless specific conditions for workers' training and risk management measures apply. This review has highlighted the need for a harmonized approach to establishing a baseline against which the success of the restriction can be evaluated.

Translation of Exposure and Epidemiology for Risk Assessment: A Shifting Paradigm

Risk assessment is a well-established process used for various types of public health decision-making, such as setting chemical site clean-up levels, developing limits on exposures to chemicals in soil, water, air and food, and determining occupational exposure limits[...].

Historical exposure to non-persistent environmental pollutants and risk of type 2 diabetes in a Spanish sub-cohort from the European Prospective Investigation into Cancer and Nutrition study

BACKGROUND

Environmental factors are believed to account for a substantial burden of type 2 diabetes mellitus (T2DM). Non-persistent environmental pollutants (npEPs) are a group of widely-used chemicals identified as endocrine/metabolic disrupting chemicals and obesogens. The aim of this study was to analyse the potential associations of serum levels of three groups of npEPs with the risk of incident T2DM.

METHODS

This is a longitudinal study within a sub-sample of Granada EPIC-Spain cohort (n = 670). We quantified serum concentrations of 7 npEPs: four parabens (Methylparaben (MP) ethylparaben (EP), propylparaben (PP) and butilparaben (BP); two benzophenones: Benzophenone 1 (BP1), Benzophenone 3 (BP3); and Bisphenol A (BPA). Exposure was assessed by means of chemical analyses of serum samples collected at recruitment, and information on potential confounders was gathered by using validated questionnaires at baseline. Follow-up was performed by review of patients' clinical records. Cox Proportional Hazards Models were used for the statistical analyses.

RESULTS

Median follow-up time was 23 years. There were 182 (27%) incident T2DM diagnoses in our sub-cohort. MP was the most frequently detected npEP, 88.42% samples above the limit of detection, and BP showed the lowest percentage of detection (19.21%). Those individuals within the fourth PP quartile (0.53-9.24 ng/ml) showed a statistically significant increased risk of T2DM (HR = 1.668 p = 0.012), while BP1 concentrations showed an inverse non-significant trend with the risk.

CONCLUSIONS

We evidenced a potential contribution of npEP exposure on T2DM, but no clear trend was observed. However, limitations in relation to exposure estimation might influence our findings and further research is warranted to confirm our results.

Bisphenol-A in the European Prospective Investigation into Cancer and Nutrition cohort in Spain: Levels at recruitment and associated dietary factors

Bisphenol A (BPA) is considered an endocrine disruptor and it is present in numerous products of daily use. The aim of this study was to analyze serum BPA concentrations in a subcohort of the Spanish European Prospective Investigation into Cancer and Nutrition (EPIC), as well as to identify potential predictors of the exposure. The population consisted on 3553 subjects from 4 EPIC-Spain centres and BPA levels were measured in serum samples by UHPLC-MS/MS. Almost 70% of the participants showed detectable BPA values (>0.2 ng/ml), with a geometric mean of 1.19 ng/ml (95% CI: 1.12-1.25). By sex, detectable percentages were similar (p = 0.56) but with higher serum levels in men (1.27 vs 1.11 ng/ml, p = 0.01). Based on the adjusted regression models, a 50 g/day increase in the consumption of added fats and oils were associated with 43% lower BPA serum levels, while sugar and confectionary was associated with 25% higher levels of serum BPA. We evidenced differential exposure levels by province, sex and age, but not by anthropometric or lifestyle characteristics. Further investigation is needed to understand the influence of diet in BPA exposure.

Improving Exposure Assessment Methodologies for Epidemiological Studies on Pesticides: Study Protocol

Background

Exposure to certain pesticides has been associated with several chronic diseases. However, to determine the role of pesticides in the causation of such diseases, an assessment of historical exposures is required. Exposure measurement data are rarely available; therefore, assessment of historical exposures is frequently based on surrogate self-reported information, which has inherent limitations. Understanding the performance of the applied surrogate measures in the exposure assessment of pesticides is therefore important to allow proper evaluation of the risks.

Objective

The Improving Exposure Assessment Methodologies for Epidemiological Studies on Pesticides (IMPRESS) project aims to assess the reliability and external validity of the surrogate measures used to assign exposure within individuals or groups of individuals, which are frequently based on self-reported data on exposure determinants. IMPRESS will also evaluate the size of recall bias on the misclassification of exposure to pesticides; this in turn will affect epidemiological estimates of the effect of pesticides on human health.

Methods

The IMPRESS project will recruit existing cohort participants from previous and ongoing research studies primarily of epidemiological origin from Malaysia, Uganda, and the United Kingdom. Consenting participants of each cohort will be reinterviewed using an amended version of the original questionnaire addressing pesticide use characteristics administered to that cohort. The format and relevant questions will be retained but some extraneous questions from the original (eg, relating to health) will be excluded for ethical and practical reasons. The reliability of pesticide exposure recall over different time periods (<2 years, 6-12 years, and >15 years) will then be evaluated. Where the original cohort study is still ongoing, participants will also be asked if they wish to take part in a new exposure biomonitoring survey, which involves them providing urine samples for pesticide metabolite analysis and completing questionnaire information regarding their work activities at the time of sampling. The participant’s level of exposure to pesticides will be determined by analyzing the collected urine samples for selected pesticide metabolites. The biomonitoring measurement results will be used to assess the performance of algorithm-based exposure assessment methods used in epidemiological studies to estimate individual exposures during application and re-entry work.

Results

The project was funded in September 2017. Enrollment and sample collection was completed for Malaysia in 2019 and is on-going for Uganda and the United Kingdom. Sample and data analysis will proceed in 2020 and the first results are expected to be submitted for publication in 2021.

Conclusions

The study will evaluate the consistency of questionnaire data and accuracy of current algorithms in assessing pesticide exposures. It will indicate where amendments can be made to better capture exposure data for future epidemiology studies and thus improve the reliability of exposure-disease associations.

International Registered Report Identifier (IRRID)

PRR1-10.2196/16448

Urinary 3-phenoxybenzoic acid levels and the association with thyroid hormones in adults: Korean National Environmental Health Survey 2012-2014

BACKGROUND

Owing to insecticidal activity at low doses with relatively low toxicity in humans, synthetic pyrethroids have been used widely for pest control in agricultural and domestic settings. Pyrethroids are suspected for potential endocrine disruption. However, the thyroid disrupting effects of pyrethroids, particularly in humans, is relatively underexplored.

OBJECTIVES

This study aimed to report 3-phenoxybenzoic acid (3-PBA) concentrations in urine, and assess its association with serum thyroid hormone (TH) levels in a representative adult population of Korea.

METHODS

Data obtained from representative Korean adults recruited in the Korean National Environmental Health Survey (2nd round, 2012-2014) were analyzed. Urinary 3-PBA levels were associated with serum thyroxine (T4), total triiodothyronine (T3), and thyroid-stimulating hormone (TSH) levels among the Korean adult population.

RESULTS

Urinary 3-PBA levels among Korean adults were >3 times higher than those reported in Canada and the United States. Urinary 3-PBA levels showed negative association with serum T4, and this pattern was not changed after stratification by sex. For T3, the association varied by sex and exposure levels. Male demonstrated the same inverse association between urinary 3-PBA and T3, but female did not show such association. Among adults in the lower half of urinary 3-PBA levels, the association with T3 was significant, while that among the remainder was marginal. The association with T4 remained significant on sensitivity analysis, after controlling for other urinary chemicals.

CONCLUSION

Urinary 3-PBA levels in the general Korean adult population were found to be generally higher than those of other countries, and were associated with decreased TH levels. Considering the importance of THs, the public health implications of pyrethroid insecticide exposure warrant further studies.

Wrangling environmental exposure data: guidance for getting the best information from your laboratory measurements

BACKGROUND

Environmental health and exposure researchers can improve the quality and interpretation of their chemical measurement data, avoid spurious results, and improve analytical protocols for new chemicals by closely examining lab and field quality control (QC) data. Reporting QC data along with chemical measurements in biological and environmental samples allows readers to evaluate data quality and appropriate uses of the data (e.g., for comparison to other exposure studies, association with health outcomes, use in regulatory decision-making). However many studies do not adequately describe or interpret QC assessments in publications, leaving readers uncertain about the level of confidence in the reported data. One potential barrier to both QC implementation and reporting is that guidance on how to integrate and interpret QC assessments is often fragmented and difficult to find, with no centralized repository or summary. In addition, existing documents are typically written for regulatory scientists rather than environmental health researchers, who may have little or no experience in analytical chemistry.

OBJECTIVES

We discuss approaches for implementing quality assurance/quality control (QA/QC) in environmental exposure measurement projects and describe our process for interpreting QC results and drawing conclusions about data validity.

DISCUSSION

Our methods build upon existing guidance and years of practical experience collecting exposure data and analyzing it in collaboration with contract and university laboratories, as well as the Centers for Disease Control and Prevention. With real examples from our data, we demonstrate problems that would not have come to light had we not engaged with our QC data and incorporated field QC samples in our study design. Our approach focuses on descriptive analyses and data visualizations that have been compatible with diverse exposure studies with sample sizes ranging from tens to hundreds of samples. Future work could incorporate additional statistically grounded methods for larger datasets with more QC samples.

CONCLUSIONS

This guidance, along with example table shells, graphics, and some sample R code, provides a useful set of tools for getting the best information from valuable environmental exposure datasets and enabling valid comparison and synthesis of exposure data across studies.

How do cancer-sniffing dogs sort biological samples? Exploring case-control samples with non-targeted LC-Orbitrap, GC-MS, and immunochemistry methods

Early identification of disease onset is regarded as an important factor for successful medical intervention. However, cancer and other long-term latency diseases are rare and may take years to manifest clinically. As such, there are no gold standards with which to immediately validate proposed preclinical screening methodologies. There is evidence that dogs can sort samples reproducibly into yes/no categories based on case-control training, but the basis of their decisions is unknown. Because dogs are sniffing air, the distinguishing chemicals must be either in the gas-phase or attached to aerosols and/or airborne particles. Recent biomonitoring research has shown how to extract and analyze semi- and non-volatile compounds from human breath in exhaled condensates and aerosols. Further research has shown that exhaled aerosols can be directly collected on standard hospital-style olefin polypropylene masks and that these masks can be used as a simple sampling scheme for canine screening. In this article, detailed liquid chromatography-high resolution mass spectrometry (LC-HR-MS) with Orbitrap instrumentation and gas chromatography-mass spectrometry (GC-MS) analyses were performed on two sets of masks sorted by consensus of a four-dog cohort as either cancer or control. Specifically, after sorting by the dogs, sample masks were cut into multiple sections and extracted for LC-MS and GC-MS non-targeted analyses. Extracts were also analyzed for human cytokines, confirming the presence of human aerosol content above levels in blank masks. In preliminary evaluations, 345 and 44 high quality chemical features were detected by LC-MS and GC-MS analyses, respectively. These features were used to develop provisional orthogonal projection to latent structures-discriminant analysis (OPLS-DA) models to determine if the samples classified as cancer (case) or non-cancer (control) by the dogs could be separated into the same groups using analytical instrumentation. While the OPLS-DA model for the LC-HR-MS data was able to separate the two groups with statistical significance, although weak explanatory power, the GC-MS model was not found to be significant. These results suggest that the dogs may rely on the less volatile compounds from breath aerosol that were analyzed by LC-HR-MS than the more volatile compounds observed by GC-MS to sort mask samples into groups. These results provide justification for more expansive studies in the future that aim to characterize specific chemical features, and the role(s) of these features in maintaining homeostatic biological processes.

Application of the comet assay for the evaluation of DNA damage from frozen human whole blood samples: Implications for human biomonitoring

This study proposes the application of the comet assay for the evaluation of DNA damage from frozen human whole blood samples that could be readily used in human biomonitoring and epidemiological studies. It was done on simply frozen whole blood samples collected from male volunteers (N = 60) aliquoted in small volumes and stored at -80 °C without the addition of cryopreservatives for a period of 5 years. To test the applicability of the alkaline comet assay for the evaluation of DNA damage in frozen whole blood, samples were quickly thawed at 37 °C and immediately embedded in an agarose matrix followed by an alkaline comet assay procedure. We concluded that the whole blood freezing and prolonged storage do not severely affect comet assay values, although background values were higher compared to our historical control data from the fresh whole blood. Even the influence of the variables tested, such as age, body mass index, smoking habit and alcohol consumption were in agreement with our previous data using fresh blood. The obtained results suggest that the comet assay could be applied to frozen blood samples, if properly stored, even for decades, which would certainly facilitate large-scale human biomonitoring and long-term epidemiological studies.

Development of a questionnaire-based insecticide exposure assessment method and comparison with urinary insecticide biomarkers in young Australian children

Environmental and behavioural factors assessed via an online questionnaire were compared to insecticide metabolite concentrations in urine collected from 61 children from South East Queensland, Australia. Metabolite concentrations (μg/L urine) were transformed using the natural logarithm prior to regression analysis and adjusted for age and creatinine. A significant dietary association was reported for vegetable intake and 3-phenoxybenzoic acid (3-PBA) (β: 1.47 for top quartile of intake versus bottom quartile of intake 95% CI: 0.36, 2.57). Intake of vegetables and fruit were also positively associated with sum non-specific organophosphate metabolites (ƩnsOP). ƩnsOP concentrations were lower when fruits and vegetables were always or almost always washed prior to cooking or eating (β: -0.69 95% CI: -1.25, -0.12). In multivariable modelling 3-PBA concentrations were also associated with hand-washing frequency (β: 1.69 95% CI: 0.76, 2.61 for <1 day versus > 3 day), presence of a dog in the home (β: 0.73 95% CI: 0.07, 1.38), frequency of pest-spray use in the summer months (β: 0.88 95% CI: 0.22, 1.54 weekly versus less than weekly) and season (β: 0.88 95% CI: 0.32, 1.44 for spring/summer versus winter/autumn). This is the first study in Australia to report dietary, behavioural and environmental factors associated with biomarkers of insecticide exposure in young children.

Testing the impact of contaminated sediments from the southeast marine coast of Tunisia on biota: a multibiomarker approach using the flatfish Solea senegalensis

Coastal marine areas are highly vulnerable to the exposure to various types of stressors and impact of chemical pollution resulting from increasing anthropogenic activities, namely pollution by metals and polycyclic aromatic hydrocarbons (PAHs). To assess ecosystem quality and functions, biomarkers can provide information about the presence and adverse effects of pollutants. Accordingly, the present study was conducted to evaluate the chronic (28 days) biologic effects of putatively contaminated sediments from the Zarzis area, located in the south of the Gulf of Gabes on the Southern Tunisian coast, on the marine flatfish Solea senegalensis. Sediments were collected at three sampling sites, impacted by wastewater discharges, aquaculture activities, and industrial contamination, and then surveyed for metals (Cd, Cu, Cr, Hg, Zn, and Pb) and organic contaminants (polycyclic aromatic hydrocarbons). The quantified biomarkers involved the determination of oxidative stress, phase II metabolism, and the extent of lipid peroxidation (catalase, CAT; glutathione peroxidase activity: total and selenium-dependent, T-GPx and Se-GPx; activities of glutathione-S-transferases, GSTs; levels of lipid peroxidation, by means of the thiobarbituric acid reactive substances assay, TBARS) and neurotoxicity (activity of acetylcholinesterase, AChE). S. senegalensis exposed to potentially contaminated sediments, collected near the aquaculture facility, presented the highest values for the generality of biomarkers tested, and a significant inhibition of AChE activity. A few lesions have been also recorded in the gills and liver tissues of S. senegalensis following chronic exposure. However, the observed lesions in gills (e.g., epithelial lifting, lamellar fusion, gills hyperplasia and hypertrophy, and leukocyte infiltration) and liver (cytoplasmic vacuolation, enlargement of sinusoids, foci of necrosis, and eosinophilic bodies) were of minimal pathological importance and/or low prevalence that did not significantly affect the weighted histopathological indices. Finally, the biological responses evidenced by this flatfish can be potentially caused by metal and PAH pollution occurring in specific areas in the southeast of Tunisia. The type and extent of the observed biochemical alterations strongly suggest that the contaminated sediments from the surveyed areas could cause early adverse biological effects on exposed biota.

Factors affecting interpretation of national biomonitoring data from multiple countries: BPA as a case study

INTRODUCTION

The use of biomonitoring data as an indicator of national levels of human exposure to environmental chemicals has grown in importance and prevalence. Nationally representative urinary bisphenol A (BPA) data are now available for Canada, the United States and Korea. Here we address the following questions: Are urinary BPA data from these countries comparable? What can be discerned regarding geographic and/or temporal similarities or differences? Are there generalizable lessons to be learned regarding comparison of biomonitoring results from different countries?

METHODS

We examined underlying methods and resultant urinary BPA data from national surveys of three countries: Canada (Canadian Health Measures Survey, CHMS, 2009-2015); United States (National Health and Nutrition Examination Survey, NHANES, 2009-2014); and Korea (Korean National Environmental Health Survey, KoNEHS, 2009-2014). We estimated BPA daily intakes on both a volume- and creatinine-adjusted basis.

RESULTS

The three countries use similar methods for analyzing urine samples for BPA and participate in external proficiency testing with acceptable results. Field blanks are only used in the CHMS program. There were program-specific differences in fasting times of participants. Median urinary BPA levels in Canada remained relatively constant over the three cycles (1.1-1.2 ng/ml), while US levels decreased (from 1.9 to 1.3 ng/ml) and Korean levels increased (from 0.7 to 1.1 ng/ml) over similar time periods. The most recent survey year data indicate that levels do not differ substantially across countries. Canadian urinary BPA levels have been stable; the subtle, non-significant decrease in intakes may be due to higher body weight in the more recent Canadian surveys. In contrast, the decrease in intakes in the US appears to be due to decreases in urinary BPA as body weights in the US have been stable. Estimated 95th percentile intakes are over an order of magnitude below current health-based guidance values.

DISCUSSION

Our assessment of urinary BPA data from Canada, the US and Korea indicates that methodological differences, methods for dilution adjustment, and population characteristics should be carefully considered when interpreting biomonitoring data. Despite the plethora of publications describing issues with use of creatinine levels for urinary dilution adjustment, there have been no major methodological advances that would assist in interpreting urinary chemical data. A combination of biomonitoring and traditional exposure assessment approaches may be needed to fully assess human exposures to BPA and other chemicals.

CONCLUSIONS

National biomonitoring surveys provide important information on population levels of chemicals such as BPA and can assist in understanding temporal and geographic similarities, differences, and trends. However, caution must be exercised when using these data to draw anything but broad conclusions, due to both intercountry methodological differences and factors affecting urinary chemical levels that are still poorly understood. While the issues raised in this paper do not appear to be a major concern specifically for the national-scale monitoring of BPA described here, they must be considered when comparing data for other chemicals measured as part of both national and smaller-scale biomonitoring-based research as well as for BPA data from other studies.

Human biomonitoring health surveillance for metals near a waste-to-energy incinerator: The 1-year post-operam study

This human biomonitoring (HBM) follow-up survey, within the SPoTT project, assessed the temporal and spatial trends of exposure to 18 metals in a cohort living around the waste-to-energy (WTE) incinerator of Turin (Italy) before (T0, 2013) and after 1-year of plant activity (T1, 2014). Urine of 380 adult individuals (186 exposed and 194 unexposed subjects, classified on fallout maps) were analyzed by sector field inductively coupled mass spectrometry. A decrease trend of the majority of metals in all subjects indicates that the overall air quality of the studied sites was not significantly compromised, also in proximity of the WTE plant, as corroborated also by air monitoring data of the regional agency. The only relevant exception was the higher Cr levels found at T1 than T0 in exposed subjects, suggesting a possible contribution from the WTE plant. Chromium, Mn and Pt urine levels were also higher in the site far from the WTE, in relation to other sources as vehicular traffic, industrial and civil activities. Whilst, As and Cd were influenced by fish intake and tobacco smoke. A very small number of individuals at T1, equally distributed in both areas, exceeded the health-based guidance values and so, at current knowledge, living near the Turin incineration did not significantly influence the exposure status of the population.

ExpoQual: Evaluating measured and modeled human exposure data

Recent rapid technological advances are producing exposure data sets for which there are no available data quality assessment tools. At the same time, regulatory agencies are moving in the direction of data quality assessment for environmental risk assessment and decision-making. A transparent and systematic approach to evaluating exposure data will aid in those efforts. Any approach to assessing data quality must consider the level of quality needed for the ultimate use of the data. While various fields have developed approaches to assess data quality, there is as yet no general, user-friendly approach to assess both measured and modeled data in the context of a fit-for-purpose risk assessment. Here we describe ExpoQual, an instrument developed for this purpose which applies recognized parameters and exposure data quality elements from existing approaches for assessing exposure data quality. Broad data streams such as quantitative measured and modeled human exposure data as well as newer and developing approaches can be evaluated. The key strength of ExpoQual is that it facilitates a structured, reproducible and transparent approach to exposure data quality evaluation and provides for an explicit fit-for-purpose determination. ExpoQual was designed to minimize subjectivity and to include transparency in aspects based on professional judgment. ExpoQual is freely available on-line for testing and user feedback (exposurequality.com).

Nanoparticles of zinc oxide defeat chlorpyrifos-induced immunotoxic effects and histopathological alterations

Background and Aim:

Chlorpyrifos (CPF) is a widely used organophosphate insecticide. Nanoparticles of zinc oxide (ZnO NPs) physically showed effective adsorbing property for some insecticides. The study was conducted to estimate the potential effect of ZnO NPs against CPF toxicity.

Materials and Methods:

Four groups of male rats were used; control group and three groups received drinking water contained 75 mg/L CPF, combined 75 mg/L CPF and 200 mg/L ZnO NPs, and 200 mg/L ZnO NPs, respectively.

Results:

CPF significantly decreased macrophage activity, serum lysozyme activity, and levels of interleukin-2 (IL-2) and IL-6; increased the percentage of DNA degeneration on comet assay of lymphocytes and significantly elevated hepatic and splenic malondialdehyde contents; and decreased their glutathione contents. The liver and spleen showed marked histological alterations after exposure to CPF with decreased expression of acetylcholinesterase. The coadministration of ZnO NPs ameliorated most of the undesirable effects of CPF, through elevation of macrophage and serum lysozyme activities, increased the levels of IL-2 and IL-6, corrected the oxidative stress markers, and alleviated most of the adverse effect exerted by CPF in liver and spleen tissues.

Conclusion:

The addition of ZnO NPs to CPF-contaminated drinking water may be useful as a powerful antioxidant agent against toxic damage induced by CPF particularly in individuals who are on daily occupational exposure to low doses of CPF.

Development and reliability assessment of a new quality appraisal tool for cross-sectional studies using biomarker data (BIOCROSS)

Background

Biomarker-based analyses are commonly reported in observational epidemiological studies; however currently there are no specific study quality assessment tools to assist evaluation of conducted research. Accounting for study design and biomarker measurement would be important for deriving valid conclusions when conducting systematic data evaluation.

Methods

We developed a study quality assessment tool designed specifically to assess biomarker-based cross-sectional studies (BIOCROSS) and evaluated its inter-rater reliability. The tool includes 10-items covering 5 domains: ‘Study rational’, ‘Design/Methods’, ‘Data analysis’, ‘Data interpretation’ and ‘Biomarker measurement’, aiming to assess different quality features of biomarker cross-sectional studies. To evaluate the inter-rater reliability, 30 studies were distributed among 5 raters and intraclass correlation coefficients (ICC-s) were derived from respective ratings.

Results

The estimated overall ICC between the 5 raters was 0.57 (95% Confidence Interval (CI): 0.38–0.74) indicating a good inter-rater reliability. The ICC-s ranged from 0.11 (95% CI: 0.01–0.27) for the domain ‘Study rational’ to 0.56 (95% CI: 0.40–0.72) for the domain ‘Data interpretation’.

Conclusion

BIOCROSS is a new study quality assessment tool suitable for evaluation of reporting quality from cross-sectional epidemiological studies employing biomarker data. The tool proved to be reliable for use by biomedical scientists with diverse backgrounds and could facilitate comprehensive review of biomarker studies in human research.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0583-x) contains supplementary material, which is available to authorized users.