Application of US EPA IRIS systematic review methods to the health effects of phthalates: Lessons learned and path forward

Occurrence of phthalates in facemasks used in India and its implications for human exposure

Synthetic polymers with additives are used in the manufacturing of face masks (FMs); hence, FMs could be a potential source of exposure to phthalic acid esters (PAEs). India stands second in the world in terms of the FMs usage since the beginning of Covid-19 pandemic. However, little is known about the PAEs content of FMs used in India. Some PAEs, such as DEHP and DBP are suspected endocrine disrupting chemicals (EDCs); hence, wearing FM may increase the risk of exposure to these EDCs. In this study, we collected 91 samples of FMs from eight Indian cities and analyzed for five PAEs viz. DMP, DEP, DBP, BBP, and DEHP. The PAEs contents in FMs ranged from 101.79 to 27,948.64 ng/g. The carcinogenic risk of N 95 with filter, N-95, and cloth masks was higher than the threshold levels. The findings indicate the need to control PAEs in FMs through regulatory actions.

Determinants of phthalate exposures in pregnant women in New York City

Previous studies have provided data on determinants of phthalates in pregnant women, but results were disparate across regions. We aimed to identify the food groups and demographic factors that predict phthalate exposure in an urban contemporary pregnancy cohort in the US. The study included 450 pregnant women from the New York University Children's Health and Environment Study in New York City. Urinary concentrations of 22 phthalate metabolites, including metabolites of di-2-ethylhexylphthalate (DEHP), were determined at three time points across pregnancy by liquid chromatography coupled with tandem mass spectrometry. The Diet History Questionnaire II was completed by pregnant women at mid-pregnancy to assess dietary information. Linear mixed models were fitted to examine determinants of urinary phthalate metabolite concentrations. Using partial-linear single-index (PLSI) models, we assessed the major contributors, among ten food groups, to phthalate exposure. Metabolites of DEHP and its ortho-phthalate replacement, diisononyl phthalate (DiNP), were found in >90% of the samples. The sum of creatinine-adjusted DiNP metabolite concentrations was higher in older and single women and in samples collected in summer. Hispanic and non-Hispanic Black women had lower urinary concentrations of summed metabolites of di-n-octyl phthalate (DnOP), but higher concentrations of low molecular weight phthalates compared with non-Hispanic White women. Each doubling of grain products consumed was associated with a 20.9% increase in ∑DiNP concentrations (95%CI: 4.5, 39.9). PLSI models revealed that intake of dried beans and peas was the main dietary factor contributing to urinary ∑DEHP, ∑DiNP, and ∑DnOP levels, with contribution proportions of 76.3%, 35.8%, and 27.4%, respectively. Urinary metabolite levels of phthalates in pregnant women in NYC varied by age, marital status, seasonality, race/ethnicity, and diet. These results lend insight into the major determinants of phthalates levels, and may be used to identify exposure sources and guide interventions to reduce exposures in susceptible populations.

Systematic evaluation of the evidence for identification of endocrine disrupting properties of Bisphenol F

Identification of endocrine disruptors (EDs) is a highly prioritized issue in the EU. However, scientific criteria to identify EDs have so far only been implemented for biocidal and plant protection products. The European Commission is working on developing a horizontal approach to the identification of EDs across legislations, based on these scientific criteria. With this study, our aim was to evaluate evidence on endocrine disrupting properties of Bisphenol F (BPF) by applying the process set out for biocidal and plant protection products in Europe. BPF is not registered under REACH and therefore assumed not to be produced in the EU > 1 ton/year, yet the substance has been detected in urine, serum, and breast milk in populations from different countries in Europe. BPF is raising concern since it is an analogue of the known ED and reproductive toxicant Bisphenol A. Relevant evidence on endocrine disrupting properties of BPF from the open literature was collected using systematic review methodology. Pre-defined inclusion criteria were developed to select relevant studies, and data was extracted. The reliability of included studies was evaluated by the Science in Risk Assessment and Policy tool, and results were converted into Klimisch categories to allow for categorization of study reliability. A weight-of-evidence approach was used to analyze the evidence and draw conclusions on endocrine-related activity and/or endocrine adversity. We found that there is sufficient evidence to conclude on an endocrine mechanism, and while evidence for adversity was not considered sufficient, we still conclude that BPF could also cause endocrine-mediated adversity. Two modes of action were postulated based on the collected data for BPF. Challenges of performing the ED assessment for data-poor chemicals and the importance of adequate reporting of studies in the open literature, especially for new approach methods, are discussed.

Innovation in regulatory approaches for endocrine disrupting chemicals: The journey to risk assessment modernization in Canada

Globally, regulatory authorities grapple with the challenge of assessing the hazards and risks to human and ecosystem health that may result from exposure to chemicals that disrupt the normal functioning of endocrine systems. Rapidly increasing number of chemicals in commerce, coupled with the reliance on traditional, costly animal experiments for hazard characterization - often with limited sensitivity to many important mechanisms of endocrine disruption -, presents ongoing challenges for chemical regulation. The consequence is a limited number of chemicals for which there is sufficient data to assess if there is endocrine toxicity and hence few chemicals with thorough hazard characterization. To address this challenge, regulatory assessment of endocrine disrupting chemicals (EDCs) is benefiting from a revolution in toxicology that focuses on New Approach Methodologies (NAMs) to more rapidly identify, prioritize, and assess the potential risks from exposure to chemicals using novel, more efficient, and more mechanistically driven methodologies and tools. Incorporated into Integrated Approaches to Testing and Assessment (IATA) and guided by conceptual frameworks such as Adverse Outcome Pathways (AOPs), emerging approaches focus initially on molecular interactions between the test chemical and potentially vulnerable biological systems instead of the need for animal toxicity data. These new toxicity testing methods can be complemented with in silico and computational toxicology approaches, including those that predict chemical kinetics. Coupled with exposure data, these will inform risk-based decision-making approaches. Canada is part of a global network collaborating on building confidence in the use of NAMs for regulatory assessment of EDCs. Herein, we review the current approaches to EDC regulation globally (mainly from the perspective of human health), and provide a perspective on how the advances for regulatory testing and assessment can be applied and discuss the promises and challenges faced in adopting these novel approaches to minimize risks due to EDC exposure in Canada, and our world.

Development of the SciRAP Approach for Evaluating the Reliability and Relevance of in vitro Toxicity Data

Efficient and successful integration of data generated from non-animal test methods must rely on reliable and relevant data. It is important therefore to develop tools and criteria that facilitate scientifically sound, structured, and transparent evaluation of reliability and relevance of in vitro toxicity data to efficiently inform regulatory hazard and risk assessment. The Science in Risk Assessment and Policy (SciRAP) initiative aims to promote such overarching goals. We present the work to develop and refine the SciRAP tool for evaluation of reliability and relevance of in vitro studies for incorporation on the SciRAP web-based platform (www.scirap.org). In the SciRAP approach, reliability evaluation is based on criteria for reporting quality and methodological quality, and is explicitly separated from relevance evaluation. The SciRAP in vitro tool (version 1.0) was tested and evaluated during an expert test round (April 2019-September 2020) on three in vitro studies by thirty-one experts from regulatory authorities, industry and academia from different geographical areas and with various degree of experience in in vitro research and/or human health risk assessment. In addition, the experts answered an online survey to collect their feedback about the general features and desired characteristics of the tool for further refinement. The SciRAP in vitro tool (version 2.0) was revised based on the outcome of the expert test round (study evaluation and online survey) and consists of 24 criteria for evaluating “reporting quality” (reliability), 16 criteria for “methodological quality” (reliability), and 4 items for evaluating relevance of in vitro studies. Participants were generally positive about the adequacy, flexibility, and user-friendliness of the tool. The expert test round outlined the need to (i) revise the formulation of certain criteria; (ii) provide new or revised accompanying guidance for reporting quality and methodological quality criteria in the “test compounds and controls,” “test system,” and “data collection and analysis” domains; and (iii) provide revised guidance for relevance items, as general measures to reduce inter-expert variability. The SciRAP in vitro tool allows for a structured and transparent evaluation of in vitro studies for use in regulatory hazard and risk assessment of chemicals.

Integrated Risk Information System (IRIS) response to "Assessing risk of bias in human environmental epidemiology studies using three tools: different conclusions from different tools"

"Assessing risk of bias in human environmental epidemiology studies using three tools: different conclusions from different tools," a recent publication in this journal, applied the study evaluation approach developed by the U.S. Environmental Protection Agency's Integrated Risk Information System (IRIS), as well as other approaches, to a set of studies examining polybrominated diphenyl ethers (PBDEs) and neurodevelopment. They concluded that use of the IRIS approach resulted in exclusion of studies, which would lead to hazard conclusions based on an incomplete body of evidence. As scientists in the IRIS program, we support the comparison of approaches to improve systematic review methods for environmental exposures; however, we believe the IRIS approach was misrepresented. In this letter, we demonstrate that the ratings attributed to the IRIS approach were not consistent with our own application of the tool. We also clarify the use of studies rated as "low confidence" and the use of an overall study confidence rating in our systematic reviews. In conclusion, the IRIS study evaluation approach is a transparent method to inform certainty in our evidence synthesis decisions and ensures consistency in the development of IRIS health assessments.

Can phthalates move into the eggs of the loggerhead sea turtle Caretta caretta? The case of the nests on the Linosa Island in the Mediterranean Sea

During the monitoring of Caretta caretta nests on the island of Linosa, 30 unhatched eggs from four nests were collected to study the presence of phthalates in their three components (shell, yolk, and albumen). Four phthalates, namely diethyl (DEP), dibutyl (DBP), di-(2-ethylhexyl) (DEHP), and dioctyl (DOTP) phthalic acid esters (PAE), which are widely used as additives in plastics, were detected in all egg components. The most frequently found phthalate was DBP, followed by DEHP in eggshell and yolk. Dimethyl- (DMP) and butylbenzyl-phthalate (BBP) were below the limits of detection for all samples. The high total phthalate recorded in the yolk suggests that contamination could arise by vitellogenesis. PERMANOVA analysis (p = 0.01) confirmed significant differences in the PAEs contamination profiles in the eggs from the four nests. This study confirms the negative impact of plastic related compounds posing questions about the potential adverse effects on organisms and their conservation status.

Knowledge Organization Systems for Systematic Chemical Assessments

BACKGROUND

Although the implementation of systematic review and evidence mapping methods stands to improve the transparency and accuracy of chemical assessments, they also accentuate the challenges that assessors face in ensuring they have located and included all the evidence that is relevant to evaluating the potential health effects an exposure might be causing. This challenge of information retrieval can be characterized in terms of "semantic" and "conceptual" factors that render chemical assessments vulnerable to the streetlight effect.

OBJECTIVES

This commentary presents how controlled vocabularies, thesauruses, and ontologies contribute to overcoming the streetlight effect in information retrieval, making up the key components of Knowledge Organization Systems (KOSs) that enable more systematic access to assessment-relevant information than is currently achievable. The concept of Adverse Outcome Pathways is used to illustrate what a general KOS for use in chemical assessment could look like.

DISCUSSION

Ontologies are an underexploited element of effective knowledge organization in the environmental health sciences. Agreeing on and implementing ontologies in chemical assessment is a complex but tractable process with four fundamental steps. Successful implementation of ontologies would not only make currently fragmented information about health risks from chemical exposures vastly more accessible, it could ultimately enable computational methods for chemical assessment that can take advantage of the full richness of data described in natural language in primary studies. https://doi.org/10.1289/EHP6994.