An approach to classifying occupational exposures to endocrine disrupting chemicals by sex hormone function using an expert judgment process

Expert-based assessment of chemical and physical exposures, and organizational factors, in past agricultural jobs

BACKGROUND

Limited data document the spectrum of exposures in the agricultural environment. We describe here the wide range of chemical and physical agents, and organizational factors, encountered in agricultural jobs held in the past in Canada and abroad.

METHODS

We used data from a population-based case-control study of prostate cancer including 3,925 male participants residing in Montreal, Canada in 2005-2012. Lifetime occupational histories and detailed job descriptions were collected in-person. Industrial hygienists and an agronomist conducted semi-quantitative evaluations of exposure, including intensity and reliability, to some 300 chemical and physical agents in each job held. Analyses focused on the 156 agricultural jobs ever held in the study population. Clusters of agricultural co-exposures were derived.

RESULTS

Agricultural jobs had taken place in 1946-2012, 53% ending in 1970 or after. Jobs were often (43%) held in Quebec, Canada; 22% in Italy, Portugal or Greece, and 10% in Haiti. Jobs entailed exposure to an average of 10 chemical agents (±7) and most were characterized by long working hours, high physical activity levels, and did not provoke stress or anxiety. Few involved early morning shifts. Exposure to 78 agents was assigned with probable or definite certainty. The most common definite or probable carcinogens were ultraviolet radiation (92% of jobs), environmental tobacco smoke (39%), diesel engine exhaust (23%), wood dust (20%), lubricating oils and greases (20%) and lead (15%). Pesticide exposure (as a group) occurred in 31% of jobs. Fifty-four percent of jobs entailed exposure to ≥2 recognized carcinogens. Exposure clusters varied according to countries and type of agricultural activities (general, animal, crops, horticulture, vineyards, etc.).

CONCLUSIONS

Findings highlight the heterogeneity of exposure patterns in past agricultural environments based on their setting and activities involved. Studies on health-related effects of farming should account for numerous potential exposures, beyond their typical focus on pesticides.

Distinct Impacts of Prenatal and Postnatal Phthalate Exposure on Behavioral and Emotional Development in Children Aged 1.5 to 3 Years

Development is a continuous process, but few studies have assessed the simultaneous impact of prenatal and postnatal phthalate exposure on children's behavioral and emotional development. A total of 491 mother-child pairs from the general population in southern Taiwan were studied from 2021 to 2022. Urinary concentrations of bisphenol A (BPA) and phthalate metabolites-mono-ethyl phthalate (MEP), mono-n-butyl phthalate (MnBP), mono-benzyl phthalate (MBzP), and mono-2-ethylhexyl phthalate (MEHP)-were measured in pregnant mothers during the second trimester and in their corresponding children aged 1.5 to 3 years. Behavioral symptoms in children were evaluated using the Child Behavior Checklist (CBCL). Odds ratios (ORs) represent a 1-unit increase in log10-transformed creatinine-corrected maternal urine concentrations. Prenatal maternal urinary MnBP levels were associated with total problems (OR = 19.32, 95% CI: 1.80-43.13, p = 0.04), anxiety (OR = 33.58, 95% CI: 2.16-521.18, p = 0.01), and sleep problems (OR = 41.34, 95% CI: 1.04-1632.84, p = 0.04) in children. Additionally, urinary MnBP levels in children correlated with total problems (OR = 7.06, 95% CI: 1.01-49.05, p = 0.04) and internalizing problems (OR = 11.04, 95% CI: 1.27-95.72, p = 0.01). These findings suggest that prenatal and postnatal exposure to dibutyl phthalate (DBP), metabolized as MnBP, distinctly affects children's behavioral development.

Ketoconazole blocks progesterone production without affecting other parameters of cumulus-oocyte complex maturation

Ketoconazole (KTZ) is widely used as a fungicide, but it is also known to target steroid hormone formation which may affect female reproductive health. Our study aims to investigate the effects of KTZ on in vitro matured bovine cumulus-oocyte complexes (COCs), as a model for female reproductive toxicity. Cumulus cells of in vitro maturing COCs produce progesterone and pregnenolone, but exposure to 10-6 M KTZ effectively blocked the synthesis of these hormones. Exposure to lower concentrations of KTZ (i.e. 10-7 M and 10-8 M) had no such effect on steroidogenesis compared to the 0.1 % v/v DMSO vehicle control. Classical parameters of in vitro COC maturation, such as oocyte nuclear maturation to the metaphase II stage and expansion of the cumulus investment, were not affected by any KTZ concentration tested. Apoptosis and necrosis levels were also not altered in cumulus cells or oocytes exposed to KTZ. Moreover, oocytes exposed to KTZ during maturation showed normal cleavage and early embryo development up to day 8 post fertilization; albeit a statistically significant decrease was observed in day 8 blastocysts produced from oocytes exposed to the lowest concentration of 10-8 M KTZ. When unexposed mature oocytes were fertilized, followed by embryo culture for 8 days under KTZ exposure, no adverse effects in embryo cleavage and blastocyst formation were observed. In conclusion, KTZ has no major impact on in vitro bovine oocyte maturation and blastocyst formation in our study, even at concentrations blocking steroidogenesis.

Occurrence and Prioritization of Human Androgen Receptor Disruptors in Sewage Sludges Across China

The global practice of reusing sewage sludge in agriculture and its landfill disposal reintroduces environmental contaminants, posing risks to human and ecological health. This study screened sewage sludge from 30 Chinese cities for androgen receptor (AR) disruptors, utilizing a disruptor list from the Toxicology in the 21st Century program (Tox21), and identified 25 agonists and 33 antagonists across diverse use categories. Predominantly, natural products 5α-dihydrotestosterone and thymidine emerged as agonists, whereas the industrial intermediate caprolactam was the principal antagonist. In-house bioassays for identified disruptors displayed good alignment with Tox21 potency data, validating employing Tox21 toxicity data for theoretical toxicity estimations. Potency calculations revealed 5α-dihydrotestosterone and two pharmaceuticals (17β-trenbolone and testosterone isocaproate) as the most potent AR agonists and three dyes (rhodamine 6G, Victoria blue BO, and gentian violet) as antagonists. Theoretical effect contribution evaluations prioritized 5α-dihydrotestosterone and testosterone isocaproate as high-risk AR agonists and caprolactam, rhodamine 6G, and 8-hydroxyquinoline (as a biocide and a preservative) as key antagonists. Notably, 16 agonists and 20 antagonists were newly reported in the sludge, many exhibiting significant detection frequencies, concentrations, and/or toxicities, demanding future scrutiny. Our study presents an efficient strategy for estimating environmental sample toxicity and identifying key toxicants, thereby supporting the development of appropriate sludge management strategies.

Toxicity analysis of endocrine disrupting pesticides on non-target organisms: A critical analysis on toxicity mechanisms

Endocrine disrupting compounds are the chemicals which mimics the natural endocrine hormones and bind to the receptors made for the hormones. Upon binding they activate the cascade of reaction which leads to permanent activating of the signalling cycle and ultimately leads to uncontrolled growth. Pesticides are one of the endocrine disrupting chemicals which cause cancer, congenital birth defects, and reproductive defects in non-target organisms. Non-target organisms are keen on exposing to these pesticides. Although several studies have reported about the pesticide toxicity. But a critical analysis of pesticide toxicity and its role as endocrine disruptor is lacking. Therefore, the presented review literature is an endeavour to understand the role of the pesticides as endocrine disruptors. In addition, it discusses about the endocrine disruption, neurological disruption, genotoxicity, and ROS induced pesticide toxicity. Moreover, biochemical mechanisms of pesticide toxicity on non-target organisms have been presented. An insight on the chlorpyrifos toxicity on non-target organisms along with species names have been presented.

A "dilute-and-shoot" column-switching UHPLC-MS/MS procedure for the rapid determination of branched nonylphenol in human urine: method optimisation and some fundamental aspects of nonylphenol analysis

Technical grade branched nonylphenol (NP) was determined in human urine by online solid phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (SPE-UHPLC-MS/MS). Prior to analysis, urine specimens were simply diluted and enzymatically deconjugated. The run time of the chromatography, including SPE and re-equilibration, was 9 min per injection. The enzymatic cleavage of NP conjugates was optimised with incurred sample material from a human metabolism study: the highest recoveries were obtained with β-glucuronidase from E. coli K 12 in 0.1 M ammonium acetate at pH 6.5, within a minimal hydrolysis time of 30 to 60 min. Using sodium acetate instead of ammonium acetate led to systematically decreased recovery rates. The analytical method was validated regarding its precision (coefficients of variation: 2.9-7.4%), accuracy (relative recovery rates: 93-105%), robustness (relative recovery rates in individual urine matrices: 92-117%), selectivity, and limit of quantification (1.0 μg L^-1). Fundamental aspects in the analysis of technical product mixtures such as NP, comprising various isomers and homologues, were considered. Validation results, an exposure scenario and the application of the procedure to real samples, show that it enables a rugged monitoring of NP exposures above, at, and significantly below health-based guidance values, corresponding to daily NP intakes in the low μg kg^-1 d^-1 range. On the other hand, background levels in non-specifically exposed populations cannot be detected with this method. Hence, while alternative approaches should be pursued for NP analysis at environmental trace level, the speed and simplicity of our method are ideal for high-throughput human biomonitoring in occupational medicine.

Application of ToxCast/Tox21 data for toxicity mechanism-based evaluation and prioritization of environmental chemicals: Perspective and limitations

In response to the need to minimize the use of experimental animals, new approach methodologies (NAMs) using advanced technology have emerged in the 21st century. ToxCast/Tox21 aims to evaluate the adverse effects of chemicals quickly and efficiently using a high-throughput screening and to transform the paradigm of toxicity assessment into mechanism-based toxicity prediction. The ToxCast/Tox21 database, which contains extensive data from over 1400 assays with numerous biological targets and activity data for over 9000 chemicals, can be used for various purposes in the field of chemical prioritization and toxicity prediction. In this study, an overview of the database was explored to aid mechanism-based chemical prioritization and toxicity prediction. Implications for the utilization of the ToxCast/Tox21 database in chemical prioritization and toxicity prediction were derived. The research trends in ToxCast/Tox21 assay data were reviewed in the context of toxicity mechanism identification, chemical priority, environmental monitoring, assay development, and toxicity prediction. Finally, the potential applications and limitations of using ToxCast/Tox21 assay data in chemical risk assessment were discussed. The analysis of the toxicity mechanism-based assays of ToxCast/Tox21 will help in chemical prioritization and regulatory applications without the use of laboratory animals.

Correlation between urinary contents of some metals and fasting plasma glucose levels: A cross-sectional study in China

Many metals are involved in the pathogenesis of diabetes, but most of existing studies focused on single metals. The study of mixtures represents real-life exposure scenarios and deserves attention. This study aimed to explore the potential relationship of urinary copper (Cu), zinc (Zn), arsenic (As), selenium (Se), and strontium (Sr) contents with fasting plasma glucose (FPG) levels in 2766 participants. The levels of metals in urine were determined by inductively coupled plasma-mass spectrometry. We used linear regression models and the Bayesian kernel machine regression (BKMR) to evaluate the association between metals and FPG levels. In the multiple metals linear regression, Zn (β = 0.434), Se (β = 0.172), and Sr (β = -0.143) showed significant association with FPG levels (all P < 0.05). The BKMR model analysis showed that the results of single metal association were consistent with the multiple metals linear regression. The mixture of five metals had a positive over-all effect on FPG levels, and Zn (PIP = 1.000) contributed the most to the FPG levels. Cu and As were negatively correlated with FPG levels in women. The potential interaction effect between Cu and Sr was observed in participants aged ≥ 60 years old (Pinteraction = 0.035). In summary, our results suggested that multiple metals in urine are associated with FPG levels. Further studies are needed to confirm these findings and clarify the underlying mechanisms.