Toxicology and Industrial Health最新文献

Occupational exposure limits (OELs) and occupational exposure bands (OEBs) provide quantitative benchmarks for worker health protection. If empirical toxicology data are insufficient to derive an OEL, an OEB is often assigned using partial toxicology data along with other relevant hazard information. There is no consensus methodology to assign OEBs for chemicals lacking any empirical toxicology data. Thus, this study developed an in silico framework for OEB assignment of data poor compounds. It relies upon computational tools to evaluate standard toxicological end points and to assign reliability ratings, which are then used to assign Global Harmonization System (GHS) hazard categories. Subsequently, the hazard categories are entered into the National Institute for Occupational Safety and Health (NIOSH) occupational exposure banding tool to assign bands for individual end points as well as an overall OEB. As a proof-of-concept, five compounds with established OELs (i.e., "knowns") were evaluated. The knowns were assigned to overall OEBs C, D, or E, four of which were equal to or lower than the OEBs based on actual harmonized GHS categories as well as established OELs, indicating that the OEBs assigned using this framework are likely to be protective. Subsequently, five compounds with little to no experimental data and no established OELs from any U.S. agency or consensus OEL-setting organizations were evaluated (i.e., "unknowns"). The unknowns were assigned to overall OEBs D or E. It was concluded that the proposed framework can be used to assign protective OEBs to compounds with little to no toxicology testing data. As additional data become available, the compound may be de-risked, and a precautionary OEB (or an OEL) can be assigned. The proposed framework provides an example of a practical methodology to evaluate data poor compounds and shows that the output of this framework is expected to be protective of worker health.

Bis-(2-Chloroisopropyl) ether (BCIPE) was used as a solvent for fats, greases, paint, varnish removers, and in spotting and cleaning solutions. However, BCIPE has not been commercially manufactured or used for numerous years. In experimental animal studies, BCIPE is moderately toxic following acute oral, dermal, and inhalation routes of exposure. BCIPE is a severe eye irritant but not a dermal irritant or dermal sensitizer. BCIPE was not genotoxic or mutagenic in in vitro and in vivo assays; it was not toxic in a 3-generation reproductive dietary study in rats. Short-term, repeated inhalation and oral exposure in rats produced increased liver and kidney weights and congestion; dermal exposure in rabbits did not produce any observable adverse effects. BCIPE did not produce a statistically significant increase in tumors in two different 2-year dietary studies in mice and rats. In mice, technical grade BCIPE produced increased incidences of alveolar/bronchiolar adenomas in females, hepatocellular carcinomas in males, and a low incidence of forestomach hyperplasia (in both sexes at the high-dose). Further investigation with technical grade BCIPE concluded that these effects were species- and dose-specific with limited, if any, relevance to humans. The NOAEL of 400 ppm (15 mg/kg/day) from the 2-year dietary study in female rats was considered the point of departure for the health-based WEEL derivation. After adjustment for duration of exposure, interindividual variability, and intraindividual variability, an 8-h time-weighted average (TWA) WEEL value of 3 ppm (21 mg/m³) was derived. This exposure limit is expected to provide a significant margin of safety against any potential adverse health effects in workers.

The healthcare industry is one of the main industries with a high prevalence of musculoskeletal disorders (MSDs). Surgical practice mostly involves repetitive tasks with fine motor control, precise motions, high levels of mental concentration, and close visual focus. This cross-sectional study aimed to define the prevalence and risk factors of MSDs and visual problems among physicians. One hundred surgical physicians and one hundred medical physicians were involved in the study. Both groups underwent assessment of socio-demographic and occupational history, alongside evaluation for musculoskeletal and visual problems. The study revealed a significantly higher prevalence of MSDs, particularly neck and back pain, as well as blurred near vision and eye dryness, among surgical physicians compared to medical physicians. Risk factors for these conditions included long working hours (≥30 h/week) in clinics or operating rooms, as well as using endoscopes and microscopes/loupes during surgery. In conclusion, MSDs and visual problems were prevalent among physicians, particularly surgical physicians. Integrating ergonomic principles across all domains of healthcare and promoting healthcare worker awareness through training and intervention programs are crucial steps in addressing these issues.

The objective of establishing occupational exposure limits (OELs) is to utilize them as a risk management tool, ensuring the protection of workers' health and well-being from hazardous substances present in the workplace. To regulate and develop an OEL, it is essential to conduct toxicological studies on both animals and humans, to determine the dose-response relationship for each chemical compound, and to determine whether the dose-response relationship is linear or non-linear. Because the OELs suggested by different organizations or countries are just the result of their scientific methods, knowledge, and judgment, this does not confirm the applicability in other countries. Therefore, it is not scientific and logical to imitate the permissible limits recommended in Western countries. In most Western Asian nations, there is a significant difference in the suggested OEL levels between the reference organizations, and in assessing and managing a specific situation's risk, using any of the proposed OELs can lead to contradictory results. Suggestions for the development and improvement of the basics of determining the OELs for chemical pollution in West Asian countries have been made.

Benzene is associated with diverse occupational and public health hazards. It exhibits an ability to rapidly permeate the skin and contaminate water and food sources, leading to dermal and ingestion exposures. Despite numerous studies examining the associations between benzene and various indicators of harm, the findings have yielded inconsistent results. Furthermore, relying solely on air concentration as a measure of benzene exposure is limited, as it fails to account for internal exposure dose and individual susceptibility. This study aimed to conduct a comprehensive review in order to present current knowledge on benzene biomarkers and their significance in evaluating exposure levels and associated health hazards. The search methodology adhered to the PRISMA guidelines and involved the application of specific inclusion and exclusion criteria across multiple databases including PubMed, Embase, and Web of Science. Two researchers independently extracted and evaluated the relevant data based on predetermined criteria. Following the screening process, a total of 80 articles were considered eligible out of the initially retrieved 1053 articles after undergoing screening and assessment for inclusion. As the level of exposure decreased, specific biomarkers demonstrated a gradual increase in limitations, including heightened background concentrations and vulnerability to confounding factors. The advancement of sampling and analysis techniques will yield new biomarkers. Additionally, when conducting practical work, it is crucial to employ a comprehensive utilization of diverse biomarkers while excluding individual metabolic variations and combined exposure factors.

The study aimed to investigate the combined effects of chlorpyrifos and cypermethrin combined on dopaminergic neurotoxicity, motor behaviours and level of selected inflammatory proteins in rats compared to either alone for delineating an interaction between these two pesticides. The rotarod and grip strength tests were employed to assess neurobehavioural changes. The striatal dopamine content and expression of tyrosine hydroxylase (TH), α-synuclein, cyclooxygenase-2 (COX-2), and tumour necrosis factor-α (TNF-α) proteins in the nigrostriatal tissue were measured. Chlorpyrifos impaired the neurobehavioural indexes, reduced the striatal dopamine level, augmented the level of α-synuclein, COX-2, and TNF-α and attenuated the expression of TH similar to but a little less than cypermethrin. Half the dose of both pesticides together produced additional neurotoxicity compared with the usual (highest employed) dose of either alone. The results showed that chlorpyrifos induced moderately less dopaminergic neurotoxicity than cypermethrin. In the combination, they produced a little higher toxicity than either pesticide alone.

Dioxin-like compounds, recognized by the World Health Organization (WHO) as among the most enduring toxic chemical substances in the environment, are linked to various occupational activities and industrial accidents worldwide. The aim of this study was to examine and present research publications on dioxins, pinpoint current research trends, identify research gaps, and highlight potential avenues for future exploration in the field. The study period for relevant research articles ranged from 1923 to December 31, 2022, and these articles were sourced from the Scopus database. The analysis involved the identification of key contributors to the field and the visualization of topics, themes, and international collaboration. VOSviewer software (version 1.6.20) was used for visualization analysis. A total of 11,620 publications on dioxins were documented in the Scopus database. The predominant category of these documents comprised 9780 original articles, which represents 84.17% of the total publications. The United States lead in the number of publications, with 3992 (34.35%), followed by Japan, with 1429 (12.3%), China, with 1005 (8.65%), and Germany, with 974 (8.38%). Before 2002, scholarly attention in this field focused primarily on the health effects, environmental fate, and mechanism of toxicity of tetrachlorodibenzo-p-dioxin (TCDD). However, a noticeable change in research focus has been observed since 2002, highlighting the emergence of a topic related to the health effects and environmental fate of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PFDFs). This study is the first to conduct a comprehensive quantitative bibliometric analysis of dioxins over time. These findings indicate a significant increase in the overall growth of the dioxin literature over the past 30 years. These findings may prove crucial in guiding and organizing subsequent investigations related to dioxins.

Research has shown that exposure to bisphenol A (BPA), a widely used plasticizer, can lead to meiotic errors, resulting in poor reproductive cell quality and infertility. Health-related concerns have prompted the search for BPA alternatives; however, evidence suggests that currently used BPA analogs, such as bisphenol S (BPS), may pose similar risks to human health. While the effects of BPA on female fertility are well documented, the impact of BPA exposure on sperm quality is poorly understood. To better understand the effects of bisphenol analogs on spermatogenesis, we synthesized a less investigated BPA analog, tetramethyl bisphenol F (TMBPF), and compared its reprotoxic potential to that of widely used BPA and BPS using C. elegans-based assays. We evaluated germ cell count, spermatid size, morphology, and activation in males treated with 0.5 mM ethanol-dissolved bisphenol analogs for 48 h as well as their cross-progeny number and viability. Our results indicated that all of the evaluated bisphenol analogs-BPA, BPS, and TMBPF-adversely affect male fertility to varying degrees. Whereas all three bisphenols reduced spermatid size, only BPA exposure resulted in impaired spermatid activation and significantly reduced brood size. In addition, a decrease in embryonic viability, suggestive of an increased incidence of sperm chromosomal aberrations, was observed following exposure to all of the tested bisphenols. Further investigation is necessary to fully elucidate the underlying mechanisms and implications of BPA, BPS, and TMBPF on spermatogenesis.

The utilization of synthetic dyes increases the risk to human health. Despite the progress of information on azo dyes, very little attention has been reported on toxicity assessment of anthraquinone dyes. Solvent Blue 35 (SB35) is one of the anthraquinone dyes likely to be encountered because of its increasing use in various industries. Whereas the design of laboratory tests is very expensive, in silico screening was used to predict the metabolic profile and toxicity effect of SB35. MetaTox software was used to predict the metabolites of phase I and II in two layers. Since airborne exposure has been considered, the pathways of inhalation and dermal absorption of SB35 were investigated through the SwissADME model based on the modified Lipinski's rule of five. To predict the biological effect and toxicity of SB35 and each of the metabolites, PASS online software was used. Chemical activity was considered according to the probability of activation values (Pa) higher than the probability of inactivation values (Pi). N- dealkylation of SB35 was predicted in the first layer, while seven active compounds were obtained in the second layer from phases I and II reactions. Investigating the physicochemical properties of SB35 confirmed inhalation absorption for occupational exposure scenarios. All metabolites are absorbed from intestinal routes based on the RO5 rules. SB35 and their metabolites have an effective substrate role for the sub-type of CYP 450 enzymes. The toxicity effect of carcinogenicity for SB35 and mutagenicity for metabolites are predicted while confirmed with some biological effects. However, reproductive disorders are pointed with SB35 by probability higher than 70%. Virtual screening methods are efficient tools for creating cost-effective predictions in the hazard's evaluation of SB35. However, a perspective view is suggested before decision-making for laboratory designing tests.