Toxicology and Industrial Health最新文献

This study aimed to estimate workers' occupational lifetime exposure to chrysotile and examine the respiratory symptoms and lung cancer risk. A total of 112 workers were interviewed about their occupational histories. Exposure modeling using information on the determinants of exposure was used to estimate chrysotile emissions. The cumulative lifetime exposure was then assessed for each worker. Respiratory symptoms were obtained using a validated questionnaire. Lung cancer mortality rate was also predicted using a model. Almost all the workers were male and young (mean age = 30 years, SD = 7). The estimated lifetime occupational chrysotile inhalation exposure ranged from 0.0001 to 0.0486 f/mL.years (median = 0.0018 f/mL.years, IQR = 0.486). A high prevalence of cough symptom (11.7%), and low estimated cancer risk (<1%) were reported. In conclusion, the lung cancer risk among our cohort of workers was at a low level because of lower cumulative lifetime occupational chrysotile exposure.

Women comprise approximately 40% of the global workforce, and many women continue to work during pregnancy. Although occupational exposure limit values (OELVs) are intended to protect all workers, many OELVs may have been established without consideration of the unique changes in pregnant workers, and many chemicals lack OELVs altogether. A short educational course was developed to address the informational needs of health professionals who have responsibility to ensure a safe workplace for pregnant employees. The course was designed to raise awareness of the key elements in risk management and their application to the pregnant worker, such as physiological changes of pregnancy that influence susceptibility to exposures; guidance for nonclinical data interpretation; exposure assessment and control strategies; and risk management in practice in a diverse regulatory environment. This paper summarizes the course content and is intended to support informed risk management decision making to protect the health of pregnant workers and their offspring.

Pyrethrin and pyrethroid are a relatively new class of pesticides with potent insecticidal properties. Pyrethrins are naturally occurring pesticides obtained from the Chrysanthemum cinerariaefolium flower, while pyrethroids are their synthetic derivatives. They are widely used as the insecticides of choice in agriculture, veterinary medicine, public health programs, and household activities. Pyrethrin, being a broad-spectrum insecticide kills a wide range of pests, while pyrethroids last longer in the environment owing to low susceptibility to sunlight, and greater stability and efficacy than parent molecules. Humans can be exposed through inhalation, ingestion, and dermal routes. Indoor usage of an insecticide poses a serious risk to human health, especially to women, children, and stay-at-home people. Although pyrethrin and pyrethroid are generally considered safe, sustained skin or inhalation exposure or direct contact with open wounds results in higher toxicity to mammals. There is a paucity of data on the impact of pyrethrin and pyrethroid on overall pulmonary health. The respiratory system, from the nose, nasal passages, airways, and bronchi to the pulmonary alveoli, is vulnerable to environmental contaminants such as pesticides because of its anatomical location as well as being a highly blood profused organ. Under and over-functioning of the respiratory system triggers diverse pathologies such as serious infections, allergies, asthma, metastatic malignancies, and auto-immune conditions. While the association between workplace-related pesticide exposures and respiratory diseases and symptoms is well documented, it is important to understand the adverse health impact of pyrethrin and pyrethroid on the general population for awareness and also for better regulation and implementation of the law.

In this presented study, the aim was to investigate the toxic effects of bisphenol S (BPS), one of the bisphenol A analogues, on the thyroid glands of male Wistar albino rats. Toward this aim, the rats (n = 28) were given a vehicle (control) or BPS at 3 different doses, comprising 20, 100, and 500 mg/kg of body weight (bw) via oral gavage for 28 days. According to the results, BPS led to numerous histopathological changes in the thyroid tissue. The average proliferation index values among the thyroid follicular cells (TFCs) displayed increases in all of the BPS groups, and significant differences were observed in the BPS-20 and BPS-100 groups. The average apoptotic index values in the TFCs were increased significantly in the BPS-500 group. The serum thyroid-stimulating hormone and serum free thyroxine levels did not show significant changes after exposure to BPS; however, the serum free triiodothyronine levels displayed significant decreases in all 3 of the BPS groups. BPS was determined to cause significant increases in the antioxidant enzyme activities of catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, as well as a significantly decreased content of reduced glutathione. The malondialdehyde level in the thyroid tissue was elevated significantly in the BPS-500 group. The data obtained herein revealed that BPS has thyroid-disrupting potential based on structural changes, follicle cell responses, and biochemical alterations including a decreased serum free triiodothyronine level and increased oxidative stress.

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.

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 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.

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.