Toxicology and Industrial Health最新文献

Flexible polyurethane foams (PUF) are used in many consumer products. PUF may contain trace levels of aromatic diamine impurities that could represent a potential health risk. The risk associated with sleeping on a PUF mattress was evaluated. Toxicity benchmarks for sensitization and non-cancer endpoints were derived from the respective points-of-departure using standard assessment factors. For the cancer endpoints, toxicity benchmarks were derived from the 25th-percentile values of animal studies. Recently published emission and migration data allowed to link exposure with the CertiPUR^TM voluntary quality limits of ≤5 mg.kg^-1 for 2,4-toluene diamine and 4,4'-methylene dianiline in PUF. Using conservative exposure scenarios, lifetime-average daily internal doses from the combined inhalation and dermal exposures were calculated. Margins of safety for non-cancer and sensitization endpoints were >10⁴. The theoretical excess cancer risk was ≤1.5 × 10^-7. It is concluded that sleeping on a mattress that satisfies the CertiPUR limit value does not pose undue risk to consumers.

Perovskite solar cells display potential as a renewable energy source because of their high-power conversion efficiency. However, there is limited understanding regarding the potential impact of perovskite on human health and the ecosystem. In this study, two sets of male Wistar albino rats received 35 injections of perovskite composite at a dosage of 0.372 mg/kg body weight. The animals underwent thorough examinations, encompassing morphometric, hematological, biochemical, histological, and behavioral analyses. Liver, kidney, and testis biopsies were processed and examined histologically. Additionally, two groups of mice (perovskite-treated and control mice, each with n = 10) underwent three behavioral tests: the Elevated Zero Maze test, Marble Burying test, and Light-Dark Box test. Perovskite-treated rats displayed a significant increase in levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, triglycerides, cholesterol, creatinine, blood urea nitrogen, white blood cells, and platelets. However, total bilirubin levels decreased, with no significant alteration in albumin values. Furthermore, exposure to perovskite composite resulted in a slight decrease in lactate dehydrogenase and red blood cell count. Histopathological examination revealed hepatic hydropic degeneration, Kupffer cells hypertrophy and hyperplasia, and renal hydropic degeneration, while testicular tissues remained unaffected. Moreover, behavioral changes were observed in perovskite-treated mice, including depression, anxiety, and compulsive burying activity. These findings suggest that exposure to perovskite can lead to significant hematological and biochemical changes, as well as hepatorenal histopathological alterations and behavioral changes. Additionally, chronic exposure to perovskite materials may induce structural and functional alterations in vital organs.

Mercury is a ubiquitous environmental xenobiotic; the primary sources of exposure to this metal are artisanal gold mining and the direct production of mercury. In Mexico, artisanal mercury mining continues to be an important activity in different regions of the country. Exposure to mercury vapors releases can have severe health impacts, including immunotoxic effects such as alterations in cytokine profiling. Therefore, in the present work, we evaluated the inflammatory cytokines profile in the blood serum of miners exposed to mercury. A cross-sectional observational study was performed on 27 mining workers (exposed group) and 20 control subjects (nonexposed group) from central Mexico. The mercury urine concentration (U-Hg) was determined by atomic absorption spectrometry, and IL-2, IL-6, IL-8, IL-10, and TNF-α were measured using a Multiplex Assay. The results showed that the U-Hg in the miners had a median value of 552.70 μg/g creatinine. All cytokines showed a significant increase in the miner group compared with the control group, except for TNF-α. In addition, we observed a positive correlation between U-Hg concentration and cytokine levels. In conclusion, mercury exposure correlated with cytokine levels (considered acute inflammatory marker) in miners; therefore, workers exposed to this metal show an acute systemic inflammation that could lead to alterations in other organs and systems.

Lead is one of the heavy metals that is toxic and widely distributed in the environment, and children are more sensitive to the toxic effects of lead because the blood-brain barrier and immune system are not yet well developed. The objective of the study was to investigate the clinical characteristics of lead poisoning in children aged 0∼6 years in a hospital in Guangxi, and to provide scientific basis for the prevention and treatment of lead poisoning. We collected and analyzed the clinical data of 32 children with lead poisoning admitted to a hospital in Guangxi from 2010 to 2018. The results showed that most of the 32 cases presented with hyperactivity, irritability, poor appetite, abdominal pain, diarrhea, or constipation. The hemoglobin (HGB), mean corpusular volume (MCV), mean corpuscular hemoglobin (MCH), and hematocrit (HCT) of the lead-poisoned children were all decreased to different degrees and were below normal acceptable levels. Urinary β₂-microglobulin was increased. Blood lead levels (BLL) decreased significantly after intravenous injection of the lead chelator, calcium disodium edetate (CaNa₂-EDTA). In addition, HGB returned to normal levels, while MCV, MCH, and HCT increased but remained below normal levels. Urinary β₂-microglobulin was reduced to normal levels. Therefore, in this cohort of children, the high-risk factors for lead poisoning are mainly Chinese medicines, such as baby powder. In conclusion, lead poisoning caused neurological damage and behavioral changes in children and decreased erythrocyte parameters, leading to digestive symptoms and renal impairment, which can be attenuated by CaNa₂-EDTA treatment.

This toxicology study was conducted to assess the impact of formaldehyde, a common air pollutant found in Chinese gymnasiums, on the brain function of athletes. In this research, a total of 24 Balb/c male mice of SPF-grade were divided into four groups, each consisting of six mice. The mice were exposed to formaldehyde at different concentrations, including 0 mg/m³, 0.5 mg/m³, 3.0 mg/m³, and 3.0 mg/m³ in combination with an injection of L-NMMA (N^G-monomethyl-L-arginine), which is a nitric oxide synthase antagonist. Following a one-week test period (8 h per day, over 7 days), measurements of biomarkers related to the nitric oxide (NO)/cGMP-cAMP signaling pathway were carried out on the experimental animals post-treatment. The study found that: (1) Exposure to formaldehyde can lead to brain cell apoptosis and neurotoxicity; (2) Additionally, formaldehyde exposure was found to alter the biomarkers of the NO/cGMP-cAMP signaling pathway, with some changes being statistically significant (p < 0.05 or p < 0.01); (3) The use of L-NMMA, an antagonist of the NO/cGMP-cAMP signaling pathway, was found to prevent these biomarker changes and had a protective effect on brain cells. The study suggests that the negative impact of formaldehyde on the brain function of mice is linked to the regulation of the NO/cGMP-cAMP signaling pathway.

Benzene, toluene, ethyl benzene, and xylene (BTEX) are prevalent pollutants in shoe industry-related workplaces. The aim of this study was to assess exposure to BTEX and their carcinogenic and non-carcinogenic risks in shoe-industry-related workplaces. This study was carried out at different shoe manufactures, small shoe workshop units, shoe markets, and shoe stores in Tabriz, Iran in 2021. Personal inhalation exposure to BTEX was measured using the National Institute for Occupational Safety and Health (NIOSH) 1501 method. Carcinogenic and non-carcinogenic risks due to inhalation exposure to BTEX were estimated by United States Environmental Protection Agency (U.S. EPA) method based on Mont Carlo simulation. Results showed that the concentrations of benzene and toluene were higher than the threshold limit value (TLV) in both gluing and non-gluing units of shoe manufactures. The total carcinogenic risk (TCR) due to exposure to benzene and ethyl benzene was considerable in all shoe industry-related workplaces. Also, the hazard index (HI) as a non-carcinogenic index was higher than standard levels in all shoe industry-related workplaces. Therefore, shoe industry-related workers are at cancer and non-cancer risks due to exposure to BTEX. Prevention measures need to be implemented to reduce the concentration of BTEX in shoe industry-related workplaces.

Male workers in copper smelting are exposed to copper, lead, and arsenic. This study aimed to assess the effects of combined exposure to these metals on male reproductive hormone levels and assesses malondialdehyde (MDA) as an oxidative stress parameter. The study was conducted on 40 copper smelter workers compared with 40 non-exposed workers. Laboratory investigations included levels of serum copper, blood lead, serum arsenic, follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and MDA. Levels of copper, arsenic, lead, FSH, and LH were significantly increased compared to controls. However, a statistically significant decrease in the mean value of testosterone was found among exposed workers. Positive correlations between serum copper and both serum FSH and MDA levels were statistically significant as were correlations between serum arsenic and MDA levels. Testosterone levels showed significant negative correlations with both copper and arsenic among exposed workers. A linear regression model of copper, arsenic, and lead levels as independent variables with FSH, LH, and testosterone as dependent variables revealed a significant negative association between serum copper and testosterone levels. The current study concluded that combined exposure to copper, arsenic, and lead in secondary copper smelters had a negative impact on male reproductive hormone levels that may be mediated by oxidative stress.

As a common additive in cigarette filters, nanosilica has been implemented to reduce the release of harmful substances in cigarette smoke. However, the potential risk of occupational exposure for cigarette factory workers is unknown. We collected physical examination data from 710 cigarette factory workers to evaluate the adverse effects of cigarette filter silica exposure. We also established mouse models induced by cigarette filter silica and crystalline silica separately to compare the lung inflammation, pulmonary function, apoptosis, and fibrosis of the two models. Workers in the rolling and packing workshop exposed to cigarette filter silica had a higher rate of abnormal lung function (17.75%) than those in the cutting workshop (0.87%). Animal experiments showed that compared with the same dose of crystalline silica, cigarette filter silica resulted in higher levels of inflammatory factors in the bronchoalveolar lavage fluid (BALF) of mice at day 7, and lower levels of total lung capacity (TLC), inspiratory capacity (IC), vital capacity (VC), and forced vital capacity (FVC) in mice at day 28. Additionally, both exposed groups of mice showed increased levels of caspase 3, collagen I (Col-Ⅰ), α-smooth muscle actin (α-SMA) and hydroxyproline (HYP) in the lungs, as well as collagen accumulation and fibrous nodules at day 28, with no significant difference between the two groups. The results suggested that cigarette filter silica caused more severe early lung inflammation and late ventilation impairment than the same dose of crystalline silica. In the future, we need to pay more attention to nanosilica protection in cigarette factories to prevent pulmonary dysfunction in workers.

The present study aimed to determine the prevalence of musculoskeletal pain, unfavorable working conditions, and assessment of occupational injuries among sawmill workers. The Nordic Musculoskeletal Questionnaire, measurement of handgrip strength, working environment, and occupational injuries were assessed among 135 sawmill workers participating in the study. The data showed that sawmill workers complained of discomfort (pain) felt primarily in the low back region of the body followed by the shoulders, hands, knees, upper back, and wrist. This study indicated that sawmill workers had less handgrip strength due to more intense manual work than control subjects. Based on the results of this study, it was concluded that sawmill workers were highly affected due to working in an awkward posture with manual material handling for an extended period of time and that these factors may lead to work-related musculoskeletal disorders as well as occupational injuries. Proper training, a proper work-rest schedule, and modifications of some working procedures may reduce injuries and work-related musculoskeletal pain.

Synthetic cosmetics, particularly hair dyes, are becoming increasingly popular among people of all ages and genders. 2,4,5,6-tetraaminopyrimidine sulfate (TAPS) is a key component of oxidative hair dyes and is used as a developer in several hair dyes. TAPS has previously been shown to absorb UVB strongly and degrade in a time-dependent manner, causing phototoxicity in human skin cells. However, the toxic effects of UVB-degraded TAPS are not explored in comparison to parent TAPS. Therefore, this research work aims to assess the toxicity of UVB-degraded TAPS than TAPS on two different test systems, that is, HaCaT (mammalian cell) and Staphylococcus aureus (a bacterial cell). Our result on HaCaT has illustrated that UVB-degraded TAPS is less toxic than parent TAPS. Additionally, UVB-exposed TAPS and parent TAPS were given to S. aureus, and the bacterial growth and their metabolic activity were assessed via CFU and phenotype microarray. The findings demonstrated that parent TAPS reduced bacterial growth via decreased metabolic activity; however, bacteria easily utilized the degraded TAPS. Thus, this study suggests that the products generated after UVB irradiation of TAPS is considered to be safer than their parent TAPS.