Toxicology and Industrial Health

Bozok, Sahin; Karaagac, Erturk; Sener, Dila; Akakin, Dilek; Tumkaya, Levent

doi: 10.1177/07482337221139586pmid: 36383165

It is well-known that wireless communication technologies facilitate human life. However, the harmful effects of electromagnetic field (EMF) radiation on the human body should not be ignored. In the present study, we evaluated the effects of long-term, prenatal exposure to EMF radiation on the myocardium of rats at varying durations. Overall, 18 pregnant Sprague-Dawley rats were assigned into six groups (n = 3 in each group). In all groups other than the control group, three pregnant rats were exposed to EMF radiation (900, 1800 and 2100 MHz) for 6, 12 and 24 h over 20 days. After delivery, the newborn male pups were identified and six newborn male pups from each group were randomly selected. Then, histopathological and biochemical analysis of myocardial samples were performed. When 24-h/day prenatal exposures to 900, 1800, 2100 MHz EMF radiation were evaluated, myocardial damage was greater in the 2100 MHz EMF-24h group than the other groups. In addition, when malondialdehyde (MDA) and glutathione (GSH) levels associated with reactive oxidative species (ROS) were evaluated, the MDA level was higher in the 2100 MHz EMF-24h group compared with the other groups. The GSH level was also lower in the 2100 MHz EMF-24h group. When the 6, 12 and 24 h/day prenatal exposures to 1800 MHz EMF radiation were evaluated, myocardial damage was greater in 1800 MHz EMF-24h group than the remaining groups (p < 0.0001). Also, MDA level was greater in the 1800 MHz EMF-24h group compared with the other groups while the GSH level was lower in this group. It was shown that myocardial tissue was affected more by long-term exposure to EMF radiation at high frequencies. The data raise concerns that the harmful effects of non-ionizing radiation exposure on cardiac tissue will increase with 5G technology.

Zhong, Mingqing; Zhang, Ruoyu; He, Xianzhi; Fu, Yu; Cao, Yuqing; Li, Yuanyuan; Zhai, Qingfeng

doi: 10.1177/07482337221138949pmid: 36398892

Titanium dioxide nanoparticles (TiO2NPs) and cypermethrin (CPM) are widely used in various fields, and they can enter the environment in different ways. Combined exposure of TiO2NPs and CPM may increase the accumulation of pollutants in organisms and affect human health. This study was undertaken to evaluate the oxidative and inflammatory parameters associated with the combined exposure of TiO2NPs and CPM in rats. Twenty-four healthy male adult SD rats were randomly divided into four groups. The first group served as the control, while groups 2, 3, and 4 were treated with TiO2NPs (450 mg/m3); CPM (6.67 mg/m3) or combined exposure of TiO2NPs and CPM by inhalation for 90 days. We investigated the oxidative damage induced through combined exposure of TiO2NPs and CPM in rats by evaluating hematology of the rats and determining the blood biochemical index. Our results demonstrated that inhalation of TiO2NPs and CPM increased the levels of oxidative stress markers such as malondialdehyde and alkaline phosphatase in the serum of rats. These were accompanied by a decreased glutathione peroxidase and total superoxide dismutase levels. Furthermore, the level of glutathione peroxidase was further decreased while malondialdehyde was increased in the combined exposure of TiO2NPs and CPM. Interestingly, pathological sections showed that different degrees of tissue injury could be seen in the liver and lung tissues of each exposure group. In summary, the combined exposure of TiO2NPs and CPM can cause increased oxidative damage in rats and damage the tissue structure of the liver and lung.

Rafieepour, Athena; R Azari, Mansour; Khodagholi, Fariba

doi: 10.1177/07482337221140644pmid: 36433804

Airborne crystalline silica (SiO2) particles are one of the most common pollutants in stone industries. Limited studies have investigated the health effects of crystalline SiO2 nanoparticles. Hence, the objective of this study was to study the cytotoxicity of SiO2 in nano and micron sizes. A mineral quartz sample in the range of 0.2–0.8 mm sizes was purchased. These particles were ground at about 5 and 0.1 microns. Human cell line A549 was exposed to micro and nanometer particles at concentrations of 10, 50, 100, and 250 μg/ml for 24 and 72 h. Subsequently, the cytotoxicity of exposed cells was investigated by measuring cell survival, ROS generation, mitochondrial permeability, and intracellular glutathione content. The results showed that crystalline SiO2 nano and microparticles decreased cell survival, increased ROS generation, damaged the mitochondrial membrane, and lowered the antioxidant content of these cells in a concentration- and time-dependent manner. The toxicity of crystalline SiO2 microparticles at concentrations ≤50 μg/mL was greater than for nanoparticles, which was the opposite at concentrations ≥100 μg/mL. Exposure time and concentration were crucial factors for the cytotoxicity of exposed A549 cells to crystalline SiO2 particles, which can affect the severity of the effect of particle size. Due to the limitation of exposure concentration and test durations in this study, further studies on the parameters of nanoparticle toxicity and underlying mechanisms could advance our knowledge.

Paridokht, Fatemeh; Soury, Shiva; Karimi Zeverdegani, Sara

doi: 10.1177/07482337221144143pmid: 36464906

Computational fluid dynamics (CFD) is an indispensable simulation tool for predicting the emission of pollutants in the work environment. Welding is one of the most common industrial processes that might expose the operators and surrounding workers to certain hazardous gaseous metal fumes. In the present study, we used computational fluid dynamics (CFD) methodology for simulating the emission of iron fumes from the shielded metal arc welding (SMAW) procedure. A galvanized steel chamber was fabricated to measure the pollutant concentration and identify the size of the fume created by the SMAW. Then, the emission of welding aerosol was simulated using a method of computational fluid-particle dynamics with the ANSYS 2020 R1 software. The highest amount of welding fumes concentration was related to iron fumes (i.e., 3045 μg/m3 with a diameter of 0.25 μm). The results of the current study indicated that the local exhaust and general ventilation system can prevent the spreading of welding fumes to the welder’s breathing zone and the surrounding environment. CFD was also found to be an efficient method for predicting the emission of the iron fumes created by SMAW as well as for selecting an appropriate ventilation system. However, further studies that take the modeling of welding-generated emission of additional metal particles and gases into account will need to be undertaken.

Lynch, Heather N; Gloekler, Lauren E; Allen, Laura H; Maskrey, Joshua R; Bevan, Christopher; Maier, Andrew

doi: 10.1177/07482337221140946pmid: 36420912

The United States Environmental Protection Agency (EPA) regulates chemical manufacture, import, processing, distribution, use, and disposal under the 2016 amended Toxic Substances Control Act (TSCA) for the purposes of protecting the public and sensitive populations—including workers—from chemical exposure risk. The publication of several TSCA risk evaluations provided a unique opportunity to evaluate the evolving regulatory approach for assessing the dermal exposure pathway in occupational settings. In this analysis, the occupational dermal exposure assessment methods employed in several TSCA risk evaluations were assessed. Specifically, a methodology review was conducted for the occupational dermal scenarios of manufacturing and feedstock use in the risk evaluations of three chlorinated organic chemicals: trichloroethylene, carbon tetrachloride, and perchloroethylene. Additionally, alternative exposure estimates were generated using the exposure model IH SkinPermTM. The review and alternative exposure analyses indicate that the current TSCA modeling approach may generate total dermal absorbed doses for chlorinated chemical manufacturing and feedstock use scenarios that are 2- to 20-fold higher than those generated by IH SkinPerm. Best-practice recommendations developed in the methodology review support a tiered, integrated approach to dermal exposure assessment that emphasizes collecting qualitative data; employing validated, peer-reviewed models that align with current industrial practices; and gathering empirical sampling data where needed. Collaboration among industry, EPA, and other stakeholders to share information and develop a standard approach to exposure assessment under TSCA would improve the methodological rigor of, and increase confidence in, the risk evaluation results.