Chronic exposure to metal fume PM2.5 on inflammation and stress hormone cortisol in shipyard workers: A repeat measurement study

Effects of occupational exposure to metal fume PM2.5 on lung function and biomarkers among shipyard workers: a 3-year prospective cohort study

OBJECTIVE

This study investigates the associations of α1-antitrypsin, inter-α-trypsin inhibitor heavy chain (ITIH4), and 8-isoprostane with lung function in shipyard workers exposed to occupational metal fume fine particulate matter (PM2.5), which is known to be associated with adverse respiratory outcomes.

METHODS

A 3-year follow-up study was conducted on 180 shipyard workers with 262 measurements. Personal exposure to welding fume PM2.5 was collected for an 8-h working day. Pre-exposure, post-exposure, and delta (∆) levels of α1-antitrypsin, ITIH4, and 8-isoprostane were determined in urine using enzyme-linked immunosorbent assays. Post-exposure urinary metals were sampled at the beginning of the next working day and analyzed by inductively coupled plasma-mass spectrometry. Lung function measurements were also conducted the next working day for post-exposure.

RESULTS

An IQR increase in PM2.5 was associated with decreases of 2.157% in FEV1, 2.806% in PEF, 4.328% in FEF25%, 5.047% in FEF50%, and 7.205% in FEF75%. An IQR increase in PM2.5 led to increases of 42.155 µg/g in ∆α1-antitrypsin and 16.273 µg/g in ∆ITIH4. Notably, IQR increases in various urinary metals were associated with increases in specific biomarkers, such as post-urinary α1-antitrypsin and ITIH4. Moreover, increases in ∆ α1-antitrypsin and ∆ITIH4 were associated with decreases in FEV1/FVC by 0.008% and 0.020%, respectively, and an increase in ∆8-isoprostane resulted in a 1.538% decline in FVC.

CONCLUSION

Our study suggests that urinary α1-antitrypsin and ITIH4 could indicate early lung function decline in shipyard workers exposed to metal fume PM2.5, underscoring the need for better safety and health monitoring to reduce respiratory risks.

Combined effect of seawater and load on methacrylate adhesive

Although the shipbuilding industry is constantly demanding new advanced joining solutions, adhesive technology is not as developed in the marine as compared to other industries. The main reason is the lack of specific knowledge that guarantees the durability of the bonded joints in optimal conditions during the life cycle of a ship. This work simulates in the laboratory a marine-like environment by immersing an adhesive in seawater and subjecting it to constant loading. The objective is to characterize the seawater absorption behavior and its consequences on the mechanical, thermal, and chemical properties of the adhesive after this aging process. Seawater ingress was determined through gravimetric tests at several load conditions of the tensile strength of the adhesive. Besides, absorption process was studied using Fick's Law, determining the diffusion coefficients. The thermal behavior was monitored with differential scanning calorimetry (DSC) and the chemical degradation was analyzed using Fourier transform infrared spectroscopy (FTIR). Also, the mechanical properties were determined by tensile tests. The surface of the adhesive (dried) was studied by Scanning Electron Microscopy (SEM) technique and the porosity was measured by physisorption with a high-performance adsorption analyzer. A numerical simulation was developed using Darcy's Law combined with continuity equation. The results show that application of loads and immersion in seawater until full saturation of seawater improve the mechanical properties of the adhesive, but it affects negatively to the glass transition temperature. This should be considered when designing adhesive bonding joints on ships.

Metal Exposure-Related Welder's Pneumoconiosis and Lung Function: A Cross-Sectional Study in a Container Factory of China

Long-term inhalation of welding fume at high exposure can cause welder's pneumoconiosis, and metals in welding dust are associated with respiratory dysfunction. This cross-sectional study, which contains 384 Chinese male workers who were or had been working in a container factory, aimed to assess the potential risk of haemal and urinary metal content in welder's pneumoconiosis. Further, we investigated their effects on lung function parameters. Metal content and lung function were measured using inductively coupled plasma-mass spectrometry (ICP-MS) and spirometer, respectively. The concentration and metal content of respirable dust as well as total dust were collected at this container factory. Lung function of cases with welder's pneumoconiosis was significantly worse, as indicated by lower values of FVC, FVC% predicted, FEV1, FEV1% predicted, MEF25% predicted, and MMEF% predicted (p < 0.05). Results of logistic regression models showed that haemal Cr and Zn were risk factors of welder's pneumoconiosis (OR = 4.98, 95%CI: 1.73-21.20, p = 0.009 for Cr; OR = 5.23, 95%CI: 1.56-41.08, p = 0.033 for Zn) after adjusted with age, BMI, working years, welding dust exposure years, and smoking status. Multiple linear regression models showed that several metals (haemal Cd and Pb; urinary Cd and Fe) were significantly associated with different lung function indices in the welder's pneumoconiosis group. Compared to non-welders, welders were exposed to considerably higher levels of respirable dust, total dust, and six kinds of metals (p < 0.05). In conclusion, haemal Cr and Zn are positively related to welder's pneumoconiosis. Meanwhile, Cd and Pb might worsen lung function in welder's pneumoconiosis.

Clinical association between trace elements of tear and dry eye metrics

Trace elements exposure is proposed to play a role in the pathogenesis of the systemic disease. Emerging studies have suggested that trace metal exposure may contribute to dry eye disease. Our study primarily aimed to investigate the association between trace metal exposure in tear samples and the presence of dry eye metrics in the shipyard industry. Overall, 84 eligible participants from the shipyard industry were included in this cross-sectional study. The parameters for identifying dry eye symptoms included O.S.D.I., SPEED, N.I.B.U.T., and ocular surface conditions, such as tear meniscus height, eye blinking, and meibomian gland area were performed by S.B.M. sistemi ocular surface analyzer. The concentration of tear trace elements was detected by inductively coupled plasma mass spectroscopy (ICP-MS). The association between tear trace elements and dry eye parameters was investigated using regression models. Participants in the exposure group had significantly higher levels of tear Pb than the control group. In the exposure group, tear Pb was significantly associated with increased SPEED and O.S.D.I. score with beta coefficients of 0.144 (95% CI 0.092, 0.197), 0.121 (95% CI 0.049, 0.194), respectively, and decreased lower and upper meibomian gland area with beta coefficients of - 0.158 (- 0.283, - 0.033) and - 0.228 (- 0.396, - 0.061), respectively. Tear trace elements exposure is considered to impact the appearance of dry eye metrics. Improving the occupational environment and monitoring the ocular surface health may benefit workers under exposure to trace elements.

Variations of Personal Exposure to Particulate Nitrated Phenols from Heating Energy Renovation in China: The First Assessment on Associated Toxicological Impacts with Particle Size Distributions

The clean heating renovation has been executed for improving particulate matter (PM) pollution in northern China since 2017. This study determined particle size distributions of nitrated phenols (NPs) in personal exposure samples and their associations with biomarkers in saliva and urine from homemakers in rural households of the Fenwei Plain, China. Remarkable reductions of 28.6-66.3% and 52.2-82.4% on PMs and total quantified NPs, respectively, were found with the substitutions of raw coal chunk and biomass by advanced clean coal. 4-Nitroguaiacol (4NG) showed the largest reductions of 81.2% among individual NP. In addition, the clean coal efficiently reduced interleukin-6 (IL-6) and 8-hydrox-2'-deoxyguanosine (8-OHdG) in the urine and saliva by 12-72%. Furthermore, significant positive correlations between urinary 8-OHdG with most of NPs in all particle sizes, urinary IL-6 with 4NG for particles with D_p > 2.5 μm and D_p = 0.25-1.0 μm and salivary IL-6 with 4-nitrocatechol and 4-methyl-5-nitrocatechol for particles with D_p > 2.5 μm, D_p = 0.5-1.0 μm, and D_p < 0.25 μm were observed but not for salivary 8-OHdG or PMs. The results provide scientific support for the clean energy reformation and demonstrate the strong particle size dependence between NPs and biomarkers.

Associations between Biomarkers of Metal Exposure and Dry Eye Metrics in Shipyard Welders: A Cross-Sectional Study

Shipyard welders are often exposed to welding metal fumes. Ocular surfaces are continually exposed to environmental hazards. However, limited information on the associations between metal exposure and dry eye metrics in occupational settings is available. This study employed a cross-sectional design that involved the participation of 59 welders and 25 administrative staff in a shipyard in northern Taiwan from September 2020 to October 2020. The participants' individual information, laboratory data, exposure to particulate matter < 2.5 μm, urinary, and toenail metal concentrations were collected. Dry eye metrics were evaluated using standardized questionnaires and a noninvasive ocular surface analyzer. Urinary V and Cr and toenail V, Cr, Mn, Fe, Ni, Zn, As, and Cd and Pb were significantly higher in the exposed group than in the control group. After adjustment for confounding factors, dry eye metrics were associated with urinary Cd (β = 0.407; p = 0.007) and toenail Pb (β = 0.482; p = 0.002). The participants with higher urinary Cd exhibited higher odds ratios for elevated dry eye metrics. Our study revealed that exposure to welding procedures increases several metal biomarkers. In addition, urinary Cd, and toenail Pb might be related to dry eye disease in shipyard welders.

Zinc Oxide Nanoparticles Promote YAP/TAZ Nuclear Localization in Alveolar Epithelial Type II Cells

We investigated roles of Hippo signaling pathway components in alveolar type II cells (AECII) after zinc oxide nanoparticle (ZnONP) exposure. ZnONPs physicochemistry was characterized using field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray (EDX) microanalysis. ZnONP deposition in human respiratory tract was estimated using multiple-path particle dosimetry (MPPD) model. MLE-12 AECII were cultured and exposed to 0, 1, and 5 μg/mL of ZnONPs for 24 h. Western blots were used to investigate signaling pathways associated with Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ), cell adherens junctions, differentiation, and senescence. ZnONPs morphology was irregular, with Zn and O identified. Approximately 72% of inhaled ZnONPs were deposited in lungs, with 26% being deposited in alveolar regions. ZnONP exposure increased nuclear YAP expression and decreased cytoplasmic YAP expression by AECII. Adherens junction proteins, E-cadherin, α-catenin, and β-catenin, on AECII decreased after ZnONP exposure. ZnONP exposure of AECII increased alveolar type I (AECI) transition protein, LGALS3, and the AECI protein, T1α, while decreasing AECII SPC expression. ZnONP exposure induced Sirt1 and p53 senescence proteins by AECII. Our findings showed that inhalable ZnONPs can deposit in alveoli, which promotes YAP nuclear localization in AECII, resulting in decrease tight junctions, cell differentiation, and cell senescence.