The Relationship between Exposure to Lead-Containing Welding Fumes and the Levels of Reproductive Hormones

Effects of PM2.5 Metal Components Derived From Porcine Farm Exposure on Sperm Function in Mice

This study aimed to identify the effects of major metal components present in particulate matter (PM)2.5 on the reproductive system, sperm function, and embryo development. Through intratracheal instillation, male mice were exposed to various concentrations of metal components, including calcium oxide (Ca), iron oxide (Fe), aluminum oxide (Al), zinc oxide (Zn), lead oxide (Pb), and a mixture of these metals, in PM2.5 collected from the porcine farm. After 14 days, testicular inflammation and abnormal sperm morphology were observed in the exposed mice. These results indicate that such metal exposure enhances inflammatory cytokines in the testis and oxidative stress-induced apoptosis. Moreover, the exposure influenced sperm deformation, capacitation status, testosterone levels, and testosterone biosynthesis. Importantly, embryo development was also found to be impacted due to decreased sperm fertility. This study demonstrates that major metal components of PM2.5 derived from porcine farm pose adverse effects on the male reproductive system.

Assessing Long-Term Impacts of Occupational Welding Fume Exposure on Respiratory Health: A 5-Year Retrospective Cohort Analysis

BACKGROUND

Welding in automobile manufacturing exposes workers to harmful fumes, impacting pulmonary function. This study examined changes in pulmonary function among welders.

METHODS

A retrospective cohort study was conducted on 1200 welders and 1200 administrative staff in the automotive industry from 2018 to 2022. Pulmonary function tests were performed according to ATS guidelines, and metal fume sampling for copper, iron, and lead was conducted in welders' respiratory zones.

RESULTS

The mean concentrations of Cu, Pb, and Fe were 0.124, 0.117, and 1.42 mg/m 3 , respectively. Pb exceeded TLV-TWA. Welders showed significantly lower pulmonary function compared with the control group ( P < 0.05).

CONCLUSIONS

Prolonged exposure to welding fumes significantly reduces pulmonary function, necessitating preventive measures.

Exposure and Health Risks Posed by Potentially Toxic Elements in Soils of Metal Fabrication Workshops in Mbarara City, Uganda

Metal fabrication workshops (MFWs) are common businesses in Ugandan cities, and especially those producing metallic security gates, window and door frames (burglar-proof), and balcony and staircase rails. The objective of this study was to comparatively assess the pollution levels and potential health risks of manganese (Mn), chromium (Cr), cadmium (Cd), lead (Pd) and nickel (Ni) in pooled surface soil samples from four 5-, 7-, 8-, and 10-year-old MFWs (n = 28) and a control site (n = 8) in Mbarara City, Uganda. The concentration of the potentially toxic elements (PTEs) was determined using inductively coupled plasma-optical emission spectrometry. Contamination, ecological, and human health risk assessment indices and models were used to identify any risks that the PTEs could pose to the pristine environment and humans. Our results showed that PTE pollution of soils is occuring in the MFWs than at the control site. The mean concentrations of the PTEs (mg kg-1) in the samples were: Mn (2012.75 ± 0.23-3377.14 ± 0.31), Cr (237.55 ± 0.29-424.93 ± 0.31), Cd (0.73 ± 0.13-1.29 ± 0.02), Pb (107.80 ± 0.23-262.01 ± 0.19), and Ni (74.85 ± 0.25-211.37 ± 0.14). These results indicate that the PTEs could plausibly derive from the fabrication activities in these workshops, which is supported by the high values of contamination factors, index of geoaccumulation, and the overall increase in pollution load indices with the number of years of operation of the MFWs. Human health risk assessment showed that there are non-carcinogenic health risks that could be experienced by children who ingest PTEs in the soils from the 7-, 8- and 10-year-old MFWs. The incremental life cancer risk assessment suggested that there are potential cancerous health effects of Cd and Ni that could be experienced in children (who ingest soils from all the four MFWs) and adults (ingesting soils from the 8- and 10-year-old MFWs). This study underscores the need to implement regulatory guidelines on the operation and location of MFWs in Uganda. Further research should be undertaken to investigate the emission of the PTEs during welding operations in the MFWs.

Zinc improves sexual performance and erectile function by preventing penile oxidative injury and upregulating circulating testosterone in lead-exposed rats

AIM

The present study evaluated the effect of lead exposure with and without zinc therapy on male sexual and erectile function.

METHODS

Twenty male Wistar rats were randomly assigned into four groups; the control, zinc-treated, lead-exposed, lead + zinc-treated groups. Administrations were per os daily for 28 days.

RESULTS

Zinc co-administration significantly improved absolute and relative penile weights and the latencies and frequencies of mount, intromission, and ejaculation in lead-exposed rats. Also, zinc ameliorated lead-induced reductions in motivation to mate and penile reflex/erection. These findings were accompanied by attenuation of lead-induced suppression of circulating nitric oxide (NO), penile cyclic guanosine monophosphate (cGMP), dopamine, serum luteinizing hormone, follicle-stimulating hormone, and testosterone. In addition, zinc alleviated lead-induced upregulation of penile activities of acetylcholinesterase and xanthine oxidase (XO), and uric acid (UA) and malondialdehyde (MDA) levels. Furthermore, zinc ameliorated the lead-induced decline in penile nuclear factor erythroid 2-related factor 2 (Nrf2) and reduced glutathione (GSH) levels, and catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) activities.

CONCLUSION

This study revealed that co-administration of zinc improves lead-induced sexual and erectile dysfunction by suppressing XO/UA-driven oxidative stress and upregulating testosterone via Nrf2-mediated signaling.

Expression deregulation of genes related to DNA repair and lead toxicity in occupationally exposed industrial workers

OBJECTIVE

Globally millions of people working in various industries and are exposed to different toxins which may affect their genetic stability and DNA integrity. Present study was designed to estimate the expression variation of genes related to DNA repair (XRCC1, PARP1) and lead toxicity (ALAD) in exposed industrial workers.

METHODS

About 200 blood samples were collected from workers of brick kiln, welding, furniture and paint industry (50/industry) along with age and gender matched controls. mRNA expression of genes was measured using RT-PCR. Serum levels of total ROS, POD, TBAR activity was calculated. Blood lead levels were estimated by atomic absorption spectrometer.

RESULTS

Relative expression of XRCC1 and PARP1 gene was significantly (P < 0.001) upregulated, while ALAD gene expression was downregulated in exposed group compared to control. Expression of XRCC1 and PARP1 was increased (P < 0.001) in exposed workers with > 30 year age compared to control with > 30 year age. Same was observed when < 30 year age group of control and exposed was compared. Likewise, XRCC1 and PARP1 expression was increased (P < 0.001) in exposed workers with > 30 year age compared to workers with < 30 year age. Whereas, ALAD gene showed significant (P < 0.01) decrease in > 30 year age workers compared to control of same age and exposed with < 30 year of age. Relative expression of XRCC1 and PARP1 was increased (P < 0.001) in exposed smokers compared to exposed non-smokers and control smokers. Whereas, ALAD gene expression reduced (P < 0.001) significantly in both groups. Blood lead content was higher (P < 0.001) in exposed group compared to control. Strong correlation was observed between XRCC1, PARP1 and ALAD gene versus age, total exposure duration, exposure per day and lead deposition. ROS, TBARS and POD activity was higher (P < 0.01) in exposed group compared to control group.

CONCLUSION

Present study suggested deregulation of genes related to DNA repair and lead intoxication in exposed group compared to controls. Strong correlation was observed between selected genes and demographic parameters. Present results revealed altered activity of oxidative stress markers which would induce oxidative damage to DNA integrity and limit the function of repair enzymes.

Toxicity of Heavy Metals and Recent Advances in Their Removal: A Review

Natural and anthropogenic sources of metals in the ecosystem are perpetually increasing; consequently, heavy metal (HM) accumulation has become a major environmental concern. Human exposure to HMs has increased dramatically due to the industrial activities of the 20th century. Mercury, arsenic lead, chrome, and cadmium have been the most prevalent HMs that have caused human toxicity. Poisonings can be acute or chronic following exposure via water, air, or food. The bioaccumulation of these HMs results in a variety of toxic effects on various tissues and organs. Comparing the mechanisms of action reveals that these metals induce toxicity via similar pathways, including the production of reactive oxygen species, the inactivation of enzymes, and oxidative stress. The conventional techniques employed for the elimination of HMs are deemed inadequate when the HM concentration is less than 100 mg/L. In addition, these methods exhibit certain limitations, including the production of secondary pollutants, a high demand for energy and chemicals, and reduced cost-effectiveness. As a result, the employment of microbial bioremediation for the purpose of HM detoxification has emerged as a viable solution, given that microorganisms, including fungi and bacteria, exhibit superior biosorption and bio-accumulation capabilities. This review deals with HM uptake and toxicity mechanisms associated with HMs, and will increase our knowledge on their toxic effects on the body organs, leading to better management of metal poisoning. This review aims to enhance comprehension and offer sources for the judicious selection of microbial remediation technology for the detoxification of HMs. Microbial-based solutions that are sustainable could potentially offer crucial and cost-effective methods for reducing the toxicity of HMs.

Occupational Exposure to Metal Fumes Among Iranian Welders: Systematic Review and Simulation-Based Health Risk Assessment

There have been numerous reports of welder's worker exposure to metal fumes. Carcinogenic and non-carcinogenic (neurological, dermal, and etc.) effects are the adverse outcomes of exposure to welding fumes. In this review study, data were collected from previous studies conducted in Iran from 1900 to 2020. The risk of carcinogenicity and non-carcinogenicity due to exposure to welding metal fumes was assessed using the United States Environmental Protection Agency (USEPA) method based on the Monte Carlo simulation (MCS). Results showed mean of metal fume concentration in gas welding was in the range of 1.8248 to 1060.6 (µg/m³) and in arc welding was 54.935 to 4882.72 (µg/m³). The mean concentration of fumes in gas welding is below the recommended American Conference of Governmental Industrial Hygienists (ACGIH) standard exposure limit except for manganese, and in the arc welding, all metal fume concentrations are below the standard exposure limit except for manganese and aluminum. The results showed that the risk of carcinogenicity due to exposure to nickel, manganese in both gas and arc welding, and cadmium in gas welding was higher than standard level (hazard quotient (HQ) more than 1). Cancer risk due to exposure to nickel in both gas and arc welding was probable (1 × 10^-6 < cancer risk (CR) < 1 × 10^-4). Health risk assessment showed that welders are exposed to health risks. Preventive measures should be applied in welding workplaces to reduce the concentrations of metal fumes.

Occupational Exposure to Physical and Chemical Risk Factors: A Systematic Review of Reproductive Pathophysiological Effects in Women and Men

The human reproductive system can be affected by occupational exposure to many physical and chemical risk factors. This study was carried out to review the studies conducted on the issue of the pathophysiological effects of occupational physical and chemical risk factors on the reproductive system of females and males. In this systematic review, the databases such as "Google Scholar," "Pub-Med," "Scopus," and "Web of Science" were used. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA 2020), the studies included in our study were published between 2000 and 2021. In order to extract the required data, all sections of the articles were reviewed. Out of 57 articles we reviewed, 34 articles were related to field studies and 23 articles to clinical studies. Among them, 43 studies dealt with the pathophysiological effects of chemical agents, six studies dealt with the pathophysiological effects of physical factors, and 8 studies dealt with the pathophysiological effects of physicochemical factors on the human reproductive system. Physical (noise, heat, and radiofrequency radiation) and chemical (such as carbamate and organophosphate pesticides, benzene, toluene, xylene, formaldehyde, NO₂, CS₂, manganese, lead, nickel, and n-hexane) risk factors had pathophysiological effects on the human reproductive system. The presence of these risk factors in the workplace caused damage to the human reproductive system. The rate of these negative pathophysiological effects can be reduced by performing appropriate managerial, technical, and engineering measures in work environments.

Selenium, oxidative stress and inflammatory markers in handicraft workers occupationally exposed to lead

Occupational Lead (Pb) exposure increases reactive oxygen species and has been reported to impact inflammatory response by modulating intracellular signaling pathways. Selenium (Se) a vital component of the antioxidant system that plays an important role in modulating cytokines. The present study evaluated Se, malondialdehyde (MDA), total antioxidant capacity (TAC) and cytokines (IL-6, TNF-α, IL-10, IL-17a) in 81 Pb exposed male workers. The median (range) of blood lead level (BLL) and Se were 5 (0.50-31.76) µg/dL and 104 (46.9-189.6) µg/L respectively. The Se, TAC levels were decreased, and MDA, IL-6 levels were increased in the high Pb group (>5μg/dL). Blood lead level independently predicted oxidative stress and antioxidant status. Selenium, TAC levels negatively and MDA, IL-6 levels positively correlated with BLL. Association of Se with IL-6 and TAC suggests some probable role of Se in the underlined mechanism of Pb toxicity.