Assessment of Heavy Metals and Related Impacts on Antioxidants and Physiological Parameters in Oil Refinery Workers in Iraq

Chemical characterization of road dust during diwali festival in Guwahati city of Assam, Northeast India

The present study focuses on the elemental analysis of road dust in Guwahati, the largest city of Assam and the largest metropolis of Northeast India during the Diwali festival. Road dust samples were collected on pre-Diwali (PD), the Day after Diwali (DaD), and one week after Diwali (WaD) from two sites (Lankeshwar; LKW and Patharquarry; PTQ). Three composite samples were collected from 3 points at each site. The elemental concentration was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The concentrations of Ba and Sr increased by 1.6 and 1.7 times, respectively, after Diwali. Among other firework-related elements (FREs), Mg, Al, K, and Cu increased at LKW following Diwali (both DaD and WaD), whereas Mg, Al, and K increased in DaD dust at PTQ. The average concentration of Traffic Related Elements (TREs) at PTQ was significantly higher than at LKW (p < 0.05; 75.40 mg/kg vs 63.96 mg/kg). Cd had the highest enrichment (EF), followed by Ni and Zn. EF for Cd, Ni, and Zn ranged from high to extremely high enrichment. Ni and Cd exhibited moderate contamination (CF). The ecological risk (ER) values for Cd at LKW and PTQ were 54.32 and 56.71, respectively, indicating a moderate ER. Pearson's correlation was performed to study the relationship between elements, while PCA analysis was used to identify the main sources of these elements. Although the health hazard indices presently do not suggest any immediate danger, hazard quotient (HQ) values for ingestion, inhalation, and dermal exposure were higher for children than adults. In children, the contribution of HQing to HI (total risk) was the highest, accounting for more than 65% of all elements. There is no apparent lifetime cancer risk due to road dust exposure through inhalation.

Polystyrene exacerbates cadmium-induced mitochondrial damage to lung by blocking autophagy in mice

Cadmium (Cd) is an environmental heavy metal, and its accumulation is harmful to animal and human health. The cytotoxicity of Cd includes oxidative stress, apoptosis, and mitochondrial histopathological changes. Furthermore, polystyrene (PS) is a kind of microplastic piece derived from biotic and abiotic weathering courses, and has toxicity in various aspects. However, the potential mechanism of action of Cd co-treated with PS is still poorly unclear. The objective of this study was to investigate the effects of PS on Cd-induced histopathological injury of mitochondria in the lung of mice. In this study, the results have showed that Cd could induce the activity of oxidative enzymes of the lung cells in mice, increasing the content of partial microelement and the phosphorylation of inflammatory factor NF-κB p65. Cd further destroys the integrity of mitochondria by increasing the expression of apoptotic protein and blocking the autophagy. In addition, PS solely group aggravated the lung damage in mice, especially mitochondrial toxicity, and played a synergistic effect with Cd in lung injury. However, how PS can augment mitochondrial damage and synergism with Cd in lung of mice requiring further exploration. Therefore, PS was able to exacerbate Cd-induced mitochondrial damage to the lung in mice by blocking autophagy, and was associated with the apoptosis.

The health effects of low blood lead level in oxidative stress as a marker, serum gamma-glutamyl transpeptidase level, in male steelworkers

Background

This study aimed to investigate the association between lead exposure and serum gamma-glutamyl transpeptidase (γGT) levels as an oxidative stress marker in male steelworkers.

Methods

Data were collected during the annual health examination of workers in 2020. A total of 1,654 steelworkers were selected, and the variables for adjustment included the workers' general characteristics, lifestyle, and occupational characteristics. The association between the blood lead level (BLL) and serum γGT level was investigated by multiple linear and logistic regression analyses. The BLL and serum γGT values that were transformed into natural logarithms were used in multiple linear regression analysis, and the tertile of BLL was used in logistic regression analysis.

Results

The geometric mean of the participants' BLLs and serum γGT level was 1.36 μg/dL and 27.72 IU/L, respectively. Their BLLs differed depending on age, body mass index (BMI), smoking status, drinking status, shift work, and working period, while their serum γGT levels differed depending on age, BMI, smoking status, drinking status, physical activity, and working period. In multiple linear regression analysis, the difference in models 1, 2, and 3 was significant, obtaining 0.326, 0.176, and 0.172 (all: p < 0.001), respectively. In the multiple linear regression analysis stratified according to drinking status, BMI, and age, BLLs were positively associated with serum γGT levels. Regarding the logistic regression analysis, the odds ratio of the third BLL tertile in models 1, 2, and 3 (for having an elevated serum γGT level within the first tertile reference) was 2.74, 1.83, and 1.81, respectively.

Conclusions

BLL was positively associated with serum γGT levels in male steelworkers even at low lead concentrations (< 5 μg/dL).

Use of Generalized Weighted Quantile Sum Regressions of Tumor Necrosis Factor Alpha and Kidney Function to Explore Joint Effects of Multiple Metals in Blood

Exposure to heavy metals could lead to adverse health effects by oxidative reactions or inflammation. Some essential elements are known as reactors of anti-inflammatory enzymes or coenzymes. The relationship between tumor necrosis factor alpha (TNF-α) and heavy metal exposures was reported. However, the interaction between toxic metals and essential elements in the inflammatory response remains unclear. This study aimed to explore the association between arsenic (As), cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), selenium (Se), and zinc (Zn) in blood and TNF-α as well as kidney function. We enrolled 421 workers and measured the levels of these seven metals/metalloids and TNF-α in blood; kidney function was calculated by CKD-EPI equation. We applied weighted quantile sum (WQS) regression and group WQS regression to assess the effects of metal/metalloid mixtures to TNF-α and kidney function. We also approached the relationship between metals/metalloids and TNF-α by generalized additive models (GAM). The relationship of the exposure−response curve between Pb level and TNF-α in serum was found significantly non-linear after adjusting covariates (p < 0.001). Within the multiple-metal model, Pb, As, and Zn were associated with increased TNF-α levels with effects dedicated to the mixture of 50%, 31%, and 15%, respectively. Grouped WQS revealed that the essential metal group showed a significantly negative association with TNF-α and kidney function. The toxic metal group found significantly positive associations with TNF-α, serum creatinine, and WBC but not for eGFR. These results suggested Pb, As, Zn, Se, and mixtures may act on TNF-α even through interactive mechanisms. Our findings offer insights into what primary components of metal mixtures affect inflammation and kidney function during co-exposure to metals; however, the mechanisms still need further research.