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Exposure to heavy metals has been associated with the generation of reactive oxygen species (ROS) among exposed individuals in occupational and environmental settings. Dust is considered a significant contributor to airborne metal exposure, and previous data suggest that their levels in dust may vary based on its particle sizes. However, no biomonitoring study has been reported so far to address the metal-induced oxidative stress using different dust fractions, particularly in occupational settings. We designed a systematic cross-sectional study involving 110 chromite mine workers stratified into loaders (n = 28), extractors (n = 47) and operators (n = 35), and controls (n = 30) to find out the association between dust-bound metal exposure and oxidative stress using urinary creatinine-adjusted metal level as a biomarker of metal exposure. Results suggested elevated urinary levels of Cr 51.34 ± 8.6 along with Pb 34.29 ± 4.39, Cd 21.1 ± 2.6, and Ni 18.98 ± 3.01 µg/g creatinine in exposed (extractor group) workers. Correlating metal levels with oxidative stress revealed elevated malondialdehyde (MDA) levels of 62.28 ± 5.52 nM/dl among the extractors showing high levels of lipid peroxidation. Furthermore, blood superoxide dismutase (SOD) was also found significantly correlated (P = 0.000) with urinary toxic metal levels among exposed workers. We report the association between metal exposure and oxidative stress in exposed mining workers that may give rise to workers' susceptibility towards genetic and non-genetic health implications. The current study emphasized on the need for exposure control measures in the chromite ore mining activity areas.

Increased E-waste generation during recent times has become a global concern, especially for developing countries that are at receiving end from the developed countries. Their improper handling and lacking management practices in developing countries including Pakistan are contributing enormous addition of toxicants into the environment and affecting the health of exposed workers associated with E-waste recycling activities. A systematic cross-sectional study was designed comprising workers associated with E-waste recycling activities in Peshawar city, Pakistan. The study aimed to investigate metal concentrations in dust, particulate matter and urine of exposed workers and correlate with oxidative stress and glutathione S-transferases genotypes (GSTM1 and GSTT1) that play a role in detoxification of metals in humans. A total of 120 blood samples comprising dismantlers (n = 52), repairers (n = 21), smelters (n = 17) and controls (n = 30) were collected. Results showed that metal concentrations were significantly higher in the dust (P = 0.020), particulate matter (P = 0.021) and urine samples (P = 0.00) as compared to controls. We observed significant increase in MDA (P = 0.00) and decrease in SOD (P = 0.00) and CAT (P = 0.00) levels among exposed subjects as compared to controls. Additionally, GSTT1 null genotype was more significantly associated with the dismantlers (P = 0.02). The study shows that E-waste workers are exposed to high level of toxic metals through dust and particulate matter, resulting in significant oxidative stress and related health implications, while GSTT1 null polymorphism is associated with increased susceptibility to these metals and induced health outcomes.

Per- and polyfluoroalkyl substances (PFASs) are a large group of chemicals reported in global environment and are responsible for various adverse impacts on humans and environment. We report a comprehensive study on occurrence of PFASs, including legacy, substitute and emerging ones, from Pakistan. Surface water samples were collected from five ecologically important freshwater reservoirs in Pakistan, namely, Head Panjnad (HP), Head Trimmu (HT), Chashma Barrage (CB), Head Blloki (HB), and Head Qadirabad (HQ). The detection frequencies of PFASs ranged between 37 %-100 %. The highest concentration of ∑

We studied cancer patients for possible PAH exposure, using urinary concentration of 1-hydroxypyrene (1-OHP) as a biomarker of internal dose of polycyclic aromatic hydrocarbons (PAHs). The subjects included in this study belonged to various socio-demographic backgrounds, and were diagnosed with cancer (i.e. lung, head and neck or digestive tract cancer). In general, we observed high concentration of urinary 1-OHP among digestive tract cancer patients, compared with the controls (CN) (mean 1.06, median 1.03 and mean 0.62, median 0.63 μmol/mol-Cr in digestive tract cancer patients and controls respectively). The concentrations of urinary 1-OHP were higher than the background level of PAHs; therefore, these groups could have been exposed to PAHs. Highest urinary 1-OHP concentration was observed in digestive tract cancer patients (median 1.25 μmol/mol-Cr) with GSTM-1 genotype. The results of PCA were consistent with qualitative and quantitative data analysis. The contribution of urinary 1-OHP eigenvector revealed a relatively high PAH-exposure among cancer patients compared with CN, while diet and age were influential parameters among cancer patients, which could have a strong link in cancer etiology in the selected exposure groups.