Evaluation of DNA damage in traffic police wardens of Pakistan due to cadmium and zinc

Air quality in urban areas is generally poor especially at traffic intersections and roadsides due to continuous vehicular emissions comprising poly aromatic hydrocarbons, heavy metals, benzene, diesel soot etc. The objective of this study was to compare the primary DNA damage in traffic police wardens occupationally exposed to airborne Cd and Zn (exposed group) and educational institution with negligible exposure to airborne Cd and Zn (control group). Blood levels of Cd and Zn in traffic police wardens and control group were determined by Flame Atomic Absorption Spectroscopy (FAAS) and DNA damage was assessed by using Comet assay. The results of this study showed significantly higher amount of Cd (0.18±0.06mgL^-1) and Zn (4.87±1.34mgL^-1) in the blood of traffic police wardens as compared to control group and according to World Health Organization, these values are 18 and 3 times more to the permissible limit of Cd and Zn respectively in human blood. In addition, significantly higher numbers of DNA damaged cells (28±13%) were observed in traffic police wardens as compared to control group (3.6±2%). Comet tail length was found to be doubled (4.7±1.7μm) in traffic police wardens as compared to the control group (2±1.2μm). These results could be linked to the concentrations of Cd and Zn in blood of traffic police wardens. In conclusion, our results showed that accumulation of Cd and Zn was higher in traffic police wardens due to air pollution (Zn and Cd) and has more damaged DNA of traffic police wardens in Pakistan.

Assessment of genotoxic effects of lead in occupationally exposed workers

The genotoxicological effects in 200 lead acid storage battery recycling and manufacturing industry workers in Hyderabad along with matched 200 controls were studied. The genetic damage was determined by comet, micronucleus (MN), and chromosomal aberration (CA) test in peripheral blood lymphocytes (PBL). The MN test was also carried out in buccal epithelial cells (BECs). Pb in ambient air, blood Pb (B-Pb) concentrations, and hematological parameters were measured. The superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), and malondialdehyde (MDA) formed were also studied. The results of the present study showed that there was a statistically significant (P < 0.01) increase in mean percent tail DNA, frequency of CA, and MN in PBL as well as in BEC as compared to controls. Pb in ambient air and B-Pb concentrations were found to be significantly higher (P < 0.01). The hematocrit, hemoglobin, and red blood cell values were significantly lowered in Pb-exposed workers in comparison to controls. SOD, GPx, and CAT levels were significantly decreased while GSH and MDA levels increased in exposed group when compared to control group. The present study suggests that environmental health standards should be enforced to control Pb contamination from battery industries to reduce human health risk.

Exposure vs toxicity levels of airborne quartz, metal and carbon particles in cast iron foundries

Aerosol dust samples and quartz raw materials from different working stations in foundry plants were characterized in order to assess the health risk in this working environment. Samples were analysed by scanning and transmission electron microscopy coupled with image analysis and microanalysis, and by cathodoluminescence spectroscopy. In addition, the concentration and the solubility degree of Fe and other metals of potential health effect (Mn, Zn and Pb) in the bulk samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, the results indicate substantial changes in quartz crystal structure and texture when passing from the raw material to the airborne dust, which include lattice defects, non-bridging oxygen hole centres and contamination of quartz grains by metal and/or graphite particles. All these aspects point towards the relevance of surface properties on reactivity. Exposure doses have been estimated based on surface area, and compared with threshold levels resulting from toxicology. The possible synergistic effects of concomitant exposure to inhalable magnetite, quartz and/or graphite particles in the same working environment have been properly remarked.

Contribution of CYP2E1 polymorphism to aging in the mechanical workshop workers

Aging is attributed to both genetic and environmental factors. Occupational exposure is one of the environmental factors with potential genotoxic effects. Researchers try to determine factors involved in genetic damages at hazards exposure that could accelerate aging. Cytochrome P450 2E1 (CYP2E1) gene contributes in activation and detoxification of the environmental hazards. This polymorphism plays an important role in susceptibility of inter-individuals to DNA damage at the occupational exposure. The current study evaluated the possible influence of this gene polymorphism in aging by genomic damages through the biomarkers alterations of micronuclei (MN), comet tail length and telomere length shortening at the exposure. In this study, buccal cells were collected from the oral cavity of exposed workers and non-exposed controls. The CYP2E1 genotypes were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The wild genotype significantly affected MN frequency (p = 0.007) and relative telomere length (p = 0.047) in the older group of workers. It was concluded that the interaction of gene polymorphism and exposure enhances DNA damage and accelerates aging consequently.

Association Between Telomere Shortening and Ageing During Occupational Exposure

Telomere length is considered as a biomarker of ageing, resulting in shortening during the process. The present investigation was an attempt to determine the relative telomere length in mechanical workshop workers. Telomere length shortening in cells during occupational exposure causes accelerated ageing. Genomic DNA was isolated from buccal epithelial cells collected from 240 individuals, comprising two groups of 120 exposed workers and 120 unexposed controls. Telomere length was measured by using real time PCR. Both telomere (T) and single copy gene (S) specific primers were used to compute the relative T/S ratio and expressed as the relative telomere length. Telomere length differed significantly between the workers and controls (p<0.05). The results showed an indirect and significant association (r=-0.356, p=0.001) between age and telomere length in the workers. This study showed that the difference in telomere length shortening was statistically significant (p<0.05) between the workers and controls. It was concluded that occupational exposure acts as a risk factor to enhance telomere length shortening and accelerate ageing.