Occupational airborne contamination in South Brazil: 2. Oxidative stress detected in the blood of workers of incineration of hospital residues

Women rag pickers at a dump in Ahmedabad: Genotoxicity and oxidative stress

Municipal solid waste (MSW) generated in Ahmedabad, India, and the surrounding area is dumped at the Pirana site; rag pickers collect materials for re-sale. We have compared genotoxicity and oxidative stress in samples from women rag pickers working at this site, with women involved only in door-to-door waste picking (in residential areas near the university campus) as "controls". The buccal Cytokinesis-Block Micronucleus (CBMN) assay showed significantly higher frequencies of Micronucleus (MN), Nucleoplasmic Bridges (NPB), and Nuclear Buds (NB) in the rag pickers than in the "controls". The buccal Micronuclei Cytome (BMCyt) assay showed significantly higher prevalence of nuclear anomalies, such as micronucleus, karyorrhexis, karyolytic cells, and nuclear buds. Blood samples from the rag pickers showed lower levels of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase), lower total serum protein concentrations, and greater lipid peroxidation compared to the "control" group. Exposure to hazardous solid waste may lead to increased oxidative damage and genotoxicity; improved safety procedures and the use of personal protective equipment are recommended.

A curated review of recent literature of biomarkers used for assessing air pollution exposures and effects in humans

This is a cross-sectional review of biomarkers used in air pollution research from January 2009 through December 2012. After an initial keyword search in PubMed retrieving 426 articles, a comprehensive abstract review identified 54 articles of experimental design that used biomarkers of exposure or effect in human studies in the area of air pollution research during this specified time period. A thorough bibliographic search of the included articles retrieved an additional 65 articles meeting the inclusion criteria. This review presents these 119 studies and the 234 biomarkers employed in these air pollution research investigations. Data presented are 70 biomarkers of exposure with 54% relating to polycyclic aromatic hydrocarbons, 36% volatile organic carbons, and 10% classified as other. Of the 164 biomarkers of effect, 91 and 130 were used in investigating effects of short-term and chronic exposure, respectively. Results of biomarkers used in short-term exposure describe different lag times and pollutant components such as primary and secondary pollutants, and particle number associated with corresponding physiological mechanisms including airway inflammation, neuroinflammation, ocular, metabolic, early endothelial dysfunction, coagulation, atherosclerosis, autonomic nervous system, oxidative stress, and DNA damage. The review presents three different exposure scenarios of chronic, occupational, and extreme exposure scenarios (indoor cooking) with associated biomarker findings presented in three broad categories of (1) immune profile, (2) oxidative stress, and (3) DNA damage. This review offers a representation of the scope of data being explored by air pollution researchers through the use of biomarkers and has deliberately been restricted to this particular subject rather than an extensive or in-depth review. This article provides a contextualization of air pollution studies conducted with biomarkers in human subjects in given areas while also integrating this complex body of information to offer a useful review for investigators in this field of study.

Coal and tire burning mixtures containing ultrafine and nanoparticulate materials induce oxidative stress and inflammatory activation in macrophages

Ultra-fine and nano-particulate materials resulting from mixtures of coal and non-coal fuels combustion for power generation release to the air components with toxic potential. We evaluated toxicological and inflammatory effects at cellular level that could be induced by ultrafine/nanoparticles-containing ashes from burning mixtures of coal and tires from an American power plant. Coal fly ashes (CFA) samples from the combustion of high-S coal and tire-derived fuel, the latter about 2-3% of the total fuel feed, in a 100-MW cyclone utility boiler, were suspended in the cell culture medium of RAW 264.7 macrophages. Cell viability, assessed by MTT reduction, SRB incorporation and contrast-phase microscopy analysis demonstrated that CFA did not induce acute toxicity. However, CFA at 1mg/mL induced an increase of approximately 338% in intracellular TNF-α, while release of this proinflammatory cytokine was increased by 1.6-fold. The expression of the inflammatory mediator CD40 receptor was enhanced by 2-fold, the receptor for advanced glycation endproducts (RAGE) had a 5.7-fold increase and the stress response protein HSP70 was increased nearly 12-fold by CFA at 1mg/mL. Although CFA did not induce cell death, parameters of oxidative stress and reactive species production were found to be altered at several degrees, such as nitrite accumulation (22% increase), DCFH oxidation (3.5-fold increase), catalase (5-fold increase) and superoxide dismutase (35% inhibition) activities, lipoperoxidation (4.2 fold-increase) and sulfhydryl oxidation (40% decrease in free SH groups). The present results suggest that CFA containing ultra-fine and nano-particulate materials from coal and tire combustion may induce sub-chronic cell damage, as they alter inflammatory and oxidative stress parameters at the molecular and cellular levels, but do not induce acute cell death.

The levels of inflammatory markers and oxidative stress in individuals occupationally exposed to municipal solid waste in Ogun State, South West Nigeria

Airway inflammation and related respiratory complaints are common symptoms among waste management workers (WMWs). This study investigated the relationship between exposure to municipal solid waste (MSW) and the levels of inflammatory markers and oxidative stress among WMW of Ogun State, South West Nigeria. A total of 280 subjects consisting of 180 WMW and 100 controls were recruited. Ten millilitres of blood were collected from antecubital vein of the subjects for analysis. Results reveal that exposure to MSW is associated with systemic inflammation and oxidative stress. Significant ( p < 0.001) elevation of ceruloplasmin (Cp) and C-reactive protein was associated with marked decreases in superoxide dismutase ( p < 0.01), catalase ( p < 0.001), and glutathione ( p < 0.05) and significant ( p < 0.001) increases in malondialdehyde (MDA) and uric acid when compared with control. Haematological disorders include significant ( p < 0.05) decreases in haemoglobin, packed cell volume, and mean corpuscular volume and significant ( p < 0.01) increase in total leucocyte count. Apart from decreased albumin ( p < 0.05) and elevated aspartate aminotransferase ( p < 0.05) activity observed in WMW, other markers of hepatic (alanine aminotransferase, alkaline phosphatase, total cholesterol and triglycerides) and renal (urea and creatinine) functions did not change significantly ( p > 0.05) when compared with the control. A positive correlation between leucocytes ( r = 0.195, p < 0.01), Cp ( r = 0.210, p < 0.01) and job duration and between Cp and MDA ( r = 0.200, p < 0.01) and Cp and leucocytes ( r = 0.260, p < 0.001) were observed in WMW. Overall, exposure to MSW predisposes to systemic inflammation and oxidative stress and Cp may be a useful biomarker for monitoring health status of Nigerian WMWs.

Antioxidant therapy attenuates oxidative stress in the blood of subjects exposed to occupational airborne contamination from coal mining extraction and incineration of hospital residues

Coal mining and incineration of solid residues of health services (SRHS) generate several contaminants that are delivered into the environment, such as heavy metals and dioxins. These xenobiotics can lead to oxidative stress overgeneration in organisms and cause different kinds of pathologies, including cancer. In the present study the concentrations of heavy metals such as lead, copper, iron, manganese and zinc in the urine, as well as several enzymatic and non-enzymatic biomarkers of oxidative stress in the blood (contents of lipoperoxidation = TBARS, protein carbonyls = PC, protein thiols = PT, α-tocopherol = AT, reduced glutathione = GSH, and the activities of glutathione S-transferase = GST, glutathione reductase = GR, glutathione peroxidase = GPx, catalase = CAT and superoxide dismutase = SOD), in the blood of six different groups (n = 20 each) of subjects exposed to airborne contamination related to coal mining as well as incineration of solid residues of health services (SRHS) after vitamin E (800 mg/day) and vitamin C (500 mg/day) supplementation during 6 months, which were compared to the situation before the antioxidant intervention (Ávila et al., Ecotoxicology 18:1150-1157, 2009; Possamai et al., Ecotoxicology 18:1158-1164, 2009). Except for the decreased manganese contents, heavy metal concentrations were elevated in all groups exposed to both sources of airborne contamination when compared to controls. TBARS and PC concentrations, which were elevated before the antioxidant intervention decreased after the antioxidant supplementation. Similarly, the contents of PC, AT and GSH, which were decreased before the antioxidant intervention, reached values near those found in controls, GPx activity was reestablished in underground miners, and SOD, CAT and GST activities were reestablished in all groups. The results showed that the oxidative stress condition detected previously to the antioxidant supplementation in both directly and indirectly subjects exposed to the airborne contamination from coal dusts and SRHS incineration, was attenuated after the antioxidant intervention.

Antioxidant intervention compensates oxidative stress in blood of subjects exposed to emissions from a coal electric-power plant in South Brazil

In the process of energy generation, particulate matter (PM) emissions derived from coal combustion expose humans to serious occupational diseases, which are associated with overgeneration of reactive oxygen species (ROS). The purpose of the present study is to better understand the relations between PM exposure derived from a coal electric-power plant and the oxidative damage in subjects (n=20 each group) directly (working at the burning area) or indirectly (working at the office or living in the vicinity of the electric-power plant=group of residents) exposed to airborne contamination, before and after daily supplementation with vitamins C (500mg) and E (800mg) during six months, which were compared to non-exposed subjects (control group). Several biomarkers of oxidative stress were examined such as levels of thiobarbituric acid reactive substances (TBARS), protein carbonyls (PC), protein thiols (PT) and vitamin E in plasma, levels of reduced glutathione (GSH) in whole blood, and of activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) in red cells. Before supplementation, TBARS and PC levels were significantly increased, levels of GSH and vitamin E were decreased, while the activities of SOD and CAT were increased in workers groups and GST were increased in all groups in compared to controls. After the antioxidant supplementation essentially all these biomarkers were normalized to control levels. The antioxidant intervention was able to confer a protective effect of vitamins C and E against the oxidative insult associated with airborne contamination derived from coal burning of an electric-power plant.