Compositions and oxidative damage of condensate, particulate and semivolatile organic compounds from gasoline exhausts

Toxicity of exhaust particulates and gaseous emissions from gasohol (ethanol blended gasoline)-fuelled spark ignition engines

In the last couple of decades, blending of oxygenated additives with gasoline has been advocated to reduce dependence on fossil fuels and to reduce hazardous health effects of gaseous emissions and particulate matter (PM) emitted by internal combustion (IC) engines in the transport sector worldwide. The primary objective of this research was to carry out a comparative analysis of exhaust PM emitted by gasohol (gasoline blended with 10% ethanol, v/v)-fulled spark ignition (SI) engine with that of baseline gasoline-fuelled SI engine. To assess the PM toxicity, physical, chemical and biological characterizations of PM were carried out using the state-of-the-art instruments and techniques. Measurements of regulated and unregulated gaseous species were also carried out at part/full loads. The results showed that the gasohol-fuelled engine emitted relatively lower concentrations of unregulated gaseous species such as sulfur dioxide (SO2), isocyanic acid (HNCO), etc. Physical characterization of exhaust particles revealed that the gasohol-fuelled engine emitted a significantly lower number of particles compared to the gasoline-fuelled engine. The presence of harmful polycyclic aromatic hydrocarbons (PAHs) and higher trace metal concentrations in PM emitted from the gasoline-fuelled engine was another important finding of this study. Biological characterizations showed that PM emitted from the gasohol-fuelled engine were less cytotoxic and had lower reactive oxygen species (ROS) generation potential. Mutagenicity of PM emitted from the gasohol-fuelled engine was also lower compared to that from the gasoline-fuelled engine. Overall, this study demonstrated that utilization of gasohol in SI engines led to the reduction in emissions, and lowering of PM toxicity, in addition to partial replacement of fossil fuels with renewable fuels.

Bioaccumulation of nickel and its biochemical and genotoxic effects on juveniles of the neotropical fish Prochilodus lineatus

Juveniles of the freshwater fish Prochilodus lineatus were exposed to three concentrations of nickel (Ni): 25, 250 and 2500 µg L(-1) or water only for periods of 24 and 96 h to test for Ni bioaccumulation, its effects on antioxidant defenses and metallothioneins, and the occurrence of DNA damage. After exposure, the fish were sampled and tissue removed from the gills, liver, kidney and muscle to test for Ni accumulation and conduct biochemical (gills and liver) and genotoxic (blood cells and gills) analyses. The results showed that Ni accumulates in the organs in different proportions (kidney>liver>gills>muscle) and accumulation varied according to exposure time. Metallothionein (MT) levels increased in the liver and gills after exposure to Ni, implying that the presence of Ni in these tissues could induce MT synthesis. We also observed that Ni exposure affected antioxidant defenses, increasing lipid peroxidation in the liver of fish exposed to Ni for 96 h at the highest concentration tested. DNA damage increased in both blood cells and gills of fish exposed to all Ni concentrations, indicating the genotoxic potential of Ni on fish. We therefore concluded that Ni accumulates in various tissues and results in oxidative and DNA damage in P. lineatus, and that the maximum permitted Ni concentration set in Brazilian legislation (25 µg L(-1)) for freshwaters is not safe for this species.

Gasoline effects on biotransformation and antioxidant defenses of the freshwater fish Prochilodus lineatus

Biochemical biomarkers in the Neotropical freshwater fish Prochilodus lineatus were evaluated following acute exposures to the water-soluble fraction of gasoline (WSFG). Fish were exposed to the WSFG diluted to 5% in water (WSFG group) or only to water (Control group) for 6, 24 and 96 h and the gills and liver were removed for the biochemical analyses. Fish exposed to WSFG for 24 and 96 h showed significant increase in the activity of 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST) both in liver and gills, pointing toward phase I and phase II biotransformation of the compounds present in the WSFG. The results also indicated the activation of antioxidant defenses in both the liver and gills after fish exposure to WSFG. The liver showed activation of catalase (CAT) and glutathione peroxidase (GPx) after 96 h exposure. An increase in hepatic content of reduced glutathione (GSH) together with decreased glutathione reductase (GR) activity was observed after 24 and 96 h of exposure to WSFG. In the gills, only catalase (CAT) activity augmented after 6 and 24 h of exposure and GSH content increased after 24 h of WSFG exposure. However, in both the organs, activation of the antioxidant defenses was not enough to prevent oxidative damage since they showed lipid peroxidation (LPO) at one of the experimental times: the liver after 6 h and the gills only after 96 h of exposure to WSFG. This may indicate better adaptation of the liver to longer exposures, starting from 24 h. As the gills are the first organ to be exposed to xenobiotics, the antioxidant defenses were triggered immediately upon exposure to WSFG and were able to prevent the occurrence of LPO during the initial times.

Health risk of semi-volatile organic pollutants in Wujin river inflow into Taihu Lake

Semi-volatile organic compounds (SVOCs), including polycyclic aromatic hydrocarbons (PAHs), phthalates and pesticides in water of Wujin river inflow into Taihu Lake, were detected for assessment of risk to human health. SVOCs were tested with Method 525.2 established by the US Environmental Protection Agency (EPA) and health risk assessment (HRA) was conducted by the hazard quotient (HQ) approach from US HRA for screening stage. The results for the liquid-solid extraction of water sample measured by gas chromatography/mass spectrometry (GC/MS) showed that three of the tested twenty-three semi-volatile organic contaminants posed potential health risk and the concentrations of 2,4-dinitrotoluene, di-n-butyl phthalate, chrysene and benzo(a)anthracene was 0.736, 15.201, 0.307, and 0.334 μg/l, respectively. SVOCs in the Wujin river water might induce risk to environmental health of Taihu Lake as a source of drinking water.

Oxidative damage of the extracts of condensate, particulate and semivolatile organic compounds from gasoline engine exhausts on testicles of rats

Oxidative damage induced by extracts of condensate, particulate matters and semivolatile organic compounds from gasoline engine exhausts were investigated in testicles of adult Sprague-Dawley rats. The results showed that gasoline engine exhaust could increase the contents of malondialdehyde and carbonyl protein, decrease activities of superoxide dismutase and glutathione peroxidase, and induce DNA damage in testicle of rat. Taking together, the gasoline engine exhaust could promote oxidative damage of bio-macromolecular in testicles of rat and oxidative stress might be an alternative mechanism for male reproductive function of male mammals.