The highly industrialized small town of Verkhnyaya Pyshma (in the Urals region of Russia) was chosen as the site of a multimedia-multipollutant risk assessment using the U.S. Environmental Protection Agency methodology. The assessment was based on routine environmental pollution monitoring data for ambient air, soils, drinking water, and food, and the international environmental epidemiology literature. Using an a priori set of the preliminary health-based criteria, we selected nine pollutants for risk assessment: total suspended particles (TSP), sulfur dioxide, nitrogen dioxide, benzo(a)pyrene (BaP), ammonia arsenic, copper, cadmium, and lead. We used dose-response functions derived from epidemiologic studies to assess individual and population risks for TSP, SO2, NO2, As, Cd, and Pb. We assessed both cancer (for BaP, As, and Cd) and non-cancer (for all the chosen pollutants but BaP) responses, but in this paper we discuss only the assessments of noncarcinogenic risks due to TSP, SO2, NO2, Pb, and Cd as examples of how the quantitative estimates of health effects can be produced by using a risk function approach. We also schematically present a modified conceptual model of multimedia-multipollutant risk assessment taking into account the experience gained with this study.
Background: Copper ore processing plants are the emission sources of aerosols having a complex chemical composition. The aerosol components polluting both the workplace air and the ambient air of the adjacent populated areas include selenium, copper, and nanoparticles of these metal oxides.
Objective: To evaluate the combined cytotoxic effect of selenium and copper oxide nanoparticles following the administration of a bioprophylactic complex.
Materials and methods: The exposure to cytotoxic chemicals was modeled on outbred female rats by a single intratracheal injection of a suspension of selenium and copper oxide nanoparticles at a concentration of 0.25 g/L, obtained by laser ablation. Cytological and biochemical parameters of the bronchoalveolar lavage fluid (BALF) were measured 24 hours after the exposure. A specially developed bioprophylactic complex was administered to a part of the experimental animals with feed and drink during a month prior to the injection.
Results: A single intratracheal instillation of the suspension of SeO and CuO nanoparticles altered BALF cytological and biochemical parameters, thus indicating their pronounced cytotoxic effect. In the group of the exposed rats administered a
preliminary course of biological prophylaxis, we observed a decrease in the absolute number of neutrophils and the neutrophil to alveolar macrophage ratio, which is an indirect indicator of the cytotoxic effect, and the activity of aspartate aminotransferase in the bronchoalveolar lavage fluid.
Conclusion: The science-based and experimentally tested complex of bioprotectors can attenuate a combined cytotoxic health effect of the exposure to selenium and copper oxide nanoparticles.
Introduction. Exposure to selenium oxide nanoparticles can be combined with exposure to copper oxide nanoparticles at working place. The type of this combined action has not been previously studied. Material and methods. Stable suspensions of selenium oxide and copper oxide nanoparticles (at a single dose of 1 or 2 mg/kg of body weight) or deionized water (control) were administered to male rats 3 times a week for 6 weeks. At the end of the exposure, the toxic effect was evaluated by a large number of the animal organism indices. The statistical significance of intergroup differences was assessed using Student’s t-test. To analyze the patterns of two-factor combined toxicity, we used the Response Surface Methodology (RSM analysis). Results. Under combined intoxication with selenium oxide and copper oxide nanoparticles, liver damage was observed, assessed by a decrease in the albumin-globulin index and the content of alkaline phosphatase in the blood serum, an increase in the number of degenerated hepatocytes. Kidney function altered as indicated by a decrease in the level of urea and uric acid in the urine, creatinine in the blood serum, an increase in degenerated cells of proximal and distal tubules. The analysis of isobolograms obtained by RSM revealed the ambiguity of the type of selenium oxide and copper oxide nanoparticles combined action, depending on which effect and at which dose level it is estimated by. Conclusion. The subchronic toxicity of selenium oxide and copper oxide nanoparticles is characterized by qualitatively similar harmful effects. At the same time, the combined action of these nanoparticles is typologically ambiguous, varying from contradirectionality to synergism.
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