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- Road tunnel, roadside, and urban background measurements of aliphatic compounds in size-segregated particulate matterPublication . Oliveira, Cesar; Martins, Natercia; Mirante, Fátima; Caseiro, Alexandre; Pio, Casimiro; Matos, Manuel; Silva, Hugo; Oliveira, Cristina; Camões, FilomenaParticulate matter samples were collected in a road tunnel in Lisbon (PM0.5, PM0.5-1, PM1-2.5, and PM2.5-10) and at two urban locations representing roadside and background stations (PM2.5 and PM2.5-10). Samples were analysed for organic and elemental carbon (OC and EC), n-alkanes, n-alkenes, hopanes, some isoprenoid compounds, and steranes. Particulate matter concentrations in the tunnel were 17-31 times higher than at roadside in the vicinity, evidencing an aerosol origin almost exclusively in fresh vehicle emissions. PM0.5 in the tunnel comprised more than 60% and 80% of the total OC and EC mass in PM10, respectively. Concentrations of the different aliphatic groups of compounds in the tunnel were up to 89 times higher than at roadside and 143 times higher than at urban background. Based on the application of hopane-to-OC or hopanes-to-EC ratios obtained in the tunnel, it was found that vehicle emissions are the dominant contributor to carbonaceous particles in the city but do not represent the only source of these triterpenic compounds. Contrary to what has been observed in other studies, the Sigma hopane-to-EC ratios were higher in summer than in winter, suggesting that other factors (e.g. biomass burning, dust resuspension, and different fuels/engine technologies) prevail in relation to the photochemical decay of triterpenoid hydrocarbons from vehicle exhaust
- Heavy metals contamination of urban soils—a decade study in the city of Lisbon, PortugalPublication . Silva, Hugo; Silva, Nelson A. F.; Oliveira, Cristina; Matos, ManuelThere is an intense and continuous growth of the world population living in cities. This increase in population means an increase in car traffic, an increase in new constructions and an increase in the production of waste that translates into an intensive use of land, particularly in terms of soil contaminants. Among other environmental contaminants, toxic metals, such as lead (Pb), cadmium (Cd), nickel (Ni) and chromium (Cr) represent a public health problem. In this study the content of toxic metals in Lisbon’s (Portugal) soils was determined. The study was conducted over approximately a decade in six city locations, with a total of about 700 samples. Each site has different urban characteristics: traffic zone, residential area, urban park and mixed areas. The study allowed to verify the heterogeneity of metal content values in the city soils and their dependence on local traffic. Metal contents were determined by graphite furnace atomic absorption spectroscopy (GFAAS). For each site the geo-accumulation index, pollution factor, degree of contamination, pollution load índex and ecological risk factor were calculated. The mean concentrations of Cd, Cr, Ni and Pb in soils were 0.463, 44.0, 46.6 and 5.73 mg/kg of dry soil, respectively. In the last year of the study the values were 0.417, 51.5, 62.4 and 8.49 mg/kg of dry soil, respectively. Cd and Ni exceeded the typical content values of these metals in the earth’s crust, indicating their anthropogenic origin. The correlation analysis revealed a significant correlation between Cr and Ni, Cd and Ni and Cd and Pb contents in the city soils. Regarding the results obtained in this long monitoring campaign, Lisbon’s soils can be considered as having low levels of pollution by these metals.
- Determination of antioxidants and total polyphenols in cabbages (Brassica Oleracea) irrigated wiht wastewater contaminated with toxic metalsPublication . Silva, Hugo F.A.; Barreiros, Ana Maria; Silva, Nelson A. F.; Oliveira, Cristina; Coelho, Jose; Matos, ManuelWater is a natural resource essential to all kinds of life. The reuse of treated wastewater (TWW) for irrigation is a possibility with challenges to be clarified at scientific level, in particular, its use in irrigation activities due to the eventual contamination of vegetables, like cabbages (Brassica oleracea), by toxic metals and other compounds harmful to humans present in these waters. On the other hand, the use of TWW for vegetable irrigation may allow significant water saving and also providing the cultivated species with nutrients, which may dispense the use of fertilizers. In this work, vegetables such as Brassica oleracea (cabbage), were planted in a greenhouse with a controlled environment (temperature and humidity) located at ISEL campus. Part of the vegetables was irrigated with tap water, and another part with TWW from two wastewater treatment plants (WWTP) located in Lisbon´s District. One of the WWTP receives only domestic wastewater (A), whilst the other one receives industrial and domesti
- Size-segregated chemical composition of aerosol emissions in an urban road tunnel in PortugalPublication . Pio, Casimiro; Mirante, Fátima; Oliveira, Cesar; Matos, Manuel; Caseiro, Alexandre; Oliveira, Cristina; Querol, Xavier; Alves, Célia; Martins, Natércia; Cerqueira, Mário; Camões, Filomena; Silva, Hugo; Plana, FelicianoAn atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5-1, PM1-2.5 and PM2.5-10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble inorganic ions and elemental composition. Three main groups of compounds were discriminated in the tunnel aerosol: carbonaceous, soil component and vehicle mechanical wear. Measurements indicate that Cu can be a good tracer for wear emissions of road traffic. Cu levels correlate strongly with Fe, Mn, Sn and Cr, showing a highly linear constant ratio in all size ranges, suggesting a unique origin through sizes. Ratios of Cu with other elements can be used to source apportion the trace elements present in urban atmospheres, mainly on what concerns coarse aerosol particles. (C) 2013 Elsevier Ltd. All rights reserved.
- Size distribution of polycyclic aromatic hydrocarbons in a roadway tunnel in Lisbon, PortugalPublication . Oliveira, Cesar; Martins, Natércia; Tavares, João; Pio, Casimiro; Cerqueira, Mário; Matos, Manuel; Silva, Hugo; Oliveira, Cristina; Camões, FilomenaAtmospheric aerosols of four aerodynamic size ranges were collected using high volume cascade impactors in an extremely busy roadway tunnel in Lisbon (Portugal). Dust deposited on the tunnel walls and guardrails was also collected. Average particle mass concentrations in the tunnel atmosphere were more than 30 times higher than in the outside urban background air, revealing its origins almost exclusively from fresh vehicle emissions. Most of the aerosol mass was concentrated in submicrometer fractions (65%), and polycyclic aromatic hydrocarbons (PAH) were even more concentrated in the finer particles with an average of 84% of total PAH present in sizes smaller than 0.49 mu m. The most abundant PAH were methylated phenanthrenes, fluoranthene and pyrene. About 46% of the total PAH mass was attributed to lower molecular weight compounds (two and three rings), suggesting a strong influence of diesel vehicle emissions on the production of local particulate PAH. The application of diagnostic ratios confirmed the relevance of this source of PAH in the tunnel ambient air. Deposited dust presented PAH profiles similar to the coarser aerosol size range, in agreement with the predominant origin of coarser aerosol particles from soil dust resuspension and vehicle wear products. (c) 201 1 Elsevier Ltd. All rights reserved.