Identification and chemical characterization of industrial particulate matter sources in southwest Spain

A detailed physical and chemical characterization of coarse particulate matter (PM10) and fine particulate matter (PM2.5) in the city of Huelva (in Southwestern Spain) was carried out during 2001 and 2002. To identify the major emission sources with a significant influence on PM10 and PM2.5, a methodology was developed based on the combination of: (1) real-time measurements of levels of PM10, PM2.5, and very fine particulate matter (PM1); (2) chemical characterization and source apportionment analysis of PM10 and PM2.5; and (3) intensive measurements in field campaigns to characterize the emission plumes of several point sources. Annual means of 37, 19, and 16 microg/m3 were obtained for the study period for PM10, PM2.5, and PM1, respectively. High PM episodes, characterized by a very fine grain size distribution, are frequently detected in Huelva mainly in the winter as the result of the impact of the industrial emission plumes on the city. Chemical analysis showed that PM at Huelva is characterized by high PO4(3-) and As levels, as expected from the industrial activities. Source apportionment analyses identified a crustal source (36% of PM10 and 31% of PM2.5); a traffic-related source (33% of PM10 and 29% of PM2.5), and a marine aerosol contribution (only in PM10, 4%). In addition, two industrial emission sources were identified in PM10 and PM2.5: (1) a petrochemical source, 13% in PM10 and 8% in PM2.5; and (2) a mixed metallurgical-phosphate source, which accounts for 11-12% of PM10 and PM2.5. In PM2.5 a secondary source has been also identified, which contributed to 17% of the mass. A complete characterization of industrial emission plumes during their impact on the ground allowed for the identification of tracer species for specific point sources, such as petrochemical, metallurgic, and fertilizer and phosphate production industries.     

Fluorescence and DOC contents of estuarine pore waters from colonized and non-colonized sediments: effects of sampling preservation

The influence of the colonization of salt marsh sediments with Halimione portulacoides was evaluated by analysing the fluorescent dissolved organic matter (FDOM) in sediment pore waters from a salt marsh at different depths. Cores of sediments at colonized and non-colonized sites were collected from a coastal lagoon (Ria de Aveiro, Portugal). The DOC content of extracted pore waters was determined and characterized by synchronous molecular fluorescence (Deltalambda=60nm) and UV-visible spectroscopies. The common practice of freezing sediment cores for further and later chemical investigation was shown not to be an appropriate methodology of sample preservation. On the contrary, freezing of extracted and filtered pore water seemed not to affect either the DOC content or the fluorescence properties of pore waters. Two types of fluorescent substances were found in the pore waters spectra; one corresponding to humic-like substances and another one resembling proteins. However, major differences were found in the spectra of pore waters depending on both depth and the presence/absence of vegetation colonization.     

Natural regeneration of the herbaceous community in a semiarid region in Northeastern Brazil

This study aimed to describe and compare the interannual changes in the diversity and population structure of herbaceous plants in an anthropogenic area that has been regenerating for 15 years and to identify the similarities and differences in the biological attributes of the community compared with the characteristics of a regenerating conserved area. In total, 105 plots measuring 1 m² were established. In each plot, the herbaceous plants were identified, and their height and stem diameter were measured for two consecutive years. The herbaceous flora of the anthropogenic area was represented by 86 species in 70 genera and 27 families, and there were no significant differences in the average richness between years. The conserved area was represented by 71 species in 63 genera and 35 families, and there was a significant difference in the total richness between areas and between years, except when comparing the richness between the conserved area and the anthropogenic area during the second year. Considering both the anthropogenic and conserved areas, 123 herbaceous species were listed, and the similarity between areas was 60 %. For the anthropogenic area, the floristic similarity between years was 95 %, and in the fragment of the conserved area, the similarity was 74 %. The diversity and density were significantly different between years and between areas. Given these results, this study suggests that 15 years of natural regeneration for the caatinga is not sufficient to reestablish its native flora with respect to its herbaceous component.     

Persistent Organic Pollutants in gull eggs of two species (Larus michahellis and Larus audouinii) from the Ebro delta Natural Park

The aim of this study was to determine the impact of priority and emerging Persistent Organic Pollutants (POPs) in gull eggs from two species, the scavenger Larus michahellis and the protected species, Larus audouinii. These two species share habitat in the Natural Park of the Ebro delta (Catalonia, Spain). Compounds studied are included or under consideration in the Stockholm Convention and comprise polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorinated compounds (OCs), perfluorinated compounds (PFCs) and short chain chlorinated paraffins (SCCPs). Four methods based in selective extraction and gas or liquid chromatography coupled to mass spectrometry were used and quality parameters are provided. OC pesticides and marker PCBs were the most abundant chemical families detected in eggs from the two species, followed by PFCs, PBDEs (especially BDE 209) and SCCPs. Dioxin-like PCBs and PCDD/Fs were also detected in all samples. The overall widespread presence of POPs is discussed in terms of feeding habits, bird ecology and anthropogenic pressures in the protected Ebro delta breeding area.     

Effect of different redox mediators during thermophilic azo dye reduction by anaerobic granular sludge and comparative study between mesophilic (30 degrees C) and thermophilic (55 degrees C) treatments for decolourisation of textile wastewaters

The impact of different redox mediators on colour removal of azo dye model compounds and textile wastewater by thermophilic anaerobic granular sludge (55 degrees C) was investigated in batch assays. Additionally, a comparative study between mesophilic (30 degrees C) and thermophilic (55 degrees C) colour removal was performed with textile wastewater, either in the presence or absence of a redox mediator. The present work clearly evidences the advantage of colour removal at 55 degrees C compared with 30 degrees C when dealing with azo coloured wastewaters. The impact of the redox mediators anthraquinone-2,6-disulfonate (AQDS), anthraquinone-2-sulfonate (AQS) and riboflavin was evident with all dyes, increasing decolourisation rates up to 8-fold compared with the mediator-free incubations. The generation of the hydroquinone form AH2QDS, i.e. the reduced form of AQDS, was extremely accelerated at 55 degrees C compared with 30 degrees C. Furthermore, no lag-phase was observed at 55 degrees C. Based on the present results we postulate that the production/transfer of reducing equivalents was the process rate-limiting step, which was accelerated by the temperature increase. It is conclusively stated that 55 degrees C is a more effective temperature for azo dye reduction than 30 degrees C, which on the one hand can be attributed to the faster production/transfer of reducing equivalents, but also to the decrease in activation energy requirements.     

Heavy metal content and speciation in groundwater of the Guadiamar river basin

This work presents the conclusions of a speciation study concerning Zn, Cd, Pb and Cu in groundwater from ten wells in the alluvial aquifers of the Guadiamar river, affected by Aznalcollar mine tailing spill (April 1998). The sampling campaign took place in January 2000, almost two years after the mining accident. Four metal fractions were determined: labile metal forms, H+ exchangeable metal forms, strongly inert forms (associated with organic and inorganic matter in solution), and forms associated with suspended matter. Total metal concentration in groundwater followed the trend Cd < Pb < Cu < Zn. The speciation study showed that Zn and Cd were present to a great extent in available forms (labile and H+ exchangeable), while Pb and Cu were found mostly in the less available forms (strongly inert). These results can illustrate the potential value of the speciation tool for the follow-up of spill-induced pollution in the area.     

Bus fleet emissions: new strategies for mitigation by adopting natural gas

Energy consumption is related to local, regional and global impacts. Thus, by comparing different replacement scenarios of diesel vehicles with compressed natural gas, this article estimates pollutants and greenhouse gases emission in the city of São Paulo, Brazil. The calculation of fuel consumption is based on fleet characteristics, in terms of vehicle age, the average annual distance travelled by bus depending on the year and average fuel consumption. These values served as a basis to develop scenarios considering that a percentage of new vehicles that will be phased out and replaced with ones running on natural gas. Results show that the total avoided emissions can range from 579 thousand tons to 1.375 million tons of carbon dioxide (CO₂₎ over 20 years, depending on the scenario. For particulate matter, accumulated avoided emissions vary from 251 thousand to 584 tons over 20 years. The replacement of diesel buses with natural gas-fuelled buses presents favourable results, in comparison with the tendency scenario for CO₂ and particulate matter. Thus, a public policy for fuel replacement in largest cities, such as Sao Paulo, has an important global impact, especially when allowing the introduction of a renewable energy source, such as biogas. It will benefit from the natural gas previous infrastructure, which is largely available in Brazil. As recommendations, we explain the need to review the city of Sao Paulo Climate Change Law to allow the use of natural gas. Fuel replacement should be integrated with a public policy/public policies and operational strategies to promote citizens´ health as well as historical, cultural and heritage conservation for the city and its future generations.     

Interview with the mayor of Curitiba on habitat II

The objectives of Habitat II were (1) in the long term to arrest the deterioration of human settlements and create the conditions to achieve improvement in the environment on a sustainable basis, and (2) to adopt a general statement on principles and related Global Action Plan to guide national and international efforts in the next two decades. We have asked the Mayor of Curitiba, Brazil Rafael Greca de Macedo to comment on the conference results. Curitiba is one of the most known example of urban ecological planning.