Assessing sustainable development in urban areas using cognitive mapping and MCDA

As interest in sustainability-related issues has increased over recent years, so too has urban sustainability risen to the fore, in academic, practitioner, and policymaking circles alike. Urban sustainability requires a balance between environmental concerns, the economy, and social development in urban areas. However, over the years, there has been an exponential increase in urban density, accompanied by increased economic activity and high levels of consumption, which have hindered urban planning and made the sustainable management of urban areas more difficult. It has therefore become increasingly necessary to combine the interests of the various stakeholders involved in – or affected by – urban planning measures, in order to achieve a balance between their needs, those of the environment and future generations, and the need for economic development. Sustainability evaluation models can in this sense be considered a baseline condition for sustainable development. However, most existing evaluation systems present limitations in terms of criteria identification and the calculation of the respective trade-offs. To address these issues, the current study aims to combine cognitive mapping and the Analytic Hierarchy Process (AHP) to prioritize the determinants of sustainable development in urban areas. The advantages and limitations of our proposal are also analyzed.     

Health risks of potentially toxic trace elements in urban soils of Manaus city,Amazon, Brazil

Environmental Geochemistry and Health - The city of Manaus is the biggest industrial city of the north Brazilian region, and a haphazard urbanization process characterizes it. The continuous...     

In Vitro Degradation and Cytotoxicity Response of Biobased Nanoparticles Prepared by Thiol-ene Polymerization in Miniemulsion

Journal of Polymers and the Environment - Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the...     

Novel Whey Protein Isolate/Polyvinyl Biocomposite for Packaging: Improvement of Mechanical and Water Barrier Properties by Incorporation of Nano-silica

Journal of Polymers and the Environment - The current global proposal for withdrawing polymers with high resistance to degradation and from fossil sources from disposable appliances, as well as the...     

Distribution of potentially harmful elements in soils around a large coal-fired power plant

An understanding of the spatial distribution and contribution of a power plant to local soil contamination is important for the planning of soil use and prioritizing remedial actions for public safety. Consequently, the aim of this study was to map the spatial distribution of potentially hazardous elements (PHEs; Cu, Pb, Zn, Ni, Cr, Fe, Mn, Cd, As, and Se) in soils around a large (796 MW) coal-fired power plant in Brazil. For the purpose, 33 soil samples were collected in the area within a radius of approximately 17.5 km from the plant and subsequently analyzed for PHEs. The frequency and direction of winds were also obtained from a meteorological station in the region. The sampling area was divided into four quadrants (northwest: N-NW; northeast: N-NE; southeast: S-SE; southwest: S-SW), and there were significant negative correlations between the distance and the concentrations of Se in the S-SE quadrant and As in the S-SW and S-SE quadrants. There were positive correlations between distance from the plant and the concentration of Mn in the N-NE quadrant and the concentration of Cd in the S-SW quadrant. The dominant direction of the winds was N-NE. The indexes used in this study showed low-to-moderate enrichment factor, but detailed analysis of the dominant quadrant of the winds showed a correlation with higher concentrations in the soils closer to the power plant for at least seven of the PHEs analyzed, especially with regard to As. Therefore, we conclude that the distribution of the metalloid As can be used as a marker of the spatial distribution of contamination from the thermoelectric plant, but the dynamics of the other elements suggests that the presence of other sources of contamination may also compromise the quality of local soils.

     

Biodegradable Polyester-Based Blend Reinforced with Curauá Fiber: Thermal,Mechanical and Biodegradation Behaviour

Biodegradable composites can be produced by the combination of biodegradable polymers (BP) as matrix and vegetal fibers as reinforcement. Composites of a commercial biodegradable polymer blend and curauá fibers (loaded at 5, 15 and 20 wt%) were prepared by melt mixing in a twin-screw extruder. Chemical treatments such as alkali treatment of the fiber and addition of maleic anhydride grafted polypropylene (MA-g-PP) as coupling agent were performed to promote polymer/fiber interfacial adhesion so that mechanical performance can be improved. The resulting composites were evaluated through hardness, melt flow index and tensile, flexural and impact strengths as well as water absorption. Thermal analysis and Fourier transform infrared spectroscopy were also employed to characterize the composites. The polymer/fiber interface was investigated through scanning electron microscopy analysis. The biodegradability of composites was evaluated by compost-soil burial test. The addition of curauá fiber promoted an increase in the mechanical strengths and composites treated with 2 wt% MA-g-PP with 20 wt% curauá fiber showed an increase of nearly 75% in tensile and 56% in flexural strengths besides an improvement in impact strength with respect to neat polymer blend. Nevertheless, treated composites showed an increase in water absorption and biodegradation tests showed that the addition of fiber retards degradation time. The retained mass of BP/20 wt% fiber composite with MA-g-PP and neat BP was 68 and 26%, respectively, after 210 days of degradation test.     

Simulating nitrogen dynamics in agricultural soils fertilized with pig slurry and urea

Within the framework of an interregional project in the Emilia Romagna region of northern Italy, the coupled MACRO-SOILN model was chosen to estimate soil protective capacity against pollutants. The aim of our study was to evaluate the model to better identify key parameters and processes that influence N losses in agricultural soils. Nitrate N content was monitored in soil under corn (Zea mays L.) fertilized with urea and/or pig slurry, in two field experiments performed on four different soils: a Fienili clay, a Barco-like silt, a Sant'Omobono silt loam, and a La Boaria silty clay soil. Measurements were compared with model predictions. For all soils, nitrate content was underestimated on average by 24 to 88% at lower N rates; it was overestimated by 1 to 104% at higher N rates. The root mean square error (RMSE) was equal to 81.1%. Simulation of crop N uptake and soil water flow, estimation of the ammonia losses at pig slurry spreading, and N transformation parameter setting were considered as possible error sources. The calibration of crop N uptake gave rise to good model efficiency index values. The RMSE for the simulation of soil water content varied between 9.8 and 20.2%. A more accurate setting of the ammonia losses and of the feces transformation parameter values could allow the RMSE for the simulation of soil nitrate content to be reduced by no more than 10 to 15%. It is possible for the model not to include the simulation of processes that could have relevant effects on the soil N dynamics.     

Participatory Development of No-tillage Systems without Herbicides for Family Farming: The Experience of the Center-South Region of Paraná

It is currently estimated that 40 million hectares worldwide are cultivated through no-tillage systems (Derpsh, 1998). Small family farms account for less than 50,000ha, half of them located in South America's Southern Cone (Wall, 1998). Many hypotheses have been offered to explain why so few small farmers have adapted to this method. The most simplistic ones relate this limited adoption to small farmers' traditionalism and to their rejection of innovation. Others point to the low technological development of animal-drawn equipment needed for this technology or the low educational level of family farmers.Results of work done in the Center-South of Paraná, Southern Brazil, by AS-PTA¹ in partnership with the region's Forum of Family Farmers Organizations, challenge these hypotheses and draw attention to the need for new approaches and processes of research and extension if the goal is to disseminate and implement appropriate no-tillage systems among family farmers. One requisite is to lower production costs of this method through elimination of herbicides and using green manure and cover crops that shift the crop-weed balance in favor of crops.