Characterization of turbulence statistics on the non-aerated skimming flow over stepped spillways: a numerical study

Environmental Fluid Mechanics - In this work we address the mean flow and turbulence statistics in the non-aerated region of a stepped spillway by using two different numerical strategies in two...     

Occurrence of tar balls on the beaches of Fernando de Noronha Island,South Equatorial Atlantic

This work reports on the widespread occurrence of tar balls on a pebble beach of Sueste Bay on Fernando de Noronha Island, a Brazilian national marine park and a preserve in the South Equatorial Atlantic. Environmental regulations preclude regular visitors to the Sueste Bay beach, and the bay is a pristine area without any possible or potential sources of petroleum in the coastal zone. In this work, these tar balls were observed for the first time as they occurred as envelopes around beach pebbles. They are black in color, very hard, have a shell and coral fragment armor, and range in average size from 2 to 6 cm. The shape of the majority of the tar balls is spherical, but some can also be flattened ellipsoids. The polycyclic aromatic hydrocarbon analyses of the collected samples revealed the characteristics of a strongly weathered material, where only the most persistent compounds were detected: chrysene, benzo(b,k)fluoranthene, dibenzo(a,h)antracene and benzo(a)pyrene.     

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.     

Biogeochemical characterization of surface waters in the Aljustrel mining area (South Portugal)

Aljustrel mining area (South Portugal) is a part of the Iberian Pyrite Belt and encloses six sulfide mineral masses. This mine is classified of high environmental risk due to the large tailings’ volume and acid mine drainage (AMD)-affected waters generated by sulfides’ oxidation. The use of biological indicators (e.g., diatoms) revealed to be an important tool to address the degree of AMD contamination in waters. Multivariate analysis has been used as a relevant approach for the characterization of AMD processes. Cluster analysis was used to integrate the significant amount and diversity of variables (physicochemical and biological), discriminating the different types of waters, characterized by the high complexity occurring in this region. The distinction of two main marked phenomena was achieved: (1) the circumneutral-Na-Cl water type (sites DA, PF, BX, BF, RO, CB), expressing the geological contributions of the Cenozoic sediments of Sado river basin, with high diatom diversity (predominating brackish diatoms as Entomoneis alata); and (2) the acid–metal-sulfated water type (sites BM, JU, RJ, AA, MR, BE, PC, AF), reflecting both the AMD contamination and the dissolution of minerals (e.g., silicates) from the hosting rocks, potentiated by the extremely low pH. This last group of sites showed lower diatom diversity but with typical diatoms from acid- and metal-contaminated waters (e.g., Pinnularia aljustrelica). In addition to these two water types, this hierarchical classification method also allowed to distinguish individual cases in subclusters, for example, treated dams (DC, DD), with alkaline substances (lime/limestone), that changed the physicochemical dynamics of the contaminated waters.

     

Differences in stable isotopes in blood and feathers of seabirds are consistent across species, age and latitude: implications for food web studies

Stable isotopes of growing feathers and blood both represent assimilated diet, and both tissues are used to study the diet and foraging distribution of marine and terrestrial birds. Although most studies have assumed that both tissues represent a difference of one trophic level to diet, the enrichment factors of blood and feathers may differ, especially where endogenous reserves are used as precursors during feather synthesis. In this study, we compare carbon and nitrogen stable isotopes of blood and simultaneously growing feathers of five species of Procellariiformes, representing five genera, different geographical regions and different life stages (chicks and adults). In all species, feathers were enriched in ¹⁵N and ¹³C compared with blood. Isotopic values of carbon and nitrogen were correlated in different tissues growing simultaneously for most species analyzed, suggesting that mathematical corrections could be used to compare different tissues. Our results imply that more care needs to be taken when comparing stable isotope signatures across studies assuming different tissues are equivalent indicators of trophic ecology.     

Analysis of potentially toxic metal constraints to apply sewage sludge in Portuguese agricultural soils

Environmental Science and Pollution Research - The application of sewage sludge (SS) in the soil can be a valuable way to increase its content of organic matter. However, the concentration of...     

Land cover along hiking trails in a nature tourism destination: the Azores as a case study

Environment, Development and Sustainability - Tourists have become increasingly interested in certain aspects of their destination, including landscape and biodiversity elements, thereby promoting...     

Environmental remediation processes by zero valence copper: reaction mechanisms

Environmental Science and Pollution Research - Recent studies have shown Cu(0) as a promising material for the removal of organic and inorganic pollutants. However, there is no review addressing...     

Effect of the Incorporation of Lysozyme on the Properties of Jackfruit Starch Films

Jackfruit starch based biodegradable films containing lysozyme were characterized for their antimicrobial activity, thickness, solubility, water vapor permeability and mechanical properties. The biodegradable films had good appearance and antimicrobial activity against Micrococcus lysodeikticus. The thickness of the biodegradable films were not affected by the variation in pH, but the addition of lysozyme increased the thickness, the thickest films being those with the highest lysozyme concentrations. The variation in pH of the filmogenic solutions affected the solubility of the biodegradable films, water solubility being greatest at pH 7.0 and with the highest lysozyme concentration. The permeability of the biodegradable films was increased by incorporating lysozyme. The lysozyme concentration and pH variation caused changes in the mechanical properties. The addition of 8% lysozyme increased the tensile strength and Young’s modulus for all the pH values studied. With respect to the release of antimicrobial activity, the diffusion of lysozyme was shown to follow Fickian transport mechanism.