Determining the areas most suitable for urban land use while minimizing impact on natural areas. The case of the Machachi Valley, Ecuador.

Due to the impact of urban growth on the environment, especially in developing countries, decision-making tools are needed to help locate the ideal areas for urban use. This study aims to identify the areas most suitable for urban use, minimizing their impact on forest land use in an area with high urban sprawl. As a new development, the study also considers the connectivity between forest-use patches and the loss of forest area as decision variables. The methodology used to determine these areas was AHP (Analytic Hierarchy Process) with GIS (Geography Information System). Twenty experts evaluated the criteria, considering forest conservation in addition to urban suitability. Socio-economic, physical, and environmental criteria and sub-criteria were scored with values from 1 to 5, with 5 indicating the maximum potential of the pixel to accommodate urban use. The study area was the Machachi Valley and the conurbation of Quito in Ecuador. The results indicate that the most suitable urban areas are located in the buffer that surrounds the initial urban use, and the land along the Pan-American Highway. The most vulnerable forest zone was in the south center of Quito and on the hillsides of the Pasochoa volcano. The results were also compared with maps that estimate the evolution of the land uses in this valley in the coming years. Based on this comparison, maintenance of current trends will result in a significant loss of native forest and fragmentation of forest patches in the lower valley. The information provided by maps of suitable urban use is a useful tool to protect the natural resources that land use policies should take into consideration.

Uso da tecnologia blockchain nas contratações públicas sustentáveis de obras rodoviárias / Uso de la tecnología blockchain en la contratación pública sostenible de obras viales / Using blockchain technology for sustainable public procurement of road works

Resumo A dificuldade de incorporar a variável ambiental nos processos de contratação é recorrente no mundo. Nesse contexto, as contratações públicas sustentáveis são um instrumento importante para reduzir o impacto ambiental das organizações. No Brasil, há incapacidade para incorporar instrumentos que permitam uma atividade pública mais eficaz e eficiente. Em contrapartida, as tecnologias digitais, como a blockchain, podem ser a solução para problemas complexos no setor público. Nos últimos anos, governos têm adotado a blockchain em diversas áreas, sendo que, no âmbito internacional, a tecnologia é utilizada em bancos de dados de alguns países. No sentido de facilitar a implantação dos critérios ambientais nos procedimentos de licitação, este estudo propõe um modelo conceitual de aplicação da blockchain para contratações públicas sustentáveis de obras rodoviárias. Com base na análise de conteúdo de 25 processos de licitação, foi realizado o mapeamento das principais atividades, o que permitiu propor uma solução integrada ao Portal Nacional de Contratações Públicas. A principal contribuição do estudo é apresentar as potenciais aplicações referentes aos aspectos ambientais para blockchain nas contratações públicas e demonstrar a viabilidade da implementação dessa tecnologia. Diante das novas perspectivas para otimizar a gestão dos processos licitatórios e prover a sustentabilidade ambiental na administração pública, entende-se que a blockchain pode auxiliar na promoção de uma estrutura de licitação confiável, descentralizada, transparente e ambientalmente sustentável.

Resumen La dificultad de incorporar la variable ambiental en los procesos de contratación es recurrente en todo el mundo. En este contexto, la compra pública sostenible es un importante instrumento para reducir el impacto ambiental de las organizaciones. En Brasil hay incapacidad para incorporar instrumentos que permitan una actividad pública más efectiva y eficiente. Por otro lado, las tecnologías digitales como la blockchain pueden ser una solución a problemas complejos en el sector público. En los últimos años, los gobiernos han adoptado la blockchain en varias áreas y, a nivel internacional, la tecnología se utiliza en bases de datos en algunos países. Con el fin de facilitar la implementación de criterios ambientales en los procedimientos de licitación, este estudio propone un modelo conceptual para la aplicación de la blockchain a las contrataciones públicas sostenibles de obras viales. A partir del análisis de contenido de 25 procesos de licitación, se mapearon sus principales actividades, lo que permitió proponer una solución integrada al Portal Nacional de Contrataciones Públicas. La principal contribución del estudio es la presentación de aplicaciones potenciales relacionadas con aspectos ambientales para la blockchain en la contratación pública, así como demostrar la viabilidad de implementar esta tecnología. Ante las nuevas perspectivas para optimizar la gestión de los procesos de licitación y dotar de sostenibilidad ambiental a la administración pública, se entiende que la blockchain puede ayudar a promover una estructura de licitación confiable, descentralizada, transparente y ambientalmente sostenible.

Abstract Governments worldwide face recurrent challenges in incorporating environmental variables into bidding processes. In this context, sustainable public procurement is an important tool for reducing the environmental impact of public organizations. Despite the emergence of digital technologies such as blockchain, which offers potential solutions to complex public sector problems, and the existing implementation of blockchain in databases by some countries, the Brazilian government has not developed the capability to adopt such instruments to improve environmental effectiveness and efficiency. This study proposes a conceptual model for the application of blockchain in sustainable public procurement of road works to facilitate the incorporation of environmental criteria into bidding procedures. Through a content analysis of 25 bidding processes related to road works, the research mapped out key activities, providing insights to propose an integrated solution for the Brazilian National Public Procurement Portal to address environmental issues in procurement processes. The study's main contribution lies in outlining potential applications of blockchain in public procurement to embrace environmental aspects, demonstrating the feasibility of implementing this technology. Given the emergence of new perspectives to optimize bidding process management and foster environmental sustainability in public administration, the research provides evidence that blockchain can help promote a reliable, decentralized, transparent, and environmentally sustainable bidding structure.

Landscape resistance index aiming at functional forest connectivity.

Resistance models may quantify the ability of the landscape to impede species' movement and represent suitable habitats. Moreover, the performance of resistance models parameterized by land-use/land cover attributes evidence that the integrity of the environments subject to urban sprawl is poorly understood. In this sense, the study assumed we could identify the forest functional connectivity in a landscape considering the disparity in the landscape mosaic. In this context, we sought to develop a landscape resistance index through structural equation modeling (SEM), supported by the criteria of heat emission, biomass, and anthropogenic barriers, obtained by remote sensing, called observed variables. The landscape studied in the Green Belt Biosphere Reserve of São Paulo has significant remnants of the Atlantic Forest, a biodiversity hotspot. However, our results indicated criteria variability in the landscape modeled through the SEM, obtaining a significant adjustment of the landscape resistance index, with comparative fit index (CFI) of 1.00 and root mean square error of approximation (RMSEA) of 0.00. The index reflects the resistance levels of the land use/land cover, expressed by the class interval, ranging from 0% (1.73) to 100% (493.88), with the highest values associated with the anthropized uses and forest isolation. Thus, our index based on environmental attributes reflects the structure of functional forest connectivity and offers a framework to design forest corridors across landscapes.

Modelo conceitual de critérios ambientais para contratação pública de obras rodoviárias federais / Modelo conceptual de criterios ambientales para la contratación pública de obras viales / Conceptual framework of environmental criteria of public procurements for federal roadwork

Resumo As Contratações Públicas Ecológicas constituem instrumento importante para reduzir o impacto ambiental das organizações. Este estudo tem por objetivo propor um modelo conceitual de critérios ambientais para contratação pública de obras rodoviárias federais. Para tanto, o conteúdo de 153 editais do órgão gestor da malha rodoviária federal brasileira, publicados entre 2006 e 2021, foi analisado e comparado com a lista de critérios relativos aos Contratos Públicos Ecológicos da União Europeia. Com base na identificação e categorização dos critérios ambientais e da classificação dos níveis de exigência desses critérios, foi possível definir a qualidade de atendimento aos fundamentos desses editais e, assim, propor um modelo que pudesse relacionar a categoria ambiental, o tipo de obra, o tipo de critério e os respectivos indicadores. Os resultados revelam um nível de atendimento aos critérios ambientais de 19%, valor baixo em comparação com os estudos realizados em países europeus. Diante dessa limitação, a proposição do modelo evidencia a necessidade de estabelecer claramente os parâmetros ambientais nos editais de licitação, no sentido de contribuir para o desenvolvimento sustentável e a melhoria contínua dos empreendimentos rodoviários.

Resumen La contratación pública ecológica es un importante instrumento para reducir el impacto ambiental de las organizaciones. Este estudio tiene como objetivo proponer un modelo conceptual de criterios ambientales para la contratación pública de obras viales federales. Se analizó el contenido de 153 avisos públicos emitidos por el órgano gestor de la red vial federal brasileña, publicados entre 2006 y 2021, y se comparó con la lista de criterios relacionados con los contratos públicos ecológicos de la Unión Europea. A partir de la identificación y categorización de los criterios ambientales, y mediante la clasificación de los niveles de exigencia de estos criterios, fue posible definir el nivel de cumplimiento de los criterios en los avisos públicos y, así, proponer un modelo que pueda relacionar la categoría ambiental, el tipo de obra, el tipo de criterio y sus respectivos indicadores. Los resultados revelan un nivel de cumplimiento de los criterios ambientales del 19%, un valor bajo en comparación con los estudios realizados en países europeos. Ante esta limitación, la propuesta del modelo destaca la necesidad de establecer claramente los criterios ambientales en los pliegos de condiciones, a fin de contribuir al desarrollo sostenible y a la mejora continua de los emprendimientos viales.

Abstract Green public procurements are important to reduce the organizations' environmental impact. This study proposes a conceptual framework for adopting environmental criteria in the public procurement for federal roadworks. Content analysis of 153 bidding terms issued from 2006 to 2021 by the public agency in charge of managing Brazil's federal road network was conducted. The results were compared to the standard list of criteria for Green Public Procurements defined by the European Union. By identifying and classifying the environmental criteria and by defining their related requirement levels, we were able to assess the level of compliance with the environmental criteria in our sample of bidding terms and propose a framework relating different environmental categories, roadwork classifications, environmental criteria, and their respective indicators. The findings reveal a low level of compliance with environmental criteria in our sample (around 19%), a value below what is found in the European context. Given current challenges in developing sustainable roadworks, the proposed model underscores the need to clearly define environmental criteria in bidding terms to foster both sustainable development and the continuous improvement of roadworks.

A worldwide meta-analysis review of restriction criteria for landfill siting using geographic information systems.

One of the most crucial parts of solid waste management is determining landfill site location, since multiple factors must be considered and there is no universal formula. The main purpose of this study is to make a worldwide systematic review of restriction criteria used for landfill siting using geographic information systems (GIS). Literature from the last years was thoroughly assessed, and 45 restrictions found were classified as environmental, economic, or social criteria. Our findings show that although the number of articles published has increased recently, they use on average seven restrictions, focusing mainly on environmental over economic and social criteria. In our boxplot statistical analysis, the most frequently used environmental restrictions are the distance from surface water resources (used in 77% of articles), slope (52%), and distance from groundwater founts (40%), with a median of 300 m, 20%, and 250 m, respectively. The most frequently used economic restrictions are distances from roads (60%), airports (40%), and power lines (18%), with medians of 275 m, 3000 m, and 75 m, respectively. The most frequently used social restrictions are distances from urban areas (45%), settlements and residential areas (40%), and cultural heritage or archaeological areas (23%), with medians of 1000 m. This information might help, on the one hand, governments to develop new legislation about landfill siting and on the other hand, decision-makers and scientists to produce new studies with different restrictive scenarios.

Selenium Enrichment in Pore Water of Estuarine Sediments Subject to Salt Marsh Vegetation Bioirrigation (Patos Estuary, Southern Brazil).

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora. The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S. alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L-1), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.