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Population growth has led to the intensification of average daily traffic (ADT), highlighting vehicles as one of the major sources of heavy metal (HM) pollution in cities. The objective of this paper is to conduct a spatial analysis of the HM pollution associated with road-deposited sediments (RDSs), based on the ADT observed in the main roads of a Latin American megacity (Bogotá, Colombia). The following risk indices were considered: Geoaccumulation Index (Igeo), Integrated Pollution Index (IPI), Ecological Risk Index (ERI), Comprehensive Potential Ecological Risk Index (CERI), Hazard Index (HI), and Carcinogenic Risk Index (CRI). The findings confirm that a size fraction < 250 μm is the most suitable for studying the risk of HMs in the RDS from the indices considered. The best HMs indicative of the relationship with ADT are Ni, Cu, and Pb. The Pb is the HM of most attention, and Cr gains positions for its toxicity level during the evaluation of ecological, non-carcinogenic, and carcinogenic risks, respectively. Finally, the linear regression models developed between ADT and each of the risk indices considered have a better fit (R2 > 0.910) compared to the linear regression models developed between ADT and HM concentrations (R2 > 0.322). [ABSTRACT FROM AUTHOR]

Bogota, the capital of Colombia, has recently presented an important expansion of its territory. This has triggered the displacement of rural and peasant areas. However, some neighboring municipalities have managed to stay out of the city's growth process thanks to their geographical conditions and have also generated important links from their agri-food systems. In these articulation processes, the governance schemes and its actors are key. This analysis seeks to answer what have been the main strategies and coordination mechanisms implemented by the Universidad Externado de Colombia (UEC) to achieve multiple interactions between the actors involved in the multifunctional and territorialized agri-food systems (MTLAFS MTLAFS). For the above, the municipality of Choachi and its relationship with Externado University as an articulator of actions that contribute to the construction of territorial and regional dynamics are taken as an illustrative case. Within the framework of the qualitative methodology, case studies were used, with the concept of governance as the axis of analysis. As part of the results, some recommendations are presented for the work of universities in multifunctional and territorialized short circuits, as well as for the understanding of the actors, mainly the university, in the governance schemes of agri-food systems. [ABSTRACT FROM AUTHOR]

What should be the policy to meet urban food needs in developing countries and those in transition? This is a key question of the Food and Agriculture Organization of the United Nations (FAO), which was posed into the "FAO's methodological and operational guide to study and understand Food Supply and Distribution Systems (FSDS) to cities in developing countries and countries in transition" in order to face the current overwhelming increase of urban population and the increasing urbanization pressures on food systems. Following some previous work in the field where it was argued that clarifying the various problems and structure behind Food Supply and Distribution Systems (FSDS) in urban environments is vital to assess policies that aim at meeting urban food needs, the purpose of this paper is to show that the methodological approach known as system dynamics modeling and simulation can lead, in terms of knowledge and/or theoretical contribution, to the unfolding of complexity in this area of research as well as bring into the analysis the relationships across a few goals of the Agenda 2030. As an additional result, we show how the developed model can be applied (case of the production of milk for consumption in the city of Bogota, Colombia) to analyze the dynamics of food supply and distribution systems in urban environments. [ABSTRACT FROM AUTHOR]

This article presents an analysis of students' conceptual understanding of technology. The study focused on two groups of seventh-grade students located in Bogotá, Colombia, living in rural and urban areas and participating in activities developed in a virtual learning network. The methods used in this study followed grounded theory (Strauss & Corbin, 2002) to generate a theoretical structure that allows explanations to be built on how participants construct concepts. A total of 1,257 analysis units were obtained. After an open, axial selective coding process, these units were classified into four categories: artifacts, materials, and instruments; social and cultural aspects; systems, knowledge and processes; and scientific applications. From these categories, the results show an ordination in transversal dimensions helicoidally articulated in the following ascending order: (1) artifacts (technological, cultural, symbolic, and scientific), (2) objectives of technological advances (transformation processes with varied purposes highlighting continuous technological change), (3) fulfillment of basic survival needs (daily life, welfare, and biological maturity), (4) artifact production in terms of process (creation, innovation, and context transformation), and (5) relationships between human beings and technology (passive role, positive interdependence, and symbiosis). In conclusion, a unidirectional concept of technology encompassing all its features cannot be built. In contrast, students construct the concept in a plural, complex way. The construction of a technology concept at the school level leads to a more comprehensive education in technology in terms of its attitudinal, volitive, and cognitive aspects, which favor cultural technology insertion in schools. [ABSTRACT FROM AUTHOR]

Rainwater Harvesting (RWH) is the practice of capturing and storing stormwater for later use. In addition to being an alternative source of water for non-potable applications, RWH is also used to effectively reduce stormwater runoff volumes and pollutant loads dropped into sewage systems. RWH is typically carried out by placing a variety of Sustainable Urban Drainage Systems (SUDS) in different locations of the urban landscape. However, because of the staggering number of potential combinations of SUDS typologies and spatial configurations that can be used, identifying a strategy that optimally selects and allocates SUDS to maximize the benefits of RWH is a complex endeavor. One of the challenges that emerges during the optimal design and location of these systems is incorporating the inherent uncertainty of the rainfall. In this paper, we develop a flexible computational framework that couples a Geographic Information System (GIS) with a two-stage stochastic mixed integer linear program (TS-MILP) to select and locate SUDS in order to minimize the use of potable water for irrigation and reduce the water runoff at a minimum cost. This framework incorporates an iterative participatory approach to engage stakeholders in the decision-making process. We tested the proposed methodology on a case study for the central campus at Universidad de Los Andes (Bogotá, Colombia). Our results showed that the expected value of the total runoff volume and the consumption of potable water can be reduced up to 67% and 50%, respectively. • A flexible computational framework to select and allocate SUDS was developed. • The objectives are minimizing the use of potable water for irrigation and reducing the water runoff at a minimum cost. • A Geographic Information System (GIS) is coupled with a two-stage stochastic mixed integer linear program (TS-MILP). • The proposed methods can be easily adapted to incorporate a wide variety of stakeholder requirements or preferences. • An iterative participatory approach is used to include stakeholders in the decision-making process. [ABSTRACT FROM AUTHOR]

The aim of this paper is to analyze the changes that have been produced in the temperature, humidity, precipitation, and edaphic parameters due to the presence of vertical gardens in the wetland "La Vaca" in Bogotá (Colombia). There are some conflicts in this wetland regarding the uses of the land due to the illegal urbanization settlements in flood-prone zones; to which a loss of the natural space of the wetland and the effects of climate warming is added. For this reason, vertical gardens are presented as an alternative for the solution to the aforementioned problems, since their implementation can act as a control barrier to possible floods considering their properties of water retention and temperature control. This work also sets its sight on knowing what changes have been produced in the environmental variables mentioned before with the presence of vertical gardens, and also on studying its temporal and spatial variability in the environment of the study area. The investigation begins with the installation of three vertical gardens with floating vegetation systems, installation of drip irrigation, and organic fertilizer built from the invasive vegetation of the wetlands. Subsequently, in the absence of vertical gardens, control areas are proposed for comparison with climatic and edaphic measurements. Finally, different statistical analyzes are performed, such as the comparison of means with parametric and non-parametric tests, among others, to determine spatial differences, and the changes that have been produced in time series. Vertical gardens are an alternative of "green growth" that make it possible to restore green areas and Riparian Buffer Zones in wetlands, using the resources of the environment to reduce costs in possible floods and the effects that are generated by climate change. [ABSTRACT FROM AUTHOR]

Urbanization has produced various social, environmental, and hydrological impacts, such as reduced biodiversity, increased urban temperatures, ecosystem degradation, air and water pollution, changes to hydrological processes, groundwater recharge alterations, increased prevalence of floods, vegetation removal, and potential increases in unstable soils. Finding solutions to mitigate the impacts of urbanization is of vital importance in the development and planning of cities, and particularly so for developing countries. One strategy gaining momentum is the use of green roofs and larger green areas (greater green cover under trees, with the purpose of increasing the permeable area) for runoff control. In this study, a simulation was carried out using the i-Tree Hydro software that involved the urban basin in the Fontibón area of Bogotá, Colombia, with the aim of observing the hydrological benefits of trees, green areas, and permeable zones. Five scenarios were proposed in which green roof coverage was implemented (20% and 50% increases in green areas in Scenarios 1 and 2), coverage under existing trees was enhanced (50% and 100% increase in Scenarios 4 and 5), and finally a complete removal of green zones in Fontibón was simulated (Scenario 3). The town is relatively susceptible to a reduction in its existing green areas, with an increase in total flow of more than 50% for one scenario considered. Thus, an increase in the permeable coverage under trees (50% and 100% increased coverage under existing trees) provided the best strategy for mitigating the impacts of urbanization by reducing the total, maximum, and average impervious flow by 3%, 4%, and 8%, respectively. Finally, an increase in permeable zones corresponding to plants was proposed via the implementation of green roofs. However, this strategy showed a response to the reduction in the lowest total flow at 1%. [ABSTRACT FROM AUTHOR]