Water, energy and nutrients are interlinked extensively with food and each other as shown in the monitoring, analysis and evaluation framework for the Water Energy Nutrient Food (WENF) nexus by Haitsma Mulier et al. (2022). This study aims to contribute to the quantification of the Water Energy Nutrient Food nexus regarding urban agriculture. It investigates the water, energy and nutrient demand of urban farms along with the presence of those resources in urban waters at three case study sites. Demands for water and nutrients (nitrogen & phosphorus) at a greenhouse in Amsterdam and a community farm and a container farm in East-Boston could be met by resources present in urban waters (rainwater and wastewater) in the direct vicinity. Whether enough energy is available to operate each of these farms is related to the type of agriculture.

This article explores climate change resilience in the water sector, and its relation to food security of poor farmers in rural of Cambodia. The research analyzed both quantitative and qualitative data by conducting a survey of 103 farmer households in Svay Chacheb and Tuol Sala communes of Basedth District, Kampong Speu province. Detailed interviews were conducted with poor households, village chiefs, commune councilors, and agriculture officials at the district level. The study found that the famers do not receive sufficient water for rice cultivation and daily consumption from the existing irrigation systems and wetlands. Additionally, storage equipment and mechanisms for resilience to the effects of climate change are limited. Most farmers spend in order to obtain sufficient water for agriculture activities such as growing crops and raising livestock. The farmers need to borrow from their neighbors and use their own existing resources when they are faced with a food shortage because support mechanisms from government agencies and Non-governmental Organization (NGOs) are limited.

The growing body of literature on the Food-Water-Energy (FWE) nexus during the last decade covers a variety of disciplinary perspectives and spatial scales. However, to date the urban FWE nexus has received less attention. In this paper, we review the FWE nexus literature with the focus on urban scale and identify gaps in the scholarly knowledge base with regard to practical applications for the FWE nexus governance in cities. Our findings suggest that there is still a mismatch between theoretical nexus governance and community perceptions. Successful governance is an iterative process, necessitating stakeholder input, reflection and response. While research developing the body of urban FWE governance knowledge has increased rapidly, reflection on those results to unpack the nexus complexity and support different governance actors is still limited. We discuss an approach for making the FWE nexus connections more visible and practical by focusing on the urban governance actors and illustrating the intersecting interests and concerns of different actors within the food, water, and energy systems. Mapping the urban governance actors to the sub-elements of the FWE systems highlights common connections and overlapping interests, paving the road toward more integrated governance and participatory solutions. Identifying the tangible and intangible connections among governance actors also helps to reduce the ambiguity of the FWE nexus, and facilitates multi-stakeholder knowledge, data or resources sharing. The resultant approach aims to disaggregate the complexity of the FWE nexus and make its governance more attainable in cities.

Identifying pathogens in food and drinking water has always been an important task. Escherichia coli (E. coli) is one of these pathogens found in food and water samples. Although there are several traditional microbiological analysis methods, the most advanced methods are based on biochemistry and molecular biology. New nanotechnology methods based on optical methods provide cheaper, more reliable, faster, and more sensitive platforms for detecting E. coli in a given sample. Various optical methods are available for the detection of E. coli. The most recently developed strategies to develop sensors for detecting E. coli are fluorescence, colorimetric, surface-enhanced Raman spectroscopy, surface plasmon resonance, localized surface plasmon resonance, and chemiluminescence. In addition, optical detection of E. coli in smartphone, paper-based, and portable devices are also considered. It has been shown that these optical nanobiosensors have high sensitivity and low detection limits for E. coli detection.

Increasing food demand has led to significant agricultural expansion globally with negative impacts on resources and the environment, a perfect manifestation of the Water-Energy-Food-Environment nexus. Whilst many tools have been developed to understand the complexity of the Water-Energy-Food-Environment nexus most have failed to explicitly consider biophysical and socio-economic aspects simultaneously. A novel Water-Energy-Food-Environment modelling toolkit is developed that integrates both these components by combining different modelling approaches including irrigation simulation, economic modelling and life cycle environmental assessment. The toolkit is demonstrated using two major agro-export crops (asparagus and table grapes) in the Ica Valley, Peru, a severely water-stressed region. The toolkit was able to provide novel insights into the implications of different farming practices on resource efficiency at the field level in relation to water and energy, under contrasting future scenarios reflecting socio-economic outcomes at the local to regional levels (e.g., food prices, employment, and income) as well as environmental impacts at local to global scales. This information enables different stakeholders to better understand the interlinkages and inter-dependences between the Water-Energy-Food-Environment nexus elements and the complex impacts of agricultural expansion beyond the immediate sector and its geographical extent, helping decision makers design more coordinated agricultural policies and support sustainable agricultural transformation. | Natural Environment Research Council (NERC): NE/R015759/1. Chilean National Agency for Research and Development (ANID/CONICYT) - FONDEF

Exploring the coupling characteristics of regional water resources and food security helps to promote the sustainable development of grain production and is of great significance for achieving global food security. From the aspects of regional “water supply”, “water use” and “water demand”, the coupling characteristics of water resources and food security were systematically revealed; the new challenges faced by regional food security from the perspective of water resources were clarified; and effective ways to promote the utilization of regional water resources and the sustainable development of grain production were explored. This paper took Northwest China, which is the most arid region, where water-resource utilization and food security are in contradiction, as the research area. The water-resource load index, the water footprint of grain production and the water-consumption footprint were used to quantify the regional water-resource pressure index, as well as the residential grain-consumption types, population urbanization, the industrial-grain-processing industry and their corresponding water-consumption footprints from 2000 to 2020. The coupling characteristics of water resources and food security were systematically revealed. The results showed the following: (1) In 2000–2020, the water-resource load index increased from 4.0 to 10.7, and the load level increased from III to I. At the same time, agricultural water resources were largely allocated elsewhere. (2) During the period, the food rations showed a significant decreasing trend, and the average annual reduction was 3.4% (p < 0.01). The water footprint of animal products increased, particularly for beef and poultry (the average annual growth rates were 9.9% and 6.3%, respectively). In addition, the water footprint of industrial food consumption increased by 297.1%. (3) With the improvement of the urbanization level, the water-consumption footprint increased by 85.9%. It is expected that the water footprint of grain consumption will increase by 39.4% and 52.3% by 2030 and 2040, respectively. Exploring how to take effective measures to reduce the water footprint to meet food-security needs is imperative. This study proposed measures to improve the utilization efficiency of blue and green water and reduce gray water and the grain-consumption water footprint from the aspects of regional planting-structure optimization potential, water-saving irrigation technology, dietary-structure transformation and virtual water trade; these measures could better relieve the water-resource pressure and promote the sustainable development of grain production and water-resource utilization.

Climate change increases the need for effective and sustainable technologies in food and agriculture. Plasma-activated water (PAW) emerges as a green and sustainable technology in food processing and production. Synergy of a myriad of reactive oxygen and nitrogen species (RNOS) in PAW contributes to desirable properties of PAW. Compared to conventional methods, PAW is fast and effective for various products, not limited by the volume or shape of the treated samples. In this review, we will first introduce the fundamentals on plasma generation, physicochemical properties and characterization of PAW. Among various approaches for activation improvement, we highlight a recent progress in improving the cold plasma activation by microbubbles. Then we critically review the treatment conditions by PAW, and effectiveness of PAW for bio-film removal, food processing, plant growth in agriculture, and environment. As the research output on PAW is expanding exponentially, this review focuses on the work published within the last two years (2020–2021) to summarize the current understanding of the principles of the effects from PAW and to reflect potentials of PAW in applications for the food science and technology.

Access to clean water, reliable energy services and adequate food supply are basic needs for life and contribute to the reduction of national and global levels of human poverty and forced migration. This study concentrated on reviewing progress made in understanding the relationship between the Water-Energy-Food (WEF) nexus and climate change adaptation, using Africa as a case study. The method used to achieve this objective was the bibliometric analysis, covering the period from 1980–2021. Data used for this study were acquired from theWeb of Science (WoS) and Scopus databases. Initially, 95 documents were retrieved from theWoS and Scopus core collection databases, but 30 duplicates were removed, and 65 documents were used. The outputs were further analysed using the bibliometric R package and VOS viewer. Analysis of the top 100 keywords in the 65 publications that link WEF nexus with climate change adaptation for Africa showed that 46 keywords fall under the application of WEF nexus, 31 keywords under the implementation of WEF nexus and 23 keywords under the implication of WEF nexus. Researchers from countries around the world have published the WEF nexus work undertaken on the African continent. Countries with the highest number of publications were South Africa, the United Kingdom, the United States of America, Germany, Kenya and Zimbabwe. Thematic analysis was used to explore the conceptual structure of WEF publications, and it produced four themes: (i) well-established concepts appropriate for structuring the conceptual framework of the field of WEF nexus in Africa; (ii) strongly developed concepts but still marginal for the field of WEF nexus in Africa; (iii) not fully developed or marginally interesting concepts for the field of WEF nexus in Africa, and (iv) significant cross-cutting concepts in the field of WEF nexus in Africa in relation to climate change adaptation. This study contributes to the growing body of literature on the WEF nexus by pointing out dominant themes from those that are still emerging in the scholarly work done in Africa. | The Water Research Commission in South Africa. | https://www.mdpi.com/journal/sustainability | am2023 | Geography, Geoinformatics and Meteorology

In view of a water-energy-food (WEF) nexus strategy, the present work assessed the bioenergy production potential of Halimione portulacoides used for the phytoremediation of nutrient-rich simulated wastewater from saltwater-based integrated multi-trophic aquaculture (IMTA). Specimens of this halophyte plant were grown in hydroponics under four different nutrient treatments with distinct nitrogen (N) and phosphorous (P) concentrations. Ultimate and proximate analysis, calorific value and thermogravimetric analysis coupled to mass spectrometry were used to assess the bioenergy potential of the non-edible biomass of the plants, namely the canes (C) and roots (R), and of commercial pellets (CP), which were used as benchmark. R and, especially, CP had higher carbon but lower oxygen content and larger volatiles but lower ashes than C. The higher heating values (HHV) of C (16–17 MJ kg⁻¹) and R (17–18 MJ kg⁻¹) were the same order as those of conventional energy crops and CP (20 MJ kg⁻¹). Although mass loss and associated gaseous emissions during temperature programmed pyrolysis occurred mainly between 250 and 650 °C for all biomasses, they took place at slightly higher temperatures for C > CP > R. In any case, the integrated gaseous emissions during the pyrolysis of C, R, and CP were very similar and included H₂, CH₄, CO, and CO₂ (syngas main constituents). Biomass production of C was affected by the nutrients load of the applied treatments, but this was not the case for R. Also, the nutrients treatments had no detectable effects on the biomasses’ ultimate or proximate analysis, HHV, thermal decomposition or resultant gaseous emissions. Thermal properties and behaviour of C and R were very similar to those of CP, showing their potential for bioenergy production and revealing that a WEF nexus strategy can be implemented in IMTA by energetic valorization of non-edible biomass of H. portulacoides used for water phytoremediation.