A Systematic Review of Methodological Tools for Evaluating the Water, Energy, Food, and One Health Nexus in Transboundary Water Basins.

Water plays a vital role in human socioeconomic development and overall well-being, making its effective management essential in achieving the Sustainable Development Goals. The close interlinkage between water, other environmental resources, and socioeconomic development have prompted the emergence and adoption of holistic and trans-sectoral concepts such as integrated water resources management and, more recently, the resource nexus. However, even such holistic approaches often exclude the one health approach, particularly at the transboundary water basins (TWBs), which not only dominate 40% of the earth but are vital in environmental and human sustainability. This review aimed to understand, evaluate, and compare assessment tools for water, energy, food, and one health (WEF + H) nexus management in TWBs. The review applied the systematic review guidelines for articles published in the Scopus database. The inclusion criteria encompassed English-language articles featuring case studies, meta-studies, or review articles with no less than three nexus resources. The review categorized the article based on criteria that focused on identifying tools capable of analyzing scenarios and policies for WEF + H in TWBs and their accessibility and easiness of implementation in case studies. Of the eighteen analyzed tools, 13 (72%) had limitations in their application at various geographical scales. Additionally, they could not integrate one health into the nexus or analyze policies through running scenarios. On the contrary, the Bayesian networks, system dynamics, agent-based models, life-cycle assessments, and input-output tools were highly accessible for efficiently conducting scenario-based WEF + H nexus assessments in TWBs.

Increased levels of multiresistant bacteria and resistance genes after wastewater treatment and their dissemination into lake geneva, Switzerland.

At present, very little is known about the fate and persistence of multiresistant bacteria (MRB) and their resistance genes in natural aquatic environments. Treated, but partly also untreated sewage of the city of Lausanne, Switzerland is discharged into Vidy Bay (Lake Geneva) resulting in high levels of contamination in this part of the lake. In the present work we have studied the prevalence of MRB and resistance genes in the wastewater stream of Lausanne. Samples from hospital and municipal raw sewage, treated effluent from Lausanne's wastewater treatment plant (WTP) as well as lake water and sediment samples obtained close to the WTP outlet pipe and a remote site close to a drinking water pump were evaluated for the prevalence of MRB. Selected isolates were identified (16S rRNA gene fragment sequencing) and characterized with regards to further resistances, resistance genes, and plasmids. Mostly, studies investigating this issue have relied on cultivation-based approaches. However, the limitations of these tools are well known, in particular for environmental microbial communities, and cultivation-independent molecular tools should be applied in parallel in order to take non-culturable organisms into account. Here we directly quantified the sulfonamide resistance genes sul1 and sul2 from environmental DNA extracts using TaqMan real-time quantitative PCR. Hospital sewage contained the highest load of MRB and antibiotic resistance genes (ARGs). Wastewater treatment reduced the total bacterial load up to 78% but evidence for selection of extremely multiresistant strains and accumulation of resistance genes was observed. Our data clearly indicated pollution of sediments with ARGs in the vicinity of the WTP outlet. The potential of lakes as reservoirs of MRB and potential risks are discussed.