Spatial assessment of pollutant loads for surface water quality management: a case study in Lai Chau city, Vietnam

The aim of this study is to present a method for estimating the pollutant load from different sources in an effort to provide improved information regarding water pollution and help control the surface water pollution, using Lai Chau city as a case study. The pollutant load was calculated in accordance with the Vietnam Environment Administration Decree No.154/2019 on the guidance for calculating the total pollutant load of river water. The pollutant sources include point sources (domestic wastewater, animal husbandry, industrial complexes and economic services) and surface sources (run-off from agricultural land uses) that generate wastes that potentially contaminate water bodies. The source locations were mapped and spatially joined with the drainage-basin map delineated from a Digital Elevation Model (DEM) to calculate the loads for the sub-basin units. Multivariate analysis then showed that the farming and domestic sources had the strongest positive loading factors for the sub-basins located in the city center and its fringe areas. Of these waste from animal husbandry account for up to 75.1% of total pollutant load. The main conclusion from the study's results is that the management approach should be changed from the total controlling mode, which is currently applied in the city, to a source specific approach based on the pollutant discharge loads and the allocated capacities

Catalyzing Transformations to Sustainability in the World's Mountains

Mountain social‐ecological systems (MtSES) are vital to humanity, providing ecosystem services to over half the planet's human population. Despite their importance, there has been no global assessment of threats to MtSES, even as they face unprecedented challenges to their sustainability. With survey data from 57 MtSES sites worldwide, we test a conceptual model of the types and scales of stressors and ecosystem services in MtSES and explore their distinct configurations according to their primary economic orientation and land use. We find that MtSES worldwide are experiencing both gradual and abrupt climatic, economic, and governance changes, with policies made by outsiders as the most ubiquitous challenge. Mountains that support primarily subsistence‐oriented livelihoods, especially agropastoral systems, deliver abundant services but are also most at risk. Moreover, transitions from subsistence‐ to market‐oriented economies are often accompanied by increased physical connectedness, reduced diversity of cross‐scale ecosystem services, lowered importance of local knowledge, and shifting vulnerabilities to threats. Addressing the complex challenges facing MtSES and catalyzing transformations to MtSES sustainability will require cross‐scale partnerships among researchers, stakeholders, and decision makers to jointly identify desired futures and adaptation pathways, assess trade‐offs in prioritizing ecosystem services, and share best practices for sustainability. These transdisciplinary approaches will allow local stakeholders, researchers, and practitioners to jointly address MtSES knowledge gaps while simultaneously focusing on critical issues of poverty and food security