An Integrated Framework for Assessing the Multiscale Environmental Risks of Domestic Waste Management Systems in Mountainous Regions

Rapid growth of domestic waste in mountainous areas of underdeveloped countries severely challenges local domestic waste management capacities and causes multiscale environmental risks. However, methods for measuring the environmental risks of the domestic waste management system (DWMS) and determining effective optimization paths are lacking. These concerns relate to several Sustainable Development Goals, including clean water and sanitation (SDG6). According to the characteristics of scattered settlements, ecological fragility, limited traffic accessibility and low waste disposal capacity in mountainous regions, we constructed an integrated environmental risk assessment framework considering hazard, exposure and vulnerability, employed the technique for order preference by similarity to ideal solution (TOPSIS) model and the barrier obstacle model for quantitative risk assessment and analysis of constraining factors, and applied the developed framework to 3756 settlements in the mountainous regions of southern Qinghai Province (MRSQP). This framework considers the total cycle and multiscale perspectives of waste collection, transportation and disposal to reveal the environmental risks of DWMS in mountainous regions. In the MRSQP, human waste exhibited overall dispersion and local group concentration. Settlements with medium-high and high environmental risks accounted for 40.04% of the total settlements. Moreover, risk levels increased from eastern agricultural areas and agro-pastoral ecotones to western pastoral areas with increasing altitude, and the risk value was 1.81, 2.51 and 3.32, respectively. The highest environmental risks were observed in nature reserves. We proposed three management modes: urban–rural integration, town centralization, and village decentralization. This framework can be used to assess the environmental risks of DWMS in remote mountainous regions worldwide, formulate multiscale risk response strategies, improve DWMS effectiveness and enhance environmental sustainability.