Evaluation of water environment quality in a typical wetland on the Qinghai-Tibet Plateau using positive matrix factorization and self-organizing map

Abstract

The Qinghai-Tibet Plateau (QTP), the world's largest plateau, harbors rich lake resources but is ecologically fragile. Vulnerable river ecosystems in these areas face significant threats from environmental and anthropogenic pressures. Thus, comprehensive water quality monitoring is essential prior to conservation efforts. This study focuses on the Selin Co International Wetland in Tibet, a model of natural wetland ecosystems. We employed methods including water quality assessment, source apportionment, and clustering analysis to evaluate the water environment. Results from the Water Quality Index (WQI) indicate overall good water quality; however, parameters such as COD, DO, TN, TP, and As require monitoring for potential exceedance. Positive Matrix Factorization (PMF) analysis reveals that the primary sources of substances are identified as natural sources (37.17%), animal disturbance sources (32.93%), and anthropogenic activities (22.31%). The results of the water source analysis using the PMF and the cluster analysis based on the self-organizing map (SOM) indicate that natural and geographical environmental factors are the primary determinants of water quality, with minimal influence from human activities. This research emphasizes the importance of these natural influences, providing a scientific foundation for the protection and management of wetlands in the QTP, which is critical for ensuring regional water resource security.