Spatiotemporal Variation Characteristics of Industrial Structure in the Yellow River Basin, China, and Its Impact on the Water Environment

The Yellow River Basin (YRB) is a vital water source and an essential ecological barrier in northern China. Currently, it faces pressing challenges related to water resource security and displays pronounced disparities in regional economic development. In recent years, with the elevation of Ecological Protection and High-Quality Development to a national strategy, examining the interaction between industrial growth and water environmental quality within the basin has become a priority. This study focuses on the mainstem of the YRB. By compiling relevant data from 2000 to 2021 and collecting water samples from 20 mainstem sites, and by integrating spatial distribution information of key industrial sectors with water quality records (including representative heavy metals and anions), we found that the basin’s economic output expanded significantly over the past two decades, approximately 11.7 times. The industrial structure evolved across provinces within the basin, exhibiting an overall upward trend in industrial upgrading; nevertheless, substantial differences in industrial composition and transformation persist between the upper and lower reaches. Spatial variations in different industries are closely associated with pollutant concentrations. In particular, major industries in the middle–lower reaches, notably concentrated in regions such as Shandong, possess high total asset values. Output from certain sectors (e.g., petroleum extraction, coal mining and processing, non-metallic mineral mining and processing) is strongly correlated with pollution changes, with marked spatial linkages between their geographic distribution and concentrations of critical heavy metals (Cu, Se, Mo, Mn, Ni). Moreover, spatial analysis of the industry–pollution nexus reveals an apparent paradox in the middle–lower YRB: high industrial output coupled with relatively low levels of heavy metal contamination. This finding highlights the pivotal role of an advanced industrial structure and elevated regional development quality in mediating the balance between economic expansion and environmental pressure. In conclusion, as a globally significant large river basin, the YRB demonstrates a tight coupling between water quality and industrial structure. The results provide spatially explicit scientific evidence and policy guidance for the coordinated advancement of industrial green transformation and water quality improvement in the YRB, offering broader insights into industrial structure patterns and pollution control strategies applicable to major river basins worldwide.