Soil heavy metals assessment of the Zhoukou riparian zone base of Shaying river basin, China: spatial distribution, source analysis and ecological risk.

Abstract

The riparian zone serves as an ecological transition area between aquatic and terrestrial environments. Understanding the spatial distribution and origins of heavy metals within this zone is crucial for studying riverine ecosystems. In this research, we assessed the occurrence forms and spatial patterns of heavy metals in the riparian zone of the Shaying River Basin in Zhoukou City. Environmental risks were preliminarily evaluated using indices such as I_geo, RI, and PLI, and the sources of heavy metals were identified through PMF. The results revealed that the overall ecological risk associated with eight analyzed heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) in this region was low. However, Cd is marked enriched and represents a significant factor contributing to the potential ecological risk within the riparian zone of the basin. The high bioavailability of Cd and Mn in the soils of nine more contaminated sites showed moderate to very high ecological risk. The PMF model identified four pollution primary sources in this region: agricultural and industrial activities (29.4%), upstream water pollution (21.1%), natural sources (26.5%), and transport-related source (23.1%). These findings establish a scientific foundation for the conservation and management of the ecological environment in the riparian zone of the Shaying River Basin in Zhoukou City. Additionally, they will serve as a reference for future research on soil heavy metal migration and sources within the Huaihe River Basin, China.