Centennial-scale source shift in potentially toxic metal(loid)s in Yangtze River

Abstract

Estuarine sedimentation is an important historical record of potentially toxic metal (PTM) emissions from human activities that can be used to improve environmental management. However, the contribution of different human activities to PTM deposition has not been accurately estimated, and their coupled relationship with riverine organic matter is typically not considered. In this study, we reconstruct the century-scale PTM depositional history of sediment cores from the Yangtze Grand Delta. Eight potential metal sources (PMSs) were identified using positive matrix factorization, and the results of lagged correlation determined the PMSs associated with the riverine discharge of the Yangtze River. Riverine PTMs were predominantly composed of Cr (79.0%), Ni (77.3%), and Pb (64.1%) but were deprived in Cu (34.9%). Glomalin-related soil protein (GRSP), which is a typical terrestrial refractory carbon, has a strong affinity for Cu, and contributed to 2.82–22.6% Cu deposition. The change in the PMS is mainly related to power generation, whereas the GRSP-bound PTM is mainly related to road construction and transportation. We advocate for responsible management of human activities in river catchments, particularly on coal-based power generation and road transportation, to maintain ecological security and promote the overall achievement of the Sustainable Development Goals.