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

Area of Science:

• Environmental Science
• Geochemistry
• Sedimentology

Background:

• Estuarine sediments offer a historical record of potentially toxic metal (PTM) emissions from human activities.
• Accurate estimation of PTM contributions from different human activities and their relationship with riverine organic matter is often lacking.

Purpose of the Study:

• To reconstruct the century-scale PTM depositional history in the Yangtze Grand Delta.
• To identify potential metal sources (PMSs) and their association with riverine discharge.
• To investigate the role of glomalin-related soil protein (GRSP) in PTM deposition and link PTMs to specific human activities.

Main Methods:

• Sediment cores were analyzed to reconstruct PTM depositional history over the last century.
• Positive matrix factorization (PMF) was employed to identify eight potential metal sources (PMSs).
• Lagged correlation analysis was used to link PMSs to riverine discharge and human activities.

Main Results:

• Riverine PTMs in the Yangtze River were dominated by Cr, Ni, and Pb, with lower concentrations of Cu.
• Glomalin-related soil protein (GRSP) showed a strong affinity for Cu, contributing significantly to its deposition (2.82-22.6%).
• Changes in PMS were primarily linked to power generation, while GRSP-bound PTMs were associated with road construction and transportation.

Conclusions:

• Human activities, particularly coal-based power generation and road transportation, significantly influence PTM deposition in estuarine environments.
• Responsible management of these activities is crucial for maintaining ecological security and achieving Sustainable Development Goals.
• Understanding the interplay between riverine PTMs, organic matter (GRSP), and anthropogenic sources is vital for effective environmental management.