A comprehensive framework for identifying contributing factors of soil trace metal pollution using Geodetector and...

Area of Science:

• Environmental Science
• Geochemistry
• Soil Science

Background:

• Accurate identification of soil pollution sources is vital for effective environmental management.
• Traditional methods like Positive Matrix Factorization (PMF) often require significant expertise, limiting objective source apportionment.
• Trace metal(loid)s (TMs) pose significant risks to soil health and ecosystems.

Purpose of the Study:

• To develop and validate a comprehensive framework for objectively identifying soil pollution sources.
• To determine the key environmental factors contributing to trace metal(loid) accumulation in the Pearl River Delta (PRD).
• To enhance the accuracy of source apportionment for trace metal(loid)s in soils.

Main Methods:

• Established a novel source analysis framework integrating factor identification and geospatial analysis.
• Applied the Positive Matrix Factorization (PMF) model for initial source identification.
• Utilized the Geodetector model to analyze the relationships between TMs and 12 environmental variables.

Main Results:

• The framework successfully identified distinct pollution sources, including natural, atmospheric, traffic/industrial, and agricultural.
• Parent material and digital elevation model were key drivers for Cr, Ni, and Cu accumulation.
• Industrial activities, roads, and atmospheric deposition significantly influenced Pb, Zn, Cd, and Hg levels, respectively.
• Arsenic accumulation was strongly linked to agricultural practices, particularly fertilizer and pesticide use.

Conclusions:

• The integrated framework significantly improves the accuracy of soil pollution source apportionment.
• Geospatial analysis effectively elucidates the complex relationships between environmental factors and TM accumulation.
• The findings provide a robust scientific basis for targeted soil pollution control strategies in the PRD.