A geochemical baseline-source analysis-multidimensional risk assessment-management response framework for lead-zinc...

Area of Science:

• Environmental Science
• Geochemistry
• Risk Assessment

Background:

• Establishing regional soil trace metal(loid) background values (BVs) is essential for accurate environmental risk assessments.
• Regional BVs are challenging to obtain, necessitating robust methodologies for accurate determination.
• Understanding metal(loid) sources is critical for effective pollution management in river basins.

Purpose of the Study:

• To establish soil trace metal(loid) background values in the Daqiao river basin using deep soil samples.
• To assess metal(loid) pollution levels and associated risks in irrigated and unirrigated areas.
• To identify and quantify pollution sources impacting soil quality in the study region.

Main Methods:

• Cumulative frequency distribution approach applied to deep soil samples (>100 cm) for BV determination.
• Multidimensional risk assessment to evaluate metal(loid) pollution across different land use areas.
• Correlation analysis and positive matrix factorization (PMF) employed for source identification and apportionment.

Main Results:

• Established average BVs for Cr, Ni, Cu, As, Cd, Pb, and Zn (mg kg⁻¹): 81.3, 41.4, 41.4, 16.6, 0.34, 43.7, 118.0.
• Highly contaminated soils with Cd, Pb, Zn, and As in irrigated areas (FI, SI, TI), primarily from wastewater irrigation (58-73%).
• Cadmium posed high ecological risks in FI (93%) and SI (96%); Cd and As presented health risks to children in irrigated regions.

Conclusions:

• Wastewater irrigation is a significant source of soil contamination, especially for Cd, Pb, Zn, and As, necessitating targeted remediation.
• Prioritize soil remediation in first- (FI), second- (SI), and third- (TI) irrigated areas, focusing on Cd, followed by Pb, As, Cu, and Zn.
• The study provides a scalable systems approach for managing legacy pollution in global mining landscapes affected by irrigation practices.