Metal(loid) Source Apportionment and Spatial Drivers in Irrigated Terrace Soils in a Typical Pb-Zn Mining Area

Area of Science:

• Environmental Science
• Soil Science
• Geochemistry

Background:

• Terraced agricultural systems are susceptible to metal(loid) contamination.
• Understanding contamination sources and spatial patterns is crucial for environmental management.

Purpose of the Study:

• To determine metal(loid) contamination levels in terraced agricultural soils.
• To identify the primary sources of metal(loid)s.
• To elucidate factors controlling metal(loid) spatial distribution.

Main Methods:

• Analysis of 1250 surface soil samples (0-20 cm depth).
• Application of Correlation Analysis (CA) and Positive Matrix Factorization (PMF) for source apportionment.
• Utilizing the forest regression algorithm to identify spatial differentiation factors.

Main Results:

• Average concentrations: Cr (132 mg/kg), Ni (62.3 mg/kg), Cu (140 mg/kg), As (42.2 mg/kg), Cd (33.8 mg/kg), Pb (535 mg/kg), Zn (2384 mg/kg).
• Cr and Ni primarily from natural soil processes; As, Cd, Pb, Zn linked to irrigation water.
• Distance to residential areas (Dis-RE) significantly impacted Cu, As, Cd, Pb, and Zn distribution.

Conclusions:

• Differentiated metal(loid) sources identified in terraced agricultural soils.
• Irrigation water is a significant anthropogenic source for several key metal(loid)s.
• Proximity to residential areas is a critical factor in metal(loid) spatial diffusion patterns.