Pollution characteristics and probabilistic risk assessment of heavy metal(loid)s in agricultural soils across the Yellow River Basin, China

Abstract

Heavy metal(loid)s (HMs) contamination in farmland soils, an environmental issue of global concern, has undergone extensive research across local and regional scales in the Yellow River Basin (YRB), China, but comprehensive studies at the basin scale remain scarce. This study, utilizing published data from 2000 to 2023, analyzed the concentrations, distribution patterns, potential sources, probabilistic ecological risks, and source-specific health risks of eight HMs (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in farmland soils across the YRB. Results indicated that while most agricultural soils are safe, 21.7% of samples for Cd, 5.6% for As, and 1.2% for Zn exceed China’s risk screening levels for agricultural soil pollution, with Hg and Cd showing the highest pollution levels. Ecological risks were generally high, with Cd and Hg identified as primary risk factors. Correlation analysis and the positive matrix factorization model identified four potential origins, contributing in descending order: traffic-industrial atmospheric deposition (37.0%), mixed agricultural-natural sources (26.7%), industrial-natural sources (14.6%), and mixed agricultural-industrial sources (14.6%). The probabilistic health risk assessment identified negligible noncarcinogenic threats to the population; however, carcinogenic hazards were concerning, particularly due to industrial activities and As. Children are more vulnerable to hazards than adults. These findings enhance our insight into soil HM pollution risks in the YRB and offer a scientific foundation for targeted pollution management and control strategies at the basin scale.

Keywords

• Heavy metal(loid)s
• Farmland soil
• Ecological-health effect
• Source apportionment
• Monte Carlo simulation