Agronomy, Vol. 15, Pages 1348: Multi-Index Assessment of Heavy Metal Contamination and Ecological Risks in Paddy Soils Along National Highways in Southern Henan Province, China

Agronomy doi: 10.3390/agronomy15061348

Authors:
Minghui Jin
Mingming Tang
Juan Liu
Jishi Zhang
Rongying Xiao

(1) Background: Road traffic emissions significantly influence heavy metal accumulation in roadside agricultural soils, posing risks to food safety. (2) Methods: This study investigated the concentrations of heavy metals (As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn) in paddy soils at 96 soil samples along National Highways G107 and G312 in southern Henan, China, to evaluate the contamination situation and ecological risks using a multimetric approach. (3) Results: Cd, Hg, Cu, and Zn exceeded provincial background levels. Cd dominated contamination, showing heavy pollution (single factor index, Pi > 5) within 40 m of G107 and moderate/heavy levels (Pi = 2–5) along G312. The Nemerow index (PN) classified both highways as slightly polluted (PN = 0.70–0.81), with higher contamination along G107. Geoaccumulation indices identified Cd as mildly/moderately polluted within 40 m of G107 and G312 and Zn as slightly contaminated within 20–40 m of G107. Despite low total ecological risk, Cd contributed >75% to cumulative risk due to its high toxicity (Tr = 30). (4) Conclusions: Road traffic constitutes one of the contributors to heavy metal accumulation in paddy soils along national highways in southern Henan Province, while agricultural cultivation adjacent to transportation corridors poses potential food safety risks.

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