Organic-based remediation of heavy metal-contaminated soils in the Taojia river basin affected by long-term non-ferrous mining and logging activities

• DOI: 10.3389/fpls.2025.1486575
• Publication Date: 2025-03-18T07:02:04Z
• Authors: Yan Zeng; Taimoor Hassan Fa...; Chenglin Yuan; Wang Li; Asma Farooq; Guangjun Wang; Yingchun Fang; Jun Wang; Wende Yan

The upper reaches of the Taojia River have been impacted by unregulated logging linked to non-ferrous metal mining, resulting in significant mineral waste accumulation. Composting has shown promise reducing heavy (HM) contamination agricultural soils. This study included two segments: first examined effects sheep manure (SM) and chicken (CM) with different concentrations on lead (Pb) dynamics vegetable second applied most effective method identified segment one assess Pb, cadmium (Cd), zinc (Zn), copper (Cu) soil, paddy, straw rice fields. Results showed that both compost types increased soil pH mildly alkaline levels, SM causing dose-dependent rises (insignificant between 2% 5%) CM inducing non-proportional alkalinity. significantly enhanced organic matter (SOM: 0.606-0.660 g/kg) compared (0.414-0.495 g/kg). Total nitrogen (TN) spiked at (0.172 but plateaued until 10% (0.210 g/kg), while linearly TN dosage. phosphorus (TP) rose proportionally remained unchanged under CM. For Pb immobilization, 5% reduced DTPA-Pb 11.877 mg/kg, it (14.006 mg/kg), whereas achieved optimal passivation (11.561 mg/kg). Correlation analyses dosage SOM, TP, available (p < 0.05), showing minimal direct influence. In fields, elevated (7.10 vs. 6.71), total Zn/Cu/Pb/Cd Pb/Cd paddy straw. Heavy speciation revealed strong inter-state correlations (excluding exchangeable Pb), TP influencing Zn, Cu, Cd levels. These findings demonstrate compost's dual role improving fertility mitigating uptake, though Zn/Cu accumulation risks require careful management.