The collaborative assessment and health risk evaluation of heavy metals (HMs) enrichment in soils and tea leaves are crucial to guarantee consumer safety. However, in high soil HM geochemical background areas superimposed by human activities, the health risk associated with HMs in soil–tea systems is not clear. This study assessed the HMs concentration (i.e., chromium (Cr), cadmium (Cd), arsenic (As), and lead (Pb)) in tea leaves and their relationship with soil amounts in the southwest region of China to evaluate the associated health risk in adults. The results revealed that the average soil concentration of Cr was the highest (79.06 mg kg⁻¹), followed by Pb (29.27 mg kg⁻¹), As (14.87 mg kg⁻¹), and Cd (0.18 mg kg⁻¹). Approximately 0.71, 4.99, 7.36, and 10.21% of soil samples exceeded the threshold values (NY/T 853-2004) for Pb, Cr, As, and Cd, respectively. Furthermore, the average concentration of Pb, As, and Cd in tea leaves was below the corresponding residue limits, but Cr was above the allowed limits. Correlation analysis revealed that the Pb, Cr, As, and Cd amounts in tea leaves were positively correlated to their soil amounts (p < 0.01) with an R² of 0.203 **, 0.074 **, 0.036 **, and 0.090 **, respectively. Additionally, approximately 40.38% of the samples were found to be contaminated. Furthermore, spatial distribution statistical analysis revealed that Lancang was moderately contaminated, while Yingjiang, Zhenkang, Yongde, Zhenyuan, Lüchun, Jingdong, Ximeng, and Menglian were slightly contaminated areas. The target hazard quotients (THQ; health risk assessment) of Pb, Cr, As, and Cd and the hazard index (HI) of all the counties were below unity, suggesting unlikely health risks from tea consumption.

High geological background and human activities are the two major pollution sources for soil potentially toxic elements (PTEs) accumulation around the world. Mining is the prime human activity that poses a serious threat to the farmland’s ecosystem safety. This study assesses the farmland safety in the typical high geological background area and the superimposed area of high background-mining activity in eastern Yunnan in China by systematic analysis of the accumulation and risk characteristics of seven PTEs such as arsenic (As), mercury (Hg), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), and chromium (Cr). Furthermore, we used Cd as the characteristic element to establish a relationship model between crop PTEs accumulation and the physical and chemical characteristics of the soil. We find that in the farmland soil from the superimposed area, the accumulation point over-standard rate of seven PTEs is higher than in the typical high geological background area. The accumulation of Pb, Cd, Cu, and Zn is related to frequent man-made mining activities. The bioavailability relationship model, using Cd as the soil-crop characteristic element, reveals that only in the crops (cereals, vegetables) of the high geological background area; the Cd bio-concentration factor significantly correlate with the physical and chemical properties of the soil. This suggests that the PTEs contaminated farmland in high geological background areas can be concomitantly restored during usage by adjusting the soil’s physical and chemical properties, while in the superimposed area, the farmland area needs prior restoration by removing man-made mining activities.

The co-occurrence of microplastics (MPs) and cadmium (Cd) in agricultural soils poses ecological risks, yet their interactions in flooded rice paddies remain unclear. Therefore, this study investigated the individual and combined effects of polyethylene MPs (mPE) and Cd on rice (Oryza sativa L.) growth, Cd accumulation, and soil microbial communities. Combined stress (5 mg/kg Cd + 1% mPE) significantly reduced rice growth (4.1–13.8% in plant height) and increased Cd accumulation in roots, stems, and seeds, driven by MP-enhanced Cd bioavailability. MPs altered soil pH, organic matter (OM), and moisture content (MC), indirectly suppressing yield. Microbial analysis revealed decreased bacterial alpha diversity (0.86–8.36%), favoring Cd-tolerant taxa (e.g., Solirubrobacteraceae), while fungal responses were weaker under flooding. Structural equation modeling indicated that Cd exerted direct toxicity through tissue accumulation, whereas MPs acted indirectly by modifying soil properties and inducing oxidative stress. Under co-exposure, MPs intensified Cd-induced oxidative stress, enhancing both direct and indirect toxicity pathways. Mantel tests identified DTPA-extractable Cd (r = 0.70) and OM (r = 0.55) as key drivers of Cd uptake. These findings highlight the complex interplay of MPs and Cd in rice paddies, with implications for managing co-contaminated agroecosystems.

Phosphogypsum (PG), a major by-product of the phosphate industry, has potential for improving acidic and nutrient-poor red soils, yet its agronomic benefits and heavy metal risks require systematic evaluation. A field experiment was conducted with five treatments, CK (soil only), GT (50% modified phosphogypsum, MPG), TT (40% MPG), ZT (50% phosphorite tailings), and DT (25% MPG + 25% lake sediment), to assess their effects on soil properties, enzyme activities, peanut growth, yield, quality, and heavy metal accumulation. All amendments improved soil structure, moisture retention, nutrient availability, and enzymatic activities. Peanut pod and kernel yields increased under all treatments, with DT achieving the greatest improvements (29.89% and 40.88%, respectively), whereas ZT showed the weakest response (1.91% and 6.26%). DT also achieved the highest soil quality index, and performed best in both yield improvement and root development. Although Cd accumulation increased under DT, heavy metal concentrations in peanut kernels remained below national food safety limits. Overall, DT was identified as the most effective amendment for enhancing red soil fertility and peanut productivity, while long-term monitoring of Cd bioavailability is recommended to ensure sustainable and safe application.