Through soil incubation experiments, the effects of aged PBAT + PLA (polybutylene adipate terephthalate + polylactic acid) film fragments were analyzed. Surface characteristics and chemical structures of the films changed significantly after one (T2) and two years (T1) of aging compared to new films (T3). Both new and aged fragments reduced soil pH, altered enzyme activities, and influenced dissolved organic matter (DOM) fluorescence. Alkaline phosphatase activity declined by 33.2%, 23.8%, and 11.6% for T1, T2, and T3, respectively, while urease and sucrase activities increased in a time-dependent manner. The degree of soil humification rose by 66.4%, 60.4%, 49.3%, and 88.6% for T1, T2, T3, and T4, respectively, compared to the control (CK). Aged films exhibited stronger DOM fluorescence intensity than new films. Tessier extraction analysis revealed a decrease in exchangeable Cd by 22.9%, 13.1%, and 10.2% for T1, T2, and T3, respectively, while organically bound Cu increased. Correlation analysis indicated a significant positive relationship between soil humification and heavy metal bioavailability. These findings provide insight into the ecological effects of biodegradable agricultural films, offering a theoretical foundation for assessing their environmental risks and safety.

Chromium (Cr) contamination poses severe risks to plant health and soil quality, requiring sustainable remediation methods. This study explored the synthesis of zirconia nanoparticles (PF-ZrO₂ NPs) from Sonchus asper extract and assessed their potential to alleviate Cr toxicity in Chinese cabbage (Brassica rapa var. pekinensis). The characterization of nanoparticles was performed through XRD, SEM, and FTIR analyses, confirming their crystalline nature, structure, and surface chemistry. The results indicated significant declines in plant growth, chlorophyll content, biomass, and nutrient uptake under Cr stress (treatments T2 and T4), accompanied by elevated oxidative stress indicators (H₂O₂, MDA) and Cr accumulation. The application of PF-ZrO₂ NPs (T3 and T5) notably reduced shoot Cr concentrations (by 58.94% and 35.90%) and improved the chlorophyll level (by 5.41% and 14.41%). Additionally, nanoparticles increased antioxidant enzyme activity (SOD, POD, CAT) and improved soil properties (pH, cation exchange capacity, nutrient retention). These findings suggest green-synthesized PF-ZrO₂ NPs are effective, environmentally friendly candidates for Cr remediation in contaminated soils.