Co-exposure to UV-328 and cadmium in radish: Interactive effects on uptake, translocation, and potential dietary risk

UV-328 and Cd are two typical pollutants prevalent in agricultural soils, originating from agricultural films, fertilizers, pesticides, and contaminated irrigation water. However, their combined toxic effects and underlying mechanisms in plants remain unclear. This study investigated the effects of UV-328 and Cd (alone and combined) on radish, focusing on accumulation, translocation, growth, carbon and nitrogen levels, polyphenol profiles, and soil microbial communities. Compared with the control, co-exposure significantly increased contaminant accumulation in plant tissues. For example, Cd accumulation in shoots increased from 0.06 μg/g dw to 15.0 μg/g dw under co-exposure conditions, accompanied by enhanced root-to-shoot translocation. Co-exposure significantly inhibited plant growth, with biomass reductions of 28.2% and 23.6% observed in C5 and P5 treatments, respectively, and reduced carbon, nitrogen, and most polyphenol contents (e.g., xanthohumol decreased from 57.4 ng/g dw to 19.4 ng/g dw). Mechanistically, co-exposure enhanced the translocation factor (TF) of both UV-328 and Cd, suggesting interaction-driven transport processes. UV-Vis spectroscopy and HPLC-ICP-MS analyses provided evidence supporting potential interactions between UV-328 and Cd, possibly involving coordination or complex species formation under certain conditions. Co-exposure also altered soil microbial community structure by enriching specific bacterial taxa potentially associated with Cd bioavailability. Overall, this study based on immature taproots shows that co-exposure to UV-328 and Cd induces interaction-driven co-accumulation, enhanced translocation, and concentration-dependent phytotoxicity, providing mechanistic insights into the environmental risks of combined organic and metal contamination.