The response of Chinese Cabbage (Brassica rapa L.) to the co-contamination of nanoplastics with different polarity and Ketoprofen

The co-contamination of micro-/nanoplastics (MNPs) and ketoprofen (KTF) threatens agricultural ecosystems and crop health. This study examines the physiological and biochemical responses of Chinese cabbage ( Brassica rapa L.) to 100 nm polyethylene (PE) and polypropylene (PP) nanoparticles, individually and with KTF. Results show that NPs and KTF significantly reduce chlorophyll, biomass, and photosynthetic efficiency, with PP exhibiting greater toxicity than PE. Exposure triggers oxidative stress, increasing reactive oxygen species (ROS), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), alongside elevated antioxidant enzyme (SOD, CAT) activities. PE accumulates in roots, causing localized damage, while PP translocates to aerial parts, inducing widespread stress. The interaction between NPs and KTF intensifies toxicity, driven by adsorption of KTF on NPs. The mechanism involves NP polarity: PE’s polar nature restricts it to roots, while PP’s non-polarity enables aerial translocation. These findings highlight the role of NP polarity and pollutant interactions in ecological risk assessment, providing insights into the mechanisms of NP-KTF co-contamination and its impact on crop health and food safety. • Combined NPs and Ketoprofen enhance oxidative stress and cellular damage in Chinese cabbage compared to single exposures. • Non-polar PP exert stronger oxidative stress effects than polar PE in Chinese cabbage roots and leaves. • NPs and Ketoprofen upregulate antioxidants yet inhibit chlorophyll, RuBisCO, and growth in Chinese cabbage.