Nano-biochar uptake and translocation by plants: Assessing environmental fate and food chain risk

Nano-biochar (N-BC) is an emerging nanomaterial with potential applications in various fields. Understanding its behavior in the environment and its interaction with plants is crucial for assessing its ecological implications and potential risks to the food chain. In this study, we investigated the absorption and transportation of N-BC by wheat and Chinese cabbage plants using microscopy techniques and stable isotope analysis. Our results revealed that N-BC particles were readily absorbed by the plants through their root systems and transported to the aboveground tissues. Scanning electron microscopy and transmission electron microscopy provided visual evidence of N-BC particles inside the plants, predominantly located in the xylem and cell walls of the cortical tissue. Stable isotope analysis confirmed the uptake and transportation of N-BC, with elevated isotopic values observed in the plant tissues exposed to ¹³C-N-BC. Our results demonstrated that around 50.2 %-52.4 % of the absorbed N-BC by plants was accumulated in the roots of wheat and Chinese cabbage, and the remaining fraction was transferred to the shoots including steam (31.0 %-32.1 %) and leaf (16.5 %-17.6 %). Importantly, we observed significant accumulation of N-BC in the edible parts of Chinese cabbage, raising concerns about its potential entry into the food chain and associated health risks. These findings highlight the need for further research to explore the specific pathways and modes of N-BC uptake and transport in plants. Monitoring the presence of N-BC in the environment and its potential impact on the food chain is crucial for ensuring food security and safeguarding human health.