Migration characteristics and toxic effects of perfluorooctane sulfonate and perfluorobutane sulfonate in tobacco.

Perfluorooctane sulfonate (PFOS) and its new substitute, perfluorobutane sulfonate (PFBS), are increasing in concentration in the environment annually, and their toxicity cannot be ignored. With an increasing amount of PFOS and PFBS entering the environment, especially into farmland soil, it is very likely to pollute tobacco-planting soil. Therefore, we chose tobacco (Nicotiana tabacum L.) as the test organism. Through the analysis of migration characteristics, we found that PFOS (0.82) is more likely to migrate within tobacco plants than PFBS (0.42). Pot experiments showed that PFOS has a more obvious inhibitory effect on the growth of tobacco. Further investigations revealed that PFOS induces oxidative stress reactions in tobacco and stimulates the increase in the activities of enzymes such as superoxide dismutase (SOD) and catalase (CAT). In addition, both PFOS and PFBS inhibit the expression of genes related to the synthesis of auxin and aroma substances in tobacco. In particular, under the exposure of 10 mg/kg PFOS, the inhibition rates are as high as 88.53 % and 92.32 % respectively. The results of this study compared the differences in toxicity between PFOS and PFBS, and provided a theoretical reference for the behavioral characteristics of new per-polyfluoroalkyl substances (PFASs) in the environment and their potential risks to the ecological environment.