Dechlorination and methylation of tetrachlorobisphenol A in hydroponic pumpkin

Tetrachlorobisphenol A (TCBPA) is widely used as an economical flame retardant and frequently detected in the environment. However, its bioaccumulation and metabolism in model organisms are unknown. Herein, pumpkin plants were hydroponically exposed to TCBPA to explore its metabolic behavior. The results indicated that TCBPA was absorbed and distributed throughout the plant, with the highest amount found in the roots (1,860 ± 63 ng), followed by the stems (99.6 ± 10.9 ng) and leaves (11.8 ± 0.9 ng). Tetrachlorobisphenol A was absorbed by the roots from the hydroponic solution, subsequently translocated to the stems and leaves. The dechlorination product of TCBPA, 3,3',5-trichlorobisphenol A, was detected in the roots (3.35 ± 0.87 ng) and stems (0.201 ± 0.018 ng), and its methylation product, TCBPA-MME, was also identified in the roots (122 ± 14 ng) and stems (2.03 ± 0.27 ng). Tetrachlorobisphenol A metabolites were predicted to be less toxic than TCBPA, indicating the potential use of pumpkin plants in TCBPA pollution remediation. The study findings clarify the absorption, migration, and transformation of TCBPA in a model organism, that is, pumpkin plants.