Uptake, Subcellular Distribution, and Metabolism of Decabromodiphenyl Ethane in Vegetables under Different Exposure Scenarios

Decabromodiphenyl ethane (DBDPE), a key alternative to deca-BDE (BDE-209), has been ubiquitous in the receiving ecosystem. However, little is known about its uptake process and fate in plants. Here, the plant absorption, distribution, and metabolism of ¹⁴C-DBDPE under two distinct exposure pathways (i.e., soil-root and airborne dust-leaf) were investigated with three vegetables (cherry radish, water spinach, and eggplant). DBDPE was absorbed and primarily accumulated in directly exposed roots and leaves, with translocation factors to other tissues of 0.04-0.77 and 0.73-12.80 × 10^-3, respectively. DBDPE in exposed leaves was more difficult to transport as most DBDPE did not enter the interior of the leaves but was stored in waxes (>90%). Furthermore, DBDPE within leaves was found to enter mostly through waxy layer penetration (>97%). The majority of ¹⁴C-DBDPE was localized in cell walls (52.6 and 75.6%, respectively) and organelles (22.7 and 45.5%, respectively) of exposed tissues, substantially restricting its in-plant translocation. Debrominated products were detected in exposed roots, but barely found in exposed leaves, as most DBDPE was blocked by the waxy layer. Moreover, DBDPE was stable in soils and dust without degradation. Our findings contribute to a deeper understanding of the environmental fate of DBDPE in soil-plant and airborne dust-plant systems.