State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; Graduate University of Chinese Academy of Sciences, Beijing 100039, China.
State Key Laboratory of Organic Geochemistry and Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
Environ Int. 2021 Oct;155:106591. doi: 10.1016/j.envint.2021.106591. Epub 2021 Apr 29.
Organophosphate esters (OPEs) are normally used as flame retardants, plasticizers and lubricants, but have become environmental pollutants. Because OPEs are normally present alongside heavy metals in soils, the effects of interactions between OPEs and heavy metals on plant uptake of OPEs need to be determined. In this study, we investigated the effects of OPEs chemical structure, plant cultivar and copper (Cu) on the uptake and translocation of OPEs by plants. The bioaccumulation of OPEs varied among plant cultivars. They were preferentially enriched in carrot, with the lowest concentrations observed in maize. OPEs with electron-ring substituents (ER-OPEs) exhibited a higher potential for root uptake than did OPEs with open-chain substituents (OC-OPEs), which could be attributed to the higher sorption of ER-OPEs onto root charged surfaces. This was explained by the stronger noncovalent interactions with the electron-rich structure of ER-OPEs. The presence of Cu slightly reduced the distinct difference in the ability of roots to take up OC-OPEs and ER-OPEs. This was explained by the interactions of Cu ions with the electron-rich structure of ER-OPEs, which suppressed the sorption of ER-OPEs on the root surface. A negative relationship between the logarithms of the translocation factor and octanol-water partition coefficient (K) was observed in treatments with either OPEs only or OPEs + Cu, implying the significant role of hydrophobicity in the OPEs acropetal translocation. The results will improve our understanding of the uptake and translocation of OPEs by plant cultivars as well as how the process is affected by the chemical structure of OPEs and Cu, leading to improvements in the ecological risk assessment of OPEs in the food chain.
有机磷酸酯（OPEs）通常被用作阻燃剂、增塑剂和润滑剂，但已成为环境污染物。由于 OPEs 通常与土壤中的重金属共存，因此需要确定 OPEs 与重金属之间的相互作用对植物摄取 OPEs 的影响。在这项研究中，我们研究了 OPEs 化学结构、植物品种和铜（Cu）对植物摄取和转运 OPEs 的影响。OPEs 在不同植物品种中的生物累积量存在差异。它们优先富集在胡萝卜中，在玉米中观察到的浓度最低。具有电子环取代基的 OPEs（ER-OPEs）比具有开链取代基的 OPEs（OC-OPEs）具有更高的根吸收潜力，这可以归因于 ER-OPEs 对带电荷的根表面的更高吸附性。这可以通过 ER-OPEs 与富电子结构之间更强的非共价相互作用来解释。Cu 的存在略微降低了根吸收 OC-OPEs 和 ER-OPEs 能力的明显差异。这可以通过 Cu 离子与 ER-OPEs 的富电子结构的相互作用来解释，该相互作用抑制了 ER-OPEs 在根表面的吸附。在仅存在 OPEs 或 OPEs + Cu 的处理中，观察到转运因子的对数值与辛醇-水分配系数（K）之间呈负相关，这表明疏水性在 OPEs 向地上部转运中起重要作用。这些结果将提高我们对植物品种摄取和转运 OPEs 的理解，以及 OPEs 和 Cu 的化学结构如何影响这一过程，从而改善食物链中 OPEs 的生态风险评估。
