Elsevier

Environment International

Volume 142, September 2020, 105888
Environment International

Uptake, phytovolatilization, and interconversion of 2,4-dibromophenol and 2,4-dibromoanisole in rice plants

https://doi.org/10.1016/j.envint.2020.105888Get rights and content
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Highlights

  • 2,4-DBA was more bioaccumulative than 2,4-DBP in leaf sheath and leaf.

  • Rice plants facilitated the volatilization of 2,4-DBA/DBP.

  • Demethylation of 2,4-DBA was far greater than methylation of 2,4-DBP in rice plant.

  • Volatilization of metabolites were efficient to reduce 2,4-DBA/DBP bioaccumulation.

Abstract

The structural analogs, 2,4-dibromophenol (2,4-DBP) and 2,4-dibromoanisole (2,4-DBA), have both natural and artificial sources and are frequently detected in environmental matrices. Their environmental fates, especially volatilization, including both direct volatilization from cultivation solution and phytovolatilization through rice plants were evaluated using hydroponic exposure experiments. Results showed that 2,4-DBA displayed stronger volatilization tendency and more bioaccumulation in aboveground rice tissues. Total volatilized 2,4-DBA accounted for 4.74% of its initial mass and was 3.43 times greater than 2,4-DBP. Phytovolatilization of 2,4-DBA and 2,4-DBP contributed to 6.78% and 41.7% of their total volatilization, enhancing the emission of these two contaminants from hydroponic solution into atmosphere. In this study, the interconversion processes between 2,4-DBP and 2,4-DBA were first characterized in rice plants. The demethylation ratio of 2,4-DBA was 12.0%, 32.0 times higher than methylation of 2,4-DBP. Formation of corresponding metabolites through methylation and demethylation processes also contributed to the volatilization of 2,4-DBP and 2,4-DBA from hydroponic solution into the air phase. Methylation and demethylation processes increased phytovolatilization by 12.1% and 36.9% for 2,4-DBP and 2,4-DBA. Results indicate that phytovolatilization and interconversion processes in rice plants serve as important pathways for the global cycles of bromophenols and bromoanisoles.

Keywords

2,4-Dibromophenol and 2,4-Dibromoanisole
Methylation process
Demethylation process
Rice plants
Phytovolatilization

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