Interconversion between methoxylated, hydroxylated and sulfated metabolites of PCB 3 in whole poplar plants
Methoxylated polychlorinated biphenyls (MeO-PCBs) are overlooked metabolites of PCBs. In general, they are more toxic to plants than their parent congeners. However, information on the fate of MeO-PCBs and the relationship between methoxylated, hydroxylated and sulfated metabolites of PCBs in plants...
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Veröffentlicht in: | The Science of the total environment 2021-09, Vol.785, p.147341-147341, Article 147341 |
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Zusammenfassung: | Methoxylated polychlorinated biphenyls (MeO-PCBs) are overlooked metabolites of PCBs. In general, they are more toxic to plants than their parent congeners. However, information on the fate of MeO-PCBs and the relationship between methoxylated, hydroxylated and sulfated metabolites of PCBs in plants is scarce. In this work, poplar plants (Populus deltoides × nigra, DN34) were hydroponically and separately exposed to 4′-methoxy-4-monochlorobiphenyl (4′-MeO-PCB 3) and 4′-PCB 3 sulfate for 10 days to investigate the uptake, translocation and metabolism of MeO-PCBs and the relationship between methoxy-PCBs, hydroxyl-PCBs and PCB sulfates within plants. Results showed that 4′-MeO-PCB 3 and 4′-PCB 3 sulfate were taken up by the roots of poplar plants and translocated from roots to shoots and leaves. 4′-OH-PCB 3 and 4′-PCB 3 sulfate were identified as the hydroxylated metabolite and sulfate metabolite of 4′-MeO-PCB 3 in poplar, respectively. In the backward reaction, 4′-OH-PCB 3 and 4′-MeO-PCB 3 were found as metabolites of 4′-PCB 3 sulfate. For exposure groups, the yields of 4′-OH-PCB 3 produced from 4′-MeO-PCB 3 and 4′-PCB 3 sulfate were 1.29% and 0.13% respectively. The yield of 4′-PCB 3 sulfate which originated from 4′-MeO-PCB 3 in wood and root samples of exposure groups was only 0.02%. Only 0.04% of the initial mass of 4′-PCB 3 sulfate was transformed to 4′-MeO-PCB 3 in the exposure groups. The sulfation yield of 4′-OH-PCB 3 was higher than hydrolysis yield of 4′-PCB 3 sulfate, indicating that formation of PCB sulfates was predominant over the reverse reaction, the formation of hydroxy-PCBs. These results provide new perspective on the transport, metabolism, and fate of MeO-PCBs, and also help to better understand sources of OH-PCBs and PCB sulfates in the environment. This study provides the first evidence of interconversion of sulfate metabolites from methoxy-PCBs and methoxy-PCBs from PCB sulfates.
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•Sulfation of methoxy-PCBs in plants was demonstrated for the first time.•First evidence of methylation of PCB sulfates in plants•Interconversion demonstrated between methoxy-, hydroxyl- and PCB sulfates in poplar |
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ISSN: | 0048-9697 1879-1026 |
DOI: | 10.1016/j.scitotenv.2021.147341 |