The use of redox potential to monitor biochemical HCBD dechlorination

Cord‐Ruwisch, Ralf; James, D.L.; Charles, W.

doi:10.1016/j.jbiotec.2009.04.001

Cited by 9 publications

(3 citation statements)

References 28 publications

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“…[34][35][36] The dechlorination products of HCBD were also detected in both environmental media and laboratory experiments. 37,38 Therefore, the most possible dechlorination products, including penta-chlorobutadiene, tetrachlorobutadiene and tri-chlorobutadiene, were analyzed in the pumpkin samples herein. Because no commercial standards were available, characteristic ions for qualitative analysis of these metabolites were chosen according to former studies.…”

Section: Mass Balance and Possible Metabolismmentioning

confidence: 99%

Bioaccumulation of hexachlorobutadiene in pumpkin seedlings after waterborne exposure

Hou

Zhang

Liu

et al. 2017

Environ. Sci.: Processes Impacts

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Hexachlorobutadiene (HCBD) has been listed as a persistent organic pollutant (POP) in the Stockholm Convention, and is now drawing more and more research interest. However, the understanding of its bioaccumulation, especially in plants, is still very limited. In this work, the behavior of HCBD in aqueous solution and pumpkin seedlings was studied through in-lab hydroponic exposure experiments. It was found that 69% of HCBD volatilized from water to the atmosphere after one day of exposure, and only 1% remained in the solution after four days. This high volatility might be the main cause of the low HCBD levels in aqueous environments. Although a great amount of HCBD volatilized into the atmosphere, only a small proportion of airborne HCBD was captured by the leaves and stems of the blank pumpkin seedling controls. The translocation of HCBD from the leaves to the bottom roots, as well as its release from the roots into the water, was detected. For the exposure groups, the pumpkin seedlings absorbed HCBD from both the hydroponic solution and the air via the roots and leaves, respectively. The concentration of HCBD in the exposed pumpkin roots linearly increased with the continuous addition of HCBD into the exposure system. Upward translocation from the roots to the leaves and downward translocation from the leaves to the roots existed simultaneously in the exposed pumpkin seedlings. However, the concentrations of HCBD in the leaves, stems and roots in the exposure group were much higher than those of the blank plant controls, suggesting little contribution from the airborne HCBD in the hydroponically exposed pumpkin seedlings. The lipid content did not show obvious effects on the bioaccumulation and biodistribution of HCBD in the pumpkin seedlings, indicating that the translocation of HCBD within the pumpkin seedlings might be an active process. This study provided new findings on the environmental behavior of HCBD, which will be helpful for understanding the exposure risks.

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Section: Mass Balance and Possible Metabolismmentioning

confidence: 99%

Bioaccumulation of hexachlorobutadiene in pumpkin seedlings after waterborne exposure

Hou

Zhang

Liu

et al. 2017

Environ. Sci.: Processes Impacts

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“…Redox potential provides insights into thermodynamic feasibility, electron donor availability, and the environmental conditions that influence chemical reactions. A continuous redox potential drop is observed during dechlorination reaction . Dolfing et al first confirmed that calculated redox potentials are accurate enough to correctly predict anaerobic degradation pathways of hexachlorobenzene, but further application to a complex dechlorination scenario has never been achieved.…”

Section: Introductionmentioning

confidence: 99%

“…A continuous redox potential drop is observed during dechlorination reaction. 45 Dolfing et al 46 first confirmed that calculated redox potentials are accurate enough to correctly predict anaerobic degradation pathways of hexachlorobenzene, but further application to a complex dechlorination scenario has never been achieved. In the present study, PCB dechlorination is transformed into a stepwise reaction sequence, and the redox potential is utilized as the indicator to predict PCB dechlorination pathways and fluxes.…”

Section: ■ Introductionmentioning

confidence: 99%

Modeled Pathways and Fluxes of PCB Dechlorination by Redox Potentials

Sun,

Xu,

Small

et al. 2024

Environ. Sci. Technol.

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Dechlorination is one of the main processes for the natural degradation of polychlorinated biphenyls (PCBs) in an anaerobic environment. However, PCB dechlorination pathways and products vary with PCB congeners, types of functional dechlorinating bacteria, and environmental conditions. The present study develops a novel model for determining dechlorination pathways and fluxes by tracking redox potential variability, transforming the complex dechlorination process into a stepwise sequence. The redox potential is calculated via the Gibbs free energy of formation, PCB concentrations in reactants and products, and environmental conditions. Thus, the continuous change in the PCB congener composition can be tracked during dechlorination processes. The new model is assessed against four measurements from several published studies on PCB dechlorination. The simulation errors in all four measurements are calculated between 2.67 and 35.1% under minimum (n = 0) and maximum (n = 34) numbers of co-eluters, respectively. The dechlorination fluxes for para-dechlorination pathways dominate PCB dechlorination in all measurements. Furthermore, the model also considers multiple-step dechlorination pathways containing intermediate PCB congeners absent in both the reactants and the products. The present study indicates that redox potential might be an appropriate indicator for predicting PCB dechlorination pathways and fluxes even without prior knowledge of the functional dechlorinating bacteria.

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