A comparative evaluation of anaerobic dechlorination of PCB-118 and Aroclor 1254 in sediment microcosms from three PCB-impacted environments

Kaya, Devrim
İmamoğlu, İpek
Sanin, Faika Dilek
Sowers, Kevin R.
Aroclor 1254 (A1254) is the most toxic commercial PCB mixture produced, primarily due to its relatively high concentrations of dioxin-like congeners. This study demonstrates a comparative evaluation of dechlorination of A1254 and PCB-118 by indigenous organohalide respiring bacteria enriched from three PCB impacted sites: Grasse River (GR), NY; Fox River (FR), WI; and Baltimore Harbor (BH), MD. PCB 118 dechlorination rates in GR, BH, and FR was 0.0308, 0.015, and 0.0006 Cl-/biphenyl/day, respectively. A1254 dechlorination rates in GR, FR, and BH were 0.0153, 0.0144, and 0.0048 CI-/biphenyl/day, respectively. A1254 dechlorination was achieved through the removal of doubly-/singly-flanked chlorines in meta and para positions of mostly penta-followed by hexa- and hepta-chlorinated congeners by 88%, 69%, and 51% in GR, and 88%, 87%, and 83% in FR, respectively, while in BH mostly hepta- (70%) followed by hexa-chlorinated congeners (66%) were dechlorinated. A previously developed Anaerobic Dechlorination Model (ADM) quantified a total of 17 toxicity-related dechlorination pathways in all three sediment microcosms. The toxic equivalency of A1254 based on seven dioxin-like congeners decreased by about 53%, 45% and 21%, in GR, FR and BH microcosms, respectively. The dechlorination products were generally tetra- and tri-chlorinated congeners with unflanked chlorines, all of which is susceptible to further degradation by aerobic bacteria. Concerning the toxic congeners, ADM can be useful to initiate further research focusing on the stimulation of the toxicity reducing pathways for risk assessment and effective remediation strategies.


Potential risk reduction of Aroclor 1254 by microbial dechlorination in anaerobic Grasse River sediment microcosms
Kaya, Devrim; İmamoğlu, İpek; Sanin, Faika Dilek; Payne, Rayford B.; Sowers, Kevin R. (Elsevier BV, 2017-01-05)
Aroclor 1254 was the second most produced commercial PCB mixture and is found in soils, sediments and sewage throughout the globe. This commercial PCB mixture is considered particularly toxic because of the relatively high concentrations of congeners with dioxin-like properties. The potential for risk reduction by microbial reductive dechlorination of Aroclor 1254 (A1254) was investigated in sediment microcosms from Grasse River (GR), Massena, NY. The specificity of A1254 dechlorination was doubly- and sing...
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An explosive material, ethylenedinitramine (EDNA), its mono and di aci forms, as well as its monovalent cation and anion forms have been considered for 6-31G (UHF) type ab initio quantum chemical treatment in order to investigate the stability of EDNA in the neutral form and when charges develop on it exposed to electrical fields during the storage, handling or explosion process. The calculations indicate stable species. The aci forms are less stable than EDNA itself and the anion form is more stable than t...
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Citation Formats
D. Kaya, İ. İmamoğlu, F. D. Sanin, and K. R. Sowers, “A comparative evaluation of anaerobic dechlorination of PCB-118 and Aroclor 1254 in sediment microcosms from three PCB-impacted environments,” JOURNAL OF HAZARDOUS MATERIALS, pp. 328–335, 2018, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40753.