Microbial reductive dechlorination of weathered and exogenous co-planar polychlorinated biphenyls (PCBs) in an anaerobic sediment of Venice Lagoon

G. Zanaroli, J. R. Pérez-Jiménez, L. Y. Young, L. Marchetti, F. Fava

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

The occurrence of reductive dechlorination processes towards pre-existing PCBs and five exogenous coplanar PCBs were investigated in a contaminated sediment of Porto Marghera (Venice Lagoon, Italy) suspended, under strictly anaerobic conditions, in water collected from the same site. PCB dechlorination started after five months of incubation, when sulfate initially occurring in the microcosms was completely depleted and methanogenesis was in progress. It was ascribed to sulfate-reducing bacteria. Several pre-existing hexa-, penta- and tetra-chlorinated biphenyls were slowly bioconverted into tri- and di-, ortho-substituted PCBs from the 5th to the 16th month of experiment. Spiked coplanar PCBs, i.e., 3,3′,4,4′-tetrachlorobiphenyl, 3,3′,4,4′,5- and 2,3′,4,4′,5-pentachlorobiphenyls, 3,3′,4,4′,5,5′- and 2,3,3′,4,4′,5- hexachlorobiphenyls, were extensively transformed (by about 90%) into lower chlorinated congeners, such as 3,3′,5,5′-/2,3′,4,4′- tetrachlorobiphenyl, 3,3′,5-, 2,4,4′-, 2,3′,4- and 2,3′,5-trichlorobiphenyl, 3,4-/3,4′- and 3,3′-dichlorobiphenyl and 2-chlorobiphenyl. The reductive dechlorination of spiked PCBs did not influence significantly the biotransformation rate and extent of pre-existing PCBs.

Original languageEnglish (US)
Pages (from-to)121-129
Number of pages9
JournalBiodegradation
Volume17
Issue number2
DOIs
StatePublished - Mar 2006

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Microbiology
  • Bioengineering
  • Environmental Chemistry
  • Pollution

Keywords

  • Coplanar PCBs
  • Marine sediments
  • Methanogenic bacteria
  • Polychlorinated biphenyls
  • Reductive dechlorination
  • Sulfate-reducing bacteria

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