title: Anaerobic biodegradation of PAHs in mangrove sediment with amendment of NaHCO3.
abstract: Mangrove sediment is unique in chemical and biological properties. Many of them suffer polycyclic aromatic hydrocarbon (PAH) contamination. However, the study on PAH biological remediation for mangrove sediment is deficient. Enriched PAH-degrading microbial consortium and electron acceptor amendment are considered as two effective measures. Compared to other electron acceptors, the study on CO2, which is used by methanogens, is still seldom. This study investigated the effect of NaHCO3 amendment on the anaerobic biodegradation of four mixed PAHs, namely fluorene (Fl), phenanthrene (Phe), fluoranthene (Flua) and pyrene (Pyr), with or without enriched PAH-degrading microbial consortium in mangrove sediment slurry. The trends of various parameters, including PAH concentrations, microbial population size, electron-transport system activities, electron acceptor and anaerobic gas production were monitored. The results revealed that the inoculation of enriched PAH-degrading consortium had a significant effect with half lives shortened by 7-13 days for 3-ring PAHs and 11-24 days for 4-ring PAHs. While NaHCO3 amendment did not have a significant effect on the biodegradation of PAHs and other parameters, except that CO2 gas in the headspace of experimental flasks was increased. One of the possible reasons is that mangrove sediment contains high concentrations of other electron acceptors which are easier to be utilized by anaerobic bacteria, the other one is that the anaerobes in mangrove sediment can produce enough CO2 gas even without adding NaHCO3.
authors: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China. Electronic address: lich@craes.org.cn.
authors: Chun-Hua
authors: CH
authors: Li
authors: Department of Biology, The Hong Kong University of Science and Technology, Hong Kong, China.
authors: Yuk-Shan
authors: YS
authors: Wong
authors: Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors: Hong-Yuan
authors: HY
authors: Wang
authors: Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China; State Key Laboratory on Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China. Electronic address: bhntam@cityu.edu.hk.
authors: Nora Fung-Yee
authors: NF
authors: Tam
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D004579:Electron Transport; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation / Q000379:methods*; D005740:Gases / Q000378:metabolism; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology; D059013:Microbial Consortia; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D017693:Sodium Bicarbonate / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D053833:Wetlands
chemical_list: D005740:Gases; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical; D017693:Sodium Bicarbonate
keywords: Anaerobic biodegradation; Electron acceptor amendment; Mangrove sediment; NaHCO(3) amendment; Polycyclic aromatic hydrocarbon