title: Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.
abstract: Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release.
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China. Electronic address: huchun@rcees.ac.cn.
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China.
authors.forename: Xiaoxiao
authors.initials: X
authors.lastname: Li
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Aquatic Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yang
mesh_terms: D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D003343:Corrosion; D060766:Drinking Water / Q000737:chemistry* / Q000382:microbiology; D052203:Ferrosoferric Oxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D010084:Oxidation-Reduction; D025341:Principal Component Analysis; D014881:Water Supply
chemical_list: D060766:Drinking Water; D007501:Iron; D052203:Ferrosoferric Oxide
keywords: Bacterial community; Corrosion scales; Microbial redox cycling; Nitrate-reducing bacteria