Bacterial biofilms formed in arsenic-containing water: biodeterioration of water network materials

The immersion of any material in a water system triggers a surface microbial colonization which simultaneously influences the corrosion behavior of the substratum. The present study was focused on the As(V) influence on the biofilm formation and their consequences on the corrosion behavior of different substrata. Commercial materials used in water distribution networks: alloys based on Fe, Zn and Cu and polypropylene (as blank) were tested in laboratory water closed circuits either in the absence or presence of 5 mg L⁻¹ As(V). Microbial sessile counting, microscopic techniques (SEM, ESEM, CSLM), and anodic polarization curves were performed. All the materials revealed very different behaviors. Except for copper, bacterial counts were higher for those coupons exposed to the water with As(V). The morphology of the corrosion products as well as the development of the corrosion process were highly influenced by the characteristics of the microbial biofilm, the nature of the substrata, and the presence or not of As(V).