Effect of arsenic on microorganisms and biofilms in MIC of water network materials

Abstract

Microorganisms in natural and artificial aquatic environments attach to wet surfaces to form a biofilm (Dexter, 2003), which causes problems such as microbially induced corrosion (MIC), increased resistance to biocides and persistence of pathogenic species. Arsenic (As) is being increasingly detected in distribution water services, generating serious sanitary and social problems throughout the Planet (Pontius et al. 1994; Masud Karim 2000). The existence of bacterial species able to grow in the presence of high concentrations of this chemical is well known (Oremland and Stolz 2005). The development of molecular techniques has allowed the study of microbial communities (Muyzer 1999). Among these techniques denaturing gradient gel electrophoresis (DGGE) is commonly used for genetic fingerprint analysis of microbial community composition, diversity and dynamics (Green et al. 2009). Electron microscopy techniques such as scanning electron microscopy (SEM) and environmental SEM (ESEM) have been important for high resolution visualization of bacterial biofilm outer surfaces. The main purpose of this work was to shed light on the effect of As(V) on the sessile bacterial communities produced on four substrata used in water distribution systems and their correlation with susceptibility to MIC of these substrata, using molecular biology and microscope techniques.