2013 Volume 62 Issue 10 Pages 389-392
Involvement of microorganisms to corrosion refers to microbiological influenced corrosion（MIC）. Systematic methods for MIC diagnosis are not established, because relationship between microbial community and progression of corrosion has not yet been clarified. Here we conducted the lab-scale corrosion test and monitored the corrosion rate and microbial community in order to investigate a relationship between microbial community and progression of corrosion, which will be basic for the MIC diagnosis. First, we collected bottom water from three different oil-storage tanks in Japan. Microbial communities in these samples differed with each other. Next, corrosion rate of these samples was estimated by measuring release rate of Fe ions from metallic Fe. An accelerated corrosion was only observed in the sample supplied with inorganic salts. DGGE analysis showed that microbial community in this sample was changed from that in starting water sample. These results indicate that the inorganic salts added, which offers a model situation of environmental water quality change, may influence the rate of microbial growth. We propose that periodical monitoring of microbial community and water quality should be carried out in order to establish useful methods for MIC diagnosis.