Testing of Enterococci as Novel Fecal Contamination Indicator in Public Water Body

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17510026
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental impact assessment/Environmental policy
• Research Institution: University of Shizuoka
• Principal Investigator: IWAHORI Keisuke University of Shizuoka, Institute for Environmental Sciences, Professor, 環境科学研究所, 教授 (40183199)
• Co-Investigator(Kenkyū-buntansha): MIYATA Naoyuki University of Shizuoka, Institute for Environmental Sciences, Assistant Professor, 環境科学研究所, 助手 (20285191)
• Project Period (FY): 2005 – 2006
• Keywords: Public water body / Enterococci / Enterolert method / M-enterococcus method / Johkasou system / Gray water / Fecal contamination indicator

Research Abstract

This research aimed at the applicability of Enterococci as a novel fecal contamination indicator in the public water body. The obtained results can be summarized as follows;
Comparing with various enterococci enumeration methods in both pure and mixed cultures, using 7 type strains of Escherichia coli, coliform group, Enterococci and their pseudopositive bacteria, it was obvious that both Enterolert and M-enterococcus methods were available, the former was recommended as the Standard Methods for the Examination of Water and the latter was as that of Wasewater in Japan. In confirmed test, the numbers of E.coli, coliform group and Enterococci were shown to be correlative and both methods had a high relation in the samples of small-scale domestic wastewater treatment system (Gappei-shori Johkasou).
Nextly, the fecal contamination indicators of the water samples in the Tomoe Basin and the effluents in the Johkasou systems installed at this Basin were surveyed. As the results, Enterococci enumerated by both Enterolert and M-enterococcus methods were applicable as the fecal indicator in the public water body. The ratio of the Tandoku-shori Johkasou to the Johkasou systems in this Basin was investigated at the end of FY 2005, because Enterococci was detected in the gray water. This ratio was more than 90% and the possibility was shown that the gray water including the fecal indicators ran down into the Tomoe Basin. Therefore, the conversion of the Tandoku to the Gappei-shori Johkasou was suggested to create the secure and safe Tomoe Basin.
Consequently, it was shown that Enterococci with E.coli and coliform group was effective as a novel fecal contamination indicator in the public water body.