Electrical Conductivity as an Indicator to Assess the Suitability of River          Water for Recreational Use

Hanna Horiguchi; Katsumi Shigemura; Madoka Kitakawa; Minato Nakazawa; Tatsuhiko Noyori; Motomu Inoue; Reo Onishi; Michika Moriwaki; Chisato Yoshimura; Mayumi Kobayashi; Toshinobu Suzaki

doi:10.2965/jwet.22-127

Original Articles

Electrical Conductivity as an Indicator to Assess the Suitability of River Water for Recreational Use

Hanna Horiguchi, Katsumi Shigemura, Madoka Kitakawa, Minato Nakazawa, Tatsuhiko Noyori, Motomu Inoue, Reo Onishi, Michika Moriwaki, Chisato Yoshimura, Mayumi Kobayashi, Toshinobu Suzaki

Author information

Hanna Horiguchi
Division of Health Sciences, Graduate School of Medicine, Osaka University, Suita, Japan
Katsumi Shigemura
Department of Public Health, School of Medicine, Faculty of Health Science, Kobe University, Kobe, Japan
Department of Urology, Kobe University Hospital, Kobe, Japan
Madoka Kitakawa
Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
Minato Nakazawa
Department of Public Health, School of Medicine, Faculty of Health Science, Kobe University, Kobe, Japan
Tatsuhiko Noyori
Toga River Conservancy, Kobe, Japan
Motomu Inoue
Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
Reo Onishi
Department of Public Health, School of Medicine, Faculty of Health Science, Kobe University, Kobe, Japan
Michika Moriwaki
Department of Public Health, School of Medicine, Faculty of Health Science, Kobe University, Kobe, Japan
Chisato Yoshimura
Center for Environmental Management, Kobe University, Kobe, Japan
Mayumi Kobayashi
Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
Toshinobu Suzaki
Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan

Keywords: urban river environment, fecal coliform density, ROC analysis, water pollution, screening method

JOURNAL OPEN ACCESS

2023 Volume 21 Issue 4 Pages 204-212

DOI https://doi.org/10.2965/jwet.22-127

Details

Abstract

Urban rivers flowing through cities are places of recreation and relaxation for citizens. However, these rivers are sometimes contaminated by Escherichia coli (E. coli). Therefore, the purpose of this study was to develop a simple method to investigate E. coli contamination in river water. From May to October 2019, water samples were collected from five locations in the Toga River in Kobe City, Japan, and the fecal coliform density (FCD) was measured, along with the electrical conductivity and the chloride ion concentration of the river water. Comparison of these water quality parameters with actual fecal coliform densities revealed a high correlation between electrical conductivity and FCD. Whereas, little correlation was found between FCD and chloride concentration. Receiver operating characteristic (ROC) analysis was used to evaluate the method that uses the electrical conductivity as an estimating parameter. The area under the curve (AUC) was used as a measure of the performance of the ROC curve algorithm. The calculated AUC value stayed high, above 0.95, over a wide range of FCD values, suggesting that this rapid monitoring method is appropriate for assessing the quantity of contaminating fecal coliforms in the range higher than 300/100 mL.

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