Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts

Waterborne outbreaks of Cryptosporidium infection through drinking tap water are a significant threat to public health. Monitoring Cryptosporidium oocyst-sized microorganisms in sand filter effluent as a surrogate indicator of Cryptosporidium oocysts can detect sand filter integrity breaches. This s...

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Main Authors: Sandrine Boivin, Hiroshi Nagaoka, Takahiro Fujioka
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Water Research X
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589914725000441
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author Sandrine Boivin
Hiroshi Nagaoka
Takahiro Fujioka
author_facet Sandrine Boivin
Hiroshi Nagaoka
Takahiro Fujioka
author_sort Sandrine Boivin
collection DOAJ
description Waterborne outbreaks of Cryptosporidium infection through drinking tap water are a significant threat to public health. Monitoring Cryptosporidium oocyst-sized microorganisms in sand filter effluent as a surrogate indicator of Cryptosporidium oocysts can detect sand filter integrity breaches. This study aimed to achieve the continuous monitoring of microbial particles (MPs) sized similarly to Cryptosporidium in sand filter effluent by remodeling an MP counter and demonstrating its validity. Instrumental settings of the MP counter (i.e., refractive index and particle diameter) were adjusted for accurate detection of Cryptosporidium parvum oocyst. The remodeled MP counter successfully detected Cryptosporidium parvum and Cryptosporidium-sized microorganisms (Saccharomyces cerevisiae and Chlorella vulgaris). Over a 7-d full-scale test, the MP counter coupled with dialysis pre-treatment continuously detected Cryptosporidium-sized (i.e., 3–8-µm) MPs at 0.2–27 counts/10 mL in the sand filter effluent. However, the variations in MP concentrations were not correlated with those in conventional indicators, such as turbidity and 1–3 or 3–7-µm particle counts, indicating that microbiological water safety cannot be guaranteed with these conventional indicators. Real-time monitoring of 3–8-µm MP concentrations allows for early detection of potential Cryptosporidium leaks through a sand filter. Abnormalities in water quality detected early would allow for effective countermeasures immediately, reducing the risk of waterborne protozoan outbreaks.
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spelling doaj-art-1261aa83d0cd4b2dae1cd8efcfdfd9b12025-08-20T02:05:52ZengElsevierWater Research X2589-91472025-05-012710034510.1016/j.wroa.2025.100345Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocystsSandrine Boivin0Hiroshi Nagaoka1Takahiro Fujioka2Graduate School of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, JapanDepartment of Urban and Civil Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo, 158-8557, JapanGraduate School of Integrated Science and Technology, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan; Corresponding author.Waterborne outbreaks of Cryptosporidium infection through drinking tap water are a significant threat to public health. Monitoring Cryptosporidium oocyst-sized microorganisms in sand filter effluent as a surrogate indicator of Cryptosporidium oocysts can detect sand filter integrity breaches. This study aimed to achieve the continuous monitoring of microbial particles (MPs) sized similarly to Cryptosporidium in sand filter effluent by remodeling an MP counter and demonstrating its validity. Instrumental settings of the MP counter (i.e., refractive index and particle diameter) were adjusted for accurate detection of Cryptosporidium parvum oocyst. The remodeled MP counter successfully detected Cryptosporidium parvum and Cryptosporidium-sized microorganisms (Saccharomyces cerevisiae and Chlorella vulgaris). Over a 7-d full-scale test, the MP counter coupled with dialysis pre-treatment continuously detected Cryptosporidium-sized (i.e., 3–8-µm) MPs at 0.2–27 counts/10 mL in the sand filter effluent. However, the variations in MP concentrations were not correlated with those in conventional indicators, such as turbidity and 1–3 or 3–7-µm particle counts, indicating that microbiological water safety cannot be guaranteed with these conventional indicators. Real-time monitoring of 3–8-µm MP concentrations allows for early detection of potential Cryptosporidium leaks through a sand filter. Abnormalities in water quality detected early would allow for effective countermeasures immediately, reducing the risk of waterborne protozoan outbreaks.http://www.sciencedirect.com/science/article/pii/S2589914725000441Rapid sand filterWater treatmentIntegrity monitoringProtozoaWater quality management
spellingShingle Sandrine Boivin
Hiroshi Nagaoka
Takahiro Fujioka
Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
Water Research X
Rapid sand filter
Water treatment
Integrity monitoring
Protozoa
Water quality management
title Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
title_full Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
title_fullStr Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
title_full_unstemmed Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
title_short Real-time detection of 3–8-µm microbial particles in sand filter effluent as a surrogate indicator of Cryptosporidium parvum oocysts
title_sort real time detection of 3 8 µm microbial particles in sand filter effluent as a surrogate indicator of cryptosporidium parvum oocysts
topic Rapid sand filter
Water treatment
Integrity monitoring
Protozoa
Water quality management
url http://www.sciencedirect.com/science/article/pii/S2589914725000441
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