1:45 PM - 3:15 PM
[O11-P33] Is it safe to drink river water? -The situation of rivers in Ehime Prefecture is thoroughly clarified.
Keywords:Water of the river, Pack Test , Filtration Test
Objective
In recent years, global interest in environmental protection and the availability of safe water resources has increased. The question, "Is it safe to drink river water?" or "Is river water truly safe?" has been raised. While it is commonly stated that drinking river water is dangerous, this assumption has not always been scientifically verified. In this study, water samples were collected from the upper, middle, and lower reaches of the Ishite and Shigenobu Rivers in Ehime Prefecture. These samples were analyzed to assess changes in water quality and determine their safety for drinking. Through a filtration experiment and simple chemical analysis, the variations in water quality along the river were examined, and the suitability of the water for consumption was objectively evaluated. Additionally, the river water was compared with tap water to better understand its safety.
Methods
Water samples were collected from three points - upstream, midstream, and downstream - of both rivers. Two main experiments were conducted:
Filtration Test
Each sample was filtered, and the residue was observed under a microscope to compare the presence and size of particulate matter.
Pack Test (Chemical Analysis)
Using a simplified water test kit, we measured:
Phosphate ion (PO4^3-): Indicator of eutrophication. Standard: < 0.05 mg/L
Nitrate nitrogen (NO3-): Pollution indicator. Desirable: < 1 mg/L
Nitrite nitrogen (NO2-): Toxic substance. Desirable: < 0.02 mg/L
Ammonium nitrogen (NH4+): Indicates wastewater impact. Desirable: < 10 mg/L
COD (Chemical Oxygen Demand): Indicates organic pollution. Desirable: <= 5 mg/L
Tap water was tested alongside for reference.
Results
Filtration Test
Upstream water appeared relatively clean, with few visible impurities. As samples moved downstream, the filter residue increased, suggesting a rise in contamination - likely from microorganisms, sediment, and suspended particles.
Pack Test
Ishite River: NO3- and NO2- levels rose downstream, indicating a growing impact from domestic wastewater.
Shigenobu River: High PO4^3- concentrations were detected in the midstream area, showing early eutrophication. COD also increased, likely due to agricultural runoff.
Tap Water: All chemical values remained within safety standards, confirming its suitability for drinking.
Considerations
Water Deterioration: Both rivers showed decreased water quality downstream due to proximity to urban and residential areas.
Ishite River: The increase in NO3- and NO2- was especially pronounced, pointing to domestic wastewater as the main pollutant.
Shigenobu River: Eutrophication likely caused by fertilizer runoff was evident even in the middle reaches.
Tap Water Comparison: Tap water, managed under strict standards, was chemically and visually safer than river water.
Summary and Prospects
This study confirmed that untreated river water from both the Ishite and Shigenobu Rivers is not safe for direct consumption, particularly in downstream areas. Pollution from human activity - both domestic and agricultural - significantly affects water quality. Future studies should include bacterial analysis and permeability tests to provide more accurate evaluations. To preserve water environments and protect public health, it is important to identify pollution sources and implement effective countermeasures.
References
(1) Arakawa Clean Aid, "What the Pack Test Numbers Tell Us."
https://cleanaid.jp/files/packtest.pdf
(2) Japan Society of Water Environment, "About Water Quality Standards."
https://www.jswe.or.jp/
(3) Matsuyama City Environmental Conservation Division, "Matsuyama City Water Quality Data"
https://www.skr.mlit.go.jp/matsuyam/river/img/
Translated by Deepl
In recent years, global interest in environmental protection and the availability of safe water resources has increased. The question, "Is it safe to drink river water?" or "Is river water truly safe?" has been raised. While it is commonly stated that drinking river water is dangerous, this assumption has not always been scientifically verified. In this study, water samples were collected from the upper, middle, and lower reaches of the Ishite and Shigenobu Rivers in Ehime Prefecture. These samples were analyzed to assess changes in water quality and determine their safety for drinking. Through a filtration experiment and simple chemical analysis, the variations in water quality along the river were examined, and the suitability of the water for consumption was objectively evaluated. Additionally, the river water was compared with tap water to better understand its safety.
Methods
Water samples were collected from three points - upstream, midstream, and downstream - of both rivers. Two main experiments were conducted:
Filtration Test
Each sample was filtered, and the residue was observed under a microscope to compare the presence and size of particulate matter.
Pack Test (Chemical Analysis)
Using a simplified water test kit, we measured:
Phosphate ion (PO4^3-): Indicator of eutrophication. Standard: < 0.05 mg/L
Nitrate nitrogen (NO3-): Pollution indicator. Desirable: < 1 mg/L
Nitrite nitrogen (NO2-): Toxic substance. Desirable: < 0.02 mg/L
Ammonium nitrogen (NH4+): Indicates wastewater impact. Desirable: < 10 mg/L
COD (Chemical Oxygen Demand): Indicates organic pollution. Desirable: <= 5 mg/L
Tap water was tested alongside for reference.
Results
Filtration Test
Upstream water appeared relatively clean, with few visible impurities. As samples moved downstream, the filter residue increased, suggesting a rise in contamination - likely from microorganisms, sediment, and suspended particles.
Pack Test
Ishite River: NO3- and NO2- levels rose downstream, indicating a growing impact from domestic wastewater.
Shigenobu River: High PO4^3- concentrations were detected in the midstream area, showing early eutrophication. COD also increased, likely due to agricultural runoff.
Tap Water: All chemical values remained within safety standards, confirming its suitability for drinking.
Considerations
Water Deterioration: Both rivers showed decreased water quality downstream due to proximity to urban and residential areas.
Ishite River: The increase in NO3- and NO2- was especially pronounced, pointing to domestic wastewater as the main pollutant.
Shigenobu River: Eutrophication likely caused by fertilizer runoff was evident even in the middle reaches.
Tap Water Comparison: Tap water, managed under strict standards, was chemically and visually safer than river water.
Summary and Prospects
This study confirmed that untreated river water from both the Ishite and Shigenobu Rivers is not safe for direct consumption, particularly in downstream areas. Pollution from human activity - both domestic and agricultural - significantly affects water quality. Future studies should include bacterial analysis and permeability tests to provide more accurate evaluations. To preserve water environments and protect public health, it is important to identify pollution sources and implement effective countermeasures.
References
(1) Arakawa Clean Aid, "What the Pack Test Numbers Tell Us."
https://cleanaid.jp/files/packtest.pdf
(2) Japan Society of Water Environment, "About Water Quality Standards."
https://www.jswe.or.jp/
(3) Matsuyama City Environmental Conservation Division, "Matsuyama City Water Quality Data"
https://www.skr.mlit.go.jp/matsuyam/river/img/
Translated by Deepl