1:45 PM - 3:15 PM
[O08-P47] Investigation of oil film-like substance and reddish-brown sediment around Sendai High School
Keywords: iron bacteria, Mitaki basalt, iron oxide
Investigation of oil film-like substance and reddish-brown sediment around Sendai High School
Rintaro Onodera, Rikuto Suzuki, Takumi Konno, Takumi Toba, Minato Narasaka
Sendai City Sendai High School
1. Research background and purpose
Reddish-brown sediment and oil film-like substances were found in many water bodies, including gutters and ponds, around Sendai High School.
(Photos 1and 2)
It looked like oil, and we felt that it might be harmful to the environment and the human body, so we started investigating. Actually, I had previously discovered a similar phenomenon in other locations, and I was curious about the relationship with the previously discovered location and the surrounding strata.
As a result of researching literature, there have been reports of reddish-brown precipitates and oil film-like substances similar to those observed around Sendai High School in various regions across the Japan, and these have been described as phenomena caused by a substance called "iron bacteria" there were.
In this research, we will investigate whether the reddish-brown precipitate and oily film-like substances discovered are caused by iron bacteria, and what is the cause of the occurrence of the discovered substances, based on literature, experiments, and inspections around schools.
2. Investigation result
The oil film-like substance and reddish-brown precipitate were not harmful to the environment or the human body, and were formed by the proliferation of iron bacteria.
We believe that the cause of the iron bacteria outbreak is the "Mitaki Basalt" which is the geological formation around Sendai High School.
3. Investigation to determine whether the discovered substance is caused by iron bacteria
1. Survey method (see map 1 for sample collection locations)
(1) Comparison with oil
(2) Observation with optical/electron microscope
(3) Measurement of iron concentration in water [phenanthroline absorption spectrophotometry]
*From reference 1, iron bacteria thrive in water containing a lot of Fe2+.
2.Results
(1) Comparison with oil
It was determined from the odor and appearance of precipitation that the oil film-like substance was not oil.
(2) Optical/electron microscopy observation
Optical microscope
The oil film-like substance is a plate-like substance as shown in photo 3.
The reddish-brown precipitate was confirmed as a linear substance as shown in photo 4.
Electron microscope (examining only the reddish-brown precipitate)
A cylindrical substance as shown in photo 5 was confirmed.
*The oil film-like substance is thought to be an iron oxide film, and the reddish-brown precipitate is thought to be iron bacteria and iron oxide.
(3)Measurement of iron concentration in water the Fe2+ concentration in the Sendai High School gutter water was extremely high at 10.45μg/ml.
3.Consideration
Based on the experimental results, we believe that the reddish-brown precipitate and oil film-like substance found are caused by iron bacteria. In addition, the water in areas where the reddish-brown precipitates and oil film-like substances found are thought to be an environment in which iron bacteria can easily breed.
4. Causes of iron bacteria
The Mitaki basalt layer is distributed in most of the locations where reddish-brown precipitates and oil film-like substances have been confirmed.
According to Reference 3, Mitaki basalt contains a large amount of iron.
(1) Research method
In areas where Mitaki basalt is distributed, we will investigate whether reddish-brown precipitates or oil film-like substances are occurring in areas other than those where they have been discovered so far.
(2) Results
Reddish-brown precipitates and oil film-like substances were newly confirmed at two locations. (Map 2)
(3)Discussion
Geological map 1 is a geological map of the area around Sendai High School. The blue stratum around Sendai High School is called the Mitaki Basalt Layer, and the survey revealed reddish-brown precipitates and oil film-like substances in the areas marked with an asterisk. Most of the confirmed areas are the Mitaki formation. (The rock that makes up the Mitaki layer is Mitaki basalt.)As a result of measuring the iron concentration in the water, a large amount of divalent iron was confirmed. Additionally, a characteristic feature of the sampling location was the presence of reddish-brown material dripping from the cliffs and concrete near the sampling location.
(Example is photo 6)
It is believed that the reason for the occurrence of iron bacteria in the survey area is that groundwater distributed in the Mitaki basalt, which contains a lot of divalent iron, gushes out from cliffs and other places.
Rintaro Onodera, Rikuto Suzuki, Takumi Konno, Takumi Toba, Minato Narasaka
Sendai City Sendai High School
1. Research background and purpose
Reddish-brown sediment and oil film-like substances were found in many water bodies, including gutters and ponds, around Sendai High School.
(Photos 1and 2)
It looked like oil, and we felt that it might be harmful to the environment and the human body, so we started investigating. Actually, I had previously discovered a similar phenomenon in other locations, and I was curious about the relationship with the previously discovered location and the surrounding strata.
As a result of researching literature, there have been reports of reddish-brown precipitates and oil film-like substances similar to those observed around Sendai High School in various regions across the Japan, and these have been described as phenomena caused by a substance called "iron bacteria" there were.
In this research, we will investigate whether the reddish-brown precipitate and oily film-like substances discovered are caused by iron bacteria, and what is the cause of the occurrence of the discovered substances, based on literature, experiments, and inspections around schools.
2. Investigation result
The oil film-like substance and reddish-brown precipitate were not harmful to the environment or the human body, and were formed by the proliferation of iron bacteria.
We believe that the cause of the iron bacteria outbreak is the "Mitaki Basalt" which is the geological formation around Sendai High School.
3. Investigation to determine whether the discovered substance is caused by iron bacteria
1. Survey method (see map 1 for sample collection locations)
(1) Comparison with oil
(2) Observation with optical/electron microscope
(3) Measurement of iron concentration in water [phenanthroline absorption spectrophotometry]
*From reference 1, iron bacteria thrive in water containing a lot of Fe2+.
2.Results
(1) Comparison with oil
It was determined from the odor and appearance of precipitation that the oil film-like substance was not oil.
(2) Optical/electron microscopy observation
Optical microscope
The oil film-like substance is a plate-like substance as shown in photo 3.
The reddish-brown precipitate was confirmed as a linear substance as shown in photo 4.
Electron microscope (examining only the reddish-brown precipitate)
A cylindrical substance as shown in photo 5 was confirmed.
*The oil film-like substance is thought to be an iron oxide film, and the reddish-brown precipitate is thought to be iron bacteria and iron oxide.
(3)Measurement of iron concentration in water the Fe2+ concentration in the Sendai High School gutter water was extremely high at 10.45μg/ml.
3.Consideration
Based on the experimental results, we believe that the reddish-brown precipitate and oil film-like substance found are caused by iron bacteria. In addition, the water in areas where the reddish-brown precipitates and oil film-like substances found are thought to be an environment in which iron bacteria can easily breed.
4. Causes of iron bacteria
The Mitaki basalt layer is distributed in most of the locations where reddish-brown precipitates and oil film-like substances have been confirmed.
According to Reference 3, Mitaki basalt contains a large amount of iron.
(1) Research method
In areas where Mitaki basalt is distributed, we will investigate whether reddish-brown precipitates or oil film-like substances are occurring in areas other than those where they have been discovered so far.
(2) Results
Reddish-brown precipitates and oil film-like substances were newly confirmed at two locations. (Map 2)
(3)Discussion
Geological map 1 is a geological map of the area around Sendai High School. The blue stratum around Sendai High School is called the Mitaki Basalt Layer, and the survey revealed reddish-brown precipitates and oil film-like substances in the areas marked with an asterisk. Most of the confirmed areas are the Mitaki formation. (The rock that makes up the Mitaki layer is Mitaki basalt.)As a result of measuring the iron concentration in the water, a large amount of divalent iron was confirmed. Additionally, a characteristic feature of the sampling location was the presence of reddish-brown material dripping from the cliffs and concrete near the sampling location.
(Example is photo 6)
It is believed that the reason for the occurrence of iron bacteria in the survey area is that groundwater distributed in the Mitaki basalt, which contains a lot of divalent iron, gushes out from cliffs and other places.