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Measurement result of radiation level (May.31, 21)

May.31, 2021 Bureau of Sewerage

Please be informed that Bureau of Sewerage measured current radiation level at boundary of water reclamation centers and radioactivity concentration of incinerator ash and kneaded ash.

1.Radioactivity level on incinerator ash

Sampling Date  4/19/2021-5/12/2021

(1) Incinerator ash

(Bq/kg)

Water Reclamation Center134Cs137Cs
Tobu sludge plant ND
(< 20)
170
Kasai ND
(< 19)
220
Miyagi ND
(< 14)
140
Shingashi ND
(< 16)
120
Nanbu sludge plant ND
(< 23)
130
Kita-Tama Ichigo ND
(< 10)
87
Minami-Tama ND
(< 10)
19
Kita-tama Nigo ND
(< 10)
110
Asakawa ND
(< 10)
45
Tamagawa Joryu ND
(< 10)
23
Hachioji ND
(< 10)
47
Kiyose ND
(< 10)
29
  • Analyzed using germanium semiconductor detector (Ge Detector)
  • ND : Not detectable
  • ( ) : Detection limit
  • "Detection limit" refers to the minimum detectable value. For example, a detection limit "<10" means that the minimum measurement is 10 Bq/kg, and "ND" means that the radioactivity concentration incinerator ash is below 10 Bq/kg. "Detection limit" is varied on samples by measurement condition.

(2) Kneaded ash

(Bq/kg)

Water Reclamation Center134Cs137Cs
Nanbu sludge plant ND
(< 16)
210
  • "Kneaded ash" is water and cement added incinerator ash for landfill disposal and prevention of scattering
  • Analyzed using germanium semiconductor detector (Ge Detector)
  • ND : Not detectable

  • ( ) : Detection limit

  • "Detection limit" refers to the minimum detectable value. For example, a detection limit "<16" means that the minimum measurement is 16 Bq/kg, and "ND" means that the radioactivity concentration incinerator ash is below 16 Bq/kg. "Detection limit" is varied on samples by measurement condition.

2.Monitored data on environmental radiation levels

Sampling Date  5/2/2021-5/21/2021

(μSv/h)

Water Reclamation CenterEast SideWest SideSouth SideNorth SideCenter
Tobu sludge plant 0.05 0.06 0.04 0.06 0.06
Kasai 0.06 0.06 0.06 0.06 0.07
Miyagi 0.05 0.06 0.04 0.06 0.04
Shingashi 0.04 0.05 0.06 0.06 0.06
Nanbu sludge plant 0.05 0.05 0.06 0.06 0.04
Kita-Tama Ichigo 0.06 0.06 0.06 0.06 0.07
Minami-Tama 0.06 0.05 0.04 0.05 0.05
Kita-tama Nigo 0.06 0.07 0.07 0.07 0.08
Asakawa 0.05 0.06 0.05 0.05 0.07
Tamagawa Joryu 0.05 0.07 0.06 0.06 0.07
Hachioji 0.06 0.07 0.07 0.08 0.08
Kiyose 0.06 0.06 0.06 0.06 0.06

※ Measured at a height of 1m using scintillation survey meter at boundaries of water reclamation centers which deal with sludge treatment

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