The document reports the results of recent sampling for radioactive iodine-131 in seawater conducted by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Tokyo Electric Power Company (TEPCO) around Fukushima Daiichi Nuclear Power Station. MEXT sampled at 10 locations between 20-40 km from the plant and detected iodine-131 concentrations up to 88.5 Bq/L. TEPCO sampled at 10 locations within 16 km of the plant and detected higher iodine-131 levels up to 1.6 Bq/cm3. Radioactive materials beyond regulatory limits were also found in some fish sampled 60 km south of the plant.

1. 20 km off the coast of Muroran,
Erimo and Kushiro (approx. 500 -
650 km north of Fukushima Daiichi NPS)
0.5 - 2.0 km off the coast
of Oarai Town (130 km south
of Fukushima Daiichi NPS)
Sampling Points around Fukushima Daiichi NPS
MEXTʼs sampling was done along a
line 30 km off the coast.
TEPCOʼs sampling points are
T1-2: around the discharge canal of Fuku-
shima Daiichi NPS
T3: around the discharge canal of Fuku-
shima Daini NPS
T4: around Iwasaka shore 16 km south of
Fukushima Daiichi NPS
T5-10: along a line 15 km off the coast

2. as of April 14 (Thu)
The Latest Results of I-131 Monitoring in Seawater by the Ministry of
Education, Culture, Sports, Science and Technology (MEXT)
Sampling Point Date Surface Depth
(Bq/L) (Bq/L)
M-A April 13 Not Detected Not Detected
M-B April 11 Not Detected Not Detected
M1 April 13 Not Detected Not Detected
M2 April 11 Not Detected Not Detected
M3 April 13 Not Detected Not Detected
M4 April 11 88.5 Not Detected
M5 April 13 64.1 Not Detected
M6 April 11 13.9 Not Detected
M7 April 13 Not Detected Not Detected
M8 April 11 12.6 Not Detected
M9 April 13 13.5 10.5
M10 April 11 12.2 Not Detected
Sampling Points by MEXT and TEPCO
The Latest Results of I-131 Monitoring
in Seawater by Tokyo Electric Power
Co. (TEPCO)
Sampling Date (Bq/cm3) Fukushima Daiichi
Point
T1 April 13 0.97 Fukushima Daini
T2 April 13 1.6
T3 April 13 1.0
T4 April 13 1.1
T5 April 11 0.19
T6 April 11 0.21
T7 April 13 0.12
T8 April 13 0.021 Radioactive iodine and cesium
beyond standards (intake limits)
T9 April 11 0.92 were detected in sand lances
T10 April 11 0.24 (sand eels) fished at the points
around 40 - 60 km south of
Fukushima Daiichi NPS.

3. Concentration of Iodine 131 in Nearby Sea of Fukushima Daiichi (1F) NPS (up to April 14)
Intake Limits in Foods 2000Bq/kg
Sand Lances fished at the points
around 40-60 km south of 1F Standard Value
20km off the coast of
Muroran, Erimo and Kushiro Not Detected Latest Value
(D1 through D3, 500-650km north of 1F)
(max. value in case of multiple points)
0.5-2.0km off the coast of
Oarai Town (O1, 130km south of 1F) Max. Value
40km south of 1F (M9, M10)
30km off the coast (M1 through M8)
15km off the coast (T5 through T10)
Iwasawa Shore
(T4, 16km south of 1F)
Fukushima Daini NPS
(T3, 10km south of 1F)
around Discharge Canal of 1F
(T1, T2)
Seawater at the point where
High-level Water was flown out
High-level Radioactive Water
in 1F site
Standard Concentration Limit in Water
0.04 Bq/cc
1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07 1.0E+08
I-131 Concentration (Water: Bq/cc Food: Bq/g)