This document summarizes a study that measured levels of radioactive cesium-134 and cesium-137 in various fish samples from Sri Lanka following the 2011 Fukushima Daiichi nuclear power plant accident in Japan. The study found trace amounts of cesium-137 in some marine fish but no detectable radioactive isotopes in freshwater fish. Two canned fish samples showed low levels of cesium-134 and cesium-137, indicating possible contamination from the Fukushima accident. However, all measured radioactivity levels were below Sri Lankan regulatory limits. The study concludes it is important to continue monitoring fish consumed in Sri Lanka for potentially harmful accumulation of radioactivity over time.

1. DETERMINATION OF CESIUM-137 AND CESIUM-134
RADIOACTIVITY LEVELS IN FISH CONSUMED BY SRI LANKANS
AFTER NUCLEAR POWER PLANT ACCIDENT OCCURRED IN
FUKUSHIMA, JAPAN.
V.A Waduge1*, E.C.J Perera2, T.N. Attanayake1, P.R.T. Cumaranatunga3, M.C.S. Senaviratne1, D.P.
Dissanayake2
1 Atomic Energy Authority, 60/460, Baseline Road, Orugodawatte, Wellampitiya.
2 Department of Chemistry, Faculty of Science, University of Colombo. Colombo 03.
3 Department of Fisheries and Aquaculture, Faculty of Fisheries and Marine Sciences &
Technology, University of Ruhuna, Matara, Sir Lanka.
Sri Lanka Association for the Advancement of Science (SLAAS)
68th Annual Sessions – 2012

2. INTRODUCTION
Fukushima nuclear reactor
•The Fukushima power station is located on the east coast of the island of Honshu
(facing the Pacific Ocean), 200 km north-east of Tokyo.
•First commissioned in 1971.
•Consist with six boiling water reactors (light water reactor).
•Energy released from neutron induced fission is used to produce steam which
drives the turbines that produce electricity
Energy released in fission
•n + 235U fission fragments + neutrons + Energy
•Noble gasses (krypton, Xenon), Iodine, Cesium, etc

3. NUCLEAR POWER PLANT ACCIDENT OCCURRED IN FUKUSHIMA, JAPAN.
•The huge earthquake and tsunami that struck Japan’s Fukushima Daiichi nuclear
power station at 14:46 on March 11, 2011.
•The tsunami knocked out backup power systems that were needed to cool the
reactors at the plant, causing several of them to undergo fuel melting, hydrogen
explosions, and radioactive releases.
•Level 7 on the International Nuclear Event Scale
Abundant
isotopes/gasses
released
Estimated amount of radioactive materials released
approximately 1
into the air (PBq)# into the ocean(PBq)
Noble gas 500 -
Iodine -131 500 11
Cesium -137 10 3.6
Cesium -134 10 3.5
#:- 1PBq(peta Becquerel)=1,000 trillion Bq=1015Bq

4. OBJECTIVE
•To determine the activity levels of Cesium- 137 and Cesium-134 in selected
species of freshwater fish, marine fish and canned fish products and to see
whether there is any significant impact from Fukushima Nuclear Power Plant
(FNPP) accident on the fish consumed by Sri Lankans at present.

5. SELECTED FISH TYPES
1) Fresh water fish species
Striped Snake-head (Opiocephalus striatus)
Long-finned eel (Anguilla nebulosa)
2) Marine fish species
Barred Spanish mackerel (Cybium commersoni)
Sail Fish (Istiophorus platypterus)
3) Canned fish
All samples were collected during the period September 2011-
March 2012

6. METHODOLOGY
• Samples were washed thoroughly with distilled water before sample preparation.
• De-scaling, and removing the inedible parts including bones, internal organs,
scales and the head.
• Canned fish samples were prepared directly using the solid mass contents after
decanting the preservative liquid.
• Edible portion of the fish were weighted and dried in an oven at 110 OC to a
constant weight.
• The dried samples were ground to a fine powder
• Transferred to polypropylene cylindrical containers (147 cm3)
• Hermetically sealed and stored for gamma spectrometry measurement.
• Counting time = 72,000 seconds (20 hours)

7. GAMMA SPECTROSCOPY
Radioisotope Energy (keV) Half Life (years)
137Cs 661.5 30.17
134Cs 604.7
795.8
2.065
•High Purity Germanium (HPGe) detector
•Data acquisition and analysis:- Genie 2000 software package (Canberra)
•Analyzed at the laboratories of Atomic Energy Authority

8. RESULT AND DISCUSSION
•The Cs- 137 and Cs- 134 were not found in detectable levels in all fresh water fish
samples.
•The sea fish species collected from local consumer market contained trace amounts
of Cs- 137
•The Cs- 137 and Cs-134 were detected in two canned fish samples indicating the
possible contamination due to the FNPP accident.
•The contaminated samples showed activities of 10.97 ± 0.99 Bq/kg dw and 6.12 ± 0.62
Bq/kg dw for Cs-137 and 8.37 ± 2.91 Bq/kg and 4.80 ± 1.75 Bq/kg dw for Cs-134
respectively.
•The activity ratios of Cs- 137 to Cs- 134 for above two samples were approximately
1.3.

9. RESULT AND DISCUSSION continued
The activity concentrations (Bq/kg dw ) of Cs- 137 measured in the edible parts of the fish and
canned fish
Category Species/Type
Number of
samples
Average Activity
(Bq/kg dw)
Marine fish
Barred Spanish mackerel (Cybium commersoni) 3 0.62 ± 0.21
Sail Fish (Istiophorus platypterus) 5 0.35 ± 0.29
Fresh water fish
Striped Snake-head (Opiocephalus striatus) 6 -
Long-finned eel (Anguilla nebulosa) 3 -
Canned fish 7 2.46 ± 1.03 #
LLD- Lower Limit of Detection,
Bq/kg dw- Becquerel per kg dry weight basis,
#- Cs- 137 was found only in two samples and average activities calculate with respect to their values.

10. RESULT AND DISCUSSION continued
The activity concentrations (Bq/kg dw ) of Cs- 134 measured in the edible parts of the fish and
canned fish
Category Species/Type Number of samples Activity (Bq/kg dw)
Marine fish
Barred Spanish mackerel (Cybium commersoni) 3 < LLD
Sail Fish (Istiophorus platypterus) 5 < LLD
Fresh water
fish
Striped Snake-head (Opiocephalus striatus) 6 < LLD
Long-finned eel (Anguilla nebulosa) 3 < LLD
Canned fish 7
[a][b][c][d][e] < LLD
[f] 8.37 ± 2.91
[g] 4.80 ± 1.75
[a][b][c][d][e][f][g]- Identification tags of canned fish samples analyzed.

11. CONCLUSION
•The result of this preliminary study shows that there is an impact on the sea-fish
due to the radioactive releases from FNPP accident.
•All the samples analyzed showed radioactivity levels less than the stipulated
levels by the regulations imposed in Sri Lanka2
•As there is a possibility of increasing radioactivity in fish to harmful levels by the
processes of bio accumulation and bio magnification, it is necessary to continue
the study for mainly consumed fish varieties in Sri Lanka for an extended period of
time

12. REFERENCE
1.The Estimated Amount of Radioactive Materials Released into the Air and the Ocean Caused by Fukushima
Daiichi Nuclear Power Station Accident Due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake ;Press Release (May
24,2012) .[cited date 2012 August 20] Available from: http://www.tepco.co.jp/en/press/corp-
com/release/2012/1204659_1870.html
2. AEA Act 19 of 1969 and gazette notification LD-B36/73-1995.07.21
3. Mohan Feroz Khan , Samuel Godwin Wesley; Biomonitoring fallout 137Cs in resident and migratory fishes
collected along the southern coast of India and assessment of dose ; Environ Monit Assess (2012) 184:2993–3011
DOI 10.1007/s10661-011-2166-8
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Hong Kong ; Appl. Radial. Isot. 1997; Vol.48,no 4,pp 515-519
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Service; January 18, 2012; 7-5700 www.crs.gov R41694: .[cited date 2012 July 15] Available from:
http://www.fas.org/sgp/crs/nuke/R41694.pdf
6. Melgunov MS, Pokhilenko NP, Strakhovenko VD, Sukhorukov FV, Chuguevskii AV; Fallout traces of the
Fukushima NPP accident in southern West Siberia (Novosibirsk, Russia). Environ Sci Pollut Res Int. [Internet] 2012
May;19(4):1323-5. Epub 2011 Nov 24. .[cited date 2012 May 5] Available from:
http://www.ncbi.nlm.nih.gov/pubmed
7. F. Korkmaz Görür , R. Keser , N. Akçay , S. Dizman ; Radioactivity and heavy metal concentrations of some
commercial fish species consumed in the Black Sea Region of Turkey; Chemosphere ;2012; 87, p356–361

13. THANK YOU.