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Zen 362 group 2 effects of disaster fukushima


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ZEN 362 assignment: Effects of disasters. In this presentation we looked at a study conducted by Yamashiro et al. (2013) about the effects of radioactive caesium on bull testes after the Fukushima nuclear plant accident.

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Zen 362 group 2 effects of disaster fukushima

  1. 1. Probably not! An Electron Probe X-ray Microanalysis tells us why. If eating bull testicles gives you power, would eating radioactive bull testicles give you super powers? Group 2: Effects of disaters Motsomane Puseletso 10483846 Ntuli Isaac 29344192 Pitswane Matshidiso 10294547
  2. 2. OUTLINE 1. Introduction 2. Methods and Materials 3. Results 4. Discussion 5. Conclusion 6. References
  3. 3. INTRODUCTION In March 2011, an earthquake led to a tsunami that caused an accident at the Fukushima Daiichi Nuclear Power Plant (FNPP), Japan.
  4. 4. INTRODUCTION •A month later, a 20km radius evacuation zone surrounding the FNPP was set up and resulted in over thousands of domestic animals being left behind. The Japanese government then ordered for the animals that were left behind to be euthanized ethically. •Their bodies were to become the model specimens for the study of the effects of exposure to radioactive materials.
  5. 5. INTRODUCTION The damage caused by chronic exposure to radionuclides is irreversible. The effect of radionuclides on reproductive organs remains a key concern because of the repercussions that would follow (such as cancers and birth defects).
  6. 6. INTRODUCTION •Up until now, the epidemiological studies of survivors from Chernobyl, Hiroshima and Nagasaki provided the data used for estimations of the risks associated with exposure to accidental nuclear radiation. Valuable data was not available for the livestock industry. •This study fills the gap by testing the effect of chronic low- dose radiation on livestock that was left behind in the evacuation zone. •The focus was particularly on 134Cs and 137Cs associated with the FNPP accident. The researchers hope that an internationally recognised framework for the protection of livestock will be developed from the results of their study, in preparation for future nuclear radiation disasters.
  7. 7. METHODS & MATERIALS • 12 euthanized cattle were collected • A mixture of bulls, calves, and foetuses • Testes from 2 euthanized bulls and 1 foetus formed the experimental group (Table 1.) • Control testes were obtained from a place outside the evacuation zone (Miyagi) which was not affected by radioactivity.
  8. 8. METHODS & MATERIALS Location Number animals Distance from evacuation zone (km) Air dose rate (μSv/h) Soil radioactivity concentration (kBq/m2) Time elapsed since nuclear accident (days) Kawauchi village 1 bull and 1 foetus 15 0.5 134Cs 230 and 137Cs 240 196 Naraha town 1 bull 17 2 134Cs 100 and 137Cs 110 315 Table 1. Testes collected from two bulls and one foetus affected by radioactivity after the 2011 FNPP nuclear accident.
  9. 9. METHODS & MATERIALS • Calculating internal and external dose rates Dosimetry assumption statistical test. Internal dose rate quantified as the average of the radioactivity of organs. External dose rate based on soil concentrations of 134Cs and 137Cs and an assumed distance between the body of the animal and the ground. • Measuring radioactivity Gamma-ray spectrometry with 3 High Purity Germanium detectors was used. HPGe detectors have specialised regions that are sensitive to ionizing radiation, like x-rays and gamma rays. The three HPGe detectors differed in efficiency and resolution.
  10. 10. METHODS & MATERIALS A HPGe detector…
  11. 11. METHODS & MATERIALS • Blood samples As soon as blood samples were collected, they were placed into ice packs. Some of the samples were manipulated on- site. • Evaluation of epididymal sperm nucleus and acrosome integrity To enhance the contrast of the nucleus and acrosome of fresh epididymal sperm under a microscope, the samples were stained with phenylindole and fluorescein isothiocyanate.
  12. 12. METHODS & MATERIALS • Morphological assessment of testis cells Testis cells were subjected to ‘fixed’ tests. They were dehydrated in differing concentrations of alcohol and paraffin. The cells were then cut into 5μm pieces before they were stained. • Electron probe X-ray microanalysis (EPMA) This is a form of x-ray spectrometry. Testicular structure specimens were analysed for trace elements of Cs (caesium), C (carbon), K (potassium), and Mo (molybdenum).
  13. 13. METHODS & MATERIALS What EPMA looks like in textbooks…
  14. 14. METHODS & MATERIALS What EPMA looks like in real-life…
  15. 15. RESULTS • Organs: testis & peripheral blood (PB) • PB from foetus could not be obtained • Similar radioactive concentrations in all organs and PB fluid • Highest concentration seen in skeletal muscles • Lowest concentration seen in PB & testis
  16. 16. RESULTS
  17. 17. RESULTS • Average and maximum internal and external exposure • 134 Cs and 137 Cs combined • Internal dose: • Bull 1: internal dose for 196 days was 1.1-1.8 mGy • Bull 2: internal dose for 315 days was 5.0-9.5 mGy • External dose: Bull 1 (2.8 mGy) was higher than bull 2 (1.9 mGy)
  18. 18. RESULTS • Total number &morphology of epididymal sperm • Spermatogenesis not disrupted in testis
  19. 19. RESULTS EPMA analysis of bull testis: Secondary electron colour map image of carbon regions. Clockwise direction: Control, bull 1, bull 2, and foetus.
  20. 20. DISCUSSION • Objective: biological response of bull testis • Why 134C and 137C specifically? • Testis: radiosensitive organ • From mother to foetus through placenta • Spermatogenesis and spermatogonia cell damage
  21. 21. DISCUSSION • HDR (high dose radiation) • Inhibitory effect on genomic & cytological changes • LDR (low dose radiation) • Stimulatory effect on: • Metabolism • Antioxidant capacity • Proliferation • Maturation • EPMA limitations
  22. 22. DISCUSSION • Other studies • Analysis of 14 bird species between Fukushima & Chernobyl • FNPP accident and farm animals • Health risk of livestock • Extrapolation of risk to humans! • Dubrova et al.: frequency of germ-line mini satellite mutations
  23. 23. DISCUSSION • In conclusion: no adverse radiation-induced effects were observed in bull testes following chronic exposure to 3.6-4.6 mGy for bull 1 and 6.9-11.4 mGy for bull 2 up-to 10 months • Air dose rate declining • Marginal areas of evacuation zone decontaminated • Long term impact of radiation: continuous investigation • Study underway: comparing whole genome sequences & foetuses • Author’s suggestions: Investigation should be extended to more animals
  24. 24. Thank you. We hope the presentation was not a disaster….
  25. 25. REFERENCES • Dubrova YE, Nesterov VN, Krouchinsky NG, Ostapenko VA, Vergnaud G, Giraudeau F, Buard J, Jefferys AJ (1997) Further evidence for elevated human minisatellite mutation rate in Belarus eight years after the Chernobyl accident. Mutation Research, 281, 267-278 • Lui G, Gong P, Bernestein LR, Gong S, Cai L(2007) Apoptotic Cell Death Induced by Low-Dose Radiation in Male Germ Cells: Hormesis and Adaptation. Critical Reviews in Toxicology. 37,587-605 • Moller AP, Hagiwara A, Matsui S, Kasahara S, Kawatsu K, Nishium I, Suzuki H, Ueda K, Mausseau TA(2012) Abundance of birds in Fukushima as judged from Chernobyl. Environmental Pollution 164, 36-39 • Otala M, Suomalainen L, Pentikainen MO, Kovanen P, Tenhunen M, Erkkila K, Toppari J, Dunkel L(2003) Protection from Radiation-Induced Male Germ Cell Loss by Sphingosine-1-Phosphate. Biology of Reproduction, 70, 759-767 • Yamashiro H, Abe Y, Fukuda T, Kino Y, Kawaguchi I, Kuwahara Y, Fukumoto M, Takahashi S, Suzuki M, Kobayashi J, Uematsu E, Tong B, Yamada T, Yoshida S, Sato E, Shinoda H, Sekine T, Isogai E, Fukumoto M (2013) The effects of radioactive caesium on bull testes after the Fukushima nuclear plant accident. Scientific Reports 3. doi:10.1038/srep02850