Friday, October 24, 2014

You can’t sense it…

This is the pollution that you can't feel by using any of the five senses. If you are overexposed to it, it might work as a timed bomb in your body and you might not know when the detonation is occurring. 
Yes, it is radioactivity. 

What is radioactive material and radioactive decay?

All materials are made of atoms. Radioactive atoms are unstable (have too much energy). Radioactive decay is the release of extra energy by radioactive atoms. The energy is called ionizing radiation may take the form of alpha particles (a), beta particles (b), or gamma rays (g). (Fentiman, Leet, & Meredith)

Electromagnetic Spectrum Illustration. See text below.
Figure 1 Types of Radiation in the Electromagnetic Spectrum
Source: (Ionizing & Non-Ionizing Radiation, 2013)

Non-ionizing radiations:
  • electromagnetic waves of longer wavelength
  • energies enough to excite the atoms and molecules of the medium through which they are moving, causing them to vibrate faster

Ionizing radiations:
  • electromagnetic radiations of short wavelength (high energy)
  • energetic rays like (a, b and g etc.) produced in radiocative decay can cause ionization of atoms and molecules of the medium through which they pass and convert them into charged ions

After releasing all the excess energy, the atoms become stable and are no longer radioactive. (Fentiman, Leet, & Meredith)

Radioactive Pollution

Living organisms are continuously exposed to a variety of radiations called background radiations.If the level of the radioactive radiations increases above a certain limit it causes harmful effects to living beings. This harmful level of radiations emitted by radioactive elements is called radioactive pollution. (RADIOACTIVE POLLUTION)

Anthropogenic Sources of Radiation
  • Diagnostic medical applications: e.g. X-rays are used in general radiology and CT scan
  • Nuclear Tests: nuclear explosion detonated for either military or peaceful purposes (carried out for non-military purpose, such as the construction of harbours and canals) (WORLD OVERVIEW)
  • Nuclear Reactors: Radiations may leak from nuclear reactors and other nuclear facilities even when they are operating normally. It is often feared that even withthe best design, proper handling and techniques; some radioactivity is routinely released into the air and water. (RADIOACTIVE POLLUTION)


Route of exposure to radiation

Figure 2 Environmental fate and human exposure of radiation
Source: (International Advisory Committee, 1991)

The environmental fate of radioactive material is quite similar to POPs as mentioned in the previous blog post, except that radioactive material emits energy. Radioactive material is suspended in air at a height of 6 to 7 km above the earth’s surface and is dispersed over long distances by winds from the test site. These radionuclides often settle down by rain and get mixed with soil and water. From there they can easily enter the food chain and finally get deposited in the human body where they cause serious health hazards. (RADIOACTIVE POLLUTION)

What happens to radiation produced?

Nuclear waste is categorized into different level:

Types of nuclear waste

Low level waste (LLW)
  • Contain small amounts of mostly short-lived radioactivity
  • Sources: hospitals, industry, nuclear fuel cycle
  • Examples: contaminated  clothing such as protective shoe covers, paper and plastics


Intermediate level waste (ILW)
  • contains higher amounts of radioactivity
  • reactor water  treatment residues and filters used for purifying a reactor’s cooling water


High level waste (HLW)
  • highly radioactive and hot
  • two distinct kinds of HLW:
spent fuel from reactors
o   Separated waste from reprocessing the used fuel

Table 1 Different types of nuclear waste
Source: (Getting to the Core of Radioactive Waste)(Radioactive Waste Management, 2014)

Different countries might have different practices and regulations for the storage and disposal of different levels of nuclear waste. 

Generally, low level radioactive gases and liquids are release into the environment under controlled, monitored conditions to ensure that they pose no danger to the public or the environment. This is due to the fact that these releases dissipate into the atmosphere or a large water source and, therefore, are diluted to the point where it becomes difficult to measure any radioactivity. By contrast, most of an operating nuclear power plant's direct radiation is blocked by the plant's steel and concrete structures. The remainder dissipates in an area of controlled, uninhabited space around the plant, ensuring that it does not affect any member of the public. (Frequently Asked Questions (FAQ) About Radiation Protection, 2012)

Practices to handle LLW/ ILW:
  • stored on-site by licensees, either until it has decayed away and can be disposed of as ordinary trash, or until amounts are large enough for shipment to a low-level waste disposal site (Backgrounder on Radioactive Waste, 2014)
  • transported to a central treatment facility
  • burnable waste is incinerated at a central site (Management of Low and Intermediate-level Radioactive Waste (The), 1989)
  • disposed of closer to the surface, in many established repositories.  Low-level waste disposal sites are purpose built, but are not much different from normal municipal waste sites (What are nuclear wastes and how are they managed?)
Low and Intermediate waste store

Figure 3 Low-level and Intermediary-level waste (LLW/ILW) repository
Source: (What are nuclear wastes and how are they managed?)

Practices to handle HLW:
  • Used fuel will still contain some of the original U-235 as well as various plutonium isotopes. Countries such as Europe and Russia separate uranium and plutonium from the wastes so that they can be recycled for re-use in a nuclear reactor.
  • Storage ponds at reactors which are often designed to hold all the used fuel for the life of the reactor
  • Future possibility: 'multiple barrier' geological disposal is planned to ensure that no significant environmental releases occur over tens of thousands of years (disposal). Waste will be immobilized waste in an insoluble matrix, seal it inside a corrosion-resistant container and locate it deep underground in a stable rock structure. (Radioactive Waste Management, 2014)
THORP Fuel Storage

Figure 4 Storage pond for used fuel
Source: (Radioactive Waste Management, 2014)

Controversies of discharging radioactive material into the environment

In the late 1940s, the nuclear industry had chosen the open ocean as a convenient place to dispose of its inconvenient wastes. In 1972, a global treatry called the London Dumping Convention had banned the dumping of high-level radioactive wastes. However, it was not effective due to the classification of radioactive wastes as high, medium, or low-level  by International Atomic Energy Agency (IAEA) was for handling purposes (for the protection of workers) and had little to do with the radio-toxicity and the isotopic composition of radioactive wastes. Low-level radioactive wastes, could also be found extremely radio-toxic and persistent isotopes.

In 1980s, nuclear industry recognized that radioactive waste dumping on the seabed was banned, so they claimed that dumping under the seabed was not banned. Nuclear industry from various countries equipped with drilling gear and/or suppository-shaped free-fall penetrators (containers which would penetrate the seabed like armour piercing bullets) ships from these countries would shoot the high-level wastes under the seabed. This was more serious than dumping on the seabed because it was impossible to monitor. In the event of leakage, the radioactive wastes would be irretrievable.

In November of 1993, the Contracting Parties to the London Convention (later of London Dumping Convention) adopted amendments banning the dumping of radioactive wastes based on the fact of “the diffusibility of the waste radionuclides in sea water which could result in transboundary transfer of these radioactive materials” as well as the “comparative difficulty of monitoring radioactive waste packages dumped at sea”. (Parmentier, 1999)

In 1996, the 1996 Protocol eventually replace the London Convention entered into forced in 2006), represented a major change of approach to question how to use the sea as a depository of waste material. It restricts all dumping except some permitted substances. (Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other )

The permitted substances containing levels of radioactivity greater than de minimis (exempt) concentrations as defined by the International Atomic Energy Agency (IAEA) and adopted by Contracting Parties, shall not be considered eligible for dumping. (1996 PROTOCOL TO THE CONVENTION ON THE PREVENTION OF MARINE POLLUTION BY DUMPING OF WASTES AND OTHER MATTER, 1972 , 2006)

This means that LLW or ILW might be eligible to dump into the sea provided that it is lower than the concentration defined by IAEA. This is the reason for many countries to discharge their LLW intot the ocean.

However, it seems that there might be some loopholes in the 1996 Protocol. For example, thousands of tons of radioactively contaminated water from the damaged Fukushima Daiichi nuclear power plant were pouring directly into the ocean. On April 4, 2011, some three weeks after the initial disaster, the Tokyo Electric Power Co. (TEPCO), with the Japanese government’s consent, decided to release 10,000 tons of “low-level radioactive water” to make room in its storage facilities for the huge volume of more highly contaminated water that had been used for emergency cooling of the damaged Dai-ichi reactors. (Pacchioli, 2013)

Japan utilizes the loophole that 1996 Protocol prohibits ocean dumping of radioactive material, limits these restrictions to vessels at sea. One of the definition of “dumping” in 1996 Protocol is “any deliberate disposal into the sea of wastes or other matter from vessels, aircraft, platforms or other man-made structures at sea”. (1996 PROTOCOL TO THE CONVENTION ON THE PREVENTION OF MARINE POLLUTION BY DUMPING OF WASTES AND OTHER MATTER, 1972 , 2006)
Hence, release of materials from land is not considered dumping.

Recently, even UN nuclear watchdog had advised the Fukushima Daiichi nuclear power plant to consider dumping toxic water (controlled discharge) into the ocean after lowering the level of radioactive materials to below the legal limit. (IAEA suggests Fukushima consider ‘controlled discharge’ of toxic water into ocean, 2013)
Beside this legal issue, the contamination might affect marine life and human. Although the ocean has the capacity to dilute nuclear contamination, signs of spreading radioactive material are being found off Japan, including the discovery of elevated concentrations of radioactive cesium and iodine in small fish several dozen miles south of Fukushima, and high levels of radioactivity in seawater 25 miles offshore.

Two events in the early 1990s — a die-off of seals in the Barents Sea and White Sea from blood cancer, and the deaths of millions of starfish, shellfish, seals and porpoises in the White Sea — have been variously attributed by Russian scientists to pollution or nuclear contamination. These suggested that these marine lives had been expose to radioactive or other toxic substances. Hence, the dilution capacity might not be totally safe. (Grossman, 2011)

Currently, the effect on marine ecosystem is unclear since no records are yet available on the exact composition of the radioactive refuse and no one knows for sure if containment vessels are intact or leaking. (TED Case Studies Arctic Sea Dumping)




Works Cited

1996 PROTOCOL TO THE CONVENTION ON THE PREVENTION OF MARINE POLLUTION BY DUMPING OF WASTES AND OTHER MATTER, 1972 . (2006). Retrieved October 24, 2014, from International Maritime Organization: http://www.imo.org/OurWork/Environment/LCLP/Documents/PROTOCOLAmended2006.pdf
Backgrounder on Radioactive Waste. (2014, June 27). Retrieved October 24, 2014, from US Nuclear Regulatory Commission: http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/radwaste.html
Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other . (n.d.). Retrieved October 24, 2014, from International Maritime Organization: http://www.imo.org/OurWork/Environment/LCLP/Pages/default.aspx
Fentiman, A. W., Leet, T. A., & Meredith, J. E. (n.d.). What Is Radioactive Material and How Does It Decay? Retrieved October 24, 2014, from Ohio State University: http://ohioline.osu.edu/rer-fact/rer_20.html
Frequently Asked Questions (FAQ) About Radiation Protection. (2012, December 11). Retrieved October 24, 2014, from US Nuclear Regulatory Commission: http://www.nrc.gov/about-nrc/radiation/related-info/faq.html#9
Getting to the Core of Radioactive Waste. (n.d.). Retrieved October 24, 2014, from International Atomic Energy Agency: http://www.iaea.org/OurWork/ST/NE/NEFW/_nefw-documents/RadioactiveWaste.pdf
Grossman, E. (2011, April 7). Radioactivity in the Ocean: Diluted, But Far from Harmless. Retrieved October 24, 2014, from Yale Environment 360: http://e360.yale.edu/feature/radioactivity_in_the_ocean_diluted_but_far_from_harmless/2391/
IAEA suggests Fukushima consider ‘controlled discharge’ of toxic water into ocean. (2013, December 4). Retrieved October 24, 2014, from RT NEWS: http://rt.com/news/iaea-fukushima-toxic-water-710/
International Advisory Committee. (1991). THE INTERNATIONAL CHERNOBYL PROJECT TECHNICAL REPORT. Retrieved October 24, 2014, from International Atomic Energy Agency: http://www-pub.iaea.org/MTCD/publications/PDF/Pub885e_web.pdf
Ionizing & Non-Ionizing Radiation. (2013, May 17). Retrieved October 24, 2014, from US Environmental Protection Agency: http://www.epa.gov/radiation/understand/ionize_nonionize.html
Management of Low and Intermediate-level Radioactive Waste (The). (1989, August). Retrieved October 24, 2014, from Nuclear Energy Agency: http://www.oecd-nea.org/brief/brief-06.html
Pacchioli, D. (2013, May 6). Seafood Safety and Policy. Retrieved October 24, 2014, from Woods Hole Oceanographic Institution: http://www.whoi.edu/oceanus/feature/seafood-safety-and-policy
Parmentier, R. (1999). GREENPEACE AND THE DUMPING OF WASTES AT SEA: A CASE OF NON-STATE ACTORS´ INTERVENTION IN INTERNATIONAL AFFAIRS. Retrieved October 24, 2014, from GREENPEACE: http://www.greenpeace.org/international/PageFiles/25797/odhistory.pdf
RADIOACTIVE POLLUTION. (n.d.). Retrieved October 24, 2014, from National Institute of Open Schooling: http://www.nios.ac.in/media/documents/313courseE/L36.pdf
Radioactive Waste Management. (2014, September). Retrieved October 24, 2014, from World Nuclear Association: http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Nuclear-Wastes/Radioactive-Waste-Management/
TED Case Studies Arctic Sea Dumping. (n.d.). Retrieved October 24, 2014, from American University: http://www1.american.edu/ted/arctic.htm
What are nuclear wastes and how are they managed? (n.d.). Retrieved October 24, 2014, from World Nuclear Association: http://www.world-nuclear.org/Nuclear-Basics/What-are-nuclear-wastes-/
WORLD OVERVIEW. (n.d.). Retrieved October 24, 2014, from Comprehensive Nuclear-Test-Ban Treaty Organization: http://www.ctbto.org/nuclear-testing/history-of-nuclear-testing/world-overview/
  

No comments:

Post a Comment