RADIOACTIVE

POLLUTION

PREPARED BY, NAVEENA GIRISHSTUDENT OF CENTRAL UNIVERSITY OF KERALAKASARAGOD

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Unstable atoms emits alpha, beta, gamma as radiation and get stable state – radioactivity

Radioactive atom / radionuclide/radioisotope – atom which emit radiation

Radioactive pollution can be defined as the emission of high energy particles or radioactive substance into air, water or land due to human activities in the form of radioactive waste.

Radioactive waste is usually the product of a nuclear process such as nuclear fission, which is extensively used in nuclear reactors, nuclear weapons and other nuclear fuel-cycles the product of a nuclear process

Sources of radioactive contaminants: Production of nuclear fuel

Nuclear power reactors

Nuclear tests carried out by Defense Personnel

Disposal of nuclear waste

Uranium Mining

Frequency and Duration of Radioactive Pollution: Continuous pollution: This type of condition exists in

uranium mines, nuclear reactors, test labs etc. where the humans are under continuous exposure to radioactive contaminants and protective clothing is required to avoid radiation exposure.

Accidental Pollution: This type of condition exists during accidental exposure to radiations by virtue of equipment failure, radiation leak, faulty protective equipment etc.

Occasional Pollution: This condition exists during isolated experiment or test of nuclear substance.

Radiation

Natural Artificial

Natural radiation

Natural - from the beginning of earth-we are always exposed to it

Cosmic rays will create +vely charged particles and high energy photons -it interact with normal atoms produce radio nuclides

It enter to earth

Uranium 235,238,thorium232,radium 226,potassium 40 etc

Alpha = helium nuclei 4he2 , it can stop by even paper sheet

Beta = electrons and positrons, stopped by glass wood etc

Gama rays = high energy photons, lead or concrete shielding to stop

Measurement SI unit Becquerel 1 Bq = 1 disintegration per second Half life – time period required to radioisotope

fall in to its half Absorbed dose ,D - energy absorbed by unit

mass of materiel , unit – gray Dose equivalent ,H – product of absorbed dose

and quality factor(relative biological effectiveness) sievert is unit

linear energy transfer = energy deposited unit length of the track with respect to x – rays (normalised to 1) – help to know damage

Radioactive pollution that is spread through the earth’s atmosphere is called “Fallout”. The atmospheric nuclear pollution become prominent during the world war 2 period when United States, Britain and Soviet Union started conducting nuclear tests in the atmosphere. The best example of fallout is the nuclear bomb attack on Hiroshima and Nagasaki, Japan in 1945 by United States of America during world war 2.

As a result of nuclear bomb attack, nearly 2,25,000 people had died as a result of long-term exposure to radiation from the

Hiroshima -atom bomb

Man made hazards

X - ray diagnosis -90% radiation

Nuclear technology – nuclear weapon manufacture, nuclear fuel cycle

Each process from mining to management leads to hazards

Nuclear reactor –electricity production

Biological effects

Ionization of H2O –H2O2 PRODUCTION

Cell damage , cell death ,DNA damage, mutations

Genes controlling cell division –disturbed – cancer

Skin ,gastro intestinal track lining –speed damage and repair

Biological effect

genetic

Stochastic

gene mutations, chromosomal

aberrations

Deterministic

Cancer inducement

somatic

Deterministic

Cell damage above threshold

level

Deterministic – high amount and high damage ,e.g. eye lens cataract , organ damage

Stochastic (random) – minor damage and repaired

hiroshima before little boy

Hiroshima after little boy

Fukushima and chernobyl nuclear disasters

Strontium

Radioactive Sr-90, like many other radio nuclides, was discovered in the 1940s in nuclear experiments connected to the development of the atomic bomb.

Strontium-90 is a by-product of the fission of uranium and plutonium in nuclear reactors, and in nuclear weapons

Strontium-90 emits a beta particle with, no gamma radiation, as it decays to yttrium-90 (also a beta-emitter). Strontium-90 has a half-life of 29.1 years. It behaves chemically much like calcium, and therefore tends to concentrate in the bones and teeth.

The accident at the Chernobyl nuclear power plant also introduced a large amount of Sr-90 into the environment

People may inhale trace amounts of strontium-90 as a contaminant in dust. But, swallowing Sr-90 with food or

Health Effects of Strontium-90 Strontium-90 is chemically similar to

calcium, and tends to deposit in bone and blood-forming tissue (bone marrow). Thus, strontium-90 is referred to as a "bone seeker." Internal exposure to Sr-90 is linked to bone cancer, cancer of the soft tissue near the bone, and leukemia.

Risk of cancer increases with increased exposure to Sr-90. The risk depends on the concentration of Sr-90 in the environment, and on the exposure

cesium

. Radioactive cesium-137 is produced when uranium and plutonium absorb neutrons and undergo fission

The half-life of cesium-137 is 30 years. It decays by emission of a beta particle and gamma rays to barium-137m.

Whether people's health is at risk is not clear, however. Epidemiologists still argue over how many cancers were caused by caesium released by Chernobyl

uses

Cesium-137 is one of the most common radioisotopes used in industry.Thousands of devices use cesium-137:

moisture-density gauges, widely used in the construction industry

leveling gauges, used in industries to detect liquid flow in pipes and tanks

thickness gauges, for measuring thickness of sheet metal, paper, film and many other products

well-logging devices in the drilling industry to help characterize rock strata

Cesium-137 is also used in medical therapy to treat cancer

•10,50,100 m depth earth

• In boxes &Containers

•Closure &post closure

Waste disposal

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