Radioactive pollution in water                                                                  

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Context: Water pollution is a severe concern for the current generation. However, radioactive pollution of water is newly emerging but is of grave concern for water pollution and human health.

What is Radioactivity?

• It is the phenomenon of spontaneous emission of particles or waves from the unstable nuclei of some
• There are three types of radioactive emissions: Alpha, Beta and Gamma.
• Alpha particles are positively charged He atoms, beta particles are negatively charged electrons and gamma rays are neutral electromagnetic radiations.
• Radioactivity is measured in Becquerel (SI unit) or in Curie. Energy absorbed per unit mass is measured by Gray, while the unit Sievert measures the quantity of radiation absorbed by human tissues.
• A small amount of radiation is found in all types of water but the extended amount of radiation is harmful to human health.
• Radioactivity in drinking water can be determined by a gross alpha test.

How radioactive contamination occurs?

• Radioactive contamination is more prevalent in groundwater as compared to surface water since it is much exposed to radioactive elements found in the rocks.
• Sometimes, magma also releases radioactive gases into the environment.
• The deposition of these radioactive gases in waterbodies also cause radioactive contamination.
• Atmospheric deposition (both dry and wet) of cosmogenic radionuclides also add radioactive nuclei in the surface water.

Radioactive contaminants are:

• A number of radionuclides are found in surface and subsurface waters, among which 3H, 14C, 40K, 210Pb, 210Po, 222Rn, 226Ra, 228Ra, 232Th and 234,235,238U are common.
• Uranium, thorium and actinium are three NORM series that contaminate water resources.
• Radium, a descendant of the NORM series, is one of the decidedly radiotoxic elements found in aquatic systems and can be penetrated into groundwater via

(i) aquifer rock dissolution

(ii) decaying of 238U and 232Th, or

(iii) desorption processes.

Sources of radioactive contamination of water:

Natural sources

• Radioactive elements are naturally found in the earth’s crust.
• Percolation of naturally occurring radioactive materials (NORM) from the soil sediments to the aquifer causes groundwater contamination.
• Oceans and seas are the natural repositories of naturally occurring uranium.

Anthropogenic sources

• In anthropogenic sources of radioactive pollution, nuclear weapon investigation, nuclear calamities, nuclear power houses and dumping of radioactive waste are major sources of contamination.
• While application of radioisotopes in industries and scientific laboratories are the minor sources.
• The application of radioactive elements in nuclear weapons, X-rays, MRI and other medical equipment causes their exposure to human beings.
• Dumping of these radioactive wastes in surface waterbodies causes water pollution.
• Nuclear reactors and nuclear warhead experiments are the key sources of human-induced radionuclides discharge.
• Nuclear reactors produce radioisotopes (Cobalt-60, Iridium-192, etc) that hand out as sources of gamma radiation in radiotherapy and numerous industrial appliances.
• Strontium-90, Caesium-137, etc are also formed by nuclear reactors, along with numerous unnecessary radioisotopic wastes.
• 40K and 7Be are the most commonly found radioactive elements in the sludge generated in sewage treatment plants.
• Mining activities of radioactive elements like uranium and thorium also pollute surface and groundwater.
• Nuclear power plants placed at the coastal regions add to the radiological contaminants in the marine water by releasing atomic wastes. Water is also used as coolants in these powerhouses, which also get contaminated.
• Nuclear submarines cause radioactive contamination in the marine environment. Radioactive pollution due to submarine accidents and sinking have been reported.

World Health Organization set guidelines for drinking water quality

• A permissible limit of reference dose level of 0.1 micro-sieverts per year.

Impacts of radioactive contamination:

• Radioactive elements have an effect on the environment and can cause a risk to human healthiness if inhaled, injected or exposed.
• Human tissues absorb radiation through polluted water and foodstuff, which can cause serious health risks.
• High doses of radiation can cause acute radiation syndrome or cutaneous radiation injury.
• Exposure to radiation causes various disorders in human physiology, including cancer, leukaemia, genetic mutations, osteonecrosis, cataracts and chromosomal disruption.
• Immediate, recoverable consequences distressing skin, lungs, genitals, and causing hair fall
• Long-standing, permanent outcomes such as various infections like radiation damage, bone marrow fatality, cataract initiation, cancer stimulation, cholera, dysentery, tuberculosis and pneumonia. Sometimes, these outcomes may be fatal also.
• Genetic effects ionizing radiation induces mutations in germ cells (male sperm cells and female egg cells) or germ cells, resulting in structural alteration in germ cell DNA that are passed on to offsprings. Hereditary disorders can lead to premature death and severe mental illness.

What can be done?

• Proper analysis and monitoring of radioactive pollutants are also required for a safe water supply.
• Prevention and precaution measures can check the anthropogenic sources of radioactive contamination in water resources.
• Various treatment methods like aeration, reverse osmosis, ion exchange and granule carbon adsorption are effective remedial measures for treating the radioactive contaminated water.

Solutions to Radioactive Pollution

• Proper Method of Disposing of Radioactive Waste: Radioactive waste cannot be incinerated or buried. Since there is a likelihood of seepage, this waste should be stored in heavy and thick concrete containers.
• Proper Labeling: Containers with such elements should be well labeled in order to make one use protective gear when handling them.
• Banning of Nuclear Tests: Nuclear power has a lot of latent power that is very destructive, these tests, though done in the deserts, end up escaping from one ecosystem to another, eventually affecting the lives of many people.
• Proper Storage: Proper storage means no harm and can minimize cases of accidental leakage.
• Reusing: Since it is not easy to store or dispose the waste, it can be recycled and used for other purposes like in another reactor as fuel thereby protecting the environment.
• Precautions at the Personal Level: The radon level needs to be removed. Those who work with radioactive material are also at great risk. They need protective measures to keep away from radioactive contamination.

https://www.downtoearth.org.in/blog/water/radioactive-pollution-in-water-a-global-concern-for-human-health-80637