Context: Researchers from South Africa have launched an anti-poaching campaign with a unique approach which involves injecting radioactive isotopes into Rhino horns. The method is claimed to be harmless for the Rhinos and allows customs agents to detect trafficked horns.
Relevance of the Topic: Prelims: Key facts about Radioactivity; Applications of Radioactivity.
Key Highlights of the Anti-Poaching Campaign
- Method: Through a non-invasive procedure, Rhino horns are tagged with low doses of radioactive isotopes. This allows for their ready detection by radiation portal monitors (RPMs) already deployed at borders, ports, and airports worldwide to identify unauthorised nuclear materials.
- Rationale: To facilitate detection of Rhino horns at international borders using existing radiation monitors to curb poaching.
- Potential: This application can be extended to other vulnerable species like elephants and pangolins.
What is Radioactivity?
- Radioactivity is the property of some unstable atoms (radionuclides) to spontaneously emit nuclear radiation (usually alpha particles or beta particles, often accompanied by gamma-rays) to transform into a more stable form. The radiation emitted can be traced using existing radiation monitors.
- Atoms found in nature are either stable or unstable.
- Instability of an atom's nucleus may result from an excess of either neutrons or protons. In such a case, the atom is radioactive and the nucleus has excess internal energy.
- A radioactive atom attempts to reach stability by ejecting nucleons (protons or neutrons), as well as other particles, or by releasing energy.
- Common examples of Radionuclides: Tritium (isotope of Hydrogen and the lightest radionuclide), Carbon-14, Caesium-137, Thorium-232, Uranium-235, Uranium-238, Plutonium-238, Plutonium-239.

Applications of Radioactivity
- Radioisotope Thermo-electric Generator (RTG): A radioactive material (Plutonium-238) is used which when decays produces heat. This heat is in turn used by a generator to produce electricity. E.g., the New Horizon spacecraft to Pluto uses RTG as an energy source for the spacecraft.
- Medical Imaging: Radioactive isotopes are used in medical imaging techniques such as CT scans and PET scans.
- Radiation Therapy: Radioactive isotopes (Cobalt-60) and (Cesium-137) are used to treat various types of cancer through radiation therapy.
- Smoke Detectors: Smoke detectors use a small amount of radioactive material to detect smoke and trigger an alarm.
- Industrial Radiography: Radioactive isotopes are used in industrial radiography to test the integrity of metal structures such as pipelines and oil rigs.
- Carbon Dating: Carbon-14 is used in carbon dating to determine the age of ancient fossils and artefacts.
- Nuclear Power: Uranium-235 is used to generate nuclear electricity through nuclear fission. Tritium is being explored as a potential nuclear fuel that can undergo nuclear fusion.
- Food Irradiation: Radioactive isotopes (Cobalt-60 and Cesium-137) are used to sterilise and preserve food products.
- Geological Dating: Radioactive isotopes (Uranium-238) are used to determine the age of rocks and minerals.
- Sterilisation: Cobalt-60 is used to sterilise medical and surgical instruments.









