Explanation:

Recently, radioactive pollution in water and associated health impacts have been reported in many parts of the globe.

• Radioactivity is the phenomenon of spontaneous emission of particles or waves from the unstable nuclei of some elements. There are three types of radioactive emissions: Alpha, Beta and Gamma.
• Alpha particles are positively charged He (Helium) atoms, beta particles are negatively charged electrons and gamma rays are neutral electromagnetic radiations.
• Radioactive elements are naturally found in the earth’s crust. Uranium, thorium and actinium are three NORM (Naturally Occurring Radioactive Materials) series that contaminate water resources.
• 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.
• Radioactivity is measured in Becquerel (SI unit) or in Curie. The unit Sievert measures the quantity of radiation absorbed by human tissues.

Hence only statement 1st is correct.