Radioactive particles in water can derive from a variety of sources, including natural decay of minerals in the earth, nuclear power plants and nuclear weapons testing. Radioactive particles in water can pose a significant health risk if consumed, as they can cause damage to DNA and increase the risk of cancers. Commonly known radioactive particles found in water sources include radon, uranium and radium, making it important to regularly test drinking water sources for these contaminants and take appropriate measures to remove them if consumed.