Monitoring the radioactivity in the environment is essential for the preservation of health and the environment. Modern techniques enable the development of faster and simpler methods, which significantly contribute to reducing environmental pollution while also providing much quicker answers to questions about whether the impact of radioactive radiation is significant at a given moment. The research is focused on developing new methods for detection of radionuclides (uranij, torij, radij) using ICP-MS technique and comparison with radiometric techniques that are routinely used. Special attention will be given to the determination of radionuclide Ra-226, initially in drinking water by developing a rapid and suitable separation method coupled by ICP-MS detection and quantification. Following the development of a method for the determination of target radionuclides in water samples, the method will be further adopted for determination in human milk and in milk powders intended for consumption by infants. This should lead to new findings and more accurate radionuclide determination as well as more precise dose estimation for the most sensitive part of human population like infants. The knowledge gained from this plan will lead to new and state-of-the-art determination methods and will provide the powerful tool for contemporary research in this specific field.