ABSTRACT
Many radionuclides are found in the environment in surface water, groundwater, and wastewater. The radionuclides are isotopes of elements that emit alpha and beta particles and gamma rays. The radioactivity measured in aqueous or solid samples can be expressed in units such as the activity per volume or mass. Instruments of several types are commercially available to detect and measure radiation. Such instruments include gas-flow proportional counters, scintillation counters, alpha spectrometers, and gamma spectrometers. Natural radioactive elements like uranium, thorium, and radium emanate alpha, beta, and gamma radiations producing a series of daughter elements that are also radioactive, ending with converting into stable nonradioactive elements. The gross alpha and the gross beta activities from natural and artificial radionuclides in samples can be measured by instruments such as the thin-window, heavily shielded, gas flow proportional counter, an internal proportional counter, and Geiger counter.
