[en] The concentrations of transuranic elements in the environment are usually extremely low. There is a need to measure actinides in water samples with lower and lower detection limits, requiring larger volume samples. A procedure is developed to provide pre-concentration and determination of actinides in large volume surface water samples. MnO₂/Fe(OH)₃ precipitation is used to pre-concentrate the actinides from model samples of drinking water and sample of leachate of soil. Pre-concentration techniques must be used to allow the sample to be presented to the extraction column in a sufficiently small volume. Plutonium and americium in a small volume of nitric acid are loaded onto extraction chromatography column, TRU Resin (Eichrom Technologies). TRU Resin has become a standard reagent in the radiochemical analysis of actinides worldwide by simplifying analysis, reducing the volumes of acid used and eliminating the need for hazardous organic extractants. Small, selective extraction column do not generate large volumes of liquid waste. The tracers Pu-242 and Am-243 are used to measure chemical yields. Americium and plutonium are co-precipitated on neodymium fluoride and determined by alpha-particle spectrometer (authors)