[en] The investigations into the radionuclide effluents as a result of the Chernobyl accident are briefly reviewed. Three ways for the estimation of the effluent are treated: the direct studies of the radioisotopes from the destroyed block; the research on the amount and composition of the radionuclides on the territory after active phase of the accident; study of the amount and composition of the radionuclides remained in the 4 block. All three ways have serious problems that are viewed in the work. New data are given in the review. They concern estimation of the fuel particles, ¹³⁷Cs, ¹³¹I effluent