Use of radiotracers in the study of the distribution of manganese and zinc in the ultrafiltrate fractions of fresh waters

The use of ultrafiltration in the study of the distribution of metals in natural waters was aided by the use of radio-tracers to spike samples prior to ultrafiltration. The activity of the filtrate could then be assessed by gamma counting. Results obtained by gamma counting were compared with those from atomic absorption spectrometry. This indicated that the optimal time interval between spiking and ultrafiltration was 2 h. Studies with manganese and zinc suggested that sorption equilibria at the outer surface of natural colloids were the major processes responsible for radioisotope and trace metal distributions.