Removal of plutonium from drinking water by community water treatment facilities

Plutonium removal factors (RF) averaged 14+-10 during a study of the effectiveness of three drinking-water treatment plants for removing plutonium from Savannah River water. Plutonium concentrations between 0.1 and 3.5 fCi/1 were measured in raw and finished water samples. From 50 to 10000 litre samples of water were concentrated by ion exchange techniques and processed to determine the concentrations of plutonium-239, 240 and to derive plutonium RFs. The similarity between RFs observed for both plutonium and suspended solids suggests a colloidal behaviour for plutonium. Flocculation and filtration appear to be the primary factors in the water treatment process contributing to plutonium removal. The similarity between the plutonium contents of finished water from treatment facilities upstream and downstream of the Savannah River Plant (SRP) indicates that there is no measurable dose-to-man from SRP plutonium releases in the water. The 70-year bone dose commitment to an individual from consumption for one year of 1.65 litres per day of treated Savannah River water, based on the plutonium concentrations of finished waters from the three treatment facilities, is 5X10-5mrem. (author)