An analysis of the tritium content in fish from Upper Three Runs Creek

In November of 1988 the F/H-area effluent treatment facility (ETF) began releasing treated waste water to Upper Three Runs Creek. Previous to that time, there has been minimal discharge of plant waste water to this tributary of the Savannah River. The ETF is designed to remove the toxic and radioactive waste materials from the effluent stream and to meet the discharge limits of the South Carolina Department of Health and Environmental Control (SCDHEC). The only radioactive nuclide not removed by the process is tritium. Tritium, an isotope of hydrogen, is chemically associated with the water molecules in the waste stream and can not be economically removed at this time. The objective of this study was to determine the relationship between the concentration of tritium in the stream water and the concentration of tritium in the fish. Fish collections were made at two locations. The most upstream location was 50 meters downstream from the SRS Road C bridge. This is immediately downstream of the effluent discharge pipe from the ETF. The other location was at the bridge of SRS Road A (SC Highway 125). The water is removed from the fish by freeze drying under vacuum. This study suggests that, on the average, the tritium concentration of fish in Upper Three Runs Creek will be in equilibrium with the tritium in the water of the creek. The water in the fish comes into equilibrium with the water in the stream quite rapidly and it is quite likely that any single fish sampled will be higher or lower in tritium content of an integrated water sample, such as those collected by the Environmental Monitoring samplers. Both the time of sampling and the sampling of a sufficient number of fish is important in obtaining an accurate estimate of the average tritium concentration in the tissue water of the fish