Determination of plutonium-239/240 in fish in Low-Level Radioactive Ocean Waste dump sites

There was concern that radioactivity might find its way into the food chain, namely fish, via low-level radioactive waste Ocean Dump Sites. This led the U.S. Food and Drug Administration, in collaboration with other Federal Agencies, to the monitoring and determination of radioactivity in fish samples from these Ocean Dump Sites. The radionuclide thought to be of major concern was plutonium-239/240. These sites were monitored at various periods from 1980. The sites were located off the coasts of New Jersey, California (near San Francisco) and Massachusetts Bay. The fish samples selected were shellfish that inhabited the ocean floor and bottom-feeders. The levels of activities required sophisticated measuring techniques since for plutonium-239/240, they were below the range. After a radiochemical procedure is used to separate the plutonium, it was measured using solid-state silicon detectors. These are coupled to a computer based multi-channel analyzer system. A plutonium-236 tracer is used to measure the recovery. The levels were found to be at background or in the 10 mBq range. (author). 10 refs., 2 tabs