Phosphogypsum disposal in the lower Mississippi River: a point source of radium

Approximately 4500 tons per day of phosphogypsum, a by-product formed during the production of phosphate fertilizer, contaminated with trace amounts of radium has been disposed of in the lower Mississippi River at Taft, Louisiana since April 1965. Permits for disposal of an additional 32,000 tons per day are being pursued by the phosphate-fertilizer industry. This activity represents a significant point source of enhanced radium (and other uranium series radionuclides). This paper presents the impact of the phosphogypsum disposal on radium in the lower Mississippi River and near-shore mixing zone of the Gulf of Mexico