of the residence times within the basin, sinks (radioactive decay) or sources of tritium, and the input function. For the Ohio River, the tritium data indicated that about 40% of the flow was composed of precipitation with residence times of less than one year (in the Ohio basin) and older waters consisted of residence times of about ten years. Thus, the short residence times (less than one year) corresponded to the "prompt-flow" component of the two-member mixing model. As for the Missouri River, results indicated that residence times were approximately four years with the prompt-flow component being around 10% (these results are due to the series of dams in the area of the Missouri River). As for the mass flux of tritium through the main stem of the Mississippi River into the Gulf of Mexico, data indicated that approximately 780 grams of tritium has flowed out of the River and into the Gulf between 1961 and 1997, an average of 7.7 PBq/yr. And current fluxes through the Mississippi River are about 1 to 2 grams per year as opposed to the pre-bomb period fluxes of roughly 0.4 grams per year. See also Hypertriton List of elements facing shortage Footnotes References External links Isotopes of hydrogen Environmental isotopes Radiochemistry Radioisotope fuels Nuclear fusion fuels Radionuclides used in radiometric dating