Tritium Levels in Leachates and Condensates from Domestic Wastes in Landfill Sites

An extensive review study of leachate composition, from landfills which have received mainly domestic wastes in the UK, has been carried out by Aspinwall & Company on behalf of the Department of the Environment. This work has provided detailed information on concentrations of a wide range of determinands. One set of analyses which has produced particularly interesting results comprises the determination of tritium. Tritium is a natural isotope of hydrogen (³H), with a half-life of 12.43 years, which decays radioactively to form stable ³He atoms, releasing beta particles. Although tritium concentrations can be measured accurately as tritium units (TU), these represent extremely low levels of activity, and concentrations of tritium well in excess of 100 000 TU would be needed before acceptable levels of radio-activity in drinking water were exceeded.
Background levels of tritium in UK rainfall rarely now exceed 50 TU although, in the 1960s, values of up to 3000 TU in rainfall were associated with atmospheric testing of atomic weapons. It was somewhat surprising, therefore, to discover that relatively high concentrations of tritium (>10 000 TU) were widespread in leachates from landfills which had received primarily domestic wastes. This paper presents results from samples taken at 30 representative UK sites, and discusses potential sources of tritium.