Environmental tracers are natural or man-made compounds or isotopes that can be used to identify mechanisms and quantify timescales of environmental processes. They include radionuclides such as 14C, tritium, 39Ar, 4He and 36Cl, stable isotopes such as δ18O and δ2H, and man-made compounds such as chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6). Releases of man-made tracers include catastrophic events such as nuclear bomb tests and gradual leakage from industrial processes.
Tracers have a wide range of applications in the environmental geosciences and have been used in BGS particularly in studies of groundwater flow and residence time.
The application of man-made tracers for dating groundwater less than 100 years old.