Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The National Water Quality Laboratory (NWQL) of the U.S. Geological Survey (USGS) has contracted with the Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, for the analysis of low-level tritium (3 H), total dissolved helium (He), total dissolved neon (Ne), and the helium-3/helium-4 isotope ratio (3 He/4 He) of dissolved helium for purposes of groundwater dating based on the tritium/helium-3 (3 H/3 He) method. The 3 H/3 He dating method can be used to date waters recharged within approximately the past 30 years and complements existing capabilities within the U.S. Geological Survey for age-dating young ground-water, such as by use of chlorofluorocarbons (see joint Offices of Water Quality and Ground Water Technical Memorandum No. 95.02, dated December 29, 1994).
Public Domain.
The National Water Quality Laboratory (NWQL) of the U.S.
The National Water Quality Laboratory (NWQL) of the U.S.
The National Water Quality Laboratory (NWQL) of the U.S.
The National Water Quality Laboratory (NWQL) of the U.S.