BGS is the UK’s leading organisation for groundwater dating and tracing. We use a wide range of environmental agents for this work including CFCs, SF6, tritium, radiocarbon and stable isotopes.
Equipment and capabilities
- Two Agilent Gas Chromatographs fitted with electron capture detectors (GC–ECD) fitted with bespoke purge and trap systems (P&T) for analysis of groundwater residence time indicators CFC–11, CFC–12, Sulphur Hexafluoride (SF6) and Halon 1301
- Agilent Gas Chromatograph fitted with Thermal Conductivity Detector (GC–TCD) and Flame Ionisation Detector (GC–FID) for simultaneous measurement of CH4 and CO2 in groundwaters
- Agilent Gas Chromatograph fitted with electron capture detector for measurement of N2O in surface and groundwaters
- Pfeiffer PrismaPlus Quadrupole Mass Spectrometer for measurement of Noble Gases He, Ne, Kr and Xe in waters
Some of our recent work includes:
- investigating residence time distribution in Chalk catchments
- using age indicators to aid water supply operational planning
- assessing the extent of induced leakage to urban aquifers
- identifying basin-scale groundwater quality trends
- understanding groundwater resources in Africa and South Asia
- evaluating the effects of large-scale quarrying on groundwater movement
- delineating the occurrence of pristine ice-age groundwaters in the UK
Why is the age of groundwater important?
There are various reasons why it can be important to know the age of groundwater in a particular aquifer. For example: does age validate the hydrogeological concept? Is the water a mixture of different ages? Is the water sustainable or being ‘mined’? Did the water recharge in pre-industrial times? Was the water recharged during the ice age, i.e. under different climatic conditions?
Which constituents can be used to date groundwater?
Some groundwater dating agents, for example radiocarbon (14C) are produced naturally in the environment and are suitable for dating waters many thousands of years old. Others, such as the chlorofluorocarbons (CFCs), are the result of artificial inputs to the environment and are best suited to dating young groundwaters. In some cases such anthropogenic compounds can also be used to trace groundwater flowpaths.
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The Inorganic geochemistry facility provides high quality analytical expertise and specialist services for the production and geochemical interpretation of inorganic data for BGS projects, and for commercial, university and public sector clients around the world.