Since the beginning of the National Methane Baseline Survey of UK Groundwaters in 2012, a total of 248 new groundwater methane (CH4) samples have been collected and analysed from five areas:
- South Wales
- East Midlands province
- Lancashire and Cheshire basins
- Cumbria and Northumberland
- southern England, comprising Kent, East and West Sussex, Surrey and Hampshire
A number of groundwater CH4 values also exist for other areas from previous research projects, in particular central and southern Scotland and parts of South Yorkshire, Nottinghamshire, Lincolnshire and areas around London. These datasets have been combined to provide a summary of CH4 concentrations in groundwater in these areas.
| Area | Concentration | (mg/l) | No. samples | |
|---|---|---|---|---|
| Minimum | Median | Maximum | ||
| Central/southern Scotland | <0.0001 | 0.0036 | 1.68 | 31 |
| Lancashire and Cheshire basins | 0.0002 | 0.0025 | 0.091 | 23 |
| East Midlands province | <0.00005 | 0.0009 | 1.32 | 93 |
| Southern England | <0.00005 | 0.0013 | 4.72 | 251 |
| South Wales | <0.0001 | 0.032 | 0.0483 | 25 |
| Cumbria and Northumberland | <0.0002 | 0.00065 | 1.434 | 16 |
| Cumbria (Environment Agency data) | <0.1 | <0.5 | 14.2 | 836 |
| Lancashire and Cheshire (Environment Agency data) | <0.01 | <0.5 | 132 | 2842 |
CH4 baseline samples have been collected from potable water supplies — either drinking water or groundwater-quality monitoring boreholes. None of the samples in the aquifers used for public water supply have exceeded the explosive limit for CH4. For additional information on research carried out by BGS on CH4in groundwater apart from baseline surveys, please go to our CH4 in UK groundwater research overview or access these key publications:
- The hydrogeochemistry of methane: evidence from English groundwaters
- The potential for methane emissions from groundwaters of the UK
CH4 in UK groundwater
Click on the regions on the map to see initial results from the survey. In addition to CH4 data, there is a regional overview of the geology, aquifers and shale-gas source rocks present. Areas with adequate CH4 data have been split by aquifer, in addition to a regional summary. Using data collected as part of the BGS and Environment Agency’s The natural (baseline) quality of groundwaters in England and Wales project, there is also a brief overview of the relevant aquifer’s groundwater quality. Further information on chemical indicators and trace elements that are not included in the summary can be found in the individual baseline reports.
Click on the regions on the map below to see results from the survey and more detail can be found in the summary report and recent publication.
Contact
Please contact BGS Enquiries (enquiries@bgs.ac.uk) for more information.