ConSEPT has been developed by the BGS to provide initial screening of potentially contaminated sites within a GIS environment. This is primarily to help Local Authorities meet the requirements of Part IIA (Contaminated Land) of the Environmental Protection Act 1990 in terms of prioritising potentially contaminated sites. ConSEPT provides a GIS site-screening tool that:
The benefit of using an integrated GIS system lies in the automation of the process, particularly the spatial linkage, which paper or spreadsheet products require to be manually entered.
The GIS tool generates a report document for each site as required, listing the sources, receptors and pathways identified for each site, along with the scoring. The scores thus obtained can also be mapped for an area of interest, to establish where high priority sites occur within an area of responsibility.
The model is based around the pollutant linkage concept:
Clarke Avenue, Loscoe, Derbyshire, April 1986
Three of the occupants were seriously injured. It was the UK’s worst landfill gas explosion.
The source, pathway, receptor linkage here was: Putrescible matter in the landfill site (source) escaped as gas and migrated up through the porous soil and rock matrix (pathway). It accumulated inside the house on Clarke Ave, causing it to explode (receptor).
This explosion could have been avoided had an assessment been carried out at the site, the potential linkage identified and either the source, pathway or receptor removed.
Characterisation of sources, pathways and receptors requires
All of these are incorporated in the GIS to bring together a wide range data for a large number of potential sources, pathways and receptors for a required area.
The method adopted by ConSEPT to evaluate datasets is based loosely on the Canadian National Classification System for Contaminated Sites, 1992.
Scores are assigned to evaluation factors using a set of scoring criteria which interrogates the data by
Each evaluation factor can be weighted to suit the unique conditions prevalent in an area, or to satisfy specific concerns (e.g. emphasis on human receptors) or to allow for gaps in the data.
These can then be combined to give source scores, pathway scores and receptor scores.
ConSEPT combines these to give pollutant linkage scores, which estimate the likely risk of pollutant linkage as realistically as possible.
Dialogue with users has helped with identification of operational requirements and useful features to assist in achieving the above objectives and in individual reporting of the results of assessment. These include:
The ConSEPT module is available for ArcGIS 9 and MapInfo.
For more information please contact:
BGS Central Enquiries
British Geological Survey