Definition of a Phase One Audit

The Phase 1 Audit is a desktop study of historic and current information sources to indicate whether a site is contaminated or not and, if so, the potential for the contamination to spread.

The information gathered in the Phase 1 Audit is used to build a conceptual model of the site and set objectives for intrusive site investigations, when required. Code of Practice – BS 10175 states that a conceptual model should be developed for any contaminated site.

Phase 1 Audits look at a broad range of information including historic uses, the topography and geology and the hydrogeology and hydrology regime (to identify potential water pollutants and their distribution paths).

The Phase 1 Audit includes consideration of the following:

  • Site history
  • Mine workings
  • Flooding potential
  • Environment agency published registers
  • Typical features of contaminative uses
  • Geology, hydrogeology and hydrology
  • Radon
  • Local authority records
  • Other published information

Audit Outcome

The results of the Phase 1 Audit are presented as a conceptual model which is a reliable representation of the environmental processes on a site and its vicinity.

The conceptual model comprises a set of written descriptions supported by quantitative and qualitative information which may include maps, borehole records, and cross sections.

The conceptual model is used to guide further investigation, interpret results, monitor changes and communicate results to stakeholders

What prompts a Phase One Audit?

The regulations covering contaminated land and the responsibilities of the government, local authorities, landowners, occupiers and other interested parties are set out in the Environmental Protection Act Part 1995 IIA.

However, contaminated land is also featured in over 160 other acts and statutory instruments covering Great Britain and Northern Ireland so the picture is far from simple.

The Act states that every local authority “shall cause its area to be inspected from time to time for the purpose of

  • identifying contaminated land; and
  • enabling the authority to decide whether such land is land which is required to be designated as a special site.”

Authorities then have a duty of serving remediation notices on responsible parties specifying what action has to be taken and at what time to clean up the site.

The act does not specify what “from time to time” means and there are many provisos on who is deemed a responsible party and when notices can be served.