April 2003


This report describes a method for deriving Site-Specific Assessment Criteria (SSAC) for use when considering the risk to human health from chronic exposure to heavy metals (except lead), metalloids and organic substances in soil. The assessment criteria represent contaminant concentrations in soils, which if exceeded may be indicative of unacceptable risks to human health. It is envisaged that the method can be used as a tool during either the detailed quantitative risk assessment or the risk management process.

The method can be used in two ways depending on whether or not the site under consideration matches a standard land use. For the defined standard land uses, default exposure factors and simplified formulae are provided in the form of paper- and spreadsheet-based worksheets. The user inputs site-specific and toxicological data into these worksheets in order to generate the SSAC.

The method can also be used to derive Site-Specific Assessment Criteria for non-standard land uses by using the full equations and exposure data contained in the report rather than a worksheet.

The method adopts the risk-based source-pathway-receptor pollutant linkage framework and a deterministic methodology. The exposure pathways considered are direct ingestion of soil and dust, consumption of homegrown or allotment vegetables, ingestion of soil attached to such vegetables, inhalation of soil vapours outdoors and inhalation of soil vapours indoors. A test for the significance of the dermal pathway is introduced. A sensitivity analysis of the method is also included in the report.

The method replaces and updates the first edition (SNIFFER 2000) to reflect the guidance in R&D Publications CLR 9 and CLR 10 (Defra and Environment Agency 2002a & 2002b), feedback of users and other developments in the field of human health risk estimation. It enables the risk assessor to incorporate the results of site-specific determinations of contaminant bioaccessibility or of Vegetable/Soil Concentration Factors.

The method should only be used by technical professionals who are familiar with assessing and managing risks to human health from land contamination but who are not necessarily experts in exposure modelling.

The method must not be used:


risk, soil, contaminant, human health, chronic exposure, Site-Specific Assessment Criteria, ingestion, vegetable consumption, inhalation, bioaccessibility, contaminated land, risk assessment, risk management

Copies of this report are available from the Foundation, price 50.00, less 20% to FWR members.

The report is available for download (5.47mb) from the Sniffer Website.