METHOD FOR DERIVING SITE-SPECIFIC HUMAN HEALTH ASSESSMENT
CRITERIA FOR CONTAMINANTS IN SOIL
PROJECT REF. LQ01
EXECUTIVE SUMMARY
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 paperand 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 nonstandard 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 sitespecific 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.
SNIFFER identifies and manages environmental research on behalf of members and stakeholders
For further information visit www.sniffer.org.uk
The method must not be used:

Where a Soil Guideline Value is available and is appropriate to the
circumstances under consideration.

Where the circumstances under consideration are represented by the CLEA
2002 software or any future replacements.

To generate generic assessment criteria.

Where the site circumstances and limitations of the method make it
inappropriate for use.

The method does not generate Soil Guideline Values. This can only be done
by the appropriate authoritative bodies in the UK, namely Defra and the
Environment Agency.
KEY WORDS
risk, soil, contaminant, human health, chronic exposure, Site-Specific Assessment
Criteria, ingestion, vegetable consumption, inhalation, bioaccessibility, contaminated
land, risk assessment, risk management
© SNIFFER 2003
All rights reserved. No part of this document may be reproduced, stored in a
retrieval system, or transmitted, in any form or by any means, electronic, mechanical,
photocopying, recording or otherwise without the prior permission of SNIFFER.
SNIFFER identifies and manages environmental research on behalf of members and stakeholders
For further information visit www.sniffer.org.uk