This section contains notes issued by Defra which will be of interest to those involved with contaminated land in both public and private sectors.

The files listed below are published in Adobe Acrobat Portable Document Format (PDF).

CLAN 1/02: Withdrawal of ICRCL Guidance Note 59/83 (2ND Edition) (15 KB)

CLAN 2/02: Contaminated Land Supplementary Credit Approvals 2003-04 (45 KB)

CLAN 3/02: Withdrawal of ICRCL Trigger Values (30 KB)

CLAN 1/03: An introduction to CLARINET (30 KB)

CLAN 1/04: 2004/05 Capital Programme Guidance Note (60 KB)

CLAN 2/04: Defra questionnaire on progress with land contamination - summer 2003 (10 KB)

CLAN 3/04: Section 86 of the Water Act 2003 (10 KB)

CLAN 4/04: Contamination of Agricultural Land & Part IIA of the EPA 1990 (52 KB)

CLAN 5/04: Ground waters & section 86 of the Water Act (10 KB)

CLAN 6/04: Update on the Soil Guideline Values Taskforce (16 KB)

CLAN 1/05: 2005/06 Capital Programme Guidance Note (57 KB)

CLAN 2/05: New advice on SGVs (24 KB)

CLAN 1/06: 2006/07 Capital Programme Guidance Note (209 KB)

CLAN 2/06 Best Value Performance Indicators (BVPI) Q&A (122 KB)

CLAN 3/06: Soil Guideline Values Taskforce (26 KB)

CLAN 4/06: Defra update on SGVs (24 KB)

CLAN 5/06: Extension of Part 2A to radioactivity (88 KB)

CLAN 6/06: Soil Guideline Values: the Way Forward (619 KB)

Soil Guideline Values (SGV) and supporting technical guidance are intended to assist professionals in the assessment of long-term risk to health from human exposure to chemical contamination in soil.

There are different SGVs according to land-use (residential, allotments, commercial) because people use land differently and this effects who and how people may be exposed to soil contamination.

SGV are 'trigger values' for screening-out low risk areas of land contamination. They give an indication of representative average levels of chemicals in soil below which the long-term health risks are likely to be minimal. Exceeding an SGV does not mean that remediation is always necessary, although in many cases some further investigation and evaluation of the risk will be carried out.

SGV should not be used where they are not representative of the site under investigation. They do not assess other types of risk to human health such as fire, suffocation, explosion, or short-term and acute exposures. They also cannot be used to assess risks to controlled waters, property, pets and livestock, or ecological receptors.

SGV are available only for a limited number of chemical substances. However, the framework reports and software provide a starting point for the assessment of a much wider range of chemicals.

Professionals and regulators assessing risks to health from land contamination are not required to use SGV and the supporting technical guidance. Alternative approaches can be used provided that they satisfy the legislative requirements.

Framework Reports

The principles and method used to derive SGV is described in two main framework reports:

• Human health toxicological assessment of contaminants in soil (Science Report Final SC050021/SR2) (PDF, 718KB)
  This report describes the technical principles and framework the EA use to derive Health Criteria Values.
• Updated technical background to the CLEA model (Science Report Final SC050021/SR3) (PDF, 1.60MB)
  This report describes the technical background to the CLEA model. It also sets out the underlying assumptions that the EA have made to predict exposure for three standard land use scenarios (residential, allotments and commercial).

Professionals should be familiar with the information in these reports before using SGV in site assessments.

SGV and TOX Reports

The EA published SGV Reports and TOX Reports for a small number of soil contaminants. TOX Reports describe the toxicology of specific chemicals or groups of related chemicals including a summary of expert group evaluations. They also set out the recommended health criteria values (HCV) used in SGV derivation.

SGV Reports discuss the available evidence for the presence of specific chemicals in soil and their fate and transport in soil systems. In addition to the SGV themselves, the SGV Reports contain other useful information to assist risk assessors.

• Published SGVs are available here
• TOX Reports for SGV derivation (INFO-RA2-2d)

CLEA Software

The EA published the calculations for deriving SGV as described in the framework reports as a spreadsheet for use by professionals in conjunction with the wider guidance. The CLEA software is written using Microsoft Excel and uses VBA macros to support functionality. In addition, a specific spreadsheet has been published to support the assessment of dioxins in soil.

• CLEA software v 1.071
• CLEA software v 1.06
• CLEA Licence Agreement
• CLEA handbook v 1.05

  The CLEA software version 1.05 handbook is still relevant to version 1.06 and 1.071 and has not been changed.

FAQs

The Environment Agency compiled a list of the most frequently asked questions (PDF, 121KB).

SGV Reports and supplementary information for specific chemicals and groups of chemicals are available for download below.

It is recommended that professionals using SGV Reports are familiar with the information in the framework reports (see below). SGV Reports published before 2009 have been withdrawn. They were prepared using previous framework guidance (R&D Publications CLR7 – 10) published in 2002, which have been superseded.

Introduction to Soil Guideline Values

• Human health toxicological assessment of contaminants in soil (Science Report Final SC050021/SR2) (PDF, 718KB)
  This report describes the technical principles and framework the EA use to derive Health Criteria Values.
• Updated technical background to the CLEA model (Science Report Final SC050021/SR3) (PDF, 1.60MB)
  This report describes the technical background to the CLEA model. It also sets out the underlying assumptions that the EA have made to predict exposure for three standard land use scenarios (residential, allotments and commercial).

Heavy metals and other inorganic compounds

• Soil Guideline Value for arsenic in soil (PDF, 385 KB)
• Soil Guideline Value for nickel in soil (PDF, 139 KB) This report has been withdrawn
• Soil Guideline Value for mercury in soil (PDF, 220 KB) This report has been withdrawn
• Soil Guideline Values for selenium in soil (PDF, 150 KB)
• Soil Guideline Values for cadmium in soil (PDF, 188 KB)

BTEX

• Soil Guideline Value for benzene in soil (PDF, 365KB)
• Soil Guideline Value for toluene in soil (PDF, 437KB)
• Soil Guideline Value for ethylbenzene in soil (PDF, 363KB)
• Soil Guideline Value for xylene in soil (PDF, 740KB)

Dioxins

• Soil Guideline Value for dioxins, furans and dioxin-like PCBs in soil (PDF, 372 KB)

Other organic compounds

• Soil Guideline Values for phenol in soil (PDF, 206 KB)

Supplementary information for the derivation of SGVs

Heavy metals and other inorganic compounds

• Supplementary information for the derivation of SGVs for arsenic (PDF, 2.33 MB)
• Supplementary information for the derivation of SGVs for nickel (PDF, 2.4 MB) This report has been withdrawn
• Supplementary information for the derivation of SGVs for mercury (PDF, 2.41 MB) This report has been withdrawn
• Supplementary information for the derivation of SGVs for selenium (PDF, 2.36 MB)
• Supplementary information for the derivation of SGVs for cadmium (PDF, 2.39 MB)

BTEX

• Supplementary information for the derivation of SGVs for benzene (PDF, 2.32 MB)
• Supplementary information for the derivation of SGVs for toluene (PDF, 2.32 MB)
• Supplementary information for the derivation of SGVs for ethylbenzene (PDF, 1.03MB)
• Supplementary information for the derivation of SGVs for xylene (PDF, 2.35 MB)

Dioxins

• Supplementary information for the derivation of SGVs for dioxins, furans and dioxin-like PCBs (PDF, 2.47MB)

Other organic compounds

• Supplementary information for the derivation of SGVs for phenol (PDF, 2.34 MB)