ATRISKsoil is an online database providing Soil Screening Values (SSVs) and Water Screening Values (WSVs) applicable to the UK for use in assessing chronic human health exposure to commonly occurring contaminants.
In 2002 the Department for Environment, Food and Rural Affairs (Defra) and the Environment Agency (EA) launched the CLEA (Contaminated Land Exposure Assessment) framework together with associated documentation and software (Contaminated Land Report (CLR) 9, CLR10, CLEA 2002 software) and a limited suite of Soil Guideline Values (SGVs) and associated toxicology reports. The framework was updated in 2002-2005 with the publication of CLEA Briefing Notes 1-4, additional SGV and toxicology reports, the CLEA handbook and CLEA UK sfotware. The CLEA 2002 software was withdrawn.
In 2008, the CLEA framework was revised and CLR9, CLR10, the SGVs and CLEA UK were withdrawn. They were replaced with draft versions of Science Report (SR) 2, SR3, SR4, SR7 and the CLEA v1.03 software. These documents were finalised in 2009 and a suite of SGVs and revised toxicology reports were released along with the CLEA v1.04 software. The CLEA v1.05 software was released later in 2009 to correct for lifetime exposure and was replaced shortly afterwards with v1.06 to correct for a password protection issue.
The SGVs have been derived according to three land uses and are applicable to long-term human exposure to soil contaminants. The three land uses are:
- Residential with the consumption of homegrown produce;
- Allotments; and
- Commercial.
To date, SGVs have been released for arsenic, cadmium, mercury (inorganic, elemental, methyl-), nickel, selenium, benzene, toluene, ethylbenzene, xylenes, phenol and dioxins, furans and dioxin-like PCBs for a sandy loam soil with a 6% soil organic matter (SOM). There is a requirement for further screening values so that a wider array of commonly encountered contaminants, both organic and inorganic, can be effectively assessed at a generic level for a wider range of land uses.
Soil Screening Values
Where SGVs are not available, Atkins has calculated SSVs. The SSVs have been derived using the CLEA software which follows the methodology laid out in SR2, SR3, SR4 and SR7. Two sets of SSVs have been derived; for a sandy loam soil with a 6% SOM and a sand soil with a 1% SOM.
Atkins has developed SSVs for the following land uses:
- Residential with the consumption of homegrown produce
- Residential without the consumption of homegrown produce
- Commercial
- Allotments (sandy loam and 6% SOM only)
- Parks
- Playing Fields (sandy loam and 6% SOM only) and
- Open spaces.
The SSVs can be applied to concentrations of contaminants identified in unsaturated soil. The SSVs are based on the CLEA framework and are, in general, considered to be based on Minimal Risk Levels. They may not meet the tests for unacceptable intake laid out within the Part 2A Statutory Guidance (Circular 01/2006).
Water Screening Values
Since the inception of the ATRISKsoil SSVs, Atkins has identified a requirement for human health WSVs for assessing the inhalation of vapours from shallow groundwater or perched water. WSVs have not been published by the Environment Agency to date. In the absence of such values, many use Drinking Water Standards which are based on oral toxicology, taste, colouration or smell rather than inhalation toxicology, or simply don’t assess groundwater or perched water. Atkins has therefore derived WSVs using the RBCA v2.5 software for the following land uses:
The WSVs can be applied to concentrations of contaminants identified in a shallow groundwater or perched water source and can provide a preliminary indication as to whether further assessment would be required.
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