Exposure to contaminated land and human health: a CL:AIRE report
ROB REUTER
ECB Bulletin January 2010
ECB Bulletin January 2010
CL:AIRE [Contaminated Land: Applications in Real Environments] is an independent, not-for-profit organisation which has been established to stimulate the regeneration of contaminated land in the UK by the application of practical sustainable remediation technologies. In December 2009, CL:AIRE published a report – The Soil Generic Assessment Criteria for Human Health Risk Assessment – which is intended as an aid in the assessment of risk to human health from exposure to contaminated land.
In order to attempt to quantify the concentration of a contaminant that may represent a risk to human health, there is a need to understand the toxicological and physico-chemical properties of the substance. These properties can then be used within a mathematical model to estimate exposure to receptors and the likely significance of the exposure with respect to human health.
To help assessors in determining whether the degree of contamination at a site is a risk to human health, the Environment Agency (EA) has developed an updated version of the Contaminated Land Exposure Assessment (CLEA) model and background guidance. The EA has also published a compilation of physico-chemical data for priority organic pollutants (SR7) and toxicology reports on specific contaminant, which allow the CLEA model to be used to create Generic Assessment Criteria (GAC). GAC derived by the EA, and published after a review by various government departments, are called Soil Guideline Values (SGV), which, when applied correctly, represent a level below which there is considered to be a minimal risk to human health from long-term exposure to the soil.
The use of SGV as screening values is extremely useful in initial assessments of potentially contaminated sites, and can help to screen out individual contaminants or even entire sites from more complex detailed quantitative risk assessment. However, historically, the EA has been slow to produce SGV and the baseline data on toxicological and physico-chemical parameters. These data are required in order to use the CLEA model to produce GAC or more site specific assessment criteria (SSAC). In the past this has led to many organisations deriving their own database of input parameters and GAC values resulting in a myriad of values and duplicated effort across organisations.
In late 2008, members of the Environmental Industries Commission (EIC) Contaminated Land Working Group agreed to collaborate to help fill this gap by producing a set of industry-agreed input parameters and GAC values for as many substances as possible. Member organisations were asked to provide professional staff with experience in risk assessment of contaminated land, and the AGS (Association of Geochemical & Geoenvironmental Specialists) and CL:AIRE also joined the project. Forty-seven professionals from twenty-six companies collaborated.
Toxicological and physico-chemical data on 44 contaminants were compiled and assessed. GAC for four standard generic land uses (residential with and without consumption of home-grown produce, allotments and commercial) and three soil organic matter contents (1%, 2.5% and 6%) were then computed for 35 of these substances using the CLEA (v1.06) model..
The final report is the culmination of hundreds of hours of work by experts from the twenty-six companies, and is available for free from the CL:AIRE website (http://www.claire.co.uk/). An Excel spreadsheet containing all of the input parameters required for the CLEA (v1.06) model can also be downloaded.
It is hoped that the GAC values and input parameters produced by this study will be used by all involved in the assessment of contaminated land. The best reward for all those who worked on the project will be for the contaminated land community to regularly use the GAC values for the assessment of risk to human health from exposure to contaminated land.
ROB REUTER
Wardell Armstrong LLP
Thynne Court, Thynne Street
West Bromwich
West Midlands B70 6PH
http://www.wardell-armstrong.com
rreuter@wardell-armstrong.com
December 2009
To help assessors in determining whether the degree of contamination at a site is a risk to human health, the Environment Agency (EA) has developed an updated version of the Contaminated Land Exposure Assessment (CLEA) model and background guidance. The EA has also published a compilation of physico-chemical data for priority organic pollutants (SR7) and toxicology reports on specific contaminant, which allow the CLEA model to be used to create Generic Assessment Criteria (GAC). GAC derived by the EA, and published after a review by various government departments, are called Soil Guideline Values (SGV), which, when applied correctly, represent a level below which there is considered to be a minimal risk to human health from long-term exposure to the soil.
The use of SGV as screening values is extremely useful in initial assessments of potentially contaminated sites, and can help to screen out individual contaminants or even entire sites from more complex detailed quantitative risk assessment. However, historically, the EA has been slow to produce SGV and the baseline data on toxicological and physico-chemical parameters. These data are required in order to use the CLEA model to produce GAC or more site specific assessment criteria (SSAC). In the past this has led to many organisations deriving their own database of input parameters and GAC values resulting in a myriad of values and duplicated effort across organisations.
In late 2008, members of the Environmental Industries Commission (EIC) Contaminated Land Working Group agreed to collaborate to help fill this gap by producing a set of industry-agreed input parameters and GAC values for as many substances as possible. Member organisations were asked to provide professional staff with experience in risk assessment of contaminated land, and the AGS (Association of Geochemical & Geoenvironmental Specialists) and CL:AIRE also joined the project. Forty-seven professionals from twenty-six companies collaborated.
Toxicological and physico-chemical data on 44 contaminants were compiled and assessed. GAC for four standard generic land uses (residential with and without consumption of home-grown produce, allotments and commercial) and three soil organic matter contents (1%, 2.5% and 6%) were then computed for 35 of these substances using the CLEA (v1.06) model..
The final report is the culmination of hundreds of hours of work by experts from the twenty-six companies, and is available for free from the CL:AIRE website (http://www.claire.co.uk/). An Excel spreadsheet containing all of the input parameters required for the CLEA (v1.06) model can also be downloaded.
It is hoped that the GAC values and input parameters produced by this study will be used by all involved in the assessment of contaminated land. The best reward for all those who worked on the project will be for the contaminated land community to regularly use the GAC values for the assessment of risk to human health from exposure to contaminated land.
ROB REUTER
Wardell Armstrong LLP
Thynne Court, Thynne Street
West Bromwich
West Midlands B70 6PH
http://www.wardell-armstrong.com
rreuter@wardell-armstrong.com
December 2009
