Issue Date: 12th May 2019
SoBRA held a one-day workshop in June 2018 entitled on the Fine Tuning DQRA’s for the Water Environment. The objective was to identify common mistakes in controlled waters risk assessment and explore potential solutions. This report presents a written record of the discussions held during the Summer 2018 workshop.
Issue Date: 30th April 2019
This report presents a methodology for derivation of AGAC that risk assessors may choose to use to help in the assessment of acute health risks from short-term exposure to contaminants in soil. In the UK, the assessment of risks to humans from land contamination has traditionally tended to focus on chronic exposure scenarios. However, focusing on chronic exposure may not always be protective of potential acute exposure scenarios, especially in non-residential settings, and/or if statistical methods are used to interpret site soil data. The report was developed to address the absence of such guidance in order to support risk assessment practitioners and promote awareness within the contaminated land sector.
27 July 2020 Corrigendum : The authors of SoBRA’s AGAC report have discovered an error in the calculation of the AGACs for the vapour pathway for benzene (adult and child), phenol (child), trichloroethene (adult and child) and vinyl chloride (child). These had been incorrectly calculated due to use of log Koc rather than Koc in the calculation spreadsheets. A new version of the report (version 2) has been produced with these values corrected (the new AGAC are higher than before) which is available on the link below.
Issue Date: June 2018
In June 2018, the Society of Brownfield Risk Assessment (SoBRA), the Geological Society Contaminated Land Group and RemSoc delivered a conference targeted towards early careers learning. Its aims were:
A commitment of this workshop has been the creation of a series of short tabular reports for each of the different discipline areas. We have produced four practical tips documents which include human health risk assessment, controlled waters risk assessment, soil vapour intrusion and improving risk assessment – field to desk. The human health, controlled waters and field to desk documents have been updated in August 2024 (v2) to reflect current legislation and guidance. The vapour intrusion document is considered to be largely superseded by the SoBRA guidance notes 1A Conceptual site model development for assessment of VI contaminant linkages in the UK, 1B Benefits of soil vapour sampling for assessment of VI risks, and 1C VI data collection considerations.
Download Human Health Tips report v2
Download Controlled Waters Tips report v2
Download Soil Vapour Intrusion report v2
Download Improving Risk Assessment – Field to Desk Tips report v2
Issue Date: 8th June 2018
SoBRA held a workshop on uncertainty in human health risk assessment in June 2016. The objective of the workshop was to consider key issues associated with the CSM and site investigation for landfill sites. Delegates were asked to consider a wide range of issues to identify those representing accepted scientific understanding and/ or good practice, and those which require further work to extend, improve or clarify current understanding or practice.
Issue Date: 24th April 2018
SoBRA held a workshop on uncertainty in human health risk assessment in June 2015. The objectives of SoBRA’s summer 2015 workshop were to define the current state of our understanding of the key issues surrounding uncertainty in human health risk assessment and to establish where there is (and is not) consensus on mitigation measures
Issue Date: 6th March 2018
SoBRA held a workshop on vapour Intrusion to Support Sustainable Risk Based Decision Making June 2017. The workshops aims were to: provide high quality speakers who could outline the challenges faced for their topic area that affect the evaluation of the vapour intrusion pathway, including CSM, site investigation, modelling and installation of mitigation measures; and to break out into workshop groups to discuss issues pertaining to a topic area in more detail and identify how such issues might be resolved. The four topic areas were CSM, site investigation, development of alternative risk assessment techniques based on scientific studies and the evaluation of mitigation measures using quantitative risk assessment.
SoBRA 2017
Volatile constituents in groundwater have the potential to cause risk to human health via volatilisation and migration of vapours into overlying buildings or outdoor air space followed by inhalation. Where the conceptual site model identifies this contaminant linkage as being of possible concern it is usually necessary to assess the risks further in order to determine whether they are acceptable or not. One method that can be used is to compare measured concentrations of volatile constituents in groundwater with conservative generic assessment criteria (GAC) protective of human health via the inhalation of groundwater-derived vapours pathway. This helps the assessor determine the level of risk associated with this particular contaminant linkage. A working group of the Society of Brownfield Risk Assessment (SoBRA) has developed a methodology and derived GAC for 66 commonly analysed volatile constituents in groundwater. The methodology utilises the Environment Agency’s (England and Wales) CLEA model to estimate the average long-term concentration in shallow groundwater (the GAC) that would lead to tolerable/minimal risk to site occupants from vapour migration and inhalation in indoor and outdoor air from chronic exposure. Screening values have been derived for residential and commercial land-use scenarios. The generic screening values are intended to complement other screening methodologies (such as exclusion depths and distances) for assessing the groundwater vapour contaminant linkages.
The report was originally published in 2017 and has been updated in 2024 (V2.0) to take account of the publication of eight Category 4 Screening Levels (C4SLs). The groundwater vapour GAC have been updated with the input parameters used in the derivation of the C4SLs for:
cis-1,2-Dichloroethene
trans-1,2-Dichloroethene
1,2-Dichloroethane
Tetrachloroethene (PCE)
Naphthalene
Chloroethene (Vinyl Chloride (VC))
Benzene
Trichloroethene (TCE)
SoBRA 2016
This SoBRA funded project creates a new methodology for identifying local sources of contamination and relationships between historical urban development and groups of potentially toxic elements (PTEs) in urban soils. The Belfast Tellus data is used to create the methodology, which is then tested on Sheffield using GBASE data. Eleven PTEs are considered within this research; arsenic (As), cobalt (Co), chromium (Cr), copper (Cu), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), tin (Sn), vanadium (V) and zinc (Zn). These elements are expected to be related to different geogenic and anthropogenic sources within the study areas.
Rebekka McIlwaine, Siobhan Cox, Rory Doherty and Mark Cave (2016)
