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
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.
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 64 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.
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)
The aim of the approach is to have a common framework that can scale to any number of activities that might take place prior, pre, during or post development. The key aims are to have a stepwise approach to enable effective screening of potential areas of concern; encourage appropriate and sufficient data collection and site investigation to support robust decision making; facilitate timely identification and understanding of risky activities and identify the point where mitigation and further Quantitative Risk Assessment is necessary to protect vulnerable on and off site receptors.
This protocol provides a draft outline of a potential activity-based sampling approach for the testing of asbestos fibre release potential from residential garden soil as part of a staged investigation strategy for land being investigated under Part 2A of the Environmental Protection Act 1990. The primary objective of the Activity-Based Sampling (ABS) protocol is to provide a reasonable worst-case estimate of current and future fibre-release and subsequent localised airborne fibre concentrations that might be possible as a result of soil disturbance.
The aim is to obtain robust activity-based dust generation data to be able to risk-rank different remediation, earthwork and construction activities, and better understand potential fugitive environmental emissions and employee exposures. This protocol is designed to provide a monitoring method by which different activities involving earthworks at brownfield sites can be monitored in a consistent way and the data from each monitoring exercise collated to inform the potential for dust release and the subsequent risk ranking of those activities.
This discussion paper presents a decision algorithm for asbestos cement fragments in residential garden soil designed to support a staged investigation strategy for land being investigated under Part 2A of the Environmental Protection Act 1990.