Generic quantitative risk assessment

Our contaminated land teams across the country offer specialist advice and assessment, including quantitative risk assessment, to develop the generic assessment undertaken during the Phase 2 investigation and to better understand the potential impact of contamination on human health and the environment. A generic quantitative risk assessment (GQRA) is a stage of land contamination risk assessment that uses generic assessment criteria (GAC) and associated assumptions to evaluate the potential risks to receptors (such as humans, animals, plants, water, etc.) from contaminants in the soil or groundwater. A GQRA is usually completed following the Phase 2 ground investigation and before a detailed quantitative risk assessment (DQRA), which uses site-specific data and models to refine the risk estimates.

RSK Geosciences Services - contaminated land - featured image

Detailed quantitative risk assessment (DQRA)

Our quantitative risk assessment specialists have extensive experience in completing DQRAs for controlled waters, human health, ground gas and vapours using the current UK and international models and software. If potential contaminant linkages are identified following the GQRA as part of the intrusive investigation, we offer two options: remediating all or parts of the site to break the linkage(s) or undertaking a DQRA to refine the GAC. The DQRA aims to reduce conservatism and to derive site-specific assessment criteria. Carrying out a DQRA is often cost-effective in the longer term, compared to the added value it provides by potentially demonstrating a reduced requirement to remediate a site and often justifying that a site is suitable for use and does not pose an unacceptable risk to the wider environment and associated receptors. Our teams can undertake modelling of hydrogeological flow to investigate the potential dispersal of contamination within complex aquifer scenarios, including plume modelling assessment with regard to Part 2A sites to determine whether clean-up of land is undertaken using regulatory powers or this action can be avoided.

Human health

We offer DQRAs for sites where the GQRA has identified exceedances of soil assessment criteria or where asbestos in soil has been identified. We have extensive experience in using the Environment Agency’s contaminated land exposure assessment (CLEA) model and BP RISC and RBCA tools. For contaminants such as arsenic, lead and cadmium, we can undertake a DQRA using laboratory bioaccessibility test data. This is particularly relevant in areas of the UK where there is naturally occurring arsenic, nickel and lead. Refining soil assessment criteria to be more site specific can negate or reduce the need for remediation, leading to a more sustainable and cost-effective outcome.

Controlled waters

Our team undertakes DQRAs for controlled waters relating to surface water, groundwater, drinking water supplies, sustainable drainage systems and environmental permit discharge consents. Through deriving remedial targets, using data collected during an intrusive investigation, we can advise a client of their potential liabilities. Should a DQRA be required, we can develop the most appropriate remedial site strategy. Our specialists can also assess sites with non-aqueous phase impact and develop appropriate remediation and remedial targets. Our staff have extensive experience in using the Environment Agency’s remedial targets methodology, together with other remediation models and assessment techniques.

Ground gas assessments

During the development of new build houses, local planning authorities and future house buyers need to be assured that the development is safe from any ground gas risks. For that reason, the understanding and assessment of ground gas, together with the independent verification of gas protection systems, are required to be signed off by regulators for the protection of human health. During the construction phase, there is a great potential for ground gases to cause serious harm in the form of intoxication and explosion. When a site is high risk, we undertake verification of gas membranes using techniques including air lance and dielectric testing. These methods are highly efficient; they cover a large area in a relatively short time and pinpoint defects in membrane integrity.

Asbestos in soil

Asbestos continues to be a challenging contaminant frequently identified on brownfield sites as a legacy of our industrial history. We specialise in advising clients about the risks posed by asbestos during the development of such sites and the mitigation measures that can be put in place to minimise the health impacts to contractors and site end-users. Our expertise in understanding legislation, health and safety procedures and risk assessment allows us to offer a wide range of services throughout the life cycle of a development project, from the initial desk study assessment through intrusive investigation and into the earthworks and remediation phases via our wealth of experience and collaboration with other disciplines in the RSK Group, such as the asbestos and waste teams.

We offer training courses via our asbestos specialists in asbestos awareness for groundworks, focusing on key legislation, current UK guidance and project case studies with particular emphasis on high-profile asbestos-impacted sites, such as an intrusive investigation on a former asbestos factory in the north of England and the remediation of a former mill site impacted by licensable asbestos for a fire training facility.

Other geoenvironmental services

RSK collage one
RSK collage two
RSK collage three
RSK collage four
RSK collage five
RSK collage six

RSK Geosciences is part of the RSK group of companies

The RSK group is a leading integrated environmental, engineering and technical services business offering bespoke end-to-end solutions to a variety of sectors. Headquartered in the UK but with an established presence throughout Europe, Africa, the Middle East, Asia and Australia, RSK helps organisations around the world achieve their business aspirations in a sustainable and efficient manner.