Land contamination investigations can be triggered for reasons including the redevelopment of potentially contaminated land via the planning system, to invetigate a pollution incident or in cases of sites with specific environmental permitting site condition reporting, according to Vivien Dent, chair of the contaminated land working group of the Association of Geotechnical and Geoenvironmental Specialists (AGS).
In either case, the process follows a tiered approach to risk assessment (stage 1 risk assessment, comprising tiers 1-3), remediation options appraisal (stage 2) followed by remediation and verification (stage 3). The process starts at tier 1 with a desktop preliminary risk assessment study, in which the initial conceptual site model is developed. If that identifies that further assessment is required, site investigation is undertaken to collate data, often commencing with an exploratory investigation. To investigate potential pollutants identified in tier 1, a tier 2 generic quantitative risk assessment is undertaken, followed by a tier three detailed quantitative risk assessment, if required. Stage 1 informs a remediation options appraisal. The most suitable is developed in a remediation strategy that is submitted to the regulatory authorities (where required) for approval, and the scheme is implemented. Following that is a verification report and, if required, long-term monitoring and maintenance.
“The site might have historically been a factory or landfill, or there might have been a petrol filling station. Made ground frequently contains asbestos. There are all sorts of contamination sources. No two sites are the same,” observes Dent.
In October 2020, the Environment Agency withdrew its old guidance, the Model Procedures for the Management of Land Contamination (LCR11), which had been in place for years. It has been replaced by land contamination risk management guidance (LCRM), first published in 2019. In announcing the development, Phil Fitzgerald, Environment Agency advisor, land contamination management, water, land and biodiversity, called it a ‘major and much-needed update.’
Dent confirms that the new guidance, which has been moved online, uses the same process for managing land contamination as before. She has noticed two major areas of change between old and new: greater focus on personnel competence and sustainability.
The old standard hardly mentions ‘competence’ at all, and with little qualification or definition.
As Dent points out, the land contamination industry had moved on from there. In 2017, the voluntary National Quality Marking Scheme (NQMS) was brought in as a quality benchmark. This voluntary vetting process involves having reports checked by a ‘suitably qualified person’, an experienced professional in the field, to verify that facts and interpretations meet required standards. The Environment Agency, which now endorses this scheme in the new guidance, says elsewhere: “The scheme can provide increased confidence and ensure that the submitted reports are of the quality we expect.”
Asked whether this was an implicit criticism of the industry, Dent replies in the affirmative. “The quality of reports varies dramatically. If you follow the guidance, you should be producing quality reports. In my experience, there are lots of reasons why reports can be poor-quality; it might be an inadequate scope, the desk study might have been carried out before the site investigation, or the conceptual model is wrong.”
“The guidance is good; people just need to be trained and clients need to be educated in what they should expect from a contamination report. ”
Dent observes that the field of land remediation is still fairly new, has seen many changes, and is still professionalising. Dent recalls when she started in the industry in the 1990s soil contamination test results were measured against standard tables of numbers, until LCR11 brought in a contaminated land model that was risk-based and more scientific. Since then there has been better reporting, she observes.
Now, the EA guidance explicitly defines what it means by a competent person. Candidates for that title need to demonstrate relevant qualifications and experience, and membership of a relevant professional organisation. They could also be a suitably qualified person in NQMS, or a registered or accredited member of the Society of Brownfield Risk Assessment, a Silc (Specialist in Land Condition), or a member of another professional association in land contamination, and have a track record.
Just as in competence, the old standard barely touched on sustainability. But times have changed, and now it is a hot topic, an attitude reflected in the new guidance. First, the EA guidance also references BS ISO 18504:2017 Soil quality – sustainable remediation.
Second, the new EA guidance references a soil and groundwater remediation sustainability standard administered by the Sustainable Remediation Forum (SuRF-UK). That organisation, which published two guidance documents on sustainability assessment last year (www.is.gd/inepih), defines sustainable remediation “as the practice of demonstrating, in terms of environmental, economic and social indicators, that the benefit of undertaking remediation is greater than its impact, and that the optimum remediation solution is selected through the use of a balanced decision-making process.”
The mention of sustainability also, as Dent points out, ties in with the National Planning Policy Framework published in 2019, whose stated objective is ‘contributing to the achievement of sustainable development’.
Even if the process remains the same, the update was needed, states Dent. The new guidance aims to improve the quality of reports. Even so, it is unlikely to drive major changes in the way that the risk management process is conducted.“Because the process remains the same, LCRM is not going to drive a need for more investigation. Hopefully it will force people to look at competence and sustainability more, which will improve the quality of investigation and reporting, and remedial options will be developed which will be more sustainable,” she concludes.
BOX: A statistical method for contamination decisions
CL:AIRE, the independent organisation promoting sustainable land reuse, has published new guidance on applying statistics to land contamination decision making entitled ‘Professional guidance: comparing soil contamination data with a critical concentration’ (www.is.gd/akecoz).
CL:AIRE’s original guidance document, published in 2008, was created to help land contamination stakeholders apply statistical methods to their data analysis. This aided decisionmaking that was required under legislative frameworks, including the planning system and the Environmental Protection Act. However, this guidance recommended a single scientific test that gave a definitive yes/no answer, or ‘bright line’, thereby creating the potential for data to be abused.
“The bright line model recommended in the original guidance could be used inappropriately when it was applied in a black-and-white fashion,” says RSK board member Peter Witherington, who sat on the steering group that shaped the new guidance.
Instead, the 2020 revision addresses the problem of potentially erroneous conclusions by dropping the reliance on a single scientific test.
It emphasises the importance of a comprehensive understanding of the data sets in the context of the conceptual site model.
RSK part-funded the project, along with the Soil and Groundwater Technology Association (SAGTA), the Nuclear Decommissioning Authority and the Environment Agency.
BOX: Environment Agency LCRM rules for dealing with new pollution
If you have caused the pollution you must:
- identify the source and clean it up quickly
- return the site to its original state and deal with any adverse effects it's caused
- put measures in place to prevent it happening again
- where appropriate comply with the Environmental Damage (Prevention and Remediation) Regulations www.is.gd/qudiqu)
See also pollution prevention guidance: www.is.gd/abucev