Automated AGS Screening Tool
Shortlisted for Brownfield Awards Category Category 2: Best Scientific/Technical/Digital Advance or Innovation
As part of a contaminated land risk assessment process following the LC:RM guidance (1), a ground investigation is typically undertaken where soil and water samples are collected and analysed in a laboratory for the presence of contaminants of concern. The laboratory results for soil, soil-leachate and water samples are then compared to the appropriate generic assessment criteria (GACs) to assess the risk posed by the potential contaminants to site receptors. This process is referred to as “screening” and enables consultants to assess the potential risk at the site and supports the production of a Conceptual Site Model (CSM).
For the last two decades, screening has been a manual and labour-intensive process by which an environmental consultant would compare individual laboratory results to the GACs typically by using a basic Excel spreadsheet. There is no standard reporting format or structure within the industry leading to different laboratories providing chemical data in a variety of formats, in multiple Excel spreadsheets and/or PDF documents. Consultants do not have any control over the reporting format which requires manual manipulation of data for every site/project. Combining all data into one spreadsheet and using the conditional formatting feature for screening is labour-intensive and vulnerable to mistakes being made.
In addition, environmental professionals have to consult other sources of information such as the geological logs and manually add information on the corresponding geological strata into the screening which to allow them to assess the sources, pathways and distribution of contamination. Finally, where exceedances of GAC values occurred, exceedance figures are manually sketched in GIS/CAD to allow the consultants to spatially visualise areas of potential contamination across the site and manually typed into tables in reports. The whole process is time-consuming, vulnerable to human error and difficult to quality control due to the multiple steps which need to be carefully checked. Results are typically stored in isolated spreadsheets rather than in databases, making it difficult to locate and interrogate data in the future.
Novel Approach to Screening
In 2018, our environmental consultants began investigating if there was a way to provide an automatable and consistent dataset to reduce the need for the time-consuming checking process which comes with traditional screening processes. We also wanted to store all data in a database providing a single source of truth and to allow us to unlock the potential of large-scale data analysis.
The AGS data format (2) developed by the Association of Geotechnical & Geoenvironmental Specialists “is a text file format used to transfer data reliably, between organisations in the site investigation industry”. It “provides a standard way to transfer ground investigation, laboratory testing and monitoring data”. As such, the AGS data format enables easy data transfer between the contractors, laboratories and consultants. It also enhances collaboration between the geotechnical and geo-environmental specialists on brownfield land development and allows storage within the same database . This provides a single source of truth for the project and enables collaborative and more robust decision-making. Hence, we decided to explore how we could use this AGS data to more effectively screen and manage our chemical datasets.
Following our initial assessment of how AGS data would be reported by laboratories we identified that there were differing interpretations of how the chemical data should be reported. To realise our ambition to automate the screening, we prepared a memo on how Atkins would require our contractors and laboratories to consistently report AGS data. We consulted with the AGS Committee Contaminated Land Working Group to ensure that our approach was consistent with their vision and to drive forward best practice for AGS data transfer. We then worked with our contractors and laboratories to help them understand why this reporting format is important to our automated goal and implement the changes required for standardisation. This consultation and memo have allowed us to receive our AGS data in a standard format which meaning we were able to develop an industry-leading AGS Screening Tool.
The AGS Screening Tool reads AGS data containing information including locations of exploratory holes, geological descriptions of strata, details of environmental soil and water samples collected on site, and chemical laboratory data.
It then separates soil, leachate, water (groundwater and surface water) data and screens the data against the respective GACs – soil data against GACs for human health and leachate and water data against GACs for water environment risk assessments. All end-use scenarios and their associated industry-specified GACs (e.g. commercial land end-use for 1% soil organic matter content, etc.) are embedded in the tool and site-specific assessment criteria can also easily be added in. This allows us to compare the results against multiple land-use scenarios very quickly, giving consultants a clearer view of the level of risk associated with the contaminants and rework is avoided if the site proposed end-use changes during the design phase.
In addition to performing as a GAC screening, the tool has additional capabilities which enhance the risk assessment process and creation of the CSM. The tool can provide the following functions:
Calculation of relative exceedance value, i.e. how many times the concentration of the contaminant exceeded the GAC;
Calculation of some of the GACs for controlled waters assessment (e.g. environmental quality standard for cadmium based on calcium carbonate concentrations within the receptor);
Matching contaminants to their respective determinand category which is not typically reported in the AGS data format such as “general inorganics”, “heavy metals and metalloids”, “total petroleum hydrocarbons”, “polyaromatic hydrocarbons” (PAHs) etc. to enable more efficient reporting;
Matching samples to their strata of origin;
Calculating average soil organic matter (SOM) content while automatically excluding soil samples impacted by organic contamination and then summarising the results for all data and also by stratum;
Assessment of benzo(a)pyrene (BaP) as a surrogate marker (3);
Summation of contaminants for specific GACs (e.g. Sum of 4 PAHs for controlled waters screening);
Provision of a list of determinands with no GAC;
Matching screening results to locations (coordinates);
Data summaries that can be used in reports, including summaries based on depths for human health (e.g. within 1 m bgl), by determinand, by borehole, and by stratum;
Output of exceedance data into GIS enabling easy production of exceedance figures for reporting;
Provision of all raw data in CSV/GIS format to enable database storage.
The inputs and outputs of the tool described above are presented in Figure 1.
Figure 1 Inputs and outputs of the AGS Screening Tool
Broad Impact and Value
The AGS Screening Tool can be used to screen data for any project that utilises laboratory data in AGS format. It can be applied for GAC screening but also for screening against site-specific screening criteria during detailed quantitative risk assessment Detailed Quantitative Risk Assessment (DQRA) stage. The tool can support brownfield remediation projects by screening against remediation/re-use criteria and visualising the screening of verification samples with automatically-produced GIS outputs.
The AGS Screening Tool represents real breakthrough within the industry as:
It enables the automated comparison of laboratory-reported chemical concentrations in AGS data format against GACs for generic and bespoke land end-use scenarios.
We are not aware of any other commercially available tools capable of screening AGS data against GACs in such an efficient, comprehensive and robust way.
The AGS Screening Tool demonstrates Atkins’ innovative approach to data management and risk assessment by encouraging interdisciplinary collaboration, safeguarding data integrity, good data management practices, and strict regulatory adherence.
It is a tool fully developed in house by our environmental consultants who upskilled themselves in data analysis and programming.
The AGS Screening Tool significantly decreases the time and cost required (by up to 75%) for screening, reporting and visualising risk assessment results and is especially efficient for large datasets. It ensures integrity of the data at each point of the process and therefore provides best practice in terms data processing, significantly reducing the potential for reporting error and checking time. The ability to analyse data spatially across the site allows for easy interpretation of the data by identifying sources of contamination and relevant pathways.
The use of the AGS Screening Tool within Atkins on various projects has highlighted the need for standardisation of AGS data. By writing the AGS memo and discussing it with the stakeholders, we are overall improving data management practices within the geo-environmental industry. Figure 2 shows benefits of the AGS Screening Tool.
Figure 2 Benefits of the AGS Screening Tool
Case Study 1
In 2020, we entered a competition for funding for a research project from the Lloyd’s Register Foundation, supported by the Open Data Institute and won. The funding allowed us to understand the potential to open-up data used in the land contamination risk assessment and we produced a white paper on our findings (4). The overall aim of the project was aiding the redevelopment of brownfield sites by potentially decreasing the cost of risk assessment and subsequently of the site redevelopment. Elements of the AGS Screening Tool were used to screen multi-project/national dataset for selected contaminants, demonstrating the potential for large-scale assessment using standardised AGS data.
During the project we demonstrated that the screening results could be anonymised into larger areas (e.g. hexgrid), as shown in Figure 3 to enable sharing of data but making sure no specific sites/boreholes can be identified. The figure demonstrates how outputs of the “national screening” could be used to enhance assessment of large areas.
Figure 3 Anonymised outputs of the AGS Screening Tool for a large area. Green areas have no/minor exceedances, dark red areas have a high number of exceedances, grey areas do not contain any data
Case Study 2
Strategic Pipeline Alliance (SPA) is an alliance between Anglian Water and construction and engineering giants working on the development of hundreds of kilometres of pipelines in the East of England.(5)(6), As part of the Deliberately Delivering Differently (3D) initiative, SPA drives innovation within the construction industry and is developing a Digital Twin for the pipeline (7).
Land contamination risk assessment for the pipeline is being undertaken by the land quality team and considers hundreds of potential sources of contamination. We facilitated early discussions about the use of the AGS Screening Tool for SPA and its contribution to the 3D initiative and presented a business case demonstrating the benefits of using the tool.
The Atkins tool is being used to support SPA in best-practice data management by supporting the storage of AGS data and screened results in a common data environment. This provides a “Digital Twin” of the potentially contaminated soils and groundwaters and a single source of truth. The screened results can be visualised on the web map in connection with design features, locations of potential sources of contamination, receptors etc. This puts the screening results in context with other datasets, enhances the interpretation of the data by the land quality team, and makes it easier to produce the CSM. Other disciplines can interrogate the data which leads to improved collaboration across SPA.
Figure 4 shows screening results for nitrate in groundwater at a specific location and how this relates to the source of contamination (landfill), the location of the pipeline and underlying strata (Lincolnshire Limestone – LL).
Figure 4 Screening results for the Drinking Water Standard within groundwater
The AGS screening tool provides significant time/cost savings during risk assessment, supports best-practice data management and enhances visualisation and interpretation of screened data.
The AGS Screening Tool has the potential to be used for large-scale data analysis, which was previously not possible. The first case study shows that the tool could be used to indicate the estimated level of risk for an area, enabling local authorities, developers and other stakeholders to clearly identify sites with lower/higher risk of contamination within their portfolio. This would enable sustainable re-use of brownfield land and enhance social value of developments.
The AGS Screening Tool could be used for automated preliminary design of large projects such as railways, pipelines or road schemes, decreasing the need for design iteration due to presence of potential land contamination. If schemes could not avoid contaminated sites, then the tool outputs could be used to better assess the risk and costs of development and remediation at an early stage of the design process.