Lab breaks speed barrier
As the cost of land remediation soars, a significant development in field-based decision making has been rolled out. Tom Idle reports on the mobile environmental laboratory
Testing the suitability of a particular field site is usually necessary for engineers and designers, who must assess potential risks for building. Things such as the corrosion of metal and concrete structures are searched for. But the current methods of taking data and then transferring it to the laboratory has caused some difficulties: it can be a tedious process with delays, confusing results and sometimes missed contaminants.
Characterising a contaminated site can be a drawn-out process, with plenty of desk study, sampling, analysis, more sampling and delays.
BGS, which is part of the Natural Environment Research Council, with connections to the government through the Office of Science and Innovation, says its mobile laboratory is the solution to these problems.
In the US, the Environmental Protection Agency (EPA) is promoting use of a more dynamic approach to field trials. The triad approach attempts to use systematic planning, dynamic work strategies and realtime measurements to compress mitigation and remediation actions.
A principle component of this approach is the use of field-based decision making based on on-site analysis. This allows for a seamless flow of site activities and thus fewer site visits.
The mobile lab's field-based decision making is comparable with fixed laboratory analysis. It is equipped with state-of-the-art analytical instrumentation, including gas chromatography-mass spectrometry (GC-MS), benchtop and handheld X-ray fluorescence (XRF), ultraviolet fluorescence spectroscopy, near infrared spectroscopy, ion chromatography and bioluminescence screening.
Real-time results means that effort can be concentrated on collecting samples where contamination has been detected. And, because the laboratory is hired per day, more samples can be collected and analysed. This could potentially result in a greater density of data and a better site characterisation - without the need for future mobilisations.
The portable GC-MS is capable of analysing halogenated and non-halogenated volatile organic compounds, including solvents; benzene, toluene, ethylbenzene, and xylenes; and oxygenates, semivolatile organic compounds, such as dichlorobenzenes, phenols and polyaromatic hydrocarbons in waters and soils. The instrument can be used qualitatively as a screening tool or quantitatively down to low ppb concentrations. Even quantitative analysis can be complete within 30 minutes of receiving the sample. Meanwhile, total petroleum hydrocarbons can be rapidly analysed and speciated to 0.1ppm in water and soil using ultraviolet fluorescence spectroscopy. Both of these instruments have been subject to US EPA verification reports to check their performance in field analysis.
The energy-dispersive XRF spectrometer is capable of analysing virtually the full range of elements of the periodic table in soils, sediments and waters. Non-destructive analysis of elements, from sodium to uranium, in concentrations from 100% down to low ppm levels, with simple, relatively inexpensive and quick sample preparation make this a valuable tool for site characterisation and remediation.
The laboratory is also equipped with a handheld version of the XRF for even faster analysis. Average sampling times are under 60 seconds and produce metal concentrations down to the low ppm range. This immediate sample turnaround time coupled with ease of XRF use, make it possible to perform an initial site assessment in a fraction of the time compared with traditional lab-based work.
The BGS is a national resource for geoscience information. With the large quantities of geographical information accumulated since the beginnings of the organisation, BGS aims to provide its customers with complete and relevant information and technology. BGS Environmental Projects covers a wide range of services, including human health, waste disposal, groundwater pollution and contaminated land. It aims to provide solutions to problems associated with ground conditions and land quality. In researching the issue of on-site analysis of contaminated land, it have furthered the effectiveness of field analysis considerably.
Maximising the potential of on-field analysis does not only benefit the engineers and designers, but also benefits home-buyers who are not prepared for all the complications of hillside living (including erosion, mudflows and maybe even landslides caused by intense rains). So, soil testing could help make potential homeowners aware of the steps to safeguard their homes. By testing being brought on-field, it means that it is far more convenient for the home buyers and the engineers hired as it is a faster way of analysing data and, as previously mentioned, is likely to be more accurate.
Businesses involved can save money by getting more of their work done in a shorter time and saving unnecessary travelling.
Because analytical results can be obtained within minutes of sample collection, it becomes clear whether additional characterisation or excavation is required and so can be done then and there. This real-time information can reduce unnecessary work and expense.
It is also cost-effective as the teams are able to identify only those samples that are suitable for further analysis at a fixed static laboratory. Even quantitative analysis can be complete within 30 minutes of receipt of the sample.
The lab can also analyse samples overnight, giving it a total capability of around 20 to 30 samples fully analysed per day.