Ashtead Technology Ltd

Monitoring contamination without excessive cost


Source: Ashtead Technology Ltd

Environmental monitoring should be undertaken with the best available technology within reasonable cost constraints (i.e. BATNEEC). However, the best technology is often the most expensive, so instrument rental is increasingly the favoured option. James Carlyle, General Manager at specialist instrument hire company Ashtead Technology Rentals, explains.

The requirement for environmental monitoring data to be reliably accurate has never been greater. The number of regulations continues to increase and the financial implications of monitoring data can be highly significant. This is perhaps more true of the contaminated land sector than any other because land values can be very high in many urban locations and the cost of remediation varies according to the monitoring results. Consequently, the accuracy and reliability of data can become the focus of disputes.

Clearly, it is vital that monitoring equipment should be the best available technology and the equipment itself should be calibrated and in good working order. This is where Ashtead Technology Rentals has an important role to play; as a specialist in environmental instrument hire, the company's engineers are able to advise on the most appropriate instrumentation and to ensure that it is delivered calibrated, tested and ready to go.

The monitoring of contaminated land and remediation work is often project based and testing is usually only required at certain stages. For these reasons it makes more sense to hire than to buy instrumentation. Furthermore, many of the best technologies for testing contaminated land are expensive and this is another significant justification for hire.

Guidance from the Environment Agency on the qualification requirements for chemical test data on contaminated soils acknowledges that portable measuring instruments can both improve the quality of contaminated land assessment and reduce costs. This is important, because laboratory tests can be expensive which tends to minimise the number of samples sent for analysis, thereby rendering the data less representative. In addition, results may not become available for some time which can result in costly delays.

Portable instruments facilitate contamination assessment at multiple points so that ‘hot spots’ can be quickly identified and results made available immediately to improve decision making on-site.

The most popular instruments are X-Ray Fluorescence (XRF) instruments for metals contamination, landfill gas analysers and PID gas detectors for the assessment of hydrocarbon pollution.

XRF instruments are expensive to purchase but can be hired for short-term projects and Ashtead customers have commented that the hire costs of an XRF analyser are easily covered by the quick and accurate determination of material that is beyond economic treatment, ensuring that contaminated volumes for disposal are kept to a minimum.
PIDs are commonly used in the assessment of sites with contamination from oil or oil derivatives and solvents. These small portable devices are highly sensitive to almost all hydrocarbons except methane for which an infrared device might be employed.

Another key benefit of hire over purchase is the access that it provides to new technology. For example, Ashtead has recently added a new portable  Laser Methane analyser to its fleet of rental instruments. It is highly selective so does not give false readings, even if other gases are present, and can detect methane at concentrations between 10 – 10,000ppm up to 150 metres away in less than 0.1 seconds, even through glass.  The device comprises a single ‘gun’ unit with no additional parts or battery packs, making it very easy to carry and operate in the field and is ideal for rapid methane surveys.

New instruments featuring the best available technology are constantly being added to the Ashtead rental fleet - details of these are available in a free catalogue or by visiting

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