“The MCERTS standard covers laboratory accreditation to ISO/IEC 17025. Laboratories can be permanent or mobile. They can also include organisations that take samples and do on-site analysis.” LCRM: Stage 1 risk assessment – GOV.UK (www.gov.uk) .
The EA has updated its guidance in October 2020 and April 2021 regarding the use of on site chemical analysis methods. The EA recognises that using on site analysis techniques is a valuable addition to the tool box environmental professionals has to enable them to understand the nature and extent of any contamination on a site. The latest guidance states that on site analysis methods, known as RMTs (rapid management techniques, ) can be used, if their protocol is followed.
Advantages of RMTs
WM3 notes the advantages of rapid management techniques:
- improve the quality of site investigations
- get immediate results
- make quicker decisions
- screen many samples at the same time
- potentially reduce investigation and remediation costs
- improve how you take samples for laboratory analysis
- help develop the conceptual site model
- define areas of contamination
- support other analytical methods
The protocol has been introduced to maintain high quality standards of analysis and data keeping. It should be used as part of a quality management system.
Environment Agency Protocol for RMTs
The WM3 rapid management techniques protocol involves:
- giving an appropriate person, the authority and overall responsibility for their use
- defining the roles and responsibilities of all staff
- document control and record keeping
- training
- standard operating procedures and sampling plans
- quality assurance, including internal and external quality control
- maintenance
- auditing of the staff
The protocol must be site specific, and approved by the EA.
A proportion of the samples, which is to be agreed with the EA, must receive confirmatory analysis from an accredited third party. The more samples that are tested, the more certain you can be that QED testing correlates well with high quality GCMS benchtop testing ( see Concawe Report.)
Suitability of the QED
The QED HC-1 hydrocarbon analyser from QROS has been designed to provide the highest level of automated Quality Control and calibration verification procedures. The computer controlled user interface allows a minimal amount of training is necessary before a user is sufficiently competent to generate valid data. The QED automatically monitors the analyser performance, the suitability of the sample being analysed and data input by the user. The calibration procedure also monitors the calibration solution used and checks if it is correct. This fulfils the requirements of the EA’s testing protocol. No other on site analyser can provide this level of QC and monitoring.
Soil Remediation
For remediation management it is not required that any samples are sent for verification because the rapid analysis methods are used for management and not any regulatory purpose. For waste classification, the waste guidance only requires the waste producer to accurately classify the waste. WM3 guidance suggests using UKAS (not MCERTS) accredited methods “where possible”, but a lab method that takes days to weeks to generate results is not practical, so in general use where time is money, UKAS methods are not possible. The advantage of speed is essential for efficient waste classification management.
A remediation contractor can use any procedure they want to classify the waste they produce provided they can prove the procedure they are using accurately describes the waste. Many waste receivers now use the QED and XRF to check incoming waste. The QED is an invaluable management tool which gives real time information allowing fast decision making without paying for laboratory analysis which takes days to give you the results you need.
For final sign off at the end of a remediation, some samples should still be sent to an MCERTS laboratory for final verification. The use of rapid methods will however ensure the verification results demonstrate the remediation has met the remediation target.
Site Investigations
Site investigations will require a few more verification samples. Typically 1 in 10 samples should be verified when the concentration of target contamination is within +/- 3 x the site limit and 1 in 50 for the rest. For sites where less than 20 samples are taken, at least 2 samples with concentration values near the site limit and 2 samples with values significantly above or below the site limit should be verified. The exact number should be agreed with the EA before starting the project.
When Laboratory and QED disagree
Sometimes lab results do not agree with the QED results. In this case, the Environment Agency will take a “lines of evidence” approach to interpreting the data. For example, it is well known that samples containing naturally occurring organic compounds such as peat and decayed leaves give an artificially high TPH result when analysed by most MCERTS accredited TPH laboratory methods. The QED sees these background organics but screens them out, reporting them as present but separate from TPH results, so is the more accurate in these cases.
Low cost laboratory analysis also cannot reliably differentiate between degraded diesel and an unknown petroleum hydrocarbon and can also fail to identify coal tar or creosote unless they know beforehand that it may be present. This issue has significant repercussions for both site investigation and waste management hazard classification. A set of QED results showing a material as degraded fuel significantly below 1000 mg/kg with a results flag indicating background organics have been detected will be considered correct. This is despite a lab verification result from the same material showing a TPH value of over 1000 mg/kg where the analysis is performed without using a full sample clean-up procedure or if the C21+ aromatics bands contribute >75% of the TPH value.
The QED analyser can identify degraded diesel as a diesel based mixture and can easily identify coal tars and creosotes. It identifies and quantifies the hydrocarbon in the same fast procedure; no other analyser can do this.
XRF Analysers
For heavy metals and other elements such as sulphur or chlorine, X Ray Fluorescence (XRF) is a technique that has been in use since the 1940s. The latest portable XRF analysers are safe to use, have detection limits that easily exceed regulatory limits and meet the EA requirements for the use of on site methods. Like the QED it takes approximately 3 minutes to generate a result.
Mobile Laboratories
Many companies both in the UK and overseas have set up a mobile laboratory with both a QED and XRF. A single operator uses both instruments to generate a full set of results within 5 minutes per sample.
QED users have confidence in their analysis, whilst getting real time results at very low cost. The analyser is available for hire or purchase. We’re always happy to talk if you have any questions!