The Environment Agency and On Site Analysis
A recent MCERTS policy update from the Environment Agency fully supports on site or rapid measurement techniques to be used for regulatory purposes. The accuracy and quality control procedures inherent in the QED make it highly suitable for use for regulatory purposes.
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 will
- improve the quality of the site investigation
- potentially reduce the cost of investigation and remediation
- provide information on characteristics of a site within a timescale that will allow you to make real-time decisions
- improve how you target further sampling for laboratory analysis
- get a better idea of contaminated areas to help develop the conceptual site model
- support other analytical methods
- If the rapid measurement technique method has MCERTS accreditation we will accept the results without any further laboratory testing.
There are currently no procedures in place that enables an on site analysis manufacturer to obtain MCERTS accreditation for their analysis method. The EA as a compromise has allowed that an organisation that is currently MCERTS accredited can use the on site analyser under its own MCERTS accreditation. This means any MCERTS accredited laboratory could carry out on site analysis for its clients using a suitable on site analysis method.
For organisations that do not have MCERTS accreditation, the EA have suggested some simple procedures to follow
- evidence of quality control and equipment calibration procedures
- evidence of training for those who carry out the on-site measurements
- complementary MCERTS accredited laboratory analysis for an appropriate proportion of the results
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 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. No other on site analyser can provide this level of QC and monitoring.
The EA will expect some samples to be sent for confirmation by an MCERTS accredited laboratory method. The number of samples needed will be site specific and depend on the project.
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.
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 not possible to use. 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. The waste receiver may wish to obtain independent results, but many waste receivers now use rapid methods to check incoming waste.
The QED hydrocarbon analyser can reliably identify and differentiate between all petroleum hydrocarbon derived materials as well as coal tar, creosote and bitumen and will be suitable for classification of all oily waste, coal tar and bitumen impacted materials.
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.
Where confirmatory samples are sent to an MCERTS lab for confirmation but the lab results do not agree with the rapid analysis methods, the EA will take a “lines of evidence” approach to interpreting the data. It is well known that naturally occurring organic compounds such as peat and decayed leaves create an artificially high TPH result when a sample containing these substances are analysed by most MCERTS accredited TPH laboratory methods. These lab methods may not be able to differentiate between degraded diesel and an unknown petroleum hydrocarbon and can also fail to identify coal tar or creosote unless they are told to look for it. The QED analyser can identify degraded diesel as a diesel based mixture and can easily identify coal tars and creosotes. 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 and all significantly below 1000 mg/kg with a results flag indicating background organics have been detected will be considered correct despite a lab verification result showing a TPH value of over 1000 mg/kg and the analysis being performed without using a full sample clean-up procedure or the C21+ aromatics bands contribute >75% of the TPH value.
The QED will provide results for total BTEX, Gasoline Range Organics, Diesel Range Organics (up to C40), TPH, total C10+ aromatics, sum 16 PAHs and a benzo-pyrene concentration. The identification of the hydrocarbon detected is also provided with a % confidence in the match. This data is generated within a few minutes of collecting a sample.
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 sample. It is possible to set up a QED and XRF in a small space/back of a van and a single operator use both simultaneously to generate a full set of results within 5 minutes per sample.