Guidance

MCERTS: performance standard for rapid measurement techniques for the chemical testing of soil

Published 27 April 2026

Applies to England

This guidance is for: 

• manufacturers of rapid measurement techniques (RMTs) for the chemical testing of soil
• test laboratories who carry out testing of equipment on behalf of manufacturers to see if it meets the required standard

The Environment Agency set up its monitoring certification scheme (MCERTS) to provide guidelines on the standards you need to meet to monitor emissions that affect the environment. 

1. Overview 

Here we describe the certification process for RMTs for the chemical testing of soil. Portable monitoring systems are field based analytical technologies used for the onsite chemical analysis of soil. An RMT is also referred to as a rapid measurement technique because it allows you to make real time decisions.

MCERTS for RMTs used for chemical testing of soil is an official certification scheme that complies with EN ISO/IEC 17065 Conformity assessment – Requirements for bodies certifying products, processes, and services. 

CSA Group UK Ltd are a certification body appointed to run this scheme for us.

The certification body appoints a certification committee to make certification decisions. The committee is made up of appropriately independent, competent person or group.

2. Introduction 

This standard specifies performance criteria for RMTs used for the chemical testing of soil. These consist of: 

• general criteria for all RMTs
• performance criteria and test procedures for testing in a laboratory
• performance criteria and test procedures for field testing

RMTs are used for the determination of the value of specified parameters of soil quality. They are used for a range of data quality objectives. This may be identification of an analyte type, semi quantitative measurement of an analyte or fully quantitative measurement of an analyte. This scheme sets performance requirements for fully quantitative measurements.

The measurands currently covered are:

• total petroleum hydrocarbons
• heavy metals as individual elements
• poly aromatic hydrocarbons

An RMT may be used to identify individual or groups of measurands. For example, differentiating diesel from other petroleum hydrocarbons or hexavalent chromium from total chromium.

The requirements in this standard allow the certification of any technology that meets the requirements. The following are examples of technologies that are currently available:

• gas chromatography coupled with mass spectrometry
• nondispersive infrared spectroscopy
• ultraviolet fluorescence spectroscopy
• visible near infrared spectroscopy
• fourier transform infrared spectroscopy
• photoionization detection
• X-ray fluorescence spectroscopy
• stripping anodic voltammetry
• immunoassay
• colorimetric

Some of the technologies require solvent extraction. Others are solvent free, non-intrusive methods.

Multi-parameter monitoring systems that measure more than one parameter may be certified according to this standard.

The measurement ranges required will be application specific. The MCERTS tests will take these conditions into account. The certification range for a specific instrument will be agreed between the manufacturer and the certification body.

3. Scope of the MCERTS scheme

This scheme was developed to provide confidence that an RMT for chemical testing of soils can provide results that are comparable to results from a permanent laboratory. It does not cover how the RMT will be used after certification is granted or the quality assurance related to its ongoing use.

An RMT can be used as part of a land contamination risk assessment. For example, to confirm the location and general concentration of pollutant plumes or to demonstrate that site remediation has reduced the target contaminants to the required concentration. For more information on the use of RMTs for land contamination risk management see the LCRM stage 1 risk assessment.

An RMT can be used for on-site verification checks of waste sampling to confirm information obtained from compliance testing. For more information on the use of RMTs in waste sampling see Appendix D, Step 1.3: Determine level of testing required, on-site verification of the Waste classification technical guidance WM3.

4. Required standards   

The following standards are required for the testing of an RMT for the chemical testing of soils under MCERTS: 

• MCERTS performance standard for laboratories undertaking the chemical testing of soil

• EN ISO/IEC 17025:2017 General requirements for the competency of testing and calibration laboratories

Test laboratories shall demonstrate to the satisfaction of the certification body that they comply with the relevant requirements of EN ISO/IEC 17025.

5. Performance tests

The RMT shall comprise of all components required to make a measurement.

Performance tests for certification of an RMT against the MCERTS requirements shall be carried out in accordance with the procedures defined in this document.

The results of previous performance tests may be acceptable to the certification body, if equivalent to MCERTS requirements and carried out independently. Manufacturers’ own laboratory and field test data may also be considered. 

Variations to the performance tests described in this standard may be acceptable if they demonstrate to the satisfaction of the certification body, the performance of the RMT against the requirements. Any such variations shall be agreed with the certification body.

6. General RMT requirements

This section describes the general requirements that are applicable to all RMTs for the chemical testing of soils.

6.1 General requirements for all RMTs

The following requirements shall be assessed by inspection or manufacturer’s statement.

The manufacturer shall state the analytes that can be detected, the measurement range for each identified analyte and the matrix that is suitable for measurement. The range (or ranges) over which the certification will be applied shall be agreed with the certification body.

All MCERTS certified RMTs shall have a unique designation that unambiguously identifies the RMT as a certified model.

The RMT shall display a readout of the measurand, in appropriate units of measurement at the time of analysis. This can either be integrated into the instrument or displayed on a linked monitor or computer.

Multiparameter instruments shall clearly identify the measurand being displayed.

The RMT shall have a means of informing the user of its operating status. This can either be by a light or by text displayed on the instrument or on a linked monitor. Examples of operating status are hardware testing condition (such as sensor condition, excitation source condition and presence of contamination), maintenance mode, analysis error or malfunction.

The RMT may operate from a mains power source that may be a direct grid connection or via a generator. It may also have a self-contained power supply that consists of primary cells, rechargeable cells or any other power source that can provide the required power under all operating conditions.

An RMT shall incorporate a method of indicating when the power supply voltage is below its normal operating limit or the battery capacity is insufficient to complete the analysis.

The RMT shall contain automatic monitoring processes of the following events that could alter the accuracy of the result:

• detection of instrument overload from the sample
• analyte concentrations over or under the calibration range
• instrument drift
• cross contamination from previous samples
• notification of user errors

The system shall alert the user that an event is occurring and mark the results obtained as potentially inaccurate if the event is not rectified.

The RMT shall be designed so that calibration can be carried out in the field, or where this is impractical, functionality checks can be carried out in the field to verify the correct operation of the RMT.

The RMT shall be able to present results in a form that can show if the document has been tampered with and results altered.

6.2 Manufacturer’s published documentation

The following guidance or statements shall be incorporated into the manufacturer’s published literature. The manufacturer shall:

• provide operating instructions that cover sample preparation and the full functionality of the RMT
• state the storage life and requirements of all scheduled spares, reagents and reference materials
• identify any special equipment required for the storage of spares and reagents and a source of such equipment
• supply documentation with replacement chemical reagents stating the measurand, measurement range or ranges and known interferences
• state any chemical, biological and physical interferents to the measurement method
• state the limit of detection for each analyte or analyte group the RMT can detect and in which matrix

The manufacturer shall state the typical time over which the RMT shall operate without requiring maintenance. The maintenance interval shall be based on typical handling, storage and use of the RMT.

7. Performance requirements

The RMT shall be evaluated in the laboratory against the precision and bias performance requirements in the MCERTS standard for laboratories undertaking the chemical testing of soil.

The RMT shall be tested in the field. This test shall include a comparison with a standard reference method. The comparison shall show that 90% of the individual measurement pairs and the mean error for all the paired measurements meet the bias requirements in the MCERTS standard for laboratories undertaking the chemical testing of soil.

If one performance target can be shown to demonstrate the performance target for another application, the certification body may agree that additional performance checks are not required.

The performance requirements that are applicable to RMTs are as follows.

7.1. Laboratory test procedures

This section describes the laboratory test procedures and performance tests.

7.1.1 General checks made by the test laboratory

The test laboratory shall:

• make sure that any sample preparation required is in accordance with the manufacturer’s sample preparation protocols
• make sure that the RMT is set up, calibrated and adjusted in accordance with the manufacturer’s instructions
• verify by inspection or by statement from the manufacture that the general requirements listed in this document are fulfilled

The test laboratory shall verify and report that the displayed operation status is correct.

The test laboratory shall report the resolution of the displayed reading.

7.1.2 Laboratory performance tests

Laboratory performance tests shall be carried out using certified reference materials that contain the compounds the RMT is designed to detect in the appropriate matrix.

The manufacturer of the RMT shall indicate where the RMT may give false results because of compound or matrix interference.

The laboratory performance tests shall meet the requirements for the selection, verification of methods given in the MCERTS standard for laboratories undertaking the chemical testing of soil. 

The laboratory tests shall demonstrate that the RMT meets the applicable performance characteristics of precision and bias in the MCERTS standard for laboratories undertaking the chemical testing of soil. 

7.2 Field test procedures

The certification body can accept evidence of field tests from a test laboratory, the manufacturer or an operator, who uses the RMT. The proposed approach shall be agreed with the certification body.

7.2.1 Objectives of the field test

The objectives of the field test are to demonstrate that the performance of an RMT is maintained under representative operational conditions and to allow an assessment of the reliability over an extended period of normal operation.

The scope of field test will depend on the RMT being tested, the intended application for the RMT and the availability of historic data, provided by the manufacture.

A test plan, detailing the proposed field test, shall be submitted to the certification body for approval. This shall include:

• nature of the site and specific application
• typical range of the measurand
• reference method used
• traceability of methods used
• installation environment

7.2.2 Requirements of the field test

The RMT under test shall be the same model as for the laboratory test. A new, fully serviced RMT may be supplied for a field test.

The field test shall include as wide a range of the proposed applications for the RMT as possible.

Typically, the RMT shall be used by at least 3 people over the period of the test. Each person shall be trained in the correct operation of the RMT and made aware of the procedures followed during the test.

The field test shall consist of at least 120 measurements. The field test shall take at least 3 months. The RMT shall be in regular and frequent use throughout this time. Historical data about reliability, performance and reproducibility can also be used as evidence if it meets the given criteria.

If the RMT is being employed outdoors, then details of the ambient conditions during the field test shall be recorded.

During the field test, the performance characteristics of the RMT shall be determined under representative operational conditions. This means that reference measurements shall only be taken when all parameters are within the rated operating conditions of the RMT.

7.2.3 Error under field conditions

The error of an RMT is determined by comparing the measurement obtained by the RMT with that of a reference method. A reference method is typically a European, international or national standard employed by a laboratory with it on their schedule of EN ISO/IEC 17025 accreditation.

If a test laboratory with EN ISO/IEC 17025 accreditation for the test method is unavailable for the matrix or the compound being tested, an agreed alternative can be used to assess analytical performance. The certification body shall approve any alternatives.

The reference material shall be compatible with the RMT analytical method and the laboratory method.

A minimum of 24 pairs of reference measurements (simultaneous determinations from the RMT and the reference method) shall be taken over the duration of the field test. The timing of readings shall be chosen such that they are:

• spread throughout the field test period
• carried out at several different times throughout the field test
• spread across as wide a range of measurand values as possible (ideally, 5%, 25%, 50%, 75% and 95% of the agreed range)
• carried out at several different points during the maintenance interval of the RMT

In terms of the spread of the test over a 3-month field test, we recommend making 40 measurements per month, with 8 of these being paired measurements. The timing being shared evenly across the test period, thus resulting in 120 measurements in total and 24 paired measurements.

Typically, the paired measurements shall be analysed within 12 hours of collection using a standard method. The analysis shall be done by a laboratory that is accredited to EN ISO/IEC 17025 for the reference method used or using an alternative that has been approved by the certification body.

For analytes with known issues of loss of analyte between sampling and subsequent analysis by the reference method, spiked samples created using an inert matrix and a known concentration of reference analyte shall be made. This sample shall be exposed to typical transport times and storage conditions.

The difference between the spiked concentration added and subsequently reported concentration by the reference laboratory method shall be used to calculate the transport bias within the reference method. This bias may be accounted for when determining the bias of the RMT.

Duplicates of test pairs can be sent to 2 separate laboratories if more than one reference method is available and widely used. Where duplicate pairs are taken, they shall be analysed using a different method for each sample. The bias test shall be compared to each reference method separately.

For each pair of reference measurements, the bias shall be determined and reported between the reference methods and the RMT method.

Additionally, it may be necessary to determine bias within the laboratory analysis. To do this, a certified reference material, containing compounds that are commonly known to interfere with the reference laboratory method, shall be analysed by the RMT and reference method.

7.2.4 Determination of mean error of field test

A comparison of the pairs of reference measurements and the RMT measurements taken during the field test shall be made to determine the mean error.

For each pair the error is the difference between the value given by the RMT and the value give by the reference method (which is assumed to be the conventional true value).

For at least 90% of the reference measurements, the error shall be less than or equal to the applicable performance characteristics of bias in the MCERTS standard for laboratories undertaking the chemical testing of soil.

The mean error, from a series of n measurements is:

The mean error shall be less than or equal to the applicable performance characteristics of bias in the MCERTS standard for laboratories undertaking the chemical testing of soil.

7.2.5 Maintenance

Any maintenance activities, scheduled or otherwise, required during the field test shall be recorded.

Settings and frequency of any maintenance or calibration routines shall be recorded.

Any changes to the frequency of any automatic or scheduled manual maintenance activities during the field test period shall be reported.

If one or more major components of the RMT are replaced during the field test, the matter shall be referred to the certification body, who shall consider whether additional data is required.

The following shall be reported with regards to each unscheduled maintenance event:

• nature of the fault
• actions required to remedy fault
• time taken in hours to remedy the fault
• any problems or difficulties experienced in following the manufacturer’s recommendations for fault diagnosis and repair
• requirement for manufacturer’s attendance on site
• any components replaced
• total time while the RMT was not operational, that is from point of failure to time the RMT was back available for use

If the total time while the RMT is not operational because of failure is more than 2 weeks, the certification body may require an extension of the test to make sure that sufficient operational data are collected.

7.2.5 Reporting of the field test

The following shall be recorded:

• the values given by the RMT for each of the measurements
• the name of the operator doing the test
• the location and time of the tests
• any recent calibration
• any recent changes to the setting of the RMT
• the ambient conditions (if used outdoors or with a field-based laboratory that is not temperature controlled)

The field test shall be summarised in a test report and submitted to the certification body for consideration by the certification committee.

8. Repairs, maintenance and modifications to certified RMT

Any spares or replacement parts for a certified RMT shall meet the same performance standards as the original parts. Operators and equipment suppliers may be required to provide evidence that the replacement parts meet the required performance standards of the original equipment as specified by the RMT manufacturer.

Modifications and general product development to a certified RMT are allowable so long as manufacturer can demonstrate that these design changes do not degrade the performance of the RMT below the MCERTS performance standards.

Manufacturers must keep detailed records and drawings of all design changes to an RMT, and have provisions for design verification, inspection and testing to make sure that the RMT still meets the required performance standards.

To meet the requirements of product certification, the certification body will conduct audits of the design changes to an RMT. Manufacturers must notify the certification body of any modifications to equipment that may have a significant effect on RMT performance.

Design modifications or extensions to the range of application of an RMT may require renewed testing. The extent of this renewed testing will depend upon the nature of the modifications to the RMT.

If there is evidence that a modification has only limited effects on the performance of the RMT, then it would not be necessary to retest the RMT completely.  

If additional compounds are added to the scope of the RMT, it may be acceptable to do a reduced schedule of tests to the applicable MCERTS performance standards, rather than a full retest.

In the case of modifications to software or a change to a component of a circuit board, documentation shall be presented to the certification body indicating the nature of the modification as well as resultant effects on operation and functionality. The certification body will then decide if further testing is required.

9. What to do next 

Find out more about MCERTS product certification on the: 

• CSA website
• MCERTS collection on GOV.UK

Contact the Environment Agency if you need any help.

General enquiries

National Customer Contact Centre
PO Box 544
Rotherham
S60 1BY

Email enquiries@environment-agency.gov.uk

Telephone 03708 506 506

Telephone from outside the UK (Monday to Friday, 8am to 6pm GMT) +44 (0) 114 282 5312

Monday to Friday, 8am to 6pm.