Improving capacity for environmental pollution monitoring with new reference materials
Pollution caused by the consumption of fossil fuels, discharge from various industries and the use of chemicals in agriculture has placed severe pressure on diminishing resources such as drinking water, wildlife habitats or land for housing. To protect human health and the environment EU legislation such as the Water Framework Directive stipulate the maximum allowable concentrations of priority pollutants. Laboratories operating in this sector need accurate, traceable measurements and key to this is the availability of certified reference materials (CRMs) that are used alongside environmental samples to determine contaminant levels. CRMs, characterised by metrologically valid procedures, contain well-defined, certified amounts of the substance under investigation. Ideally the material or ‘matrix’ from which these are composed should match or simulate that of the samples under investigation, such as soil or water for environmental analysis. The manufacture of CRMs and methods for taking and testing samples are detailed in international and European standards and generating CRMs is usually assigned to National Metrology Institute (NMIs) or Designated Institutes (DIs). However, due to the wide range of possible pollutants and the complexity, variability and instability of environmental samples, it is difficult for many measurement institutes in emerging EURAMET countries to develop appropriate reference materials.
This project brought together nine measurement institutes from across Europe to disseminate the knowledge possessed by more experienced NMIs and DIs and extend the capacity to produce CRMs for environmental analysis. Three candidate CRMs were made; representative of samples that environmental and monitoring laboratories typically analyse. Two were for inorganic elemental pollutants, one composed of river water spiked with arsenic, cadmium, nickel, lead, selenium and mercury, and a second from soil containing those contaminants plus an additional seven others. The third candidate, the first of its type ever produced, was created from groundwater containing PFOS (perfluorooctane sulfonate) and PFOA (perfluorooctanoic acid), that are extremely persistent organic contaminants with known human health effects. Each was characterised through a series of comparison exercises using validated methods. Twenty-two laboratories from seventeen countries were involved in the water CRM exercise, utilising four different measurement techniques, and for the soil CRM seven different techniques were used. Both comparisons used two potential primary measurement methods, Isotope dilution mass spectrometry (IDMS) and instrumental neutron activation analysis (INAA), linked for the first time to the commonly used aqua regia method for contaminant extraction. Results from these have already provided confidence in the measurement capabilities of an accreditation laboratory in Slovenia. For the novel organic CRM an international Key and Pilot study (CCQM-K156 / P198) was launched.
As a result of the project new CRMs with known analyte amounts are available to laboratories for environmental analysis in Europe. In addition, all the institutes involved now have the capacity to carry out all aspects of CRM development and certification, which will ultimately contribute to a more reliable and harmonised approach to pollution monitoring, helping to protect human health and the environment and fulfil EU regulations.