IMEP-23: The Eight WFD PAHs in Water in Presence of Humic Acid

IMEP-23 is linked to the Water Framework Directive (WFD). It studied the capability of control laboratories to measure the eight WFD PAHs in the presence of humic acid in a water matrix. Humic acid simulates natural colloidal organic matter and is known to adsorb PAHs. This gives rise to various issues that are of large importance for the control laboratories. Participants' results were benchmarked against the IMEP certified reference values. On average 80 % of the z scores was satisfactory. Zeta scores were calculated for those laboratories who provided an uncertainty estimate. These were less satisfactory and this shows that many laboratories encounter difficulties to provide a reasonable uncertainty estimate.JRC.D.4-Isotope measurement

Reference Materials for the Monitoring of the Aquatic Environment. A Review with Special Emphasis on Organic Priority Pollutants.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Comparison of Different Techniques Used for the Determination of Mineral Oil Hydrocarbons from Polluted Soil.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Accurate Quantification of PAHs in Water in the Presence of Humic Acid Colloids using Isotope Dilution Mass Spectrometry

The effect of colloids on the analytical recovery of PAHs from water samples has been investigated. The studies were performed using synthetic humic acid as colloid model and a mixture containing the 16 PAHs on the priority list of the US Environmental Protection Agency. The presence of humic acid reduced the extraction efficiency between 10 to 75 % confirming that hydrophobic compounds are strongly bound to colloidal organic material and the real content of the PAHs might be underestimated. Therefore an analytical protocol was developed for the accurate determination of PAHs in the presence of colloids based on isotope dilution mass spectrometry. The procedure compensates for losses due to sorption of PAHs and can be used for the determination of the total PAH concentration in water, i.e. dissolved PAHs plus PAHs adsorbed on colloids. To obtain realistic estimates it is essential to allow a certain time for equilibration between the isotope spike and the aqueous matrix. This time may vary between 5 and 24 h and is correlated to the water solubility and hydrophobicity of PAHs. The achieved protocol allows to obtain recoveries ranging from 94 to 105 %. Expanded uncertainty of the measurement was between 5-7 % for all PAHs. A comparison between liquid extraction and solid phase extraction for extraction of PAHs from water samples rich in colloidal material showed that both extraction methods produced comparable results.JRC.D.2-Reference material

Challenges in the Preparation of Water Matrix Reference Materials for PAHs and Pesticides: Examples from the SWIFT-WFD Proficiency Testing Schemes

In accordance with the Article 8 of the Water Framework directive (WFD), EU Member States are required to establish monitoring programmes of the surface and groundwater quality within each river basin district. As such data are the basis for regulatory decisions and measures required to achieve WFD environmental objectives, appropriate analytical quality assurance/quality control (QA/QC) tools have to be implemented by the monitoring laboratories. In this respect, Reference Materials (RMs) play an unquestionable key role. Within the framework of SWIFT-WFD project, several approaches for the preparation of matrix RMs for the analysis of polycyclic aromatic hydrocarbons (PAHs) and pesticides in water have been exploited and used in wide-scale Proficiency Testing (PT) schemes. The different strategies employed in the preparation of water matrix RMs for organic analytes are hereby presented and described. Through the review of PT scheme results, some reflections about the applicability and suitability of the different approaches are presented.JRC.D.2-Reference material

Critical Evaluation of Interlaboratory Comparisons for PAHs and Pesticides in Organic Standard Solutions in Support of the Implementation of the Water Framework Directive

Several proficiency tests were organized within the framework of a European project called SWIFT-WFD in view of implementation of the Water Framework Directive (WFD). Among others, the parameters studied were PAHs and pesticides in organic standard solutions. The aim of this study was to evaluate the state of the art in Europe and possible sources of bias in calibration procedures. More than 30 laboratories across Europe took part in this study. These laboratories used their regular in-house analytical methods. The analytical results obtained are discussed. The averages of the results for all analytes agreed partially with the values of the gravimetric sample preparation. Most of the participants in both exercises obtained satisfactory Z-scores. However significant outlier rates (in most of the cases around 20 % of the submitted data sets) indicate that laboratories across Europe need to improve the quality of the analytical data they deliver. Some questions regarding the use of Z-scores to evaluate the laboratory performance are also raised.JRC.D.2-Reference material

IMEP-23: The Eight EU-WFD Priority PAHs in Water in the Presence of Humic Acid

Recently, the International Measurement Evaluation Programme (IMEP) organized an interlaboratory comparison on total concentrations of eight polycyclic aromatic hydrocarbons (PAHs) in natural inland waters. It was carried out in support to the European Union Water Framework Directive (EU-WFD) that lists these eight as priority substances. As sample matrix, we used groundwater spiked with humic acid as a model for the colloidal substances that are present in natural inland waters. Humic substances can adsorb PAHs, but we found that some laboratories did not apply analytical procedures that sufficiently accounted for this. One of these laboratories was involved in establishing the reference values. We show how this impacted on the reliability of their measurements. Many participants accepted our invitation to report their measurement uncertainties. We assessed their results against our reference values and uncertainties, and provided z and zeta scores. Although the overall measurement capability appears satisfactory, there is room for improvement of analytical procedures as regards the use of measurement standards.JRC.D.5-Food Safety and Qualit

Preparation of Reference Materials for Proficiency Testing Schemes

The present framework for Community action in the field of water policy (Water Framework Directive, WFD) (European Commission, 2000) aims at maintaining and improving he aquatic environment in the European Union. The success in the implementation of the WFD depends on the achievement of reliable monitoring data, which assure good managing strategies and potential remediation actions in water bodies at EU-level. To obtain reliable data, water analysis laboratories must develop quality assurance (QA) systems and assure not only internal quality control (QC), but also external quality control such as regular participation in proficiency testing (PT) schemes. The European Commission finded the project "Screening method for Water data Information in support of the Water Framework Directive" from January 2004 till March 2007 (SWIFT-WFD). One of the activities undertaken in hte SWIFT-WFD project was the production of quality control tools. In this chapter, the preparation of selected water reference materials, and other quality control tools such as calibrants and multi-component standard solutions, is described. The produced materials were used in three PT schemes with the participation of a total of 94 laboratories from 21 European countries.JRC.D.2-Reference material