Validation of European horizontal methods for the analysis of PAH, PCB and dioxins in sludge, treated biowaste and soil

Background Draft standards for the determination of organic pollutants in the solid matter of environmental matrices such as sludge, treated biowaste and soil have been basically developed in the framework of the European standardisation project HORIZONTAL. A research project financed by the German Federal Environment Agency was initiated to finalise some of these CEN standard drafts, since fully validated standard procedures are crucial for the evaluation of their reliability in the context of implementation in legislation on environmental health. Approach Appropriate test materials (< 2 mm particle size) were prepared and homogenised from contaminated soils, sludge and treated biowaste containing polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dioxins, furans and dioxin-like-PCB and served, along with reference solutions, as the basis for international interlaboratory comparisons. Performance data of three analytical standard procedures were obtained by the statistical evaluation of results received from 11 to 29 participants per test material. Results The overall variation coefficients of reproducibility (between-lab standard deviations) for the sum parameters were roughly between 10 and 35%. The variation coefficients of repeatability (within-lab standard deviations) range between 3 and 8% and show no trend considering the substance groups or matrices. The highest coefficients of reproducibility were found for the analysis of PAH, which were between 26 and 35%, depending on the matrix, whereas 7–17% reproducibility was observed for toxicity equivalents (TEQ) comprising dioxins, furans and dl-PCB. Conclusions Overall, the results confirm that the procedures described in the Technical Specifications are fit for purpose for all three matrices and that the feasibility of the HORIZONTAL approach, to cover several matrices with one standard per analyte, was thereby proven.