Evaluation of methods for the analysis of soils according to § 8 of the German Federal Soil Protection Act (BBodSchG)
The German Federal Soil Protection Act establishes the conditions for effective soil protection and remediation of contaminated sites. In the German Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV) limiting values and methods for the determination of environmentally harmful substances in soils are fixed. The aim of this project was to evaluate selected methods by comparative investigations and proficiency testing schemes. New methods for the determination of inorganic and organic pollutants should be developed and compared with the existing standard
methods. Despite the widespread use of ICP-OES up to now no national or international standard is available for the determination of heavy metals in soil extracts with this analytical method. The influence of spectral and non spectral interferences on the accuracy of the results was systematically investigated, especially based on aqua regia soil extracts. Analyte concentration equivalents were determined, too. Based on these results a proposal for a standard was submitted to the corresponding working group of ISO TC 190.[...]
Validation of a European standard for the determination of hexavalent chromium in solid material
(2007)
A European standard for the determination of Cr(VI) in solid material has been elaborated in the framework of an international co-operation and finally validated in the course of an interlaboratory comparison. The procedure is based on the alkaline digestion prescribed by EPA method 3060A followed by ion chromatography and determines an operationally defined content of Cr(VI), including water-soluble and insoluble chromates. A preliminary robustness study was carried out in order to compare different extraction methodologies and to study the equivalency of different analytical methods for the determination of Cr(VI) in alkaline extracts of soil and waste materials. During an interlaboratory validation trial with 19 European laboratories a set of 4 samples (2 soil and 2 waste samples) was analysed to determine performance characteristics for different combinations of digestion and detection methods. With the procedures prescribed by the new European standard (EN 15192) acceptable results were obtained for both soil samples and one of the waste samples (sludge). However, for the second waste sample (fly ash) a large deviation in analytical results was observed. This indicates that particularly for waste materials a possible occurrence of strong matrix effects has to be considered and supplementary quality control data are needed in order to assess the validity of analytical results. The accuracy of the determination of Cr(VI) in solid matrices remains a challenging field in terms of maximum extraction efficiency and minimum species interconversion.