Example of a graphical representation of interlaboratory comparison results

Example of a graphical representation of interlaboratory comparison results

Source: BAM

The Bundesanstalt für Materialforschung und -prüfung (BAM) organises an interlaboratory comparison on organic and inorganic parameters in contaminated soil every year in September.


BAM offers its interlaboratory comparison programme for external quality assurance which is aimed in particular at test laboratories which must participate in interlaboratory comparisons because of an existing or requested accreditation. In addition, all other laboratories have the opportunity to participate on a voluntary basis.


The basis for the interlaboratory comparisons is an agreement between the Regional Finance Office (OFD) Hanover as the Federal Government’s Centre for Soil and Groundwater Protection, and the Bundesanstalt für Materialforschung und -prüfung (BAM).


BAM dispatches contaminated soil or sediment samples as interlaboratory comparison samples, in which both inorganic and organic pollutants are to be determined. Organisation and implementation are carried out according to the guidelines DIN EN ISO/IEC 17043 and DIN ISO 13528. The results are evaluated according to DIN 38402-45.

Samples will be provided for German laboratories seeking accreditation. All correspondence, all protocols, reports and related papers concerning this PT round will be provided in German only.


Soil samples for interlaboratory comparisons

Soil samples for interlaboratory comparisons

Source: BAM

The following parameters were determined in soil samples in past interlaboratory comparisons:

  • Polycyclic aromatic hydrocarbons (PAH)
  • Total petroleum hydrocarbons (TPH, ISO 16703)
  • Polychlorinated biphenyls (PCB)
  • Elements (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn)
  • Total cyanide


The statistical evaluation of the results is carried out according to DIN 38402-A 45:2014-06 "Interlaboratory comparisons for external quality control of laboratories" using the combined Hampel/Q method estimation procedure, a method of robust statistics.


The costs for an interlaboratory comparison, including evaluation and final report, vary according to the respective sample and range between €200 and €300, plus VAT. Information on current sample prices can be found in the information on this year's interlaboratory comparison and in the webshop.

Information on the current interlaboratory comparison

27th BAM Interlaboratory Comparison on Contaminated Soil, September/October 2021


Applications are to be sent to the BAM webshop.