The European guideline 2003/53/EC limits the amount of soluble Cr(VI) in cement and cement based products up to a maximum of 2 ppm.
The test method described in the norm EN 196-10 considering the quantification of Cr(VI) in an aqueous solution, is based on the use of an indicator, the s-diphenylcarbazide (DPC). This constituent forms with the Cr(Vi) and, solely with the hexavalent form of the metal, a characteristic coloured complex that enables to characterize quantitatively the Cr(VI) content. The revelation of this coloured complex necessitates the acidification of the solution.
An preliminary oxidation step has been added during the norm publication. The necessity of this additional operation, that renders the test execution more complex and overestimate the measured values of Cr(VI) contents, is therefore questioned by different labs.
The CRIC-OCCN participates in a working group, created par ATILH (PRA-01-01-bis) in order to compare the method described in the norm with the alternative methods without additional oxidation step.