Reaction mass of diiron carbide, diiron phosphide and triiron phosphide

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption: screening

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the physicochemical properties of the substance indicate that it can be expected to have a low potential for adsorption

Justification for type of information:

Fe3P is a solid (particulate/powder) inorganic substance with a very low solubility (<< 1 mg/L) as demonstrated in water solubility tests according to EU Method A.6 and OECD Guideline 105, and in Transformation/Dissolution tests that were conducted in accordance to OECD Guideline N° 29.
Particles of solid Fe3P will not bind to suspended solids or soil particles, and the limited fraction of Fe3P that dissolves will not be present as Fe3P, but will transform immediately to soluble Fe- and P-species. The actual speciation will depend on the physicochemical properties of the receiving environment, with each species having its own binding properties.

In addition, both iron and phosphorus are ubiquitously present in the environment, and are naturally occurring constituents of suspended solids and soil particles (in the actual matrix or present as adsorbed hydroxides, phosphates, etc). As a consequence the outcome of an adsorption/desorption test with Fe3P will always be compromised since a fraction of the measured Fe/P concentrations in solution or in the suspended solids/soil particulates will originate from the particles themselves. Taking into account the low solubility of Fe3P, these fractions may be significant. In addition, undissolved Fe3P particles will be included when analysing the Fe and P-content of the solid fraction, as it would technically impossible to separate the particulate Fe3P from soil/suspended solid particulate.