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EC number: 267-956-0
CAS number: 67953-76-8
Concentration in water (ppm)
Measured octanol/water partition coefficient
3.39 x10 -4
average partition coefficient value =
3.15E-4 ( low Pow = -3.50)
log Kow [HEDP-xK]: <-3.5
A log Kow value of -3.5
was reported for the parent acid, HEDP-H in a reliable study conducted
according to generally accepted scientific principles comparable to an
appropriate test guideline. The method has been adequately described in
the report. The result is considered to be reliable and has been
assigned as key study.
HEDP-xK is freely soluble in water
and, therefore, the HEDP anion is fully dissociated from its potassium
cations when in solution. The HEDP anion has four P-OH groups that can
be ionised. They lose hydrogen to form a negatively charged group (P-O-).
As the pH increases, the number of ionised groups increases. Under any
given conditions, the degree of ionisation of the HEDP species is
determined by the pH of the solution. At a specific pH, the degree of
ionisation is the same regardless of whether the starting material was
HEDP acid or salt.
Therefore, the log Kow measured
for HEDP-H is directly relevant for HEDP-xK. The log Kow for
an ionising substance will vary with pH as the ionised species will have
a greater hydrophilicity and lower log Kow than the neutral
species. The pH was not measured in the study with HEDP-H, however, a
solution of HEDP-H in unbuffered water will have a very low pH.
Therefore, the log Kow for HEDP-xK is reported as <-3.5.
For further details of the
speciation of HEDP see PFA 2022 attached in Section 13 of the IUCLID dataset
(Assessment reports: Speciation of HEDP).
PFA 2022: HEDP speciation at pH
relevant to Ecotoxicology and Toxicology, Reference: PFA.224.612.001,
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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