Registration Dossier

Environmental fate & pathways

Adsorption / desorption

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The adsorption potential of the substance is low.

Key value for chemical safety assessment

Koc at 20 °C:
1

Additional information

Since no study is available for assessing the adsorption/desorption potential of 1,2,3-Propanetriol, homopolymer (CAS 25618-55-7), in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, data from a structurally related substance was used supported by QSAR calculations for the main components of the substance. Further justification for the read-across approach is given within the environmental fate and pathways (chapter 5) overall endpoint summary.

The key study with Reaction mass of 3-[3-(2,3-dihydroxypropoxy)-2-hydroxypropoxy] propane-1,2-diol, 3-(2,3-dihydroxypropoxy)propane-1,2-diol,3-[3-[3-(2,3-dihydroxypropoxy)-2-hydroxypropoxy]-2-hydroxypropoxy]propane-1,2-diol (List No 915-741-3) was performed according to OECD guideline 121 under GLP conditions (Brekelmans 2009). In the chromatogram of the test substance solution recorded on the MS detector, one peak was observed at m/z 167.0 amu (diglycerol) and one at m/z 241.0 amu (triglycerol). Both peaks had a retention time of 1.55 minutes. Under the same analytical conditions, the retention time of acetanilide (log Koc = 1.26) was 2.18 minutes on the UV detector which is equivalent to a retention time of 2.27 minutes on the MS detector. Because the major constituents in Polyglycerol-3 eluted before Acetanilide, it was concluded that the log Koc of Polyglycerol-3 at neutral pH is < 1.26 (Koc < 10.82).

As the substance is composed of different homologues, the Koc values were additionally calculated for the representative components (mono- to tetraglycerol) using KOCWIN v2.00 based on the Molecular Connectivity Index (MCI). This model has no universally accepted definition of model domain. Since some components are outside the training set of the MCI model, the results should be taken with caution. The definite values may not be fully reliable, but indicate a low adsorption potential, which is also to be expected based on the low Kow (-1.65 - -5.41) and the water solubility of the main components. Nevertheless, the glycerol component fits into the domain of the training set and the resulting Koc value of 1 is reliable. The Koc values of the polyglycerol components were calculated to be 10, which supports the result of the key study. Based on this information, it can be assumed that the adsorption potential of 1,2,3-Propanetriol, homopolymer (CAS 25618-55-7) is low.