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Toxicity to aquatic algae and cyanobacteria

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Description of key information

EC50 (72h) > 1000 mg/L, NOEC (72h) >= 1000 mg/L (nominal) for Pseudokirchnerella subcapitata (OECD 201, limit test)

Key value for chemical safety assessment

Additional information

Since no studies investigating the toxicity to algae of 1,2,3-Propanetriol, homopolymer (CAS 25618-55-7) are available, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read across to the two structurally related analogue substances 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) and glycerol (CAS 56-81-5) was conducted. This read-across is justified in detail in the overall endpoint summary in IUCLID Section 6.1. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substances were used for the assessment. Both read-across substances represent main components of the target substance (mono- to tetraglycerol). Thus, the aquatic toxicity pattern given by these read across substances are considered to be adequately assessing the aquatic toxicity pattern of 1,2,3-Propanetriol, homopolymer (CAS 25618-55-7).


The key study investigated the toxicity of 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) to freshwater algae (Jansen et al., 1992). The limit test was performed according to the OECD Guideline 201 under GLP conditions using Selenastrum capricornutum (=Pseudokirchnerella subcapitata) as test organism. A static test design was applied. The analytic of the test substance confirmed the nominal test concentration. As no algal growth inhibition was observed after an exposure time of 72 h the EC50 is determined to be > 1000 mg/L and the NOEC is determined to be >= 1000 mg/L based on the nominal concentration.


In a supporting study Scenedesmus quadricauda was exposed to the read-across substance glycerol (CAS 56-81-5) for 72 h (Bringmann & Kühn, 1978). The study was conducted prior to GLP and test guidelines, but sufficient data is available for interpretation of the results. Cell growth inhibition was recorded after an exposure time of 8 days. A static test design was applied. A 72 h EC50/EC10 is determined to be > 10000 mg/L based on nominal test concentrations.


Based on the results from the read-across substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which show consistent results for the main components of the target substance (mono-, polyglycerols), it can be concluded that 1,2,3-Propanetriol, homopolymer (CAS 25618-55-7) will not exhibit acute nor chronic effects to algae up to 100 mg/L. Thus, it can be considered that the substance is not harmful to algae.