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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC20 (72h) = 1.978 mg/L for Desmodesmus subspicatus (QSAR estimation)

ErC50 (96 h) = 1.4 mg/L for Selenastrum capricornutum

The ErC50 (96 h) is used for PNEC (intermittent release)-calculation. The PNEC-values for freshwater and marine water are calculated on the basis of a HC5-approach.

Key value for chemical safety assessment

Additional information

The acute toxicity of alcohol ethoxylate (C9-11, < 2.5 EO, CAS 68439-46-3) to aquatic algae was investigated in a 96-hours test with Selenastrum capricornutum (Stephenson, 1985). This key study was conducted without analytical monitoring of the test substance concentration and did not follow a defined guideline. The test revealed an ErC50 (96 h) of 1.4 mg/L test item.

Since only a few data on the long-term aquatic toxicity for the mixtures within the category are available, the assessment on long-term toxicity is based on alcohol ethoxylate specific QSARs (Wind & Belanger, 2006; Boeije et al., 2006; Belanger et al, 2006). The QSARs considered all three trophic levels (algae, invertebrates and fish). The effects are described as EC20 values, since the QSARs are more robust for the EC20 values than for NOEC or EC10 values. For the described mixture (C9 -11, <2.5 EO, CAS 68439-46-3) the QSAR for long-term toxicity on green algae Desmodesmus subspicatus (Wind & Belanger, 2006) result in an EC20-value of 0.711mg/L based on biomass and 1.978 mg/L based on growth rate, respectively. This result (ErC20 = 1.978 mg/L) is used as key value for classification and labeling.