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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Testing is not scientifically justified as this substance is hydrolytically unstable. Therefore, the read-across result of the 16-h toxicity threshold of isooctanol to Pseudomonas putida (cell multiplication); 63 mg/l, based on the nominal concentrations, is used as key value in CSA. 

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
63 mg/L

Additional information

As the target substance hydrolyses rapidly (half-life < 10 minutes) the toxicity to microorganisms is related to this main organic degradation product (alcohols, C7-9-iso, C8-rich; Exxal 8) of the target substance. Therefore, it was justified to use the toxicity of the main decomposition product as a key value in CSA. This degradation product (Exxal 8) released from the target substance in contact with water consist mainly of isooctanol (93 %). The read-across justifications in Annexes of the CSR present more information on the purity of these source substances.

According to the ECHA Guidance on information requirements and chemical safety assessment, in absence of activated respiration test, toxicity results to microbial bacteria can be used for evaluate the inhibitory effects of chemicals to STP micro-organisms. Therefore, the result of the P.putida cell multiplication inhibition test of the organic hydrolysing product (isooctanol; the main constituent of Exxal 8) with Klimisch score 2 is used to calculate the PNEC STP.