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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The lowest results for xylene isomers is a 28 day NOEC of 16 mg/L for o-xylene

The experimental NOEC was used for the chemical safety assessment.

The estimated EL50 values from TLM QSAR were 71.286 - 90.449 mg/L. The lowest EC50 from the TLM QSAR estimated values was used as EC50 for the chemical safety assessment.

Key value for chemical safety assessment

EC50 for microorganisms:
71.286 mg/L
EC10 or NOEC for microorganisms:
16 mg/L

Additional information

Biodegradation tests were carried out on all three xylene isomers following OECD 301F guidelines using a mixed inoculum of non-adapted sludge and soil micro-organisms. In the toxicity control vessels, containing the individual xylene isomers with the reference substance sodium benzoate, none of the xylene isomers exhibited inhibitory effects on the micro-organisms. The 28 day NOEC (nominal concentration) is therefore 16 mg/L for m-xylene and 16.2 mg/L for o-xylene and p-xylene.

A TLM modeling framework was used to support values derived experimentally.

The TLM EC50 lowest value was used as key value for the chemical assessment due to a lack of information in the supporting experimental studies and because result to be more conservative compared to the lowest value from the supporting experimental study from Blum et al (1991).

The estimated EL50 values from TLM QSAR were 71.286 - 90.449 mg/L, The lowest EC50 from the TLM QSAR estimated values was used as EC50 value for the chemical safety assessment.