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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

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Administrative data

Link to relevant study record(s)

Description of key information

3 h EC50 >5.0 mg/L, OECD 209 (Boeri, 2004)

Key value for chemical safety assessment

EC50 for microorganisms:
5 mg/L

Additional information

In the key study, an activated sludge respiration inhibition test was carried out in accordance with the OECD 209 guideline under GLP conditions.

Activated sludge obtained from a wastewater treatment facility was used in this test. The test was carried out under static conditions with a control, solvent control and five concentrations of the test material over a 3 hour exposure period. The highest tested nominal concentration, 5.0 mg/L, was the apparent water solubility limit for 4-chloro-o-xylene under test conditions. Nominal concentrations were used for all calculations.

The test material did not inhibit respiration of the activated sludge by more than 50 % at any tested concentration. The EC50 determined during a reference toxicant test with this batch of activated sludge and 3,5-dichlorophenol was 6.9mg/L, which is within the acceptable range of 5 to 30 mg/L. The 3-hour EC50 for activated sludge exposed to 4-chloro-o-xylene was greater than 5.0 mg/L, the highest tested concentration and the approximate water solubility limit of the test material.