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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

The inhibition of the degradation activity is not anticipated when introduced in appropriately low concentrations.

Key value for chemical safety assessment

Additional information

Short-term effects of the hydroxyethylpiperazine mixture (piperazine: 14.57 %, HEP: 37.768 %, DiHEP: 19.90 %) on the respiration rate of domestic activated sludge were studied in an OECD 209 GLP guideline study. No inhibitory effects were observed. The 3 -h EC10 was > 1000 mg/L (BASF, 2012; report No. 08G0722/11G120).

The results are supported by a second short-term respiration study. The toxic effect of the hydroxyethylpiperazine mixture on microorganisms was studied in a short-term respiration inhibition test according to ISO 8192B. The inoculum was derived from a wwtp treating domestic sewage. The respiration activity was not inhibited by the reaction mass. Instead a promoting effect on the respiration activity was noted (+50%). The 30 -min EC20 was determined to be greater than 875 mg/L (BASF AG, 1990; report no. 1880758).

The low toxicity to microorganisms is also supported by the results of a growth inhibition test with Pseudomonas putida according to Bringmann and Kühn. The 17-h EC10 for the hydroxyethylpiperazine mixture was determined to be 170 mg/L (BASF AG, 1989).

It can be concluded that the inhibition of the degradation activity is not anticipated when the reaction mass is introduced in appropriately low concentrations.