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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

Key value for chemical safety assessment

EC50 for microorganisms:
6 000 mg/L
EC10 or NOEC for microorganisms:
830 mg/L

Additional information

A study was conducted to assess the toxicity of the read across substance, C8-18 and C18-unsatd. DEA, to the bacteria Pseudomonas putida according to DIN Guideline 38412 L8, in compliance with GLP. Pseudomonas putida colonies, in triplicate, were exposed to the test substance (directly diluted in test medium) at nominal concentrations of 0.01, 0.05, 0.10, 0.50, 1.00, 2.50, 5.00 and 10.00 g/L. Inhibition of cell growth compared to controls was recorded after 16 h. Under the conditions of the study, the nominal 16 h EC50 and EC10 were 6.0 and 0.83 g/L (i.e. 6000 and 830 mg/L), respectively (Poth, 1992).

A study was conducted to determine the toxicity of the read across substance, isoC18 MIPA (100% active), to microorganisms according to OECD Guideline 209 and Commission Directive 87/302/EEC, Part C, in compliance with GLP. Activated sludge was exposed to the test substance at nominal concentrations of 0, 10, 32, 100, 320 and 1000 mg/L for 3 h. In addition, two controls and three different concentrations of the reference substance 3,5 -dichlorophenol (5, 16 and 50 mg/L) were tested. The respiration rate (oxygen consumption) of the aerobic activated sludge fed with standard amounts of synthetic wastewater was measured. The inhibitory effect of the test substance was expressed as a percentage of the mean respiration rate of the controls. Up to and including the nominal concentration of 1000 mg/L, the test substance had no inhibitory effect on the respiration rate of activated sludge after the incubation period of 3 h. The respiration rates were in the range of -9.2 to ‑17.8% compared to the controls. The 3 h EC50 of the reference substance 3,5 -dichlorophenol (positive control) was calculated to be 7.0 mg/L and therefore was in the accepted range of 5 -30 mg/L, confirming the suitability of the used activated sludge. Under the study conditions, the 3 h EC50 of the test substance to microorganisms was determined to be >1000 mg/L (nominal) (Batscher, 1999).