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Toxicity to microorganisms

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Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when Isobutyl acrylate is introduced into biological treatment plants in appropriately low concentrations.

EC50 (30 min) > 1000 mg/L (domestic activated sludge, OECD TG 209)

Key value for chemical safety assessment

Additional information

Two experimental studies on toxicity to microorganisms are available for the target substance isobutyl acrylate.

Key information

In a test with domestic activated sludge the inhibition of oxygen consumption was examined according to OECD TG 209 and in compliance with GLP regulations (BASF AG, 2001). After 30 minutes incubation, no inhibition of oxygen uptake was observed at the only test concentration of 1000 mg/L. The validity of the test and the suitability of the used sludge was confirmed by the performance of the reference substance 3,5-dichlorophenol (EC20 = approx. 1.8 mg/L). In this test the EC50 of isobutyl acrylate was determined to be > 1000 mg/L (nominal).

Supporting information

In addition, there is an older non GLP study conducted according to the national German Standard DIN 38412, part 27 in which the effect of Isobutyl acrylate on the oxygen consumption of Pseudomonas putida was determined after an incubation time of 30 min (BASF AG 1992). The nominal test concentrations were 625, 1250, 2500, 5000, 10000 mg/L. As a result, the 30-minute EC10 and EC50 were found to be 2850 and 6400 mg/L (nominal) , respectively.

Conclusion

Based on the most current and reliable information (BASF AG, 2001) the EC50 of isobutyl acrylate is considered to be > 1000 mg/L (nominal). This value is supported by results of an additional study to the national German Standard DIN 38412, part 27 (BASF AG, 1992) as the 30-minute EC10 and EC50 were determined to be 2850 and 6400 mg/L (nominal) , respectively. in conclusion, the inhibition of the degradation activity of activated sludge is not anticipated when Isobutyl acrylate is introduced into biological treatment plants in appropriately low concentrations.