Isobutyl acrylate

Short-term toxicity to aquatic invertebrates

Description of key information

Based on data from the structural analogue n-butyl acrylate, isobutyl acrylate is considered to be acutely toxic to freshwater invertebrates.
EC50 (48 h) = 8.2 mg/L (measured), (Daphnia magna, OECD TG 202, flow through) (n-butyl acrylate)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

8.2 mg/L

Additional information

Experimental data are available for the target substance isobutyl acrylate (CAS 106 -63 -8) as well as for the source substances tert-butyl acrylate (CAS 1663 -39 -4) and n-butyl acrylate (CAS 141 -32 -2).

 

Isobutyl acrylate

In a short term test with Daphnia magna conducted according to the EU Method C.2 a 48-hour EC50 value of 9.7 mg/L was found (BASF AG, 1988). The nominal test concentrations were 0.4, 0.8, 1.6, 3.13, 6.25, 12.5, 25 and 50 mg/L. In this study conducted in open test vessels, under static conditions and without analytical monitoring, the volatility of isobutyl acrylate was not taken into consideration. Thus, this study is only valid with restrictions.

 

In another study following the EU Method C.2 conducted under static conditions the 48-hour EC50 was determined to be 19.8 mg/L (BASF AG, 1991). The nominal test concentrations were 3.13, 6.25, 12.5, 25, 50 and 100 mg/L. In this study conducted in open test vessels and without analytical monitoring, the volatility of isobutyl acrylate was not taken into consideration. So this study is only valid with restrictions.

 

n-butyl acrylate

Valid experimental data from the structural analogue n-butyl acrylate are available. An acute toxicity study with Daphnia magna (BAMM, 1990) indicated the 48-hour EC50 for n-butyl acrylate was 8.2 mg/L based on mean measured concentrations. This study followed EPA OTS 797.1300 using a flow-through design. Nominal exposure concentrations ranged from 1.2 to 20 mg/L and mean measured concentrations ranged from 1.4 to 17 mg/L. Complete immobilization occurred in the highest concentration (17 mg/L, measured). The NOEC was 2.4 mg/L (measured).

 

tert-butyl acrylate

In an acute toxicity study with Daphnia magna (BASF AG, 2001) the 48-hour EC50 was found to be 8.74 mg/L based on mean measured concentrations. This study followed OECD TG 202 using a static design (closed system). Nominal exposure concentrations ranged from 3.13 to 100 mg/L. The analytical recovery rate was after 0h and 48 h in all analyzed test solutions below 80 %. The effective concentrations mentioned in the study report were based on a median analytical recovery rate in the range of the beginning effect (12.5 mg/L) between 0 h and 48 h (46 %). Complete immobilization occurred at the second highest concentration (23 mg/L, measured). The NOEC was 5.75 mg/L (measured).

 

Conclusion

Since isobutyl acrylate is readily biodegradable and moderately volatile, only test results from studies with analytical monitoring were used for the hazard assessment for freshwater invertebrates. By applying a read across approach and under worst case assumption the EC50 (48 h) of isobutyl acrylate is considered to be 8.2 mg/L based on data from the structural analogue n-butyl acrylate (BAMM, 1990).