Rape oil, reaction products with diethanolamine

Short-term toxicity to aquatic invertebrates

Description of key information

Considering that the lower 48-h EC50 value of 0.9 mg/L obtained from a acute daphnia toxicity study with structurally similar amides, C16-18 (even-numbered) and C18-unsatd., N,N-bis(hydroxyethyl) was attributed to the presence of impurities, the more reliable acute 48 h EC50 value in freshwater invertebrates of 3.2 mg/L was considered more appropriate for hazard assessment of HE Rape Oil, reaction product with diethanolamine.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3.2 mg/L

Additional information

A study was conducted to determine the acute toxicity of the structurally similar amides, C16-18 (even-numbered) and C18-unsatd., N,N-bis(hydroxyethyl) to Daphnia magna in a static system. Juvenile water fleas were exposed for 48 hours to the test substance at 0, 0.5, 0.7, 1.0, 1.4, 2.0, 2.8, 4.0, 5.6 and 8.0 mg/L. Immobility was recorded at 24 and 48 hours. Under the study conditions, the 48-h EC50 of the test substance for Daphnia magna was 0.9 mg/L (nominal). The 48-h NOEC was 0.5 mg/L (nominal) (Scholz N, 1991).

 

An acute toxicity study according to OECD guideline 202 was performed to evaluate the immobilisation potential of structurally similar amides, C8-18 (even-numbered) and C18-unsatd., N, N-bis(hydroxyethyl) in Daphnia magna. The test animals in duplicate petri-dishes, were exposed to the test material at 0, 1, 2, 4, 8 and 16 mg/L conc. under static conditions. Observations were performed at 0, 24 and 48 hours to determine the % immobilised daphnids in the control and test dishes. Based on the results, the test material was considered to be acutely toxic to Daphnia. The 48 hour EC50 value was determined to be 3.2 mg/L (Olsson T, 1994).

 

Another study was conducted to evaluate the acute toxicity of the structurally similar amides, C12-18(even numbered) and C18-unsatd., N,N-bis(hydroxyethyl) to Daphnia magna under static conditions. The procedures followed OECD guideline 202 with deviations. Daphnia magna (20 per dose) were exposed to the test material in a concentration range of 1-11 mg/L for 24 hours and immobilities were determined at 24 hours. Based on the results, the 24 hour EC0, EC50 and EC100 were 2.0, 3.3 and 5.6 mg/L, respectively and the test substance was determined to be toxic to Daphnia magna (Gode, 2001). The lower 48-h EC50 value of 0.9 mg/L obtained from the above guideline compliant acute daphnia toxicity study conducted with structurally similar amides, C16 -18 (even-numbered) and C18-unsatd., N,N-bis(hydroxyethyl) is probably attributed to the presence of impurities (such as unreacted DEA) which is introduced due to the use of fatty acid containing oils as the starting material. This is further supported by a higher 48-h EC50 value of 3.2 mg/L obtained with a shorter chain structurally similar amides, C8-18 (even-numbered) and C18-unsatd., N, N-bis(hydroxyethyl) which was not synthesised from oils as the starting material and thereby having less impurities. Considering the above information, the reliable acute 48 h EC50 value in freshwater invertebrates of 3.2 mg/L was considered for the assessment of the read across substance amides, C18(unsatd.), N,N-bis(hydroxyethyl) amides, C16-18 (even-numbered). 

 

Based on read-across these values will be used for the assessment of HE Rape Oil, reaction product with diethanolamine.