Asparagine

Endpoint summary

Description of key information

- QSAR estimation using the Estimation Programs Interface (EPI) SuiteTM v4.1 containing the ECOlogical Structure Activity Relationship (ECOSAR) software of short-term toxicity to aquatic invertebrates and short-term toxicity to fish, for Daphnia magna the following value was predicted: 48h LC50 = 6070000 mg/L, the prediction of short-term toxicity to fish revealed three classes of structures: For aliphatic amines the LC50 was determined to be 1.69E006 mg/L, for amides the LC50 was 5.73E006 mg/L and for neutral organics the LC50 was 1.83E007 mg/L.

- study conducted according to OECD guideline 201, GLP, green alga (Pseudokirchneriella subcapitata) were exposed 72h under static conditions to 114 mg L-asparagine hydrate/L corresponding to 100 mg L-asparagine/L, no inhibition of growth rate, EC50 > 114 mg/L L-asparagine hydrate corresponding to 100 mg L-asparagine/L; NOEC = 114 mg/L L-asparagine hydrate corresponding to 100 mg L-asparagine/L.

Additional information

The ECOSAR estimation revealed that algae are the most sensitive species for determination of any toxic effect, i.e. the lowest EC50 values were predicted. Hence, in order to susbtantiate this estimation a study according to OECD guideline 201 was performed. In line with the results from the ECOSAR estimation the EC50 values which were generated for the two functional groups that were detected, i.e. aliphatic amines and amides and the neutral organic, were above the limit concentration of 100 mg/L. Due to the expected low aquatic toxicity testing of short-term toxicity to aquatic invertebrates and short-term toxicity to fish was omitted and the QSAR estimation preformed instead is considered to be sufficient to predict the ecotoxicologicaql properties of L-asparagine.

- The short-term toxicity to fish of L-asparagine was determined by QSAR prediction using the Estimation Programs Interface (EPI) SuiteTM v4.1 containing the ECOlogical Structure Activity Relationship (ECOSAR) software.

Three different classes of chemicals were detected by the program and the LC50 value for all three classes was calculated. For aliphatic amines the LC50 was determined to be 1.69E006 mg/L, for amides the LC50 was 5.73E006 mg/L and for neutral organics the LC50 was 1.83E007 mg/L. All values were far above the limit concentration of 100 mg/L and since the functional groups of the test item fall within the applicability domain of the model used, the substance is considered to be not toxic to fish up to the limit concentration.

- Also the short-tern toxicity to aquatic invertebrates was determined with a QSAR prediction conducted with the EPISuite TM; ECOSAR v1.11 software. Because the same QSAR prediction model as compared to the short-term toxicity to fish was used, likewise the same chemical classes were detected. In consideration of the results of all three chemical classes, several LC50 values are estimated.  All LC50 values predicted for L-asparagine were far above the 100 mg/L limit concentration. Since the substance falls within the applicability domain of the used model and the predicted values are more than 10-fold greater than the water solubility, no toxic effects are expected to occur up to saturation limits with respect to short-term toxicity to aquatic invertebrates.

- In a GLP-study according to OECD test guideline 201 growth inhibition of  Pseudokirchneriella subcapitata after 72h of treatment with 114 mg/L (nominal concentration) L-Asparagine H2O was determined. The test item exhibited no adverse effects on  Pseudokirchneriella subcapitata during the incubation period. No growth rate or yield inhibition as compared to the control occurred. All Validity criteria were fulfilled and the test system was considered valid as indicated by the results of the test with the reference substance potassium dichromate. Thus, the EC50 of L-Asparagine H2O was determined to be 114 mg/L corresponding to a EC50 of > 100 mg/L for L-Asparagine. The NOEC for  L-Asparagine H2O was determined to be 114 mg/L corresponding to a NOEC of 100 mg/L for L-Asparagine.