L-alanine

Endpoint summary

Additional information

The results from a fully completed GLP study for short-term toxicity to daphniae reveal that L-alanine does not show aquatic toxicity.

The test results for acute toxicity of L-alanine to daphnia were:

The 48-hour NOEC was determined to be 100 mg test item/L. The 48-hour LOEC was determined to be > 100 mg test item/L and the 48-hour EC50 value was determined to be > 100 mg test item/L.

In a weight of evidance approach the available data clearly indicate that the 96 h LC50 for fish is above 100 mg/L. First the LC50 for fish was estimated by using OECD QSAR Toolbox (Version 2.3; data base version: 2.1.8/1.00).

The LC50 was estimated by QSAR prediction based on trend analysis. The LC50 for short-term fish toxicity (96h) of L-alanine was calculated to be 26300 mg/L. This low toxicity was further confirmed by experimental results with the similar substance L-valine as well with experimental results with another proteinogenic amino acid (DL-methionine). These experimental results could be used for read-across purposes as the substance show similar physico-chemical properties and a similar toxicological/ecotoxicological profile.

Toxicity to algae:

Data from a higher trophic level (fish) are available which show that aquatic toxicity does not occur. Aquatic toxicity also does not occur at the trophic level of invertebrates (Daphnia magna). In accordance with Annex XI No. 1.2 there is sufficient weight of evidence from several independent sources of information leading to the assumption/conclusion that the substance does not cause aquatic toxicity to algae.

Despite of that a limit test (pre-experiment) for short-term toxicity to aquatic algae was performed. No effects were reported at the concentration of 1000 mg/l. A cell count of the cell density at this concentration showed no inhibition in the cell number in comparison to the control cell density.

This is not surprising. L-alanine is a naturally occurring essential amino acid which is omnipresent in nature. It is a basic metabolite and building block of all living organisms and cells and is also a nutrient for algae. Thus significant toxicity to algae can be excluded.

The results do not trigger classification.

In respect of REACH Art. 14 in conjunction with REACH Annex I a CSA is required which includes an exposure assessment if the particular substance fulfils the criteria for any of most hazard classes or categories set out in Annex I to regulation 1272/2008 or is assessed to be a PBT / vPvB (for details see REACH Annex I, Section 0.6.3.). Annex I, Section 5.0 of the REACH Regulation states that the exposure assessment “shall cover any exposures that may relate to the hazards identified in Sections 1 to 4”.

Thus REACH requires that the exposure assessment is closely linked to the hazard assessment, which may identify hazards either for the environment, or for human health, or for both. The hazard assessment (including the classification) as well as the performance of an exposure assessment are focused either on possible effects on the environment or on possible effects on human health. L-alanine is not hazardous for the environment, nor for human health. Thus an exposure assessment within the Chemical Safety Assessment for L-alanine is not required.