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Diss Factsheets
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EC number: 200-795-6 | CAS number: 73-22-3
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Additional information
Short-term toxicity to fish, invertebrate, and algae
Reliable experimental results from acute toxicity testing of two trophic levels (daphnids, algae) are available; no experimental data are available for fish. Due to the low toxicity of L-tryptophan to daphnids and algae it is to be expected that the acute toxicity to fish will be low as well. Therefore the acute toxicity to fish was calculated using ECOSAR which supports this assumption (96 h LC50>850 mg/L). The toxicity of L-tryptophan to Daphnia magna and Desmodesmus subspicatus was investigated in guideline studies. The 48h LC50 and 72 h EC50 for Daphnia magna and Desmodesmus subspicatus were determined to be >100 mg/L nominal each.
Long-term toxicity to fish and invertebrate, and algae
In Annex IX of Regulation (EC) No 1907/2006, it is laid down that chronic toxicity tests shall be proposed by the registrant if the chemical safety assessment indicates the need to investigate further the effects on aquatic organisms. According to Annex I of this regulation, the chemical safety assessment triggers further action when the substance or the preparation meets the criteria for classification as dangerous according to Directive 67/548/EEC or Directive 1999/45/EC or is assessed to be a PBT or vPvB. The hazard assessment of L-tryptophan reveals neither a need to classify the substance as dangerous for the environment, nor is it a PBT or vPvB substance, nor are there any further indications that the substance may be hazardous to aquatic organisms. According to reliable study results, L-tryptophan is considered to be rapidly degraded in the environment and the bioaccumulation potential is regarded to be insignificant. For the algae Desmodesmus subspicatus a 72 h NOEC=100 mg/L (nominal) was determined in a guideline study. Based on the available information the performance of chronic studies with fish and invertebrates is assumed to be not justifiable.
Toxicity to microorganisms
According to REACH Regulation (Annex VIII, 9.1.4, column 2) the study on respiration inhibition of activated sludge does not need to be done if the substance is readily biodegradable. L-Tryptophan proved to be readily biodegradable and fulfilling the 10-d-window criterion (77% biodegradation after 28 d). In the toxicity control containing both test and reference item (20 mg/L each) 75% biodegradation based on ThCO2 occurred within 14 d thus indicating that the test item was not inhibitory at the concentration tested. Based on these results, the study on respiration inhibition of activated sludge is assumed to be not justifiable.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.