Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.
The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 298-680-9 | CAS number: 93820-97-4
Sediment toxicity
Administrative data
Link to relevant study record(s)
Description of key information
Based on all the available information, toxicity to sediment organisms byOctadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4)is not expected to be of concern.
Key value for chemical safety assessment
Additional information
No experimental data is available for the toxicity ofOctadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) to sediment organisms. However, based on all the available information, toxicity to sediment organisms is not expected to be of concern.
The substance is characterized by readily biodegradability, poor water solubility (< 5 µg/L, OECD 105) and is expected to have a high potential for sorption to particles in soil and sediment based on its high log Kow (> 10.0, KOWWIN v1.68). Biodegradation and adsorption to suspended matter are favorable to the effective removal of a substance in sewage treatment plants (STP). Therefore, only negligible discharge into the aquatic environment is expected to occur via STPs. Whatever fraction should still reach the water compartment is expected to undergo rapid and ultimate degradation and the remainder will adsorb to organic soil and sediment particles where sediment organisms are potentially exposed via feed and contact with suspended organic particles. However, based on the physico-chemical properties, the bioavailability of the substance is expected to be low due to its strong binding behavior. Therefore, chronic exposure of sediment organisms is unlikely. Furthermore, the substance is not toxic to aquatic organisms up to the limit of water solubility.
Intrinsic properties and fate
Octadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) is readily biodegradable according to OECD guideline criteria. According to the Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2017), readily biodegradable substances can be expected to undergo rapid and ultimate degradation in most environments, including biological STPs. Therefore, only low concentrations of this substance are expected to be released into the environment, if at all.
Furthermore, the substance has an estimated log Kow of > 10.0 and is poorly water soluble (< 5 µg/L, OECD 105). The Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2017) states that once insoluble chemicals enter a standard STP, they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms. Thus, discharge into the aqueous/sediment compartment is likely to be negligible and chronic exposure of sediment organisms is improbable.
Aquatic ecotoxicity
Based on the available toxicity data for aquatic algae as well as on the long-term toxicity data for aquatic invertebrates and algae, Octadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) is not expected to cause acute or chronic toxicity to aquatic organisms up to its limit of water solubility (< 5 µg/L, OECD 105). Moreover, due to the low water solubility, it is highly unlikely that relevant, bioavailable concentrations of the substance will ever occur in the water phase, i.e. that concentrations high enough to induce any measurable acute and/or chronic effects in aquatic organisms are ever attained.
Significant deviations from this overall ecotoxicological profile are not expected and it is thus concluded that Octadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) is unlikely to cause toxic effects to sediment organisms.
Metabolism/Bioaccumulation
Octadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) is a long-chain aliphatic ester and the biochemical processes involved in the metabolization of aliphatic esters, comprising enzymatic hydrolysis and subsequent metabolization of the corresponding hydrolysis products carboxylic acid and alcohol components, are ubiquitous in the animal kingdom. Thus, in the rather unlikely event of uptake and absorption by aquatic organisms, long-chain aliphatic esters are expected to be enzymatically hydrolyzed by ubiquitous carboxylesterases into their corresponding free fatty acid and alcohol components. The metabolism of the hydrolysis products is well established and not of concern in terms of bioaccumulation (Heymann, 1980; Lech & Bend, 1980; Lech & Melancon, 1980; Murphy & Lutenske, 1990; Sand et al., 1973). The fact that the substance is readily biodegradable is an additional indication that metabolism is very likely and concentrations will be low in exposed organisms. In consideration of all the available information, it is concluded that the potential for bioaccumulation is low.
Conclusion
Due to the ready biodegradability and high adsorption, only negligible concentrations of the substance are expected to be discharged into water bodies, if at all. Whatever fraction is released is expected to rapidly degrade or adsorb to particles of sediment and soil where sediment organisms are potentially exposed via feed and contact with suspended organic particles. However, based on the physico-chemical properties of the substance (i.e. strong binding behaviour), bioavailability is expected to be low. If uptake and absorption should occur, extensive and fast biotransformation of the substance and its metabolites is expected by the action of carboxylesterases (initial hydrolysis to alcohol and fatty acid).
Furthermore, the available aquatic toxicity data suggest that no toxic effects occur up to the limit of water solubility. Moreover, due to the low water solubility of the substance, relevant concentrations of the substance are not expected to ever be attained in water. Therefore, it is concluded that Octadecanoic acid, C16-18-alkyl esters (CAS No. 93820-97-4) does not pose a risk to sediment organisms.
REFERENCES
Heymann, E. (1980): Carboxylesterases and amidases. In: Jakoby, W.B., Bend, J.R. & Caldwell, J., eds., Enzymatic Basis of Detoxication, 2nd Ed., New York: Academic Press, pp. 291-323.
Lech, J., Melancon, M. (1980): Uptake, metabolism, and deposition of xenobiotic chemicals in fish. EPA-600 3-80-082. U.S. Environmental Protection Agency, Duluth, MN, USA.
Lech, J.J. & Bend, J.R. (1980): Relationship between biotransformation and the toxicity and fate of xenobiotic chemicals in fish. Environ. Health Perspec. 34, 115-131.
Murphy, P.G., Lutenske, N.E. (1990): Bioconcentration of haloxyfop-methyl in bluegill (Lepomis macrochirus Rafinesque). Environ. Intern. 16, 219-230.
Sand, D.M., Rahn, C.H., Schlenk, H. (1973): Wax esters in fish: Absorption and metabolism of oleyl alcohol in the gourami (Trichogaster cosby). J Nutr 103: 600-607.
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.
