Dodecyl myristate

Sediment toxicity

Additional information

Based on all the available information, toxicity to sediment organisms is not expected to be of concern.

 

No experimental data are available for the toxicity of thetarget substance Dodecyl Myristate (CAS 2040-64-4)to sediment organisms. However, the substance is characterized by poor water solubility (< 1 µg/L) and only negligible discharge to the aquatic environment is expected to occur via sewage treatment plants (STPs) due to: a) ready biodegradability and b) the high adsorption properties of the substance, resulting in an effective removal in sewage treatment plants. 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.

Based on all the available information, toxicity to sediment organisms is therefore not expected to be of concern.

Intrinsic properties and fate

Dodecyl Myristate (CAS 2040-64-4)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.

Dodecyl Myristate (CAS 2040-64-4)has an estimated log Kow of > 10.0 and is poorly soluble in water (< 1 µg/L). 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 short-term toxicity data for aquatic invertebrates and algae, as well as the long-term toxicity data for aquatic invertebrates and algae,Dodecyl Myristate (CAS 2040-64-4)is not expected to cause acute or chronic toxicity to aquatic organisms up to its limit of water solubility (< 1 µg/L). Moreover, due to the low water solubility, it is highly unlikely that relevant, bioavailable concentrations of the test item will ever occur in the water phase, i.e. that concentrations high enough to induce any measurable acute or chronic effects in aquatic organisms are ever attained.

Significant deviations from this overall ecotoxicological profile are not expected and it is thus concluded thatDodecyl Myristate (CAS 2040-64-4)is unlikely to cause toxic effects to sediment organisms.

Metabolism/Bioaccumulation

Dodecyl Myristate (CAS 2040-64-4) is a long-chain aliphatic ester. In case of uptake andabsorption by aquatic organisms, long-chain aliphatic esters are expected to be enzymatically hydrolyzed by ubiquitous carboxylesterases into its 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). 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 target 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 thatDodecyl Myristate (CAS 2040-64-4)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.