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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

N-methyl-N-[C18-(unsaturated)alkanoyl]glycine (EC 701-177-3) has a low potential for bioaccumulation.

Key value for chemical safety assessment

Additional information

Experimental data on the bioaccumulation potential of N-methyl-N-[C18-(unsaturated)alkanoyl]glycine (EC 701-177-3) is not available. N-methyl-N-[C18-(unsaturated)alkanoyl]glycine (EC 701-177-3) has a log Kow of 3.5 – 4.2 (20 °C, EU A.8, HPLC ). Since, the substance is ionisable with a pKa of 5 at 20°C (OECD 112), the distribution coefficient (log D) at pH 4, pH 7, and pH 9 was calculated for the main substance components, N-methyl-N-oleoylglycine and N-[methyl-[(9Z,12Z)-1-oxo-9,12octadecadienyl glycine. The estimated log D values for the two substance components are 6.19 and 6.21 at pH 4, 3.52 and 3.55 at pH 7, and 2.66 and 2.69 at pH 9 (SPARC v4.6). In accordance with ECHA Guidance R.11 (ECHA, 2017) the substance is not considered to meet the trigger value of 4.5 for the B-assessment in aquatic species as the log Kow and the Log D for the environmentally relevant pH value of 7 are below this trigger value.In addition, according to ECHA Guidance R.11 (ECHA, 2017) there is low potential for accumulation in air breathing organisms. A log Koa of 5 was calculated for the substance, in combination with the log Kow > 2 these values indicate a potential to biomagnify in terrestrial food chains. However, it was clearly indicated in the guidance that a biomagnification potential is only assumed for substances with high chemical absorption efficiency from the diet, no biotransformation after absorption and negligible active transport (in or out). The evaluation of the toxicokinetic behavior indicates that the two main components of the substance sarcosine and fatty acid are expected to be metabolized and eliminated by all living organisms due to their ubiquity in biotic systems. In addition, oral absorption studies with a structurally closely related substance (Sodium lauroyl sarcosinate) demonstrated rapid absorption and excretion within 48 h. Based on the behavior of structurally similar substances (i.e. N-acyl amino acids), which are known to undergo the detoxification and excretion pathways of xenobiotic carboxylates (Farrel, 2008), urinary excretion is expected to be the main excretion route of N-methyl-N-(C18-(unsaturated)alkanoyl)glycine (EC 701-177-3). For further details on the toxicokinetic behavior please refer to the toxicokinetic statement in IUCLID section 7.1.

Furthermore, the substance is characterized by a water solubility of 0.44 mg/L (EU A.6, column elution method) and ready biodegradability. According to the Guidance on information requirements and chemical safety assessment, Chapter R.7b, readily biodegradable substances can be expected to undergo rapid and ultimate degradation in most environments, including biological sewage treatment plants (STPs) (ECHA, 2016). Thus, only negligible concentrations of the substance are likely to be released into the environment through conventional STPs. In addition, if released into the environment, the substance will not persist.

Moreover, the BCF was estimated by (Q)SAR, using the regression-based and Arnot-Gobas methods implemented by the BCFBAF model v3.01 (EPI Suite v4.11). The BCF was calculated for three constituents, N-methyl-N-oleoylglycine and N-[methyl-[(9Z,12Z)-1-oxo-9,12octadecadienyl glycine as main components andoleic acid, which is of minor importance due to a lower percentage. The calculation was performed with log Kow values of 3.5 and 4.20 as input parameters (corresponding to the boundaries of the experimentally determined log Kow values). The substance components only partially fall within the applicability domain of the model due to ionization in the environmentally relevant pH range of 4 - 9. However, the results can serve as an indication of trends. The calculated BCFs obtained with the Arnot-Gobas model ranged between 95.39 and 264.5 L/kg wet-wt (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic), which is well below the screening criterion for bioaccumulation of 2000 (REACH, Annex XIII; R.7c, ECHA, 2017; R.11, ECHA, 2017). The calculated BCF obtained with the regression-based method was 3.16 L/kg wet-wt for all three constituents and both log Kow values. The obtained values suggest that the substance has a low potential for bioaccumulation.

Taking all these information into account, such as log D and Log Kow, metabolisation and excretion as well as BCF values, it can be concluded that bioaccumulation of N-methyl-N-[C18-(unsaturated)alkanoyl]glycine (EC 701-177-3) is unlikely to occur.