Ethanaminium, 2-hydroxy-N-(2-hydroxyethyl)-N,N-dimethyl-, esters with C16-18 and C18-unsatd. fatty acids, chlorides

Endpoint summary

Additional information

Aquatic bioaccumulation

No experimental data for MDEA-Esterquat C16-18 and C18 unsatd. are available. According to REACH regulation (Annex XI, 1.5), a study on aquatic bioaccumulation does not need to be conducted for the substance under investigation if data from structurally closely related material are available.

Measured BCF data are available for Dimethyldioctadecyl ammonium chloride (DODMAC, CAS-No. 107 -64 -2). DODMAC has a chemical structure similar to the compound Dimethylbis [2-[(1-oxooctadecyl)oxy]ethyl]ammonium chloride (compound I). Compound I (Ethanaminium, 2 -hydroxy-N-(2 -hydroxyethyl)-N,N-dimethyl-, diesters with C16 -18 and C18 -unsatd. fatty acids, chlorides ca. 90%) is the molecular moiety of the registration substance (MDEA-Esterquat C16-18 and C18 unsatd. ) for which the highest bioaccumulation potential is to be expected. Compound I differs from DODMAC by the ester linking groups between the alkyl chains (of C18 chain length) and the headgroup (effectively the dimethyl ammonium group).

Regarding the BCF of the MDEA-Esterquat C16-18 and C18 unsatd. , the BCF is expected to be lower than that of DODMAC:

The chemical structure of the MDEA-Esterquat C16-18 and C18 unsatd. includes, in contrast to DODMAC, two polar ester moieties that lower BCF and which are susceptible to biodegradation and/or hydrolysis which also will result in a lower BCF of the MDEA-Esterquat C16-18 and C18 unsatd. . DODMAC is poorly biodegradable and much more stable than MDEA-Esterquat C16-18 and C18 unsatd. . For DODMAC no abiotic degradation is to be expected, for biotic degradation in water the degradation rate is very low (1.4 x 10E-4/d) (EU 2002).

The BCF of DODMAC was determined in a study in which juvenile fish (Pimephales promelas) were exposed for 24 h under flow-through conditions, followed by a depuration period of 72 h. A BCF of 104 L/kg was calculated based on the uptake rate constant (k1) of 1.35 mg/g x h and the depuration rate constant (k2) of 0.013 mg/g x h.

The measured BCF values for similar substances (DODMAC, DHTDMAC=dihydrogenated tallow alkyl dimethyl ammonium chloride) are 12 -32 L/kg (BUA-Report 191, 1995) and 13 - 256 L/kg (EU RAR, 2002). The EU RAR (2002) concluded 'bioaccumulation is indicated, but is assumed that it is low under environmental conditions. A BCF of 13 L/kg is used in the risk assessment ...'

This is further supported by a QSAR calculation that yielded a calculated BCF value for MDEA-Esterquat C16-18 and C18 unsatd. of 70.8 L/kg (EPIWIN v3.20, BCFWIN v2.17). As thisQSARmodeldoes not include metabolism,it can be considered a conservative estimate of BCF.

The low bioavailability of the substance (due to rapid and strong sorption to negatively charged surfaces in the aquatic environment) in combination with the rapid (bio)degradation of the bioavailable fraction (mainly due to the hydrolysis of the ester bond), make high bioconcentration factors for the substance even more improbable (Comber et al., 2003 in Hera, 2008).

For MDEA-Esterquat C16-18 and C18 unsatd. a BCF of the same order of magnitude as for DODMAC is to be expected. The above information is considered as sufficient to support the conclusion that the bioaccumulation potential of MDEA-Esterquat C16-18 and C18 unsatd. is expected to be low.

 

Terrestrial bioaccumulation

Measured BCF data are available for the structurally similar substance DODMAC. (Data on BCF in fish see 4.1.3.)

Sediment accumulation tests with 14C-DODMAC and Lumbriculus variegatur respectively Tubifex tubifex showed biota sediment accumulation factors (BSAF) of 0.28 - 0.78 after 28 days. The main uptake route was sediment ingestion (EU RAR 2002).

Terrestrial plants (tomato, bean, cucumber and radish seedlings) showed a concentration of 0.01 to 0.05 mg DODMAC/kg in seedlings with 2 mg DODMAC/kg soil (EU RAR 2002). A biota-to-soil accumulation factor of 0.005 - 0.025 is calculated from this numbers.

For MDEA-Esterquat C16-18 and C18 unsatd. the terrestrial bioaccumulation is expected to be of the same order of magnitude as that of DODMAC. The above information is considered as sufficient to support to the conclusion that the terrestrial bioaccumulation potential of the registration substance is expected to be low.

 

Justification for read-across

This read-across is based on the hypothesis that source and target substance have similar environmental fate properties based on similar physicochemical properties, common functional groups and structural similarities.

The target substance MDEA-Esterquat C16-18 and C18 unsatd. (Reaction products of C16-18/C18 unsaturated fatty acid with methyl diethanolamine, MeCl quaternised) is a UVCB substance consisting of diesters of mainly saturated C16 and C18 fatty acids with MDEA (Methyldiethanol amine) as amine backbone.

The source substances DODMAC and DHTDMAC exhibit large structural similarities with the target substance. Details are described below.

Therefore, read-across from the existing bioaccumulation data on the source substance is considered as an appropriate adaptation to the standard information requirements of Annex IX, 9.3 of the REACH Regulation for the target substance, in accordance with the provisions of Annex XI, 1.5 of the REACH Regulation. The justification of the proposed read-across approach is elaborated in the next chapters.

 

2. Justification for read-across

2.1 Substance Identity

Table 1: Substance identities

	Source substance DODMAC	Source substance DHTDMAC	Target substance MDEA-Esterquat C16-18 and C18 unsatd.
CAS number	107-64-2	61789-80-8	1079184-43-2
EC number	203-508-2	263-090-2	620-174-7
Fatty Acid	C18	tallow C16-18, C18‘	tallow C16-18, C18‘ (IV (iodine value) = 20)
Chain length distribution	(*)	C12 </=2 % C14 1 - 5 % C16 25 - 35 % C18 ca. 65 % C20 </=2 %	<C16 <7% C16, 16‘ 26-35% C18 42-52% C18‘ 15-20% C18‘‘, 18‘‘‘ </= 1.5% >C18 </= 2%
Amine			MDEA
Anion	Chloride	Chloride	Chloride

(*) Dimethyldioctadecylammonium chloride (DODMAC) as an isolated substance is not produced or used in a commercial range. But it is one of the active components of the technical product ditallowdimethylammonium chloride (DHTDMAC)

 

2.2 Structural similarity

a. Structural similarity and functional groups

 

Figure 1 (see attachment): Structures of source substance (DODMAC) and target substance (MDEA-Esterquat C16-18 and C18 unsatd.)

 

The target substance, MDEA-Esterquat C16-18 and C18 unsatd. , consists of an amine backbone (MDEA = Methyldiethanol amine) esterified with long chain fatty acids C16, C18 and C18 unsaturated (IV = 20). The main reaction product is the dialkylester compound, next to that small amounts of the monoalkylester may be formed. The amine function is quaternised with two methyl groups. The counterion is Chloride.

DODMAC is one of the active components of the technical product DHTDMAC. DHTDMAC is produced of tallow fatty acid via the nitrile to result in the amine, which is then methylated twice to the quaternised amine. The counterion is Chloride.

Both, source and target substances have similar chain length distribution, a quaternised and dimethylated amine function and Chloride as counterion.

 

2.3 Differences

The chemical structure of the target substance MDEA-Esterquat C16-18 and C18 unsatd. contains, in contrast to the source substances, two polar ester moieties which are susceptible to hydrolysis/degradation.

3. Physicochemical properties

Table 2: Physicochemical properties

Endpoint	Source substance DODMAC (EU, 2009)	Source substance DHTDMAC (EU, 2009)	Target substance MDEA-Esterquat C16-18 and C18 unsatd.
Molecular weight	586.52 g/mol	567 - 573 g/mol	697 g/mol
Physical state	Solid	Solid	Solid
Melting point	72-122 °C	60 - 65 °C	54°C
Boiling point	decomposition at 135 °C	decomposition at 120 °C	No boiling point up to 250°C
Vapour pressure	negligible because of the salt character	negligible because of the salt character	1E-09 Pa at 20°C
Surface tension	11 mN/m at 20 °C (saturated solution; method: film balance)	No data, read-across from DODMAC	68.3 mN/m - not in line with the expected surface active behaviour of the substance
Water solubility	2.7 mg/L	Insoluble	17.6 mg/L at 19.7°C
log Kow	3.8	No data, read-across from DODMAC	No data, read-across from DODMAC

 

4. Conclusion

The purpose of determining the bioconcentration factor is to assess whether there is any potential for the chemical to accumulate in organisms to a high degree and for further transfer up the food chain.

As demonstrated above, the physicochemical properties and structures of source and target substances are similar enough to support the read-across approach.

The main difference is the fact that the chemical structure of the target substance MDEA-Esterquat C16-18 and C18 unsatd. includes, in contrast to the source substances, two polar ester moieties that would lower the BCF.

Moreover these ester moieties are also susceptible to biodegradation and/or hydrolysis. DODMAC on the contrary is poorly biodegradable (EU, 2009) and much more stable than MDEA-Esterquat C16-18 and C18 unsatd. .

In HERA (2008) it is concluded that: “Based on the measured Log BCF value of DODMAC (also considered to be a conservative estimate for esterquats (Table 3), the esterquats have a relatively low bioaccumulation potential. The low bioavailability of the esterquats (due to rapid and strong sorption to negatively charged surfaces in the aquatic environment) in combination with the rapid (bio)degradation of the bioavailable fraction (mainly due to the high probability of hydrolysis of the ester bond), make high bioaccumulation factors of esterquats even more improbable. Hydrolysis will lead to production of the more soluble degradation products and hence rapid elimination.”

Thus, the results from the source substances can also be applied for the target substance MDEA-Esterquat C16-18 and C18 unsatd. as a conservative estimation.

 

References

EU, 2009: European Union Summary Risk Assessment Report - dimethyldioctadecylammonium chloride (DODMAC) - with addendum, available online: http://publications.jrc.ec.europa.eu/repository/handle/111111111/5276

 

HERA, 2008:Esterquats Environmental Risk Assessment Report, available online: http://www.heraproject.com/files/17-E-01-03-2008%20%20HERA%20EQ%20Environment%20Final%20Draft.pdf