Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Although not required under REACH Annex VIII following information about bioaccumulation will be given:

Aquatic bioaccumulation

No experimental data for MDEA-Esterquat C18 satd. 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 target substance and is the molecular moiety of the target substance (MDEA-Esterquat C18 satd.) for which the highest bioaccumulation potential is to be expected. MDEA Esterquat C18 satd. 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 C18 satd., the BCF is expected to be lower than that of DODMAC:

The chemical structure of the MDEA-Esterquat C18 satd. 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 C18 satd. DODMAC is poorly biodegradable and much more stable than MDEA Esterquat C18 sat. 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 RAR, 2009).

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, 1997) and 13 - 256 L/kg (EU RAR, 2009). The EU RAR (2009) 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 C18 satd. of 70.8 L/kg (EPIWIN v4.11, BCFBAF v3.01). As this QSAR model does 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 C18 satd. 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 C18 satd. 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 C18 satd. is a monconstituent substance consisting of diesters of mainly saturated 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.

 

2. Justification for read-across

2.1 Substance Identity

Table 1: Substance identities

Source substance

DODMAC

Source substance

DHTDMAC

Target substance

MDEA Esterquat C18 satd.

CAS number

107-64-2

61789-80-8

67846-68-8

EC number

203-508-2

263-090-2

267 -382 -0

Fatty Acid

C18

tallow
C16-18, C18‘

tallow
C18
(IV (iodine value)
< 1)

Chain length distribution

(*)

C12 </=2 %

C14 1 - 5 %

C16 25 - 35 %

C18 ca. 65 %

C20 </=2 %

C16 8%

C18 92%

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

Figure 1 (see attachment): Structures of source substance (DODMAC) and target substance (MDEA Esterquat C18 satd.)

 

a. Structural similarity and functional groups

 The target substance, MDEA Esterquat C18 satd., consists of an amine backbone (MDEA = Methyldiethanol amine) esterified with the long chain fatty acids C18 (IV < 1). 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 C18 satd. 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 C18 satd.

Molecular weight

586.52 g/mol

567 - 573 g/mol

703 g/mol

Physical state

Solid

Solid

Solid

Melting point

72-122 °C

60 - 65 °C

54°C; read across from MDEA-Esterquat C16 -18 and C18 unsatd.

Boiling point

decomposition at 135 °C

decomposition at 120 °C

No boiling point up to 250°C; read across from MDEA-Esterquat C16-18 and C18 unsatd.

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; read-across from MDEA-Esterquat C16-18 and C8 unsatd.

Water solubility

2.7 mg/L

Insoluble

17.6 mg/L at 19.7°C; read-across from MDEA-esterquat C16 -18 and C18 unsatd.

log Kow

3.8

3.8; read-across from DODMAC

3.8; 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 C18 satd. 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 C18 satd.

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 C18 satd. 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

191 BUA-Report: Dioctadecyl Dimethyl Ammonium Chloride (DODMAC) CAS-No. 107-64-2, Dihydrogenated Tallow Alkyl Dimethyl Ammonium Chloride (DHTDMAC) CAS-No. 61789-80-8, 1. Dezember 1997

Comber MH,de Wolf W, Cavalli L, van Egmond R, Steber J, Tattersfield L, Priston RA. Assessment of bioconcentration and secondary poisoning of surfactants. Chemosphere.2003 Jul;52(1):23-32.