Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Environmental fate and pathways data of MDEA Esterquat C18 satd. are not available. Therefore, studies of the structurally similar source substances MDEA-Esterquat C16-18 and C18 unsatd. and DODMAC (Dimethyldioctadecylammonium chloride) are taken into consideration. A justification for read across is given below.

Stability

Hydrolysis

According to REACH regulation (Annex VIII, 9.2.2.1, column II), the study on hydrolysis as a function of pH does not need to be conducted if the test substance is readily biodegradable according to OECD Guideline 301B.

Though not tested, hydrolysis of MDEA-Esterquat C18 satd. seems likely as the molecule contains ester links within the head-group which are susceptible to hydrolysis.

 

Biodegradation

Screening tests

Ready and inherent biodegradability tests

The biodegradation of the structurally similar source substance MDEA-Esterquat C16-18 and C18 unsatd. was studied in accordance with the OECD TG 301B and in compliance with GLP standards for 28 d. MDEA-Esterquat C16-18 and C18 unsatd. was applied at 2 concentrations of 10 and 20 mg/L. CO2 production was analysed at day 0 and after 1, 4, 5, 7, 8, 11, 14, 18, 22, and 28 days of incubation. The two test treatments (10 and 20 mg/L) reached > 60% CO2 production and met the 10-d window. Therefore MDEA-Esterquat C16-18 and C18 unsatd. fulfills the OECD criteria of ready biodegradability.

 

Anaerobic biodegradation

The anaerobic biodegradation of the structurally similar source substance MDEA-Esterquat C16-18 and C18 unsatd. was studied during a period of 61 d using anaerobic digester fermenting sludge obtained from a dairy and municipal waste water treatment plant in accordance with the ECETOC Technical report number 28 (comparable to OECD 311), and in compliance with GLP standards. MDEA-Esterquat C16-18 and C18 unsatd. was applied at concentrations of 25, 50, 75, and 100 mg C/L. At test concentrations of 50 and 75 mg C/L the degradation (based on total inorganic carbon both in gaseous and liquid phase) was 90.9% and 89.4%, repectively. The test substance MDEA-Esterquat C16-18 and C18 unsatd. can be defined as "highly biodegradable" under the anaerobic conditions of the test.

Simulation tests

Water

Although not required under REACH Annex VIII following information about biodegradation simulation tests in water with the structurally similar source substance MDEA-Esterquat C16 -18 and C18 unsatd. will be given:

 

The removal of MDEA-Esterquat C16-18 and C18 unsatd. in an aerobic sewage treatment simulation test was investigated in a continuous activated sludge test system using influent and activated sludge collected from the wastewater treatment plant at Bochum (Germany) that receives primarily domestic wastewater. The study was conducted in accordance with OECD 303A, Simulation test - Aerobic Sewage Treatment, Activated Sludge Units and GLP standards. On average >99% parent MDEA-Esterquat C16-18 and C18 unsatd. was removed during the three weeks removal period. This was based on an average measured effluent concentration of 7.067 +/- 4.788 µg/L. However, the detection limit for the effluent samples was 12.72 µg/L. Based on the fluctuation in the effluent concentration and the highest effluent concentration observed (16 µg/L) the minimal removal during the test phase would have been 99.1%. The concentration of MDEA-Esterquat C16-18 and C18 unsatd. on the activated sludge solids was 50.43 µg/g over the three weeks removal period. The mass balance calculated in the 3 weeks removal period showed that more than 99% of the removed MDEA-Esterquat C16-18 and C18 unsatd. was eliminated by primary biodegradation.

The results of a further experiment (in accordance with an early version of the newly adopted OECD 314) with non-adapted activated sludge indicated that MDEA-Esterquat C16-18 and C18 unsatd. and its hydrolysis products were fully biodegraded by microbes in unacclimated activated sludge. After 24 hr 20% of the parent remained. HP-1 (mono fatty acid ester) had virtually disappeared and HP-2 (diethanol dimethyl ammonium chloride) reached a maximum of 16%. The amount of activity incorporated into biomass was 25% and the amount trapped as 14CO2 was 35% during the same period. After seven days, the percentage of radioactivity converted to 14CO2 and incorporated into biomass totalled more than 75%, while the level of HP-2 remained at less than 5%. Based upon the kinetics of parent disappearance and metabolite production, it appears that MDEA-Esterquat C16-18 and C18 unsatd. is initially biologically hydrolyzed to HP-1, which very rapidly is hydrolyzed to HP-2, which is incorporated into biomass or evolved as 14CO2 without further accumulation of intermediates. HP-1 and HP-2 were both transient intermediates that did not accumulate. The half life for parent based upon the first order rate (k1) of primary degradation equalled 7 to 14 hrs using the equation t1/2=0.693/k1. Based on the kinetics of mineralization to 14CO2, the half life for mineralization equalled 18 -24 hr.

In an influent die-away experiment, cold and radiolabelled MDEA-Esterquat C16-18 and C18 unsatd. were dosed at a combined concentration of 1 mg/L in raw domestic sewage. No mineralization was observed in the test system. Primary degradation was observed in the biotic treatment. The Rad-TLC analysis of the biotic treatment indicates that parent underwent degradation after a short lag period. The % parent remaining after 6, 24 and 48 h was 57%, 29% and 12%, respectively. Based on an initial recovery of ca. 70% from both treatments, it appears the half-life of parent in influent would be ca. 20 h. Due to the very low recovery of radioactivity from the water extract after the 6 h sampling interval and post lyophilization, the characterization of these extracts is inconclusive. However, it can be concluded that intermediates more polar than parent were present in the 24 and 48h samples because the majority of the radioactivity partitioned into the water phase and not into the ethyl acetate phase. The study is not reliable due to methodological deficiencies. It can, however, be regarded as a supportive study. 

Soil

Although not required under REACH Annex VIII following information about biodegradation in soil with the structurally similar source substance MDEA-Esterquat C16 -18 and 18 unsatd. will be given:

The extent of mineralization and the resulting half-life was calculated for 14C MDEA-Esterquat C16-18 and C18 unsatd. and its hydrolysis product in sludge amended soils collected from Amelia/Batavia Sewage treatment plant (14C-CO2-Production Test in Sludge-Amended Soil and Soil). Volumes of 3 different sludge amended soils were incubated at desired temperatures with specific amounts of radiolabelled test and control substances to determine the biodegradability of the substances. The experiments were conducted at different time periods using a range of test concentrations (0.1 -10 ppm). The % of 14CO2 production of MDEA-Esterquat C16-18 and C18 unsatd. ranged from 21-48% over > 100 days. This corresponds to a measured half-life of 11-39 days in sludge amended soil. The half-life of the hydrolysis product ranges from 7 to 28 days (Procter and Gamble, 1987).

The study is not completely valid due to missing details of the study design. However it is regarded as a supportive study.

 

Bioaccumulation

Aquatic bioaccumulation

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

No experimental data on 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 registration 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. 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=104 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 (BUA-Report 191, 1995) and 13 -256 (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 ...'. The calculated BCF value for MDEA Esterquat C18 satd. is 71 L/kg (EPIWIN v4.11, BCFBAF v3.01). 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 (13 L/kg) 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.

 

Transport and distribution

Adsorption/desorption

The adsorption/desorption of the structurally similar source substance MDEA-Esterquat C16-18 and C18 unsatd. was investigated in a study conducted according to OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method), US-EPA Pesticide Assessment Guidelines, Subdivision N. Chemistry: Environmental fate. Section 163-1. Leaching and adsorption/desorption studies; 1982), Commission Directive 95/36/EC amending Council Directive 91/414/EEC. Annex I, Section 7.1.2. Adsorption and desorption. Official Journal of the European Communities no L172 (1995), and EPA OPPTS 835.1110 (Activated Sludge Sorption Isotherm) using two sludges and three soils. The sludges were taken from wwtps treating predominantly domestic wastewater. The soils included a loamy sand (Speyer 2.2 soil), a sandy loam (Speyer 2.3 soil) and a clay (Speyer 6S).During the stability test and the adsorption/desorption kinetic experiment it was found that [Me-14C] MDEA-Esterquat C16-18 and C18 unsatd. was not fully stable under the experimental conditions based on TLC results. Therefore, the results described should be applied to [Me-14C] MDEA-Esterquat C16-18 and C18 unsatd. and its degradation products. A Koc=20225 was calculated as the geometric mean of the two sludges and the two soils whereas a Koc=828 was calculated as geometric mean for the two sludges and a Koc=494 x 10³ as geometric mean for the two soils. According to the classification of Blume & Ahlsdorf (1993), these results indicate a high sorption onto sludges and a very high sorption onto soil. As MDEA-Esterquat C16-18 and C18 unsatd. is readily biodegradable under aerobic conditions, highly biodegradable under anaerobic conditions and not fully stable in the presence of sludges and soils as could be shown during the adsorption/desorption study it can be assumed that both in sludges and soils degradation takes place and decreased the potential for geoaccumulation significantly.

 

Justification for read-across

For details on substance identity and detailed ecotoxicological profiles, please refer also to the endpoint summary Aquatic toxicity in the IUCLID file.

Substance identities

The target substance MDEA Esterquat C18 satd. is a monoconstituent substance composed of diesters of saturated C18 fatty acids (IV < 1) with MDEA (Methyldiethanol amine) as amine backbone.

The first source substance MDEA Esterquat C16-18 and C18 unsatd. is a structurally similar UVCB substance composed of diesters of the long chain fatty acids C16, C18 and C18 unsaturated (iodine value, IV < 25) with MDEA (Methyldiethanol amine) as amine backbone

The second source substance DODMAC (Dimethyldioctadecylammonium chloride) is a structurally similar substance composed of C16 and C18 alkyl chains bound to a quaternised and dimethylated amine function.

 

Source substances

Target substance

 

MDEA-Esterquat C16-18 and C18 unsatd.

DODMAC (DHTDMAC)

MDEA Esterquat C18 satd.

CAS number

1079184-43-2

61789-80-8

67846-68-8

EC number

620-174-7

263-090-2

267-382-0

Fatty Acid

C16-18, C18’ (IV < 25)

C16-18

C18 (IV < 1)

Chain length distribution

<C16 <7%

 

C16, 16‘, 17 26-35%

C18 42-52%

C18‘ 15-20%

C18‘‘, 18‘‘‘ </= 1.5%

>C18 </= 2%

C12: </=2 %

C14: 1 - 5 %

C16: 25 - 35 % C18: ca. 65 %

 

 

C 20: </=2 %

 

 

C16 8%

C18 92%

Amine

Methyldiethanol amine

Dimethyl amine

Methyldiethanol amine

Anion

Chloride

Chloride

Chloride

 

Structural similarity

a. Structural similarity and functional groups

The target substance, MDEA Esterquat C18 satd., consists of an amine backbone (MDEA = Methyldiethanolamine) esterified with the long chain fatty acid C18 saturated (IV < 1). The main reaction product is the dialkylester compound, next to that a smaller amount of the monoalkylester is formed. The amine function is quaternised with two methyl groups. The counter ion is Chloride.

The first source substance, MDEA-Esterquat C16-18 and C18 unsatd., consists of the same amine backbone (MDEA = Methyldiethanolamine) but esterified with a mixture of the long chain fatty acids C16, C18 and C18 unsaturated (IV < 25). Similar to MDEA Esterquat C18 satd. the main reaction product is the dialkylester compound (83-87%), next to that small amounts of the monoalkylester (4.5-8%) may be formed. The amine function is quaternised with two methyl groups. The counter ion is Chloride.

The source substance DODMAC (Dimethyldioctadecylammonium chloride) is one of the active components of the technical product DHTDMAC (dihydrogenated tallow alkyl dimethyl ammonium chloride). DHTDMAC consists of about 65% C18 (DODMAC) and 25-35% C16 and bound to a quaternised and dimethylated amine function. The counter ion is again Chloride.

Figure 1: Structures of source substance DODMAC and MDEA-Esterquat C16-18 and C18 unsatd. and the target substance MDEA Esterquat C18 satd. (see attached image file)

b. Differences

There are small differences in fatty acid chain length distribution (additional shorter and less saturated fatty acid chains in the first source substance MDEA-Esterquat C16-18 and C18 unsatd.) between the target substance and the first source substance MDEA-Esterquat C16-18 and C18 unsatd.which may be of relevance for local effects but are not considered to be of relevance for the environmental fate of the substances.

The target and the first source substance have a methyldiethanol amine backbone whereas the second source substance DODMAC contain a dimethyl amine. The main difference of these two chemical structures is that the target substance MDEA Esterquat C18 satd. and the first source substance MDEA Esterquat C16-18 and C18 unsatd. have, in contrast to the second source substance DODMAC, two polar ester moieties.

The molecular weights of the target substance MDEA Esterquat C18 satd. and the source substances MDEA-Esterquat C16-18 and C18 unsatd. and DODMAC are in a comparable range. Experimental data regarding physical chemical properties are not available for MDEA Esterquat C18 satd. Therefore for most endpoints a read-across approach from the structurally very similar MDEA-Esterquat C16-18 and C18 unsatd. was applied. Both source substances have comparable physical chemical properties (see IUCLID section 4).

Differences in transformation and degradation processes

The second source substance DODMAC has, in contrast to the target substance MDEA Esterquat C18 satd. and the first source substance MDEA Esterquat C16-18, no ester moieties which are susceptible to hydrolysis and/or degradation. DODMAC is therefore poorly biodegradable and much more stable than MDEA Esterquat C18 satd. 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).

Conclusion

The structural and physicochemical similarities between the source and the target substances support the read-across hypothesis. The target substance MDEA Esterquat C18 satd. is the main component of the first source substance MDEA Esterquat C16-18 and C18 unsatd. and together with the great structural similarity of the remaining additional components there is no reason to believe that there are differences in the environmental fate and pathways between the target and the first source substance.

For the endpoint BCF data of the second source substance DODMAC were used. Regarding the BCF of 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.