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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

Phototransformation in air

Due to the very low emissions of MDEA-Esterquat C16-18 and C18 unsatd. to air (negligible vapour pressure) the extent of photodegradation in air has no relevance for the environmental fate of this class of chemicals.

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 C16-18 and C18 unsatd. 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 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 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

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 totaled 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 equaled 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 equaled 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.

 

Sediment

According to REACH regulation (Annex IX, 9.2.1.4, column II), the biodegradation simulation test in sediment does not need to be conducted if the substance is readily biodegradable.

 

Soil

According to REACH regulation (Annex IX, 9.2.1.3, column II), the study on biodegradation in soil does not need to be done if the substance is readily biodegradable.

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

No experimental data on MDEA-Esterquat C16-18 and C18 unsatd. are available. According to REACH regulation (Annex XI, 1.5), the 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 compoundDimethylbis[2-[(1-oxooctadecyl)oxy]ethyl]ammonium chloride (compound I).Compound I 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=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 C16-18 and C18 unsatd. is 71 (EPIWIN v3.20, BCFWIN v2.17). 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 (13 L/kg) is to be expected. The above iformation 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

According to REACH regulation (Annex X, 9.3, column II), further studies on bioaccumulation shall be proposed based on the outcome of the risk assessment. The risk assessment did not indicate the need for further testing.

 

Transport and distribution

Adsorption/desorption

The adsorption/desorption of 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.

 

Henry's Law constant

No experimental data are available. Based on the low water solubility and the very low vapour pressure, MDEA-Esterquat C16-18 and C18 unsatd. can be considered as non-volatile from aqueous solution.

 

Distribution modelling

The calculation of the Mackay Level I failed as the log Kow which is needed as input parameter can not be determined due to the surface-active properties of MDEA-Esterquat C16-18 and C18 unsatd. . Based on the available data, it can be assumed that MDEA-Esterquat C16-18 and C18 unsatd. will not volatilize from aqueous solution. According to the results of adsorption/desorption experiments, MDEA-Esterquat C16-18 and C18 unsatd. will mainly adsorb to soil and sediments.The distribution to biota is negligible.

 

 

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