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Biodegradation in water and sediment: simulation tests

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Endpoint:
biodegradation in water: simulation testing on ultimate degradation in surface water
Type of information:
experimental study planned
Justification for type of information:
EXPERIMENTAL STUDY PLANNED: AEROBIC MINERALISATION IN SURFACE WATER SIMULATION BIODEGRADATION TEST (Pelagic test)

EXPERIMENTAL STUDY PLANNED:
1. Simulation testing on ultimate degradation in surface water (Annex IX, Section 9.2.1.2.; test method: Aerobic mineralisation in surface water – simulation biodegradation test, EU C.25./OECD TG 309) at a temperature of 12 °C with the registered substance (as specified below under “name of the substance for which the study result will be used”).
2. Identification of degradation products (Annex IX, 9.2.3.) using an appropriate test method with the registered substance.

NAME OF THE SUBSTANCE TO BE USED IN THE PLANNED STUDY:
The test is intended to be performed using 14C labelled N-octadecyl- N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride with the 14C-label located in the long alkylchain next to the nitrogen. Labelling in the propylchain was dissuaded by the Synthesis lab (Selcia).

NAME OF THE SUBSTANCE FOR WHICH THE STUDY RESULT WILL BE USED:
The testing proposal is intended to be used for N-C16-18 (even numbered) and C18 unsaturated-N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride (CAS no. 1211950-04-7; EC no. 629-716-7). The results as obtained in an OECD TG 309 study and identification of degradation products with 14C labeled N-octadecyl- N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride (14C18-DQ) will be used in the registration dossier of ” N-C16-18 (even numbered) and C18 unsaturated-N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride (Tallow-DQ) .

COMPOSITION OF THE SUBSTANCE FOR WHICH THE STUDY WILL BE USED:
Because it is important that the biodegradation of each constituent and relevant impurity present in concentrations at or above 0.1% (w/w) or, if not technically feasible, in concentrations as low as technically detectable are assessed, the composition of the product as included in the CSR is summarized in the table 1 below.
Table 1: Composition of N-C16-18 (even numbered) and C18 unsaturated-N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride
EC. No.: Abbreviation %
N-C16-18 (even numbered) and C18 unsaturated-N,N,N',N',N'-pentamethylpropane-1,3-bis(aminium) dichloride 629-716-7 Tallow-DQ Boundary composition
N-dodecyl-N,N,N',N',N'-pentamethylpropane-1,3-diaminium dichloride C12-DQ 0 -3
N,N,N,N',N'-pentamethyl-N'-tetradecylpropane-1,3-diaminium dichloride C14-DQ 0 - 7
N-hexadecyl-N,N,N',N',N'-pentamethylpropane-1,3-diaminium dichloride C16-DQ 15 - 40
N-heptadecyl-N,N,N',N',N'-pentamethylpropane-1,3-diaminium dichloride C17-DQ 0 - 3
N,N,N,N',N'-pentamethyl-N'-octadecylpropane-1,3-diaminium dichloride 230-985-4 C18-DQ 15 - 45
N,N,N,N',N'-pentamethyl-N'-[(9E)-octadec-9-en-1-yl]propane-1,3-diaminium dichloride 230-754-8 C18'-DQ 10 - 47
N,N,N-trimethyldodecan-1-aminium chloride 203-927-0 C12-MAQ 0 - 3
trimethyl(tetradecyl)ammonium chloride 224-958-6 C14-MAQ 0 -1
cetrimonium chloride 203-928-6 C16-MAQ 0 - 5
N,N,N-trimethylheptadecan-1-aminium chloride C17-MAQ 0 - 3
trimethyloctadecylammonium chloride 203-929-1 C18-MAQ 0 - 9
(9E)-N,N,N-trimethyloctadec-9-en-1-aminium chloride C18'-MAQ 0 - 9
3-[C12-C18 evennumbered, C18 unsatured-alkyl (methyl)amino]-N,N-dimethylpropan-1-aminium chloride Tallow-DMMQ 0 - 3
N-(C12-C18 evennumbered, C18 unsatured-alkyl)-N,N',N'-trimethylpropane-1,3-diamine 272-192-6 PPAD-TTM 0 - 3

Tallow-DQ contains besides to a series of linear alkyl-DQ’s also a series of readily biodegradable Mono Alkyl Quats (MAQ). The tallow alkyl diamine starting material contains some (± 8%) remaining tallow alkyl amines which are during the quaternization of the diamine quaternized to monoalkyl quats. Finally, there are two constituents, ± 0.2% Trimethylated diamine (EC no.: 272-192-6; PPAD-TTM) and ± 1% methylated monoquat (Tallow DMMQ) which are the result of an incomplete quaternization of the amine groups of the tallow alkyl diamine starting material. PPAD-TTM (CAS no.: 1275611-65-8) is observed to be readily biodegradable but Tallow DMMQ is like the alkyl-DQ’s expected to be partly degraded.

JUSTIFICATION OF THE SUBSTANCE TO BE USED IN THE PLANNED STUDY:
The C18 constituent is in the perspective of the biodegradation simulation study according to OECD 309 considered to be a realistic worst-case source substance for read across to Tallow-DQ. Table 1 shows that C18-DQ is one of the main constituents of Tallow-DQ and it is expected to have the lowest bioavailability.
Sorption to soil is observed to be in the same range for the C16, C18= and C18-DQ in the OECD TG 106 study. Sorption of linear alkyl amines/ammonium compounds is mainly driven by ionic interaction and to a lesser extend to the to the alkylchain related hydrophobic interaction (Droge & Goss, 2013) which explains the comparable sorption. Droge & Goss also showed that sorption (slightly) increases with the length of the alkyl chain which is in agreement with the predictions by EPIsuite’s KocWIN. According to REACH guidance R.16 there is evidence that there exists some sort of dependence between bioavailability and the degradation rate. The lower the bioavailability the lower the degradation rate and it is therefore considered justified to use the 14C18-DQ in the OECD TG 309 as a realistic worst-case and use the result from this study for read across to the Tallow-DQ.
Abbreviation Covered by testing with 14C-C18-DQ
Tallow-DQ
C12-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C14-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C16-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C17-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C18-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C18'-DQ yes Rapid primary degradation of constituent but not completely mineralized based on OECD 301D test with Tallow-DQ
C12-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9) and C12-MAQ
C14-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9)
C16-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9) and C16-MAQ
C17-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9)
C18-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9) and C18-MAQ
C18'-MAQ No Constituent readily biodegradable based on OECD 301D test with Tallow-MAQ (CAS no: 68002-61-9) and C18'-MAQ
Tallow-DMMQ* yes * Tallow Diamine Methyl Mono Quat
PPAD-TTM No Constituent readily biodegradable based on OECD 301D test with PPAD-TTM (CAS no: 1275611-65-8)

REASONING OF SELECTION AEROBIC MINERALISTATION IN SURFACE WATER
In general, it is recommended to start testing with the OECD TG 309 if it is technically feasible.
OECD TG 309 is the preferred first biodegradation simulation study for the following reasons:
• The aquatic compartment is considered to be the most relevant environmental compartment due to the large global volume of water: by default water compartment receives significant amount of emissions directly or indirectly, and transports/distributes the substance through e.g. deposition and run-off.
• Based on the relatively high water solubility of Tallow-DQ of 790 mg/L (pH 7, 23°C) it is considered that the water compartment is the most relevant environmental compartment.
• Sorption of cationic surfactants can result in the formation of NER. The OECD TG 309 pelagic (with a default concentration of suspended solids of 15 mgdw/L) minimizes potential NER formation.
• OECD TG 309 is conducted under aerobic conditions. This is considered as a relevant test condition as P assessment should first consider aerobic degradation.
• OECD TG 307 would considering the use in building and construction be the second biodegradation simulation study to consider but based on the high expected NER formation not the first choice as it is expected that similar results are found in the simulation study according to OECD TG 309 and that these results can be interpreted so that a conclusion on the persistency can be derived on the remaining compartment(s).


EXPECTED OUTCOME OF THE BIODEGRADATION SIMULATION STUDY:
Available GLP/non-GLP studies: Neither GLP nor non-GLP studies are available investigating the aerobic mineralization in surface water in a simulation biodegradation test according to OECD TG 309 (pelagic test).
Many (n>20) ready biodegradability screening tests have however been performed with Tallow-DQ to assess the biodegradation potential. These tests were performed as OECD TG 301D non-GLP screening tests using silicagel and humic acid to mitigate the toxicity to the inoculum, using natural river water, adapted and unadapted activated sludge as inoculum, and none of these test resulted in ≥60% biodegradation within 28 days. All studies reached a plateau without reaching 60% biodegradation as presented in the graph below.

These results strongly indicate that the primary degradation of Tallow-DQ is fast but that the substance is not completely mineralized in the relatively short time frame. Based on the tests with adapted activated sludge and the inherent test according to OECD 302A, it is expected that similar results would be found in the simulation study according to OECD TG 309 and that these results can be interpreted so that a conclusion on the persistency can be derived on the remaining compartment(s).

References:
Droge, S.T.J. and Goss, K.W. 2013. Development and Evaluation of a New Sorption Model for Organic Cations in Soil: Contributions from Organic Matter and Clay Minerals. Environmental Science and Technology, 47:14233-14241.

Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.11. United States Environmental Protection Agency, Washington, DC, USA.


ANNEX 1: KOCWIN calculations of main constituents of Tallow-DQ

SMILES : CCCCCCCCCCCCCCCCCCN(C)(C)CCCN(C)(C)(C)
CHEM : C18-DQ
MOL FOR: C26 H58 N2
MOL WT : 398.77
Soil Adsorption Coefficient (KOCWIN v2.00):
Koc : 6.523E+005 L/kg (MCI method)
Log Koc: 5.814 (MCI method)


SMILES : CCCCCCCCC=CCCCCCCCCN(C)(C)CCCN(C)(C)(C)
CHEM : C18’-DQ
MOL FOR: C26 H56 N2
MOL WT : 396.75
Soil Adsorption Coefficient (KOCWIN v2.00):
Koc : 6.523E+005 L/kg (MCI method)
Log Koc: 5.814 (MCI method)


SMILES : CCCCCCCCCCCCCCCCN(C)(C)CCCN(C)(C)(C)
CHEM : C16-DQ
MOL FOR: C24 H54 N2
MOL WT : 370.71
Soil Adsorption Coefficient (KOCWIN v2.00):
Koc : 1.964E+005 L/kg (MCI method)
Log Koc: 5.293 (MCI method)

Qualifier:
according to guideline
Guideline:
OECD Guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test)
GLP compliance:
yes
Transformation products:
not specified
Endpoint:
biodegradation in water: sewage treatment simulation testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28-10-2009 - 05-02-2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Test performed under GLP according guidelines with a few accpetable (minor) deviations, meeting all validity criteria
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
More information on justification of the read across of the STP simulation study can be found in the read across document included in Chapter 13
Qualifier:
according to guideline
Guideline:
OECD Guideline 303 A (Simulation Test - Aerobic Sewage Treatment. A: Activated Sludge Units)
Deviations:
yes
Remarks:
minor acceptable deviations
Principles of method if other than guideline:
A few minor deviations to the guidelines were introduced. The primary settled sewage was collected weekly and stored in the refrigerator until
required instead of a daily collection of wastewater. The units consisted of aeration vessels capable of holding only 0.35 L from which the liquor
was then passed continuously to settler of 0.30 liter capacities
GLP compliance:
yes (incl. QA statement)
Radiolabelling:
no
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Details on inoculum:
Secondary activated sludge to inoculate the test at the start was collected on 28-10-2009 from the wastewater treatment plant (WWTP) Nieuwgraaf in Duiven, The Netherlands. The WWTP Nieuwgraaf is an activated sludge plant treating predominantly domestic sewage. 0.35 liter of secondary activated sludge containing approximately 3 g/L dry weight was used as an inoculum for each CAS unit. This dry weight was obtained by diluting the sludge
obtained from the treatment plant. The primary settled sewage was collected from the same plant weekly and stored frozen until required.
Duration of test (contact time):
48 d
Initial conc.:
50 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
DOC removal
test mat. analysis
Details on study design:
CAS unit
The CAS test was performed in Hussmann-type units constructed of glass . The units consisted of an aeration vessel capable of holding 0.35 liter from which the liquor was passed continuously to a settler of 0.3 liter. The domestic waste water liquor in a cooled vessel was supplied with a pump. The liquor passed through the aeration vessel and settler and treated effluent left the apparatus to be collected in a vessel. Aeration was achieved through a capillary on the bottom of the aeration section at a rate of approximately 8 L/h of air. Sludge accumulating around the top of the aeration vessel was returned in the system once a day by brushing.

Stock suspension
A suspension of oleyl bis(2-hydroxyethyl)amine of 7.3 g/L in deionized water was directly added to the test unit using a syringe pump. The stock was prepared by adding 7.3 g of test substance to 0.7 L of deionized water. A homogenous suspension was obtained by acidifying the stock to a pH of
approximately 5.5 by adding HCl. A suspension was obtained by stirring for a few hours on a magnetic stirrer. The final stock suspension was made
up to 1.0 L with deionized water giving a concentration of 7.3 g/L. The particles in this suspension did not precipitate. The flow rate of the syringe
pump was 9.6 mL/day giving a nominal concentration of the test substance in the influent of the unit of 50 mg/L at a sewage supply rate of 1.4 L/day

Procedures of the CAS test
The CAS test was performed according to ISO (1995), EC (1988) and OECD (1981) test guidelines. The test and control unit were not coupled.
The units were started with activated sludge. The aeration was achieved by operating an air-lift. The aeration rate was regulated so that the activated
sludge was kept in suspension and the dissolved oxygen concentration was at least 2 mg/L. This oxygen concentration in the aeration vessel was
measured at least two times a week. The domestic sewage supply was supplied at a rate of approximately 1.4 L/day to give a hydraulic retention time
of 6 hours. The flow was checked by measuring the total volume of effluent over a 24-hour period. After brushing, 35 mL of sludge was daily
removed from the aeration tank to maintain a sludge retention time of 10 days. The effluent samples (50 mL) were taken from the settler.
The NPOC values were primarily used to assess the performance of biological treatment system fed with oleyl bis(2-hydroxyethyl)amine containing
wastewater and to preliminary follow the removal of the test substance during the test period.
NPOC values of the last period of the test were used to calculate the mean removal percentage. The daily removal percentages were calculated by the
following equation: 100 x (CT-(Ct-Cc)) / CT. Where CT is the carbon of the test compound measured as NPOC added to the settled sewage,
Ct is the carbon found as NPOC in the effluent of the CAS unit spiked with the test substance and Cc is the carbon found as NPOC in the effluent of
the control CAS unit.
The analysis values in the test and control unit were treated as paired observations. Outliers of the mean difference (Xd) series were eliminated
according to the Dixon test at a 95% probability level. From the set of 'n' paired observations the mean difference (Xd) and the standard deviation (Sd) were calculated. The Sd is calculated with the following formula (see attached report). The statistical significance of the observed difference was then
assessed from the t-statistics given by the following equation: (see attached report). The critical value of t at the required confidence level was\
obtained from statistical tables for a one tailed test with n-1 degrees of freedom. The percentage biodegradation/removal was given by;
(SL-Xd)/SL x 100 where Xd the mean difference and SL is the spiking level, both values being expressed in mg/L carbon.
The 95% confidence interval was calculated as follows: tn x Sd /SQRT(n) where tn is the t statistic for a two-tailed test, n-1 degrees of freedom,
P = 0.05.

Specific analyses of oleyl bis(2-hydroxyethyl)amine were used to determine the primary removal of the test substance. The removal percentage of
oleyl bis(2-hydroxyethyl)amine was determined with the following equation; (Is-Es)/Is x 100, where Is is the nominal test substance concentration in
the influent and Es is the mean of the measured test substance concentrations in the effluent.
The concentration of the test substance in the mixed liquid suspended solids (adsorbed on the activated sludge) (Csludge) and the theoretical
maximum concentration on sludge are used to assess the removal of the test substance by adsorption. Provided biodegradation nor evaporation of
the test substance occurs in the system, the theoretical maximum concentration of oleyl bis(2-hydroxyethyl)amine adsorbed onto the sludge is;
Cmax adsorption = Is x SRT/HRT, where SRT is the sludge retention time, HRT is the hydraulic retention time (both expressed in days) and Is is the
nominal test substance concentration in the influent. The removal of oleyl bis(2-hydroxyethyl)amine by adsorption is;
removal (%) = 100 x Csludge/Cmax adsorption.




Reference substance:
not required
Test performance:
Test conditions and validity of the test
The incubation temperature of both CAS units ranged from 19 to 21°C. The pH of the effluent of both CAS units varied from 7.0 to 7.4.
The oxygen concentrations measured in both units were always ≥3.9 mg/L (Table I). These test conditions are believed to allow biodegradation by
micro-organisms present in activated sludge.
The CAS test was started with a high concentration of aerobic micro-organisms (3.0 g/L dry weight) maintained by the daily addition of primary
settled sewage and sludge from a full-scale treatment plant. The daily removal of 35 mL of activated sludge from the aeration vessel resulted in a
sludge retention time of 10 days. The dry weight in the CAS units ranged from 2.4 to 3.0 g/L (Table I).
The performance of the control unit was checked by measuring the COD removal at Day 14 and at day 48 and the concentrations of ammonium and
nitrite in the effluent (Day 14). At Day 14 the COD contents (mean of two measurements) in the influent and effluent were 416 and 43 mg/L,
respectively. At day 48, the COD levels in the influent and effluent were 461 and 38 mg/L, respectively. COD removal percentages at both days were
90 and 92. The ammonium and nitrite concentrations in the effluent at Day 14 were <2.5 and <2.0 mg/L. These results demonstrate that the test is valid.
% Degr.:
102
St. dev.:
0.8
Parameter:
DOC removal
Remarks on result:
other: 15 measurements from day 34 - 48
% Degr.:
> 99.99
Parameter:
test mat. analysis
Remarks on result:
other: analysed in effleunt of test unit from day 44 to 48
% Degr.:
0.16
Parameter:
test mat. analysis
Remarks on result:
other: removal from influent throug adsorption onto sludge assessed in two samples day 47 and 48
Transformation products:
no
Details on transformation products:
These high NPOC removal percentages strongly indicate that oleyl bis(2-hydroxyethyl)amine is biodegraded completely. Formation of water soluble
compounds during biological treatment of oleyl bis(2-hydroxyethyl)amine can be excluded.
Evaporation of parent compound:
no
Volatile metabolites:
no
Residues:
no

NPOC concentrations in the effluent of the control and test unit and the calculated removal percentages of oleyl bis(2-hydroxyethyl)amine. The data in grey part of the table are used to calculate the biodegradation percentage.

Time (days)

NPOC (mg/L)

Removal (%)

 

Control

Test

 

-4

13.7

11.4

 

-2

12.1

10.9

 

2

9.5

11.4

95

0

10.8

18.2

80

6

11.0

11.3

99

9

11.7

10.7

103

13

12.7

10.2

107

16

13.9

16.2

94

20

12.7

12.1

102

23

8.3

8.8

99

27

9.7

11.8

94

30

7.5

9.4

95

34

9.1

8.2

102

35

12.0

9.5

107

36

10.3

8.0

106

37

12.7

9.3

109

38

10.2

8.8

104

39

10.9

8.2

107

40

11.0

11.3

99

41

10.5

10.2

101

42

11.4

10.5

102

43

13.0

14.9

95

44

12.1

12.2

100

45

13.9

13.7

101

46

12.8

12.3

101

47

12.6

12.5

100

48

13.7

13.9

100

Concentrations ofoleyl bis(2-hydroxyethyl)aminemeasured in the effluent and mixed liquid suspended solids (adsorption onto sludge) and removal percentages from the influent and by adsorption onto sludge, respectively.

Time (days)

Concentration (μg/L)

Removal (%)

Effluent

44

<0.06

>99.999

45

<0.06

>99.999

46

<0.06

>99.999

47

<0.06

>99.999

48

<0.06

>99.999

Time (days)

Concentration (mg/L)

Removal (%)

Mixed liquid suspended solids

47

3.2

0.16

48

3.2

0.16

Validity criteria fulfilled:
yes
Remarks:
COD removal in the control unit at Day 14 and day 48 of 90 and 92% resp. The ammonium and nitrite concentrations in the control effluent at Day 14 were <2.5 and <2.0 mg/L. These results demonstrate that the test is valid
Conclusions:
The CAS test demonstrates that oleyl bis(2-hydroxyethyl)amine almost completely removed from the wastewater in conventional biological
wastewater treatment plants. Oleyl bis(2-hydroxyethyl)amine is primarily removed by biodegradation.
102±0.8% NPOC removal, determined in effluent samles from test unit during 15 days from day 34 to 48
>99.999% removal of test substance calculated with specific analysis in effluent samples taken from day 44-48
0.16 % removal of test substance through adsorption onto sludge calculated with specific analysis in sludge samples taken on day 47 and 48.

Test performed under GLP according guidelines with a few accpetable (minor) deviations, meeting all validity criteria
Executive summary:

The continuous activated sludge (CAS) test was performed according to ISO Guidelines, and in compliance with the OECD principles of Good Laboratory Practice.Oleyl bis(2-hydroxyethyl)amine was exposed to micro-organisms maintained by addition of domestic wastewater in the CAS test.

Oleyl bis(2-hydroxyethyl)amine was spiked at a nominal influent concentration of 50 mg/L (37.0 mg/L carbon; calculated) for a period of 48 days and included a control fed with domestic wastewater only.

The immediate high removal percentages can be attributed to adsorption and probably biodegradation. The mean removal percentage of oleyl bis(2-hydroxyethyl)amine calculated over 15 measurements obtained from day 34 to 48 of the test was 102±0.8% (95% confidence interval). These high removal percentages strongly indicate that oleyl bis(2-hydroxyethyl)amine is biodegraded completely. Formation of water soluble compounds during biological treatment ofoleyl bis(2-hydroxyethyl)amine can be excluded.

An accurate assessment of the removal of oleyl bis(2-hydroxyethyl)amine was established with specific analyses. The method (LC-MS/MS) for the determination of oleyl bis(2-hydroxyethyl)amine was valid with regard to the linearity, repeatability of the injections, limit of quantification (LOQ), limit of detection (LOD), recovery and system stability. The mean removal percentage of oleyl bis(2-hydroxyethyl)amine in the test unit was quantified with the specific analysis from day 44 to 48 was >99.999% using octadecenyl bis(2-hydroxyethyl) amine as representative component as a worst-case. These analyses demonstrate that the removal of oleyl bis(2-hydroxyethyl)amine is complete. Oleyl bis(2-hydroxyethyl)amine concentrations in the mixed liquid suspended solids (activated sludge) of the reactor sampled on days 47 and 48 were 3.2 mg/L. Mean removal percentages of oleyl bis(2-hydroxyethyl)amine reaction from the influent through adsorption onto sludge assessed in two samples was therefore 0.16 % demonstrating that oleyl bis(2-hydroxyethyl)amine is primarily removed by biodegradation.

In conclusion, the CAS test demonstrates that oleyl bis(2-hydroxyethyl)amine almost completely removed from the wastewater in conventional biological wastewater treatment plants.Oleyl bis(2-hydroxyethyl)amineis primarily removed by biodegradation.

Description of key information

Based on the available studies on biodegradation is diquat C16 -18 quickly degraded into a metabolite which has a lower sorption potential than the parent. Due to the accumulation of the metabolite as observed in a SCAS test (van Ginkel et al, 2010) diquat C16-18 can not be considered as readily biodegradable. It is very unlikely that a quick further degradation of the metabolite will occur in soil or sediment. Further testing in soil or sediment is therefor not expected to deliver more information.  For sediment therefore a half life value of 30000 days is used until better soil/sediment biodegradation data become available.

Based on the ready biodegradability tests with adapted activated sludge and the inherent test according to OECD 302A (SCAS), it is expected that similar results are found in the simulation study according to OECD TG 309 as in the ready tests and that the results of the OECD 309 test can be interpreted so that a conclusion on the persistency can be derived on the remaining compartment(s). The confirm our expectations an OECD TG 309 study is planned to be performed.

The removal of N,N,N’,N’,N’’-pentamethyl-N-C16-18 (even numbered) C18 unsat.-alkyl-1,3-propanediammonium chloride (oxidation of the alkyl chain) in biological wastewater systems through read-across is assumed to be 99.99% removal from the wastewater and 99.98% removal by biodegradation.

Key value for chemical safety assessment

Additional information

Water: Based on the ready biodegradability tests with adapted activated sludge and the inherent test according to OECD 302A (SCAS), it is expected that similar results are found in the simulation study according to OECD TG 309 as in the ready tests and that the results of the planned OECD 309 test can be interpreted so that a conclusion on the persistency can be derived on the remaining compartment(s).

Sediment

Based on the available studies on biodegradation, diquat C16-18 is degraded quickly into a metabolite which has a lower sorption potential than the parent. Due to the formation of the metabolite as observed in a SCAS test (van Ginkel et al, 2010) diquat C16 -18 can not be considered as readily biodegradable. It is very unlikely that a quick further degradation of the metabolite will occur in soil or sediment. Further testing in soil or sediment is thereful not expected to deliver more information. For sediment therefore a half life value of 30000 days is used for the sediment until better soil/sediment data become available.

The half-life of the bioavailable fraction of N,N,N’,N’,N’’-pentamethyl-N-C16-18 (even numbered) C18 unsat.-alkyl-1,3-propanediammonium chloride

in the water phase of soils is expected to be in the order of a few days, which is based on experiments with dialkyldimethylammonium salts (van Ginkel et al, 2003).

Biological wastewater treatment

Chemically N,N,N’,N’,N’’-pentamethyl-N-C16 -18 (even numbered) C18 unsat.-alkyl-1,3 -propanediammonium chloride has an alkyl chain linked directly to a nitrogen atom of methylated 1,3-diaminopropane. Other water soluble fatty amine deravatives are also characterized by an alkyl group linked directly to a nitrogen of the hydrophilic moiety (diethanolamine and dimethylbenzylamine). These surfactants are in contrast to N,N,N’,N’,N’’-pentamethyl-N-C16-18 (even numbered) C18 unsat.-alkyl-1,3-propanediammonium chloride completely degraded because the hydrophilic moieties are biodegradable. However, the biodegradation of all surfactants is initiated by an attack on the alkyl chain serving as carbon and energy source for the micro-organisms. The fatty acids are degraded through the b-oxidation cycle. In each cycle, the alkyl chain is progressively shortened by two carbons yielding one molecule of acetyl-CoA. The acetyl-CoA generated in b-oxidation enters the TCA cycle, where it is further oxidised to carbon dioxide and water.

The oxidation of the alkyl chain (primary degradation) is the key to justification of the use of read-across of the results obtained continuously-fed activated sludge (CAS) unit fed with domestic wastewater spiked with fatty amines. The results of structurally related substances are given below. 

 

The removal percentages of the parent compounds of Oleyl bis(2-hydroxyethyl)amine (CAS 25307-17-9)

degraded through oxidation of the alkyl chain from the influent and removal by biodegradation in CAS unit is given below (Akzo Nobel 2010).

 

Surfactant

Removal from wastewater (%)

Removal by biodegradation (%)

Oleyl bis(2-hydroxyethyl)amine (CAS 25307-17-9)

99.999

99.84

For C12 -16 -BKC (CAS 68424 -85 -1) identically high removal and biodegradation percentages in the continuous activated sludge test (CAS test; OECD 303A) were observed (draft CAR BKC (published 07 -09 -2011, Circa.europe.eu)). These data show that for readily biodegradable cationic surfactants in general very high removal percentages will be observed in continuous activated sludge tests. When operated properly, the fraction removed by biodegradation is only influenced by the fraction sorbed in the CAS test (long alkyl chain cationic surfactants are non-volatile).

For the removal of N,N,N’,N’,N’’-pentamethyl-N-C16-18 (even numbered) C18 unsat.-alkyl-1,3-propanediammonium chloride (oxidation of the alkyl chain) in biological wastewater systems therefore also very high removal percentages are anticipated (for the parent). Based on read-across from CAS test results from other cationic surfactants like C12 -16 -BKC and Oleyl bis(2-hydroxyethyl)amine

>99.99% removal from the wastewater and >99.8% removal by biodegradation in the treatment system are considered to be realistic worst-case removal percentages for N,N,N’,N’,N’’-pentamethyl-N-C16 -18 (even numbered) C18 unsat.-alkyl-1,3 -propanediammonium chloride in conventional waste water treatment plants.