Fatty acids, C10-12, esters with polylactic acid, sodium salts

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

August 24th - September 21st, 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study was performed according to GLP requirements, no critical deviations from the study plan were observed

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

, pH of test water was 7.1 instead of 7.4 +/- 0.2 as mentioned in the study plan

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

yes

Remarks:

, pH of test wtaer was 7.1 insetad of 7.4 +/- 0.2 as mentioned in the study planwas

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Melting range: 0,7-10,2 °C 240°C
- Boiling point: substance decomposites at approx. 240°C
- Vapour pressure: 1.84 mPa
- Water solubility (under test conditions): 0,12 g/L
- Stability of test material at room temperature: 36 months
- pH dependance on stability: Hydrolysis of substance is to be expected at pH > 7

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):
Activated sludge (microorganisms from a domestic wate water treatment plant) was supplied by sewage plant Rossdorf, Germany.
- Storage conditions: Sludge was re- suspened in test water after washing and aerated overnight.
- Storage length: 1 day
- Preparation of inoculum for exposure:
- Pretreatment: The aerobic activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in tap water and centrifuged again. This procedure was done three times. The sediment was re-suspended in test water and aerated overnight.
- Initial cell/biomass concentration: Aliquots of washed sludge corresponding to 4g dry matter per litre wer mixed with test water
- Water filtered: yes
- Type and size of filter used, if any: cotton wool filter

Duration of test (contact time):

28 d

Initial conc.:

3.04 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
Reconstituted Water:
In deionised water analytical grade salts were added to
prepare the following stock solutions:
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2
H2O, 0.5 g NH4Cl filled up with deionised water to
1000 mL volume
b) 22.5 g MgSO4 x 7H2O filled up with deionised water to
1000 mL volume
c) 36.4 g CaCl2 x 2H2O filled up with deionised water to
1000 mL volume
d) 0.25 g FeCl3 x 6H2O filled up with deionised water to
1000 mL volume
In order to avoid precipitation of iron hydroxide in the stock solution d) immediately before use, one drop of concentrated HCl per litre was added.1 mL of the stock solutions a) - d) were combined and filled to a final volume of 1000 mL with deionised water. The test medium was aerated for 20 minutes and allowed
to stand for about 20 hours at the test temperature. The dissolved oxygen concentration was 8.4 – 8.5 mg/L at about 20.0 – 21.4 C.


- Test temperature: 21.6-22.3°C
- pH: 7.1 (at the start of the test)
- pH adjusted: no, but 1 drop HCl was added to the stock solution to avoid precipitation of iron hydroxide
- CEC (meq/100 g):
- Aeration of dilution water: yes, aeration was performed for 20 min. to yield a concentration of dissolved oxygen of 8.4-8.5 mg/L
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: Karlsruher flasks 268 ml volume with glass stoppers
- Number of culture flasks/concentration: 16 bottles containing the test item and inoculum, 16 bottles containing the reference item sodium benzoate and inoculum (procedure control), 16 bottles containing only inoculum (inoculum control), 10 bottles containing the test item, sodium benzoate and inoculum (toxicity control)
- Method used to create aerobic conditions: The test solution was aerated before used in the test. The oxygen concentration was 8.4 - 8.5 mg/l.
- Measuring equipment: The oxygen concentrations were electrochemically measured in an airtight system with an O2 - electrode (WTW Oxi 340, Wissenschaftlich Technische Werkstätten GmbH, Weilheim, germany) under constant stirring.
- Test performed in closed vessels due to method given by OECD 301 D

SAMPLING
- Sampling frequency: Oxygen measurements were performed in duplicate on days 0,3,5,7,12,14,21 and 28.
(Measurments of toxicity controls were done only on days 0,7,14,21 and 28)
- Sampling method:


CONTROL AND BLANK SYSTEM
- Inoculum blank: 2.5 ml of filtered inoculum were diluted in 5 L of aqueous test medium
- Toxicity control: 14.9 mg of test item and 20.3 mg of sodium benzoate (THOD 14.44 mg/L O2) were thouroghly mixed into 5 L of aqueous medium. Then 2.5 ml of filtered inoculum was added
- Procedure control: 4.06 mg/L sodium benzoate (THOD 1.666 mg/L O2) were diluted in 5 L of aqueous medium. 2.5 ml of filtered inoculum was added.
- Test item: 15.2 mg of dermosoft decalact (THOD 2.577 mg/L) were diluted in 5 L of aqueous medium. Then 2.5 ml of filtered inoculum was added.
STATISTICAL METHODS:
Oxygen measurements were performed in duplicate. Mean values were calculated.

Reference substance:

benzoic acid, sodium salt

Remarks:

Purity: 100.4%

Preliminary study:

not applicable

Parameter:

% degradation (O2 consumption)

Value:

66

St. dev.:

0

Sampling time:

28 d

Details on results:

Biodegr adation of Test Item
Percentage Biodegradation: Under the test conditions the percentage biodegradation of
Dermosoft® decalact reached in the mean 42 % after
3 days of incubation and continuously increased to 64 %
after 12 days and 66% after 28 days. The results are represented
in Tables 1 - 3 and Figure 1.
Conclusion: The percentage biodegradation exceeded 60 % within the
10-day window.

Parameter:

BOD5

Value:

5.2 other: mg/L

Results with reference substance:

Degradation of sodium benzoate reached 71% after 3 days and was 98% at day 28.
O2 depletion was 6.6 (mg/L) after 28 days of exposure

Validity Criteria of the Study

Inoculum Control: Oxygen depletion in the inoculum control did not exceed 1.5 mg O2/L after 28 days.

Oxygen Concentration: The residual oxygen concentration in the test flasks did not drop below 2.4 mg O2/L at any time. According to the test guideline, the residual oxygen concentration in the test flasks should not drop below 0.5 mg O2/L at any time except the analytical method is capable to detect these amounts. The oxygen concentration dropped below 0.5 mg/L in the toxicity control due to the complete biodegradation of sodium benzoate. The oxygen measurement equipment used is able to detect an amount of 0.1 mg/L oxygen in aqueous solutions.

Test Item: The difference of duplicate values for the degradation of Final Report (2nd Original) IBACON Project 76951161 - Ready Biodegradability of Dermosoft® decalact in a Closed Bottle Test page 18 of 23 the test item at the plateau, at the end of the test and at the end of the 10-day window was less than 20 %.

Reference Item (Sodium Benzoate): The percentage degradation of the reference item sodium benzoate should reach the level for ready biodegradability (> 60 %) by exposure day 14. The degradation was 71 % after 3 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The percentage biodegradation exceeded 60 % within the 10-day window. The test item can therefore be considered as ready biodegradable.

Executive summary:

Ready Biodegradability of Dermosoft® decalact in a Closed Bottle Test following the methods laid down in:

Commission Regulation 440/2008/Ec Method C.4 -E (Closed Bottle Test) and OECD Guideline No. 301 D: "Ready Biodegradability: Closed Bottle Test", adopted July 17, 1992

The purpose of this study was to determine the ready biodegradability of the test item Dermosoft® decalact. The test item was exposed to activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. A Closed Bottle Test was chosen for the determination of the ready biodegradability since the test item is well soluble in test water at the recommended test concentration.

Under the test conditions the percentage biodegradation of Dermosoft® decalact reached in the mean 42 % after 3 days of incubation and continuously increased to 64 % after 12 days and 66% after 28 days. The results are represented in Tables 1 - 3 and Figure 1. Conclusion: The percentage biodegradation exceeded 60 % within the 10-day window. The validation criteria are fulfilled. Oxygen Concentration: The residual oxygen concentration in the test flasks did not drop below 2.4 mg O2/L at any time. According to the test guideline, the residual oxygen concentration in the test flasks should not drop below 0.5 mg O2/L at any time except the analytical method is capable to detect these amounts. The oxygen concentration dropped below 0.5 mg/L in the toxicity control due to the complete biodegradation of sodium benzoate. The oxygen measurement equipment used is able to detect an amount of 0.1 mg/L oxygen in aqueous solutions. Test Item: The difference of duplicate values for the degradation of Final Report (2nd Original) IBACON Project 76951161 - Ready Biodegradability of Dermosoft® decalact in a Closed Bottle Test page 18 of 23 the test item at the plateau, at the end of the test and at the end of the 10-day window was less than 20 %. Reference Item (Sodium Benzoate): The percentage degradation of the reference item sodium benzoate should reach the level for ready biodegradability (> 60 %) by exposure The test item can therefore be considered as ready biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 Sep - 09 Oct 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study was performed according to GLP requirements. Deviations were reported but assesed as non-critical by the study director.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

yes

Remarks:

, but the deviations from study plan were assessed to be uncritical for the outcome of the study

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

yes

Remarks:

, but the deviations from study plan were assessed to be uncritical for the outcome of the study

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht Rheinland-Pfalz, Mainz, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge:
The sludge was taken from a biologic sewage treatment plant which is treating mostly domestic sewage. Sludge was taken on Sep 7th, 2012, from the activation basin of ESN (Stadtentsorgung Neustadt) sewage treatment plant, located in Altenschemel, NW-Lachen - Speyerdorf in Germany.
- Pretreatment: The sludge was filtrated, washed with tap water twice, then washed with resuspended test medium. Then aerated for ≥ 12 hours.
- Concentration of sludge: 25,0 mg dry matter/L, determined by 4120 mg suspended sludge/L.

Duration of test (contact time):

28 d

Initial conc.:

35.1 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

other: nominal organic carbon content

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 20.5 - 23.0 °C
- pH: 6.94 - 7.62
- pH adjusted: no
- Inoculum concentration: 25 mg/L
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 2000 mL glass flasks
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, moistened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 m-NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
- Details of trap for CO2 and volatile organics if used: flask containing a solution of Ba(OH)2

SAMPLING
- Sampling frequency: Sampling was done on days 0, 2, 4, 7, 9, 11, 14, 18, 22 and 29
- Sampling method: 10 samples of 1 mL each were taken from each front scrubber flask. On day 29, samples from both flasks were taken.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 flasks, containing mineral medium and inoculum
- Abiotic sterile control: yes, 1 flask, containing test item, mineral medium and HgCl2
- Toxicity control: yes, 1 flask, containing test item, positive control, mineral medium and inoculum
- Positive control: yes, 2 flasks, containing positive control, mineral medium and inoculum

Reference substance:

aniline

Remarks:

Phenylamine C6H5NH2, CAS 62-53-3

Parameter:

% degradation (CO2 evolution)

Value:

75

Sampling time:

28 d

Remarks on result:

other: mean of two replicates

Details on results:

The following data were determined for the test item dermosoft® decalact:
10-day-window: day 2 – 12
degradation at the end of 10-day-window 64 %
degradation flask 1: 73.7% after 28 d
degradation flask 2: 75.8% after 28 d
degradation at the end of the test 75 %
pass level following guideline: 60% at the end of 10-day-window

Results with reference substance:

Aniline was chosen as positive control.
Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.
All validity criteria were met. Degradation of the positive control was 63 % after fourteen days.

Table 1: Validity criteria for OECD 301B.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	2.1%	yes
Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).	14 day	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	74%	yes
The IC content of the test substance suspension in the mineral medium at the beginning of the test must be less than 5% of the TC.	<1%	yes
The total CO2 evolution in the inoculum blank at the end of the test should not normally exceed 40 mg/L medium.	9.7 mg/L	yes

Validity criteria fulfilled:

yes

Remarks:

Please refer to Table 1 at "Any other information on results incl. tables"

Interpretation of results:

readily biodegradable

Conclusions:

• The test item dermosoft® decalact is considered as “readily biodegradable“.
• The degree of biodegradation reached 75 % after 28 days.
• The 10-day-window began on day 2, at its end, 64 % were reached, surpassing the pass level of 60 % given in the OECD guideline.

Executive summary:

The test item dermosoft® decalact was tested using a concentration of nominally 20 mg organic carbon/L (corresponding to 35.1 mg dermosoft® decalact/L) in test medium following OECD 301B and EU-Method C.4-C.

 Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control was 63 % after fourteen days. 

The following data were determined for the test item dermosoft® decalact:

10-day-window:                                                                                                               day 2 – 12
degradation at the end of 10-day-window                                                                              64 %
degradation at the end of the test                                                                                            75 %
pass level following guideline:                                               60% at the end of 10-day-window

 

Therefore, when applying the 10-day-window, dermosoft® decalact is readily biodegradable following OECD 301B/EU C.4-C.

 

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

24 Aug - 21 Sep 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

adopted July 17, 1992

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

May 30, 2008

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Aerobic activated sludge (microorganisms from a domestic wastewater treatment plant) was supplied by the sewage works of Darmstadt, Germany
- Pretreatment: The aerobic activated sludge used for this study was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in tap water and centrifuged again. This procedure was done three times. An
aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined.
- Concentration of sludge: 1.5 g dw/L

Duration of test (contact time):

28 d

Initial conc.:

33 mg/L

Based on:

test mat.

Initial conc.:

84 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 22°C
- pH: 6.7 – 7.5
- pH adjusted: no
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: BSB Sensomat system, Aqualytic Dortmund
- Measuring equipment: The consumption of oxygen was determined by measuring the change of pressure in the flasks.
- Details of trap for CO2 and volatile organics if used: Potassium hydroxide solution (45%)


CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Abiotic sterile control: 1
- Toxicity control: 1

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

63

Sampling time:

28 d

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 84% after 14 days and to 97% after 28 days of incubation.

In the toxicity control containing both, the test item and the reference item sodium benzoate, 66% biodegradation was noted within 14 days and 71% biodegradation after 28 days of incubation. Thus, the test item can be assumed to be not

inhibitory to the aerobic activated sludge microorganisms.

The 10-day windows began one day after application, the mean value was calculated to be 24% biodegradation. Therefore, the end of the 10-day window was day 11. After correction for the mean biochemical oxygen demand of the

inoculum controls the mean biodegradation percentage based on ThODNH4 at the end of the 10-day window was 48%, the 10-day window was not passed.

Table 1: Validity criteria for OECD 301F.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	<20%	yes
Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).	>60% after 5 days	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	66% after 14 days	yes
The oxygen uptake of the inoculum blank is normally 20-30 mg O2/L and should not be greater than 60 mg/L in 28 days.	20 mg/L	yes

 

Validity criteria fulfilled:

yes

Remarks:

Please refer to "Any other information on results incl. tables"

Interpretation of results:

readily biodegradable, but failing 10-day window

Description of key information

Readily biodegradable (75% after 28 d, OECD 301 B)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Three GLP studies on biodegradability following different OECD guidelines are available for Fatty acids, C10-12, esters with polylactic acid, sodium salts. In a key study following OECD guideline 301B, the biodegradation rate was determined by measuring the CO2 evolution. The determined degradation rate was 75% after 28 days. The ten-day window criterion was met. In a second key study, conducted according to OECD guideline 301D, the degradation rate was determined by measuring the O2 consumption of the inoculum. The determined degradation rate after 28 days was 66%; the ten-day window criterion was met.

In a supporting the study, the oxygen consumption of the inoculum was measured in a manometric respirometry test according to OECD 301F. A degradation rate of 63% was determined after 28 days, but the ten-day window criterion was not met.

Based on the available key study results, the substance is considered to be readily biodegradable according to OECD criteria.