Icosyl acrylate

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:

weight of evidence

Study period:

from 2012-05-23 to 2012-06-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal waste water treatment plant Mannheim, Germany.
- Storage conditions: The inoculum was collected from the aeration tank of the plant and aerated in the laboratory until use. A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 96 hours at 22 ± 2° C.
- Preparation of inoculum for exposure: At the day of exposure the suspension was washed one time with drinking water. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight.
- Pretreatment: none
- Concentration of sludge: Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration of 30 mg/L dry weight.

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

other: Total Organic Carbon (TOC)

Initial conc.:

26 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Solubilising agent (type and concentration if used): The amount of 66.2 mg test substance was added to a volumetric flask. After addition of about 800 mL demineralized water the mixture was stirred for about 3 hours and made up to the mark afterwards. The test substance was not completely dissolved, verified by visual inspection.
- Test temperature: 22 +/- 2°C
- pH adjusted: no
- Suspended solids concentration: 30 mg/L dry weight

TEST SYSTEM
- Culturing apparatus: 2 L incubtion bottles
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: aeration with carbon dioxide free air
- Measuring equipment: The TIC- and DOC-analyses were performed as repeat determination, using a TOC-analyzer equipped with an auto sampler (Shimadzu TOC-5000A).
- Test performed in closed vessels: yes
- Test performed in open system: no
- Details of trap for CO2 and volatile organics if used: The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes. Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately.

CONTROL AND BLANK SYSTEM
- 2 test substance assays
- 1 reference substance assay
- Inoculum blank: yes; 2 blank control assays.
- Inhibiton control: yes; 1 inhibition control test assay
- Toxicity control: yes

Reference substance:

aniline

Test performance:

The validity criteria were fulfilled.

Parameter:

% degradation (CO2 evolution)

Value:

80 - 90

Sampling time:

28 d

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2012-01-24 to 2012-04-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

Principles of method if other than guideline:

Remark1: The test temperature was slightly below required the range for the first three weeks of the exposure period. An impact to the test result can be excluded.
Remark2: The validity criterion: The content of DIC in the blank control at start of exposure at the test concentration of 20 mg/L TOC should be <0.5 mg/L was slightly failed. An impact of the test result can be excluded.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany.
- Preparation of inoculum for exposure: The inoculum was collected on 01 February 2012 from the aeration tank of the plant and aerated in the laboratory until use. A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm.
To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 48 hours at 22 ± 2° C.
- Exposure: At the day of exposure the suspension was washed one time with tap water. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight.
- Concentration of sludge: Aliquots of 7.5 mL were added to the test vessels to obtain a activated sludge concentration of 30 mg/L dry weight.

Duration of test (contact time):

60 d

Initial conc.:

20 mg/L

Based on:

other: Total Organic Carbon (TOC)

Initial conc.:

13 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: The used mineral medium complies with the test guideline OECD 301B.
- The pH-values in the test vessels were measured and adjusted to 7.4 ± 0.2, if necessary and aliquots of activated sludge suspension were added to all test vessels, to adjust the concentration of activated sludge to 30 mg/L dry weight. Samples for DICmeasurement (validity criterion) from the blank control assays were taken.
At the end of exposure, the pH values were measured in each test vessel. For stripping of carbon dioxide, dissolved in the test medium, each test vessel was acidified by adding 2 mL of concentrated hydrochloric acid. Since the test substance was insufficiently soluble in water, no DOC-measurements could be performed. The aeration was continued for about 24 hours and the released carbon dioxide amounts in both traps of each test vessel were determined and added to the calculated amount of the previous sampling day.
- Aereation: At the start of the exposure phase the test vessels were connected with an aeration unit and the bubble aeration with carbon dioxide free air was started after connecting the several test vessels with the absorption units.
- The test assay of the reference control was already terminated after an exposure period of 28 days without acidification of the test vessel.

TEST SYSTEM
- Culturing apparatus: The Carbon Dioxide Evolution Test was performed in 2 L incubation vessels.
- Number of culture flasks/concentration: The test volume was 1.5 L. The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes.
- Test performed: The test assays were prepared at the day of exposure. First, the required volumes of demineralized water and the solutions of mineral salts were dosed to all test vessels. For preparation of the test vessels with test substance, the required amounts of the test substance aliquots for a test concentration of 10 mg/L TOC were weighed onto small glass plates (microscope cover slips) and completely added with glass plates to the vessels of the test substance assays and to the vessel of the inhibition control. Because of poor water solubility of test substance these test assays were treated for few minutes in an ultra sonic bath to ensure an even distribution of test substance in test medium.
Finally enough reference substance stock solution was added to reach 20 mg TOC/L in the reference substance assay and 10 mg TOC/L in the inhibition control

ANALYSIS
- The TIC -was performed as repeat determination, using a TOC- analyzer equipped with an auto sampler (Shimadzu TOC-5000A). The system works with a combustion/nondisperse infrared gas analysis method. For calibration of the TOC-Analyzer, standard samples were measured before start of measurements to prove the conformity with the calibration curve. The samples for TIC-analysis (absorption solution) were measured without further treatment.

- Determination of total organic carbon by combustion The determination of total carbon in solids is performed using a solid sample module SSM-5000A connected with a TOC-analyzer (Shimadzu TOC-5000A). The test substances are combusted at 900 °C in a continuous oxygen stream at a temperature of 900 °C under addition of tungsten oxide to support a steady combustion and the formed carbon dioxide is measured in the TOC-analyzer unit using the infrared gas analysis method. A separate determination of total inorganic carbon (TIC) is not necessary with usual test substances. Since TIC content in such substances can be excluded the measured carbon dioxide is equivalent to the organic content of the test compound.

Aliquots of the test substance were weighed on small porcelain jars and overlaid with a small amount of tungsten oxide. The jars were inserted in the combustion unit and the organic part of the test substance was oxidized to carbon dioxide and measured as described above. The analysis was performed as a triple determination.

SAMPLING
- Sampling frequency: Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analyzed separately.
- Sampling method: The TIC-value of the freshly prepared sodium hydroxide solution was determined and considered by the calculation of biogenic produced carbon dioxide amount. The test assays were stirred on magnetic stirrers; the aeration was performed with carbon dioxide free air at a flow rate of approximately 800 mL per hour.






CONTROL AND BLANK SYSTEM
- 2 blank control assays
- 2 test substance assays
- 1 inhibition control test assay
- 1 reference substance assay

Reference substance:

aniline

Test performance:

Remark: After addition of the test substance to the mineral medium the test assays were treated for about 10 minutes in an ultra sonic bath to ensure an even distribution of the test substance in the medium.

Parameter:

% degradation (CO2 evolution)

Value:

> 60 - <= 70

Sampling time:

60 d

Details on results:

The required pass level for the biodegradability was reached. At the end of exposure after 60 days the degree of biodegradation was 60-70 % CO2/ThCO2 in this test. The degree of biodegradation was calculated as mean of the values from two test assays at the end of exposure.
Based on determined rate of biodegradation at the end of exposure the test substance can be evaluated biodegradable under enhanced test conditions.
The results in this study are consistent with all validity criteria and the test is valid according to the guideline of this study. No deviations from the test guidelines or other incidents occurred during the course of the reported test which may have influenced the results.

DEGREE OF BIODEGRADATION
Duration of the adaptation phase: 25 days
Degree of biodegradation of the test substance at the end of the ten-day window: not applied
Degree of DOC removal of test substance at the end of exposure: --
Degree of biodegradation of the test substance at the end of exposure, mean value: 60-70 % CO2/ThCO2
Reference substance: aniline Degree of biodegradation of the reference substance after 14 days: 68 % CO2/ThCO2
Degree of biodegradation in the inhibition control after 14 days: 54 % CO2/ThCO2
Test temperature: 22

VALIDITY OF CRITERIA

Measured DIC-concentrations in the blank controls at begin of exposure (mean value): 0.7 mg/L
Amount of produced CO2 in the blank controls at the end of exposure (mean value): 27.7 mg/L
Deviation of the degree of biodegradation of the test substance in the plateau phase should be <20%: yes
The degree of biodegradation of the reference substance should be >60% CO2/ThCO2 after 14 days: yes
The degree of biodegradation in the inhibition control should be>25 % CO2/ThCO2 after 14 days: yes
The content of DIC in the blank control at start of exposure at the test concentration of 20 mg/L TOC should be <0.5 mg/L: 1noThe validity criterion was slightly failed. An impact of the test result can be excluded.
The amount of produced CO2 in the inoculum blank (“blank controls”) at the end of exposure (mean value) should be <70 mg/L: yes

Parameter:

COD

Value:

60 other: CO2/ThCO2

Results with reference substance:

Degree of biodegradation of the reference substance after 14 days: 68 % CO2/ThCO2

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2013-02-14 to 2013-03-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(Commission Regulation 2008/440/EC)

Deviations:

no

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
- Water solubility: Poorly soluble

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany
- Storage conditions: Aerated in the laboratory until use
- Preparation of inoculum for exposure: Suspension was washed one time with drinking water.
- Pretreatment: Suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 48 hours at 22 ± 2° C. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight. Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration.
- Concentration of sludge: 30 mg/L dry weight.


- Water filtered: Yes
- Type and size of filter used: Finely woven mesh

Duration of test (contact time):

28 d

Initial conc.:

26 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium:
Solution A solved in 1000 mL:
KH2PO4 : 8.50 g
K2HPO4 : 21.75 g
Na2HPO4 × 2 H2O : 33.40 g
NH4Cl : 0.50 g
Solution B: CaCl2 × 2 H2O : 36.40 g /1000 mL
Solution C: MgSO4 × 7 H2O : 22.50 g /1000 mL
Solution D: FeCl3 × 6 H2O : 0.25 g /1000 mL
15 mL solution A, 1.5 mL solution B, 1.5 mL solution C and 1.5 mL solution D was used for the preparation of the test assays.

- Test temperature: 22 +/-2 °C
- pH: 7.4 +/-0.2
- pH adjusted: Yes
- Aeration of dilution water: Yes, aeration was performed with carbon dioxide free air at a flow of approximately 800 mL per hour

TEST SYSTEM
- Culturing apparatus: Vessel
- Number of culture flasks/concentration:
2 blank control assays (BC)
2 test substance assays (TS)
1 inhibition control test assay (IH)
1 reference substance assay (RS)
- Method used to create aerobic conditions: Aeration
- Measuring equipment:
TIC- and DOC-analyses were performed as repeat determination, using a TOCanalyzer equipped with an auto sampler (Shimadzu TOC-5000A). The system workswith a combustion/non-disperse infrared gas analysis method.

SAMPLING
- Sampling frequency:
Dissolved organic carbon (DOC): At the begin and end of the exposure for blank control and reference substance
Since the test substance was insufficiently soluble in water, no DOC-measurements could be performed from the test assay of the inhibition control and from the test substance test assays.
Produced carbon dioxide amount in the test vessels respectively Degree of Biodegradation (% CO2/ThCO2): Daily (over 28 days)
Measurement of total inorganic carbon (TIC): Daily (over 28 days)
- Sampling method: Decrease of dissolved organic carbon (DOC) samples were taken from the test vessels of the blank control and from the test vessel of the reference substance control and the DOC content was determined after centrifugation (approx. 15 minutes at 4000 rpm).
- Sample storage before analysis: Storage at room temperature, avoid temperatures >35°C, no direct sun light

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Toxicity control: Yes

STATISTICAL METHODS: Yes (mean value and standard deviation)

Reference substance:

aniline

Preliminary study:

No

Test performance:

VALIDITY CRITERIA
Measured DIC-concentrations in the blank controls at begin of exposure (mean value): 0.6 mg/L
Amount of produced CO2 in the blank controls at the end of exposure (mean value): 27.8 mg/L
Deviation of the degree of biodegradation of the test substance in the plateau phase should be <20%: Yes
The degree of biodegradation of the reference substance should be >60% CO2/ThCO2 after 14 days: Yes
The degree of biodegradation in the inhibition control should be>25 % CO2/ThCO2 after 14 days: Yes
The content of DIC in the blank control at start of exposure at the test concentration of 20 mg/L TOC should be <1 mg/L: Yes
The amount of produced CO2 in the inoculum blank (“blank controls”) at the end of exposure (mean value) should be <70 mg/L: Yes

Parameter:

% degradation (CO2 evolution)

Value:

50 - 60

Sampling time:

28 d

Details on results:

Degree of biodegradation of the test substance at the end of the ten-day window: Not applied
Degree of biodegradation in the inhibition control after 14 days: 66 % CO2/ThCO2

Results with reference substance:

Degree of biodegradation of the reference substance after 14 days: 77 % CO2/ThCO2

Description of key information

The biodegradation potential for the group is assessed based on data available for 2-Propenoic acid C12-14-alkyl esters (CAS 84238-60-8), 2-Propenoic acid C16-18-alkyl

esters (CAS 90530-21-5) and 2-Propenoic acid, C18-22-alkyl esters (CAS 85085-17-2).

 

Table 1 . Results on screening tests for biodegradation in water        

Ester	Method	Final Biodegradation (%)	10 Day Window Criteria met	Reference
2-Propenoic acid, C12-14alkyl esters [84238-60-8]	OECD 301 B (CO2Evolution Test)	80 - 90 (28 d)	60 - 70 %	BASF SE 2012
2-Propenoic acid, C16-18-alkyl esters [90530-21-5]	OECD 301 B (CO2Evolution Test)	50 - 60 (28d)	Not applied	BASF SE 2013
2-Propenoic acid, C18-22-alkyl esters [85085-17-2]	OECD 301 B (CO2Evolution Test)	60 - 70 (60 d)	Not applied	BASF SE 2013

 

Conclusion

Data from studies with 2-Propenoic acid, C16-18-alkyl esters (CAS 90530-21-5) revealed biodegradation. Nevertheless, the strict criteria for ready biodegradation were not fulfilled. As the test substance consists of different constituents the 10-day window is not applicable.

To be able to finally conclude on this endpoint additional data form another long chain acrylates were considered. 2-Propenoic acid C12-14-alkyl esters (CAS 84238-60-8) was shown to be clearly readily biodegradable. 2-Propenoic acid, C18-22-alkyl esters (CAS 85085-17-2) show that the test substance is nearly completely degraded after 60 days and can thus be judged to be ready biodegradable, but failing the 10- day window. Such a prolonged test is not available for 2-Propenoic acid C16-18 and C18-22 -alkyl esters (CAS 90530-21-5; 85085-17-2), but similar results are expected, as the longer C-chained acrylates represent a worst case in this sense.

 

Taking all data together, the long-chain acrylate esters category is considered to be readily biodegradable but failing the 10 - day window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

A biodegradability test of the read across substance (mixture of CAS no. 2156-97-0 and 21643-42-5) was performed which allows the biodegradability to be measured in an aerobic aqueous medium. The biodegradability was determined in the determination of the biodegradability in the CO2 -Evolution Test performed according to OECD guideline no. 301B.

The initial test concentration was 20 mg/L TOC, equivalent to approx. 26 mg/L test substance. The duration of the exposure was 28 days and the test system (inoculum) was activated sludge from the municipal sewage plant Mannheim, Germany.

The degree of biodegradation of the test substance was 80 -90 % CO2/ThCO2 after an exposure period of 28 days. That means that the test substance was readily biodegradable under the conditions of this test.