2,2-dimethyl-1,3-propanediyl didecanoate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions (purity not reported, no GLP data)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Station Epuration Wavre 2nd Stage, 23 Feb 1999
- Concentration of inoculum: > 1000000 CFU/mL (verification with Sanicheck) (CFU = Colony Forming Unit)

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Clearly chemically defined medium
- Test temperature: 22.1 - 22.4 °C
- pH: 7.2 - 7.3
- Aeration of dilution water: 24 h with CO2-free air (50 - 100 mL/min)

TEST SYSTEM
- Culturing apparatus: Container flask with 3 L of solution test and 30 mL inoculum
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: CO2-free air
- Details of trap for CO2 and volatile organics if used: The produced CO2 reacts with Ba(OH)2 to give a precipitate of Barium carbonate.

SAMPLING
- Sampling frequency: Sampling was performed on day 0, 2, 6, 9, 15, 19, 23 and 28.
- Sampling method: The produced CO2 was determinated in titrating the remaining Ba(OH)2 with HCl and phenolphtaleine.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

Reference substance:

benzoic acid, sodium salt

Remarks:

3 g/L

Parameter:

% degradation (CO2 evolution)

Value:

93.1

Sampling time:

28 d

Details on results:

Within the 10-day time window the 60% level was passed. Therefore, the test substance is regarded as readily biodegradable.

Results with reference substance:

Degradation: 77.7% after 9 days, 60% pass level was reached.

Table 1: Biodegradation of test (mean of 2 replicates) and reference substance

Day	Reference		Test substance
	% CO2 produced	%CO2 total	% CO2 produced	%CO2 total
0	0.0	0.0	0.0	0.0
2	40.5	40.5	14.0	21.0
6	28.7	69.1	15.7	44.5
9	8.6	77.7	15.4	67.6
15	3.9	81.7	12.4	86.2
19	5.1	86.8	2.8	90.3
23	3.1	89.9	1.2	92.1
28	1.2	91.1	0.7	93.1

 

Table 2: Biodegradation of the replicates of the test substance

Day	Test substance 1		Test substance 2
	% CO2 produced	%CO2 total	% CO2 produced	%CO2 total
0	0.0	0.0	0.0	0.0
2	20.7	20.7	21.3	21.3
6	19.8	40.5	27.2	48.5
9	26.8	67.3	19.3	67.8
15	17.2	84.5	20.0	87.8
19	4.5	89.0	3.9	91.7
23	1.7	90.7	1.9	93.5
28	1.0	91.7	1.0	94.5

 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Sep - 10 Oct 2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions (purity not reported)

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from the aeration tank of a municipal waste water treatment plant, ARA Werdhölzli,
Zürich, Switzerland (06 Sep 2006)
- Pretreatment: The sludge was washed twice with tap water.

Duration of test (contact time):

28 d

Initial conc.:

22.6 mg/L

Based on:

other: TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Aerobic mineral salts medium prepared with deionised water
- Test temperature: 22 ± 0.5 °C
- pH adjusted: Yes, the pH-value was checked at the beginning and at the end of the test and adjusted to pH 7.4 (± 0.2) with NaOH or HCL.
- Suspended solids concentration: 30 mg/L
- Continuous darkness: Yes, temperature-controlled dark room

TEST SYSTEM
- Culturing apparatus: 2500 mL closed glass bottle containing a total volume of test solution of 2000 mL
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: Aerated with synthetic CO2-free air for a maximum test period of 28 days.
- Measuring equipment: Shimadzu 5050 TOC-Analyzer using the NPOC-mode for DOC-determination
- Details of trap for CO2: The air leaving the individual vessels was passed through gas-absorption bottles filled with NaOH. The trapped CO2 was determined as inorganic carbon (IC).

SAMPLING
- Sampling frequency: on Day 0, 1, 3, 7, 10, 14, 17, 21, 24 and 28
- Sampling method: Samples were centrifuged (15 min at 4500 g) and acidified to pH < 2. Prior to analysis the samples were sparged with CO2-free
high purity air for 10 min to remove inorganic carbon.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 replicates

Reference substance:

benzoic acid, sodium salt

Remarks:

20.3 mg/L (TOC)

Parameter:

% degradation (CO2 evolution)

Value:

90.2

Sampling time:

28 d

Details on results:

Within the 10-day time window the 60% level was passed. Therefore, the test substance is regarded as readily biodegradable.

Results with reference substance:

Degradation: 83.1% after 14 days, 60% pass level was reached.

The biodegradation of the test substance reached 74% at the end of the 10-d window.

 

Table 1: Biodegradation of test substance

Time (days)	Test substance 1		Test substance 2
	Total CO2 release in test sample (mg IC/L)	Degradation (%)	Total CO2 release in test sample (mg IC/L)	Degradation (%)	Mean degradation (%)
0	0.0	0.0	0.0	0.0	0.0
1	0.0	0.0	-0.1	-0.1	0.0
3	1.7	4.3	2.0	5.7	5.0
7	10.3	37.0	8.7	30.2	33.6
10	16.0	58.4	15.3	55.4	56.9
14	19.9	75.5	20.0	75.9	75.7
17	21.1	81.4	21.3	82.4	81.9
21	23.0	86.4	22.8	85.6	86.0
24	23.1	86.8	24.0	90.6	88.7
28	23.7	88.1	24.6	92.2	90.2

 

Table 2: Biodegradation of reference substance and Inoculum blank

Time (days)	Reference substance		Inoculum blank
	Total CO2 release in test sample (mg IC/L)	Degradation (%)	Total CO2 release in test sample (mg IC/L)
0	0.0	0.0	0.0
1	0.6	3.3	0.0
3	7.7	34.3	0.8
7	14.2	60.4	1.9
10	17.6	73.0	2.8
14	19.7	83.1	2.8
17	20.3	87.1	2.7
21	21.6	89.5	3.5
24	21.7	89.8	3.5
28	22.3	91.3	3.8

 

 

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

Summary of available data used for the endpoint assessment of the target substance

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification document provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Parameter:

% degradation (CO2 evolution)

Value:

90.2

Sampling time:

28 d

Remarks on result:

other:

Remarks:

source, CAS 85186-86-3, Oleon, 2006, CO2 Evolution, RL2

Parameter:

% degradation (CO2 evolution)

Value:

93.1

Sampling time:

28 d

Remarks on result:

other:

Remarks:

source, CAS 31335-74-7, Croda, 1999, CO2 Evolution, RL2

Interpretation of results:

readily biodegradable

Conclusions:

A degradation of 90.2 – 93.1 % was observed after 28 d. Therefore, the test item can be considered as ready biodegradable.

Reference 4

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Remarks:

The substance is not fully compliant with the applicability domain of the model. However, this calculation is used in a weight of evidence approach, in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2. It is adequately documented and justified. For more detail see field `overall remarks, attachments´.

Justification for type of information:

1. SOFTWARE
Vega version 1.1.3

2. MODEL (incl. version number)
Ready Biodegradability Model (IRFMN) v. 1.0.9

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached information on the model provided by the developer. Further information on the OECD criteria as outlined by the applicant is provided below under "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See attached information and information as provided in "Any other information on results incl. tables".

6. ADEQUACY OF THE RESULT
See assessment of adequacy as outlined in the "Overall remarks, attachments" section.

Principles of method if other than guideline:

- Software tool(s) used including version: Vega v1.1.3

- Model(s) used: Ready biodegradability model (version 1.0.9)
Full reference and details of the used formulas can be found in:
Meylan W.M., Howard P.H., Boethling R.S. et al. Improved Method for Estimating Bioconcentration / Bioaccumulation Factor from Octanol/Water Partition Coefficient. 1999, Environ. Toxicol. Chem. 18(4): 664-672

- Model description: see field 'Justification for non-standard information', 'Attached justification' and 'any other information on Material and methods'

- Justification of QSAR prediction: see field 'Justification for type of information', 'Attached justification' and/or 'overall remarks'

GLP compliance:

no

Remarks:

not applicable

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks on result:

other: The substance was predicted to be readily biodegradable

For detailed information on the results please refer to the attached report.

Interpretation of results:

readily biodegradable

Description of key information

90.2% biodegradation (28 d, OECD 301B); read-across

93.1% biodegradation (28 d, OECD 301B); read-across

Additional information

No study is available in which the ready biodegradability of Neopentyl glycol dicaprate (CAS No. 27841-06-1) was assessed.Therefore, read-across to the following structurally and chemically closely related source substances was performed in accordance with Regulation (EC) No 1907/2006 Annex XI, section 1.5 in order to fulfill the data requirements for this substance: Fatty acids, C8-18 and C18-unsatd., esters with neopentyl glycol (CAS 85186-86-3) and 2,2-dimethylpropane-1,3-diyl dioctanoate (CAS 31335-74-7). The source substances are characterized by similar chemical structure and are therefore considered suitable representatives for the assessment of the ready biodegradability of the target substance. A detailed read-across justification in provided in IUCLID section 13. The robustness of the endpoint is supported by QSAR calculations using the VEGA Ready Biodegradability Model.

One study is available for the source substance Fatty acids, C8-18 and C18-unsatd., esters with neopentyl glycol (CAS 85186-86-3). The study was performed according to OECD guideline 301B (CO2Evolution Test) under aerobic conditions and used activated, domestic, non-adapted sludge as inoculum. The initial test item concentration was 22.6 mg/L (based on TOC). After 28 d, a biodegradation of 90.2% (based on CO2evolution) was observed. The 60% pass level of the 10-day-window was fulfilled. The source substance Fatty acids, C8-18 and C18-unsatd., esters with neopentyl glycol (CAS 85186-86-3) can therefore be considered readily biodegradable according to OECD criteria.

One study is available for the source substance 2,2-dimethylpropane-1,3-diyl dioctanoate (CAS 31335-74-7). The study was performed according to OECD guideline 301B (CO2Evolution Test) under aerobic conditions and used activated sludge as inoculum. The initial test item concentration was 20 mg/L (based on TOC). After 28 days, a biodegradation of 93.1% (based on CO2evolution) was observed. The 60% pass level of the 10-day-window was fulfilled. The source substance 2,2-dimethylpropane-1,3-diyl dioctanoate (CAS 31335-74-7) can therefore be regarded as readily biodegradable according to OECD criteria.

The endpoint is supported by QSAR calculations using the VEGA (1.1.4) Ready Biodegradability Model (v1.0.9). The target substance Neopentyl glycol dicaprate (CAS No. 27841-06-1) was predicted to be readily biodegradable. The substance is not fully compliant with the applicability domain of the model. However, this calculation is used in a weight of evidence approach, in accordance to the REACh Regulation (EC) No 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2.

Based on the available results from structurally related read-across substances (in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, and based on QSAR calculations (VEGA (1.1.4); Ready Biodegradability Model (v1.0.9)), it can be concluded that the target substance Neopentyl glycol dicaprate (CAS No. 27841-06-1) is readily biodegradable.