Dodecanoic acid, 2,2-dimethyl-3-oxopropyl ester

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004-08-18 to 2004-11-24

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:

adopted 1992

Deviations:

no

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: ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf
- Pretreatment: The sludge was filtrated and washed with tap water twice, then washed with and resus-pended in test medium. It was then aerated for >= 12 hours. The dry matter was deter-mined as 6400 mg suspended solids/Liter.

Duration of test (contact time):

28 d

Initial conc.:

45.1 other: mg/1500 mL

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: in accordance to the guideline
- Test temperature: 21 +/- 2°C
- Aeration: yes

TEST SYSTEM
- Culturing apparatus: tetst vessles containing 1500 mL
- Number of culture flasks/concentration: Two controls, two flasks containing aniline as reference item, two flasks containing test item, one flask containing test item and HgCl2 (testing for abiotic degradation) and one flask containing test item and aniline (testing for toxic effects) were tested.
- Measuring equipment:
• carbon analyzer TOC5050A
• pH-meter 340i wtw
• glass and polypropylene measuring cylinders and flasks
• glass thermometer 20020912-15
• scales Mettler Toledo AB 184 SA and Sartorius 1403

- Details of trap for CO2 and volatile organics if used: The emitted CO2 was trapped in 0.25-molar NaOH.

SAMPLING
- Sampling method: From each replicate, ten samples were taken in order to determine the emitted CO2 (on days 2, 5, 7, 9, 12, 15, 19, 23, 28 and 29). The sample volume was 1 mL. The resulting change in the volume of the front scrubber was considered in the calculation of emitted CO2. Until day 28, all samples were taken from the scrubber flask directly connected to the test flask (front scrubber). On day 28, 1 mL HCl conc. was added to each test flask in order to drive off dissolved CO2. On day 29, samples from both scrubber flasks were taken.

CONTROL AND BLANK SYSTEM
- Reference control: aniline
- Abiotic control: test item and HgCl2
- Toxicity control: test item and aniline

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

97

Sampling time:

28 d

Details on results:

The degree of biodegradation reached 97 % after 28 days. The 10d-window began on day 2, at its end, 74 % were reached, superceding the pass level of 60 % given in the OECD guideline. The test item can be considered as „readily biodegradable“. The abiotic degradation reached 9 %.

Results with reference substance:

The reference compound reached the pass level of 60 % on day 7 (criterion: <= 14 days)

Degradation Values

Day	Ref 1	Ref 2	Test 1	Test 2	Mean	Abiot. Control	Toxic. Control
2	0.7	-0.1	13.8	24.1	19.0	3.3	8.1
5	58.1	59.8	47.0	46.6	46.8	3.0	44.2
7	73.6	76.9	66.0	60.2	63.1	3.5	67.8
9	81.8	81.2	73.5	69.1	71.3	4.0	71.0
12	82.2	85.1	74.6	73.6	74.1	5.1	79.8
15	93.2	93.8	84.1	85.3	84.7	4.4	77.3
19	98.0	98.6	89.1	89.6	89.3	5.1	79.6
23	101.2	105.5	92.9	93.1	93.0	6.2	80.1
28	100.8	99.2	98.8	95.2	97.0	9.3	81.6
29	95.7	97.0	90.9	91.2	91.1	8.3	76.8

Since the values of day 29 are obtained from the addition of the flasks A and B, an increase (values in flasks B of the test higher than in those of the control) or a decrease (values in flasks B of the test lower than in those of the control) of degradation can be observed. OECD assessment follows the values obtained on day 28.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item was considered to be ready biodegradable, as it reached a degradation of 91 % after test period.

Executive summary:

The test item was tested using a test item concentration corresponding to 20 mg organic carbon/L (nominal) in test medium following OECD 301B and EU-Guideline C.4-C. Aniline was chosen as reference item. Activated sludge was used as inoculum (concentration in the test 25 mg dry matter/L). The test was left running for 28 days. All validity criteria were met. Degradation of the reference item was 75 % after seven days. The degradation of test item at end of the test was 91 %. Therefore the test item was considered to be readily biodegradable.

Description of key information

The biodegradation potential of test item was assessed in CO2 evolution test according to OECD guideline 310B and EU method 4.C. After 28 days degradation of 2,2-Dimethyl-3-lauroyloxy-propanal was 91 %. The degradtion at end of the 10-day-window was 74 %.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The test item was tested using a test item concentration corresponding to 20 mg organic carbon/L (nominal) in test medium following OECD 301B and EU-Guideline C.4-C. Aniline was chosen as reference item. Activated sludge was used as inoculum (concentration in the test 25 mg drymatter/L). The test was left running for 28 days. All validity criteria were met. Degradation of the reference item was 75 % after seven days. The degradation of test item at end of the test was 91 %. Therefore the test item was considered to be readily biodegradable.