Isooctadecyl pivalate

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:

2015-07-29 until 2015-08-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with current guidelines and GLP compliance.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

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 (e.g. location, sampling depth, contamination history, procedure): sewage treatment plant
Ruhrverband Kläranlage, Sunthelle 6, 57392 Schmallenberg, Germany
- Date of sampling: 29th July 2015
- Storage conditions: No storage
- Preparation of inoculum for exposure: No washing, the concentration was adjusted to 3.0 g/L and verified by dry mass
measurement.
- Pretreatment: Kept aerobic until use
- Concentration of sludge in the test: 29.6 mg dry mass/litre

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

test mat.

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

(20 mg test mat. = 60.5 mg ThOD ; 100 mg test mat. = 302.3 mg ThOD)

Details on study design:

- The concentration in the test assays were 20 mg per litre mineral test medium (5 mg/250 mL) and 100 mg per litre mineral test medium (25 mg/250 mL), respectively. 20 mg test item correspond to 60.5 mg ThOD. 100 mg test item correspond to 302.3 mg ThOD. The required amount of test item was added directly on a weight basis via Teflon discs. Subsequently, the required volume of aqueous reference stock solution and
mineral medium were added to the vessels.
- The concentration in the test vessels with reference item (procedural control, toxicity control) was 100 mg per litre mineral test medium (25 mg/250 mL).
- A further solution containing both test and reference item at the same concentrations as in the individual solutions (test item 100 mg/L, reference item 100 mg/L) was prepared to determine the possible toxicity of the test item against the inoculum.
- Further flasks with mineral medium only were prepared for inoculum controls.
- Abiotic controls were also prepared to measure any possible abiotic degradation; a solution of the test item at about 100 mg/L was sterilized by the addition of 1 mL/L HgCl2 (10 g/L).
- In all test assays except of the abiotic controls, 2.04 mL of the inoculum stock solution were transferred for inoculation (per 250 mL) resulting in a concentration of 29.6 mg dry mass/litre (7.41 mg dry mass/250 mL).

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

81

St. dev.:

8.2

Sampling time:

28 d

Remarks on result:

other: 20 mg/L test mat.

Parameter:

% degradation (O2 consumption)

Value:

53.8

St. dev.:

4.2

Sampling time:

28 d

Remarks on result:

other: 100 mg/L test mat.

Details on results:

The test material was degraded by an average of 75 % within the 10-day-window in the 20 mg/L assay. Since 20 mg test material correspond with 60.5 mg ThOD ( therefore, meeting the required concentration of 50-100 mg ThOD/L), the result fulfills the requirements for ready biodegradability according to the OECD 301 guideline.

Results with reference substance:

The reference item was degraded by an average of 89 % by Exposure Day 14, thus confirming suitability of the activated sludge. At the end of the test (Day 28), the reference item was degraded by an average of 94 %.

Percent degradation. Degradation (%) after 14 days.

vessel	Test suspension 100 mg/L	Test suspension 20 mg/L	Abiotic control 100 mg/L	Procedural control 100 mg/L	Toxicity control 100 + 100 mg/L
1	26.6	73.6	0.0	91.0	34.9
2	30.9	60.4	0.0	86.8	38.3
Mean	28.8	67.0	0.0	88.9	36.6
SD	3.0	9.4	0.0	3.0	2.4

Percent degradation. Degradation (%) after 28 days.

vessel	Test suspension 100 mg/L	Test suspension 20 mg/L	Abiotic control 100 mg/L	Procedural control 100 mg/L	Toxicity control 100 + 100 mg/L
1	56.7	86.8	0.0	95.2	46.8
2	50.8	75.3	0.7	93.4	50.4
Mean	53.8	81.0	0.3	94.3	48.6
SD	4.2	8.2	0.5	1.3	2.6

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

According to the guideline, Diisostearyl malate can be considered as being readily biodegradable.

Executive summary:

At the Fraunhofer Institute for Molecular Biology and Applied Ecology the ready biodegradability of the test item was investigated according to the manometric respirometry test design and carried out according to the OECD guideline for Testing of Chemicals No. 301 F (1992) and the Council Regulation (EC) No 440/2008 of 30 May 2008.

The ready biodegradability of the test item was investigated at a concentration of 100 mg/L (ThOD = 302 mg/L) and 20 mg/L (ThOD = 61 mg/L), respectively, in a manometric respirometry test using domestic aerobic activated sewage sludge incubated at 22°C in the dark over 28 days under continuous stirring. The biochemical oxygen demand (BOD) was measured daily and the percentage degradation was calculated from the theoretical oxygen demand (ThOD) after correcting for the BOD of inoculum controls.

The biodegradation of Isooctadecyl pivalate in the static test was found to be at mean 54 % with a standard deviation of 4.2 % for a concentration of 100 mg test item per liter and at mean 81 % with a standard deviation of 8.2 % for a concentration of 20 mg test item per liter after 28 days. For a concentration of 100 mg test item per liter biodegradation within the 10-day-window was found to be 38 %. For a concentration of 20 mg test item per liter biodegradation within the 10-day-window was found to be 75 %. The test item had no inhibitory effect on the activity of activated sludge microorganisms at the tested concentration.

In the procedural controls, the reference substance sodium benzoate was degraded by an average of 89 % by exposure day 14, and reached an average biodegradation of 94 % by the end of the test (day 28), thus confirming suitability of the activated sludge.

Description of key information

Readily biodegradable: 81% after 28 d (O2 consumption, OECD 301F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The ready biodegradability of Isooctadecyl pivalate (CAS 58958-60-4) was investigated according to the manometric respirometry test design and carried out according to the OECD 301 F.

The ready biodegradability of the test item was investigated at a concentration of 100 mg/L (ThOD = 302 mg/L) and 20 mg/L (ThOD = 61 mg/L), respectively, in a manometric respirometry test using domestic aerobic activated sewage sludge incubated at 22°C in the dark over 28 days under continuous stirring. The biochemical oxygen demand (BOD) was measured daily and the percentage degradation was calculated from the theoretical oxygen demand (ThOD) after correcting for the BOD of inoculum controls.

The biodegradation of Isooctadecyl pivalate in the static test was found to be at mean 54 % with a standard deviation of 4.2 % for a concentration of 100 mg test item per liter and at mean 81 % with a standard deviation of 8.2 % for a concentration of 20 mg test item per liter after 28 days. For a concentration of 100 mg test item per liter biodegradation within the 10-day-window was found to be 38 %. For a concentration of 20 mg test item per liter biodegradation within the 10-day-window was found to be 75 %. The test item had no inhibitory effect on the activity of activated sludge microorganisms at the tested concentration.

In the procedural controls, the reference substance sodium benzoate was degraded by an average of 89 % by exposure day 14, and reached an average biodegradation of 94 % by the end of the test (day 28), thus confirming suitability of the activated sludge.

In conclusion, the test substance can be considered to be readily biodegradable according to the OECD criteria.