Decyl laurate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to analogue approach justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Parameter:

% degradation (O2 consumption)

Value:

67

Sampling time:

28 d

Remarks on result:

other: BOD/ThOD

Remarks:

Source: CAS 3234-85-3, METI, 1992, O2 consumption

Parameter:

% degradation (test mat. analysis)

Value:

94

Sampling time:

28 d

Remarks on result:

other:

Remarks:

Source: CAS 3234-85-3, METI, 1992, O2 consumption

Parameter:

% degradation (CO2 evolution)

Value:

87

Sampling time:

28 d

Remarks on result:

other:

Remarks:

Source: RA-A, CAS 5303-24-2, Croda, 2016, CO2 evolution, 28 d

Interpretation of results:

readily biodegradable

Conclusions:

According to results of two experimental GLP-guideline studies following CO2 evolution (OECD 301 B) and O2 consumption (OECD 301 C) of two structurally closely related source substances, the target substance can be considered readily biodegradable. The lower degradation values of the O2 consumption study were retained as worst case key values (67% based on O2 consumption, 94% based on test material, OECD 301 C, CAS 3234-85-3); read-across

Description of key information

Readily biodegradable (67% in 28 d, OECD 301 C and 87% in 28 d, OECD 301 B); read-across          

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

There is no study available, in which the ready biodegradability of the target substance decyl laurate (CAS 36528-28-6) was assessed according to OECD guideline and GLP. Therefore, read-across to the structurally related source substances octyl laurate (CAS 5303-24-2) and tetradecanoic acid, tetradecyl ester (CAS 3234-85-3) was conducted in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5. The source substances are characterized by similar fatty acid and alcohol components and are therefore considered suitable representatives for the assessment of the ready biodegradability of the target substance. A detailed justification of the analogue approach is provided in IUCLID section 13.

The study with the source substance octyl laurate (CAS 5303-24-2) was performed according to OECD guideline 301 B and GLP. A nominal concentration of 13 mg/L test item, corresponding to 10 mg/L TOC, was inoculated with non-adapted activated sludge at a concentration of 30 mg/L suspended solids for 28 d under aerobic conditions. Degradation was followed by measuring the produced CO2 trapped in the CO2 absorber vessels filled with 0.05 M NaOH in regular intervals throughout the exposure period. An inoculum blank, procedure and toxicity control were run in parallel. The degradation phase of the test item began on Day 2 when degradation reached 36%. After 29 d, the degradation of the test item had reached 87%. The procedure control confirmed the suitability of the inoculum and the toxicity control indicated that the substance is not inhibitory to the inoculum at the tested concentrations. Therefore, the substance is readily biodegradable according to OECD guideline criteria.

The study with the source substance tetradecanoic acid, tetradecyl ester (CAS 3234-85-3) was conducted according to OECD guideline 301 C and GLP. A nominal concentration of 100 mg/L test item was inoculated with a mixed inoculum composed of activated sludge from STPs, freshwater from rivers and lakes, marine water and marine sediment for 28 d under aerobic conditions. Degradation was followed by continuous measurement of O2 consumption and TOC removal as well as regular test material analysis by GC-FID. After 28 d, the test item reached a degradation of 67% (BOD). Since the substance reached the pass level for OECD 301C (biodegradation is > 60% after 28 d, no 10-day window required) the test item is readily biodegradable according to the OECD criteria.

Based on the structural similarities between the target and source substance, it can be concluded that the target substance decyl laurate (CAS 36528-28-6) is readily biodegradable according to OECD criteria. The more conservative results obtained for the second source substance (CAS 3234-85-3) are retained as key value.