2-Hexadecen-1-ol, 3,7,11,15-tetramethyl-

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,7,11,15-tetramethylhexadec-2-en-1-ol

EC Number:

616-221-6

Cas Number:

7541-49-3

Molecular formula:

C20H40O

IUPAC Name:

3,7,11,15-tetramethylhexadec-2-en-1-ol

Specific details on test material used for the study:

6.1 Test Item
Designation in Test Facility: 20061504G
Date of Receipt: 15. Jun. 2020
Condition at Receipt: Ambient temperature, in proper conditions
6.1.1 Specification
The following information concerning identity and composition of the test item was pro-vided by the sponsor.
Name 3,7,11,15-tetramethyl-2-hexadecen-1-ol
Batch no. PL200101
CAS no. 7541-49-3
Composition 3,7,11,15-tetramethyl-2-hexadecen-1-ol 96.6 %
Storage room temperature (20 ± 5 °C); Nitrogen filled, sealed and stored at room temperature
Expiry date 19. Jan. 2022
Stability stable under storage conditions
Appearance Colorless to light yellow clear oily liquid
Purity 96.6 %
Homogeneity homogeneous
Production date 20. Jan. 2020
EC no. 616-221-6
Molecular formula C20H40O
Molecular weight 296.53 g/mol
Vapour pressure not stated
Solubility in solvents H2O: unknown; EtOH: not stated; acetone: not stated; CH3CN: not stated; DMSO: not stated;
Stability in solvents H2O: not stated; EtOH: not stated; acetone: not stated; CH3CN: not stated; DMSO: not stated

6.1.2 Storage in Test Facility
The test item was stored in the fridge in a closed vessel at 2-8 °C from 15. Jun. 2020 to 20. Oct. 2020, which is uncritical according to sponsor’s information. From then on, the test item was stored in the test facility in a closed vessel at room temperature (20 ± 5 °C).
6.1.3 Pre-Treatment
The carbon content of 81.01 % was calculated by molecular formula given by the sponsor. The test item was added directly, the amounts were calculated from the carbon content of the test item.
The test item was pipetted into the flasks directly, using the density 0.852 g/cm3 given by the sponsor (first experiment) and weighed directly in the second experiment see chapter 11.1. The amounts were calculated from the carbon content, determined by molecular formula.

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

6.3.1 Specification
Activated sludge from a biologic sewage treatment plant was used as inoculum. The cho-sen plant treats mostly domestic sewage.
6.3.2 Source and Pre-Treatment of inoculum
6.3.2.1 Source
The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf.
Date of collection: 15. Jan. 2021, batch no: E20210115.
6.3.2.2 Pre-Treatment
The sludge was filtrated through a cloth, washed with test medium (2x) and resuspended in test medium. It was then aerated until use. The dry matter was determined to contain
3.50 g of suspended solids/L.

Duration of test (contact time):

ca. 28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

ca. 24.8 mg/L

Initial test substance concentration 2

Initial conc.:

ca. 25.3 mg/L

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

7 PERFORMANCE OF THE STUDY
7.1 Preparations
The medium was prepared from the stock solutions. The stock solution of the positive control was prepared and its organic carbon was measured. The inoculum was taken from its source, washed, aerated and the dry matter was determined.
The test vessels were filled with medium and inoculum. Then, all flasks were aerated for 72 hours with purified, CO2-free, moistened air to purge the system of CO2.
7.2 Experimental Parameters
Flask volume 1500 mL
Apparatus blanks 2, containing mineral medium only
Blank Controls 2, containing mineral medium and inoculum
Positive control flasks 2, containing positive control, mineral medium and inoculum
Test flasks 2, containing test item, mineral medium and inoculum
Abiotic control 1, containing test item, mineral medium and HgCl2
Toxicity control 1, containing test item, positive control, mineral medium and inoculum
Inoculum concentration: 25.0 mg/L
Temperature 19.4 – 21.9 °C without direct lighting
Duration 28 days
The test was performed with a nominal start concentration of 20 mg organic carbon/L of the test item.

The following amounts of test item and positive control were added to the flasks:
Table 7.2 a Amounts of test item and positive control in the flasks
Flask Positive Control 1 Positive Control 2 Test 1 Test 2 Abiotic Control Toxicity Control
Amount Test item
in mg / L -- -- 24.8 25.3 25.9 26.7
Amount Aniline
in mg / L 26.3 26.3 -- -- -- 26.3
organic C (calculat-ed)
in mg / L 20.0 20.0 20.1 20.5 21.0 41.6
The added amount of test item and positive control is based on the TOC content (total organic carbon. The TOC content of the poorly soluble test item was calculated by molecular formula given by the sponsor. The TOC content of the water-soluble positive control was determined by TOC measurement of a stock solution.
Note: All calculations are performed with unrounded values. Therefore, recalculation with rounded val-ues may lead to slightly different results.

7.3 Apparatus
The test vessels were aerated with purified (by activated charcoal), CO2-scrubbed, mois-tened air. The scrubbing of carbon dioxide was achieved by bubbling the purified air through a flask containing 1.5 M NaOH. To control the absence of CO2, the air was then led through a flask containing a solution of Ba(OH)2 before reaching the test vessels.
Magnetic stirrers were used to prevent deposition of inoculum.
The emitted CO2 was trapped in 0.25 M NaOH. Two scrubbers containing 100 mL each were connected in series to the test vessels. The initial IC value of the 0.25 M NaOH was separately determined in each flask.
7.4 Sampling
From each front scrubber flask, 10 samples were taken in order to determine the emitted CO2 (on day 0, 2, 4, 7, 9, 11, 14, 18, 23 and 29). The sample volume was 1 mL. The result-ing change in the volume of the front flask was considered in the calculation of emitted CO2 (see also chapter 8.3.1).
On day 28, 5 mL HCl 2 M was added to each test flask in order to drive off dissolved CO2. On day 0 and 29, samples from both scrubber flasks were taken.
7.5 CO2 Determination
Analyses of the emitted CO2 were made by IC measurement using the carbon analyser TOC multi N/C 2100S, Analytik Jena. Each sample was measured in duplicate or triplicate, respectively (depending on the variation between the measured values). The carbon ana-lyser was calibrated with freshly prepared reference solutions containing potassium hy-drogen phthalate (TC), sodium hydrogen carbonate and sodium carbonate (IC). Quality control samples were measured on each measuring day.

Reference substance

Reference substance:

aniline

Remarks:

Positive Control

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 76.5

Sampling time:

28 d

% Degradation 2

Key result

Parameter:

% degradation (CO2 evolution)

Value:

ca. 45

Sampling time:

10 d

Details on results:

• The test item 3,7,11,15-tetramethyl-2-hexadecen-1-ol is considered as “not readily biodegradable“.
• The degree of biodegradation reached 76.5 % after 28 days.
• The 10-day-window began on day 5, at its end, 45 % degradation were reached, missing the pass level of 60 % given in the OECD guideline.
• Therefore, when applying the 10-day-window, the test item 3,7,11,15-tetramethyl-2-hexadecen-1-ol is not readily biodegradable following OECD 301B and EU C.4-C respectively. As degradation reached the pass level of 60% in the course of the test, 3,7,11,15-tetramethyl-2-hexadecen-1-ol is considered as ultimately biodegradable, within 28 days.
• Abiotic degradation was not observed.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

when applying the 10-day-window, the test item 3,7,11,15-tetramethyl-2-hexadecen-1-ol is not readily biodegradable following OECD 301B and EU C.4-C respectively. As deg-radation reached the pass level of 60% in the course of the test, 3,7,11,15-tetramethyl-2-hexadecen-1-ol is considered as ultimately biodegradable, within 28 days.

Executive summary:

Two experiments were performed. Due to a leakage in one test flask, a validity criterion (difference within replicates) was not met and therefore the experiment was repeated under the same conditions. The results of the first experiment are not stated in the report, but will be kept together with the other raw data in the GLP archive of the test facility.

 

The test item3,7,11,15-tetramethyl-2-hexadecen-1-olwas tested using a concentration of nominally 20 mg organic carbon/L3,7,11,15-tetramethyl-2-hexadecen-1-olin test medium following OECD 301B and EU-Method C.4-C.

 

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control surpassed the pass level of 60 % after 10 days.

 

The following data were determined for the test item3,7,11,15-tetramethyl-2-hexadecen-1-ol:

10-day-window:                                                                                                                 day 5 – 15
degradation at the end of 10-day-window                                                                             45 %
degradation at the end of the test                                                                                            77 %
pass level following guideline:      60 % at the end of 10-day-window for pure substances

                                                                        respective 60 % at the end of the test for mixtures

 

 

 

Therefore, when applying the 10-day-window, the test item3,7,11,15-tetramethyl-2-hexadecen-1-olisnotreadily biodegradablefollowing OECD 301B and EU C.4-C respectively. As degradation reached the pass level of 60% in the course of the test,3,7,11,15-tetramethyl-2-hexadecen-1-olis considered asultimately biodegradable,within 28 days.