Alcohols, C12-13, branched and linear, ethoxylated, sulfates, sodium salts

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:

05 May – 03 Jun 2022

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:

July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure):activated sludge from the municipal wastewater treatment plant AZV Breisgauer Bucht.
- Pretreatment: The activated sludge was washed twice with tap water by settling the sludge, decanting the supernatant and re-suspending the sludge.
- Concentration of sludge: 30 mg dry solids per litre

Duration of test (contact time):

28 d

Initial conc.:

20 mg/L

Based on:

TOC

Initial conc.:

54.8 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: mineral medium acc. to guideline
- Test temperature: 21.0 – 22.7°C
- Suspended solids concentration: 30 mg/L dry solids
- Continuous darkness: no (diffuse light)

TEST SYSTEM
- Culturing apparatus:
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: aerated by the passage of carbon dioxide-free air
- Measuring equipment: tIC measurement was performed with a total carbon analyser (TOC-L Shimadzu)
- Details of trap for CO2 and volatile organics if used: 200 mL 0.2 M NaOH

SAMPLING
- Sampling frequency: day 4, 7, 11, 14, 21 and 28
- Sampling method: NaOH was sampled from the CO2-absorber flasks

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 3 replicates
- Toxicity control: yes, 1 replicate

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (CO2 evolution)

Value:

93

Sampling time:

28 d

Remarks on result:

other: 93.0% of ThCO2

Details on results:

The mean CO2-evolution of the blank flasks was 24.9 mg/L on day 28.
A degradation of 82.6% within 14 days was determined in the toxicity control.

Results with reference substance:

The reference substance reached a degradation of 69.1% after 4 days (92.8% after 28 d)

Table 1: Mean degradation rates

	Day 0	Day 4	Day 7	Day 11	Day 14	Day 21	Day 28	Day 28 with IC reactor
Mean test substance	0	40.3	70.0	88.9	87.8	93.8	93.5	93.0
Mean reference substance	0	69.1	79.2	88.6	91.3	94.6	92.5	92.8
Toxicity control	0	29.7	56.3	79.2	82.6	91.4	91.0	90.4

Table 2: Validity criteria for OECD 301B.

Criterion from the guideline	Outcome	Validity criterion fulfilled
Difference of extremes of replicate values of the removal of the test chemical at the plateau, at the end of the test or at the end of the 10-d window, as appropriate, is less than 20%.	> 20%	yes
Percentage degradation of the reference compound reached the pass level by day 14 (≥ 60%).	91.3 within 14 d	yes
The toxicity control should degrade to at least 35% (based on DOC) or at least 25% (based on ThOD or ThCO2) within 14 d.	82.6% within 14 d	yes
The IC content of the test substance suspension in the mineral medium at the beginning of the test must be less than 5% of the TC.	<5%	yes
The total CO2 evolution in the inoculum blank at the end of the test should not normally exceed 40 mg/L medium.	24.9 mg/L on day 28	yes

 

Validity criteria fulfilled:

yes

Remarks:

Please refer to Table 2 at "Any other information on results incl. tables"

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: 93% (CO2 evolution) in 28 days (OECD 301B)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

One screening studies on the ready biodegradability of Alcohols, C12-13, branched and linear, ethoxylated, sulfates, sodium salts is available. The study was conducted according to OECD guideline 301B. The degradation rate was followed by measuring the CO2 evolution during the 28 day incubation period. After 28 days a degradation rate of 93% was determined. Based on the study results the substance is considered readily biodegradable acc. to OECD criteria.