Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

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:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

EC Number:

247-556-2

EC Name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Cas Number:

26264-05-1

Molecular formula:

C18H30O3S.C3H9N

IUPAC Name:

sodium dodecylbenzenesulfonate

Test material form:

liquid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

other: microbial activity introduced by inoculation with secondary effluent

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The source of test organisms was secondary effluent freshly obtained from a municipal sewage treatment plant: 'Waterschap Aa en Maas', 's-Hertogenbosch, The Netherlands, receiving predominantly domestic sewage.
- Storage length: Not specified
- Preparation of inoculum for exposure: Not specified
- Pretreatment: Secondary effluent was filtered through a coarse filter paper, the first 200 mL were discarded. The filtrate was kept aerated until inoculation.
- Concentration of sludge: 4 mL filtrate of secondary effluent per litre of final volume.
- Water filtered: yes
- Type and size of filter used, if any: Coarse filter paper

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

1.5 mg/L

Based on:

ThOD

Initial test substance concentration 2

Initial conc.:

4 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Standard as per OECD guideline
- Additional substrate: Not specified
- Solubilising agent (type and concentration if used): None
- Test temperature: 22 to 23°C
- pH: between 7.4 and 7.6 at the start of the test
- pH adjusted: No
- CEC (meq/100 g): Not specified
- Aeration of dilution water: No
- Suspended solids concentration: Not specified
- Continuous darkness: yes


TEST SYSTEM
- Culturing apparatus: 250 to 300 mL BOD bottles with glass stoppers
- Number of culture flasks/concentration: Duplicate
- Method used to create aerobic conditions: Standard O2 in water
- Method used to create anaerobic conditions: Not applicable
- Measuring equipment: Oxygen meter:WTW oxygen meter supplied with a WTW CellOx 325 oxygen electrode, electrolyte type ELY/G.
- Test performed in closed vessels due to significant volatility of test substance: Not applicable although test conditions were closed.
- Test performed in open system: No

SAMPLING
- Sampling frequency: Days 0, 7, 14, 21 and 28.
- Sampling method: Sampled with O2 probe
- Sterility check if applicable: Not applicable
- Sample storage before analysis: O2 measured at specified timepoints

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes (only inoculum, no test item)
- Abiotic sterile control: No
- Toxicity control: Yes (sodium acetate at 2 mg/L, test substance at 1.5 mg/L and inoculum).
- Procedure control: Yes (sodium acetate at 2 mg/L and inoculum)

STATISTICAL METHODS: Not required

Reference substance

Reference substance:

acetic acid, sodium salt

Results and discussion

Test performance:

1. Oxygen depletion in the inoculum blank was not significantly higher than 1.5 mg O2/L after 28 days (1.52 mg O2/L).
2. The residual concentration of oxygen in the test bottles was > 0.5 mg/L at any time.
3. Differences between duplicate biodegradation values (expressed as mg O2/L) were less than 20% (1% at the end of the experiment).
4. In the procedure control, sodium acetate was degraded by at least 60% (107%) within 14 days.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

>= 62 - <= 67

Sampling time:

28 d

Details on results:

The relative biodegradation values calculated from the O2 measurements performed during the test period of 28 days revealed significant biodegradation of the test substance at both concentrations, i.e. 67 % and 62 % for the low and high concentration respectively, based on ThOD. Since the substance is a UVCB it is anticipated that a sequential biodegradation of the individual components takes place. Therefore, the 14-day window will not be applied to interpret the results of this test. In the toxicity control more than 25% biodegradation occurred within 14 days (54%, based on ThOD). Thus, the toxicity control showed that the test substance did not inhibit microbial activity.

BOD5 / COD results

Results with reference substance:

In the procedure control, sodium acetate was degraded by at least 60% (107%) within 14 days.

Any other information on results incl. tables

Biodegradation Percentages at Different Points in Time

Test medium		% Biodegradation after x days^1)
		0	7	14	21	28
Procedure control^2)	A	0	67	104
	B	0	59	110
	mean	0	63	107
	Δ	0	8	6
Test item low^3)	A	0	23	47	45	62
	B	0	26	42	62	63
	mean	0	25	45	54	63
	Δ	0	3	5	17	1
Test item high^3)	A	0	26	46	50	56
	B	0	21	45	49	57
	mean	0	24	46	50	57
	Δ	0	5	1	1	1
Toxicity control	A	0	20	53
	B	0	30	54
	mean	0	25	54
	Δ	0	10	1
^1): Calculations were performed with the mean oxygen concentrations of t=0 and  the oxygen depletion as given in the Appendix.
^2): ThOD sodium acetate (reference item): 0.78 mg O2/mg
^3): ThOD Test substance: 2.49 mg O2/mg

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

In conclusion, the test substance was considered to be readily biodegradable under the conditions of the closed bottle test performed presently.