Alcohols, C12-14, ethoxylated, sulfates, sodium salts

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

04 Jun - 22 Jul 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

GLP compliance:

yes

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): municipal sewage plant: Marl-Ost
- Preparation of inoculum for exposure: centrifugation at 3000 rpm for 15 min. Dry weight: 5.03 g/L. The supernatant was discarded and the sludge resuspended with mineral medium. After another centrifugation step 15 min at 3000 rpm, the sludge was resuspended.
- Concentration of sludge: 25.2 mg/L (according to OECD 301 ≤ 30 mg suspended solids/L≙ 10^7 - 10^8 cells/L, corresponding to 8.4 x 10^6 - 8.4 x 10^7 cells/L) dry weight: 5.03 g/L
- Water filtered: yes

Duration of test (contact time):

28 d

Initial conc.:

10.5 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: solution A: 8.5 g KH2PO4, 21.75 g K2HPO4, 33.3 g NaHPO4 x 2 H2O and 20.0 g (NH4)Cl; solution B: 22.5 g MgSO4 x 7 H2O; solution C: 27.5 g CaCl2; solution D: 0.25 g FeCl3 x 6 H2O
- Test temperature: 20.0 °C - 22.2 °C
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 200 ml Erleneyer flasks
- Number of culture flasks/concentration: 2

SAMPLING
- Sampling frequency: 0, 7, 14, 21, 27 and 28 days
- Measuring equipment: Shimadzu DOC analyser


CONTROL AND BLANK SYSTEM
- Inoculum blank: yes (2 replicates)
- Reference substance: yes (2 replicates)

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (DOC removal)

Value:

100

Sampling time:

28 d

Results with reference substance:

DOC removal: 100% after 28 days

Table 1: mean DOC removal

	% DOC-removal after x days
Day	0	7	14	21	27	28
Test substance	0	95	100	98	101	100

Interpretation of results:

readily biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Sep - 20 Oct 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: final effluent of activated sludge plant Hochdahl, Germany
- Initial cell/biomass concentration: 1 mL/L effluents corresponding to approx. 2E+04 - 2E+06 cells/L

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

act. ingr.

Initial conc.:

5 mg/L

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 20 +/- 1 °C
- Continuous darkness: yes or diffuse lighting

TEST SYSTEM
- Culturing apparatus: conical shoulder bottles
- Test performed in closed vessels: yes
- Number of culture flasks/concentration: 2

SAMPLING
- Sampling frequency: day 0, 7, 14, 21, 28
- Sampling method: iodometric determination of oxygen concentration, analytics of nitrogen compunds

CONTROL AND BLANK SYSTEM
- Inoculum blank: 4
- Procedure control: 2

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

>= 77

Sampling time:

28 d

Results with reference substance:

Biological degradation (% BOD/COD) after 7, 14, 21 and 28 days: 73, 80, 83 and 89%

Table 1: Degradation in percent after 7, 14, 21 and 28 days

	% BOD/COD (ThOD) after x days
Test substance	7	14	21	28
2 mg a.i./L	61	67	77	79
5 mg a.i./L	58	65	73	77

Table 2: Validity criteria for OECD 301.

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%).	80%	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.	80%	yes
Oxygen depletion in the inoculum blank should not exceed 1.5 mg dissolved oxygen/L after 28 days.	< 1.5 mg/L	yes
The residual concentration of oxygen in the test bottles should not fall below 0.5 mg/L at any time.	> 0.5 mg/L	yes

Validity criteria fulfilled:

yes

Remarks:

The validity crietria according to OECD 301 are fulfilled (for details see table 3 under "any information on results")

Interpretation of results:

readily biodegradable

Description of key information

Readily biodegradable: >=77% (O2 consumption) in 28 days (OECD 301D)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two studies investigating the ready biodegradability of Alcohols, C12-14, ethoxylated, sulfates, sodium salts are available.

The key study was conducted according to OECD 301D using final effluent of a predominantly domestic sewage treatment plant as inoculum. The cell concentration was approximately 2,000 to 2,000,000 cells/L. The oxagen consumpiton of the inoculum was tested at a test substance concentration of 1 mg a.i./L and 5 mg a.i./L respectively. The pass level of 60% degradation based on BOD/ThOD was reached between days 7 and 14 for both test concentrations. At day 28 a degradation rate of ≥ 77% based on O2 consumption was determined.

The supporting study was performed following EU Method C.4-A . The degradation rate was determined by measuring the DOC removal during the 28 d incubation period. A DOC removal of 100% was determined.

The substance is considered readily biodegradable based on the available screening studies.