Phosphoric acid C12-alkyl and C18-alkyl esters, potassium 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:

key study

Study period:

from 2018-07-05 to 2018-10-30

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)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

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: collected from the aeration tank of a sewage treatment plant unit treating predominantly domestic sewage at Siddaganga Institute of Technology, Chandana complex, Tumkur – 572103, India
- Storage conditions: aerated in the laboratory
- Storage length: 7 days
- Pretreatment: aearation in mineral medium for 7 days to reduce the CO2 background
- Concentration of sludge: 3.806 g/L suspended solids
- Initial cell/biomass concentration: 30 mg/L suspended solids in 23.6 mL inoculum

Duration of test (contact time):

28 d

Initial conc.:

15 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium prepared according to guideline OECD 301A
- Test temperature: 22 ± 2 °C

TEST SYSTEM
- Culturing apparatus: 5 L amber glass bottles
- Number of culture flasks/concentration: 2
- pH: 7.29 - 7.75
- Test performed in closed vessels: covered with black polyethene in order to exclude light
- Other: The solutions were continuously stirred with stir bars and plates. The sampels were continuously flushed with air at rate of 30 - 100 mL /minute

SAMPLING
- CO2 trapping: with bottles containing 100 mL 0.0125 N Barium hydroxide at the end of the test series.
- Determination of residual Ba(OH)2: every 2 days

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

Reference substance:

acetic acid, sodium salt

Test performance:

During the first ten days, the analysis of CO2 was made every third day and then at least fifth day until the 28th day.

Key result

Parameter:

% degradation (CO2 evolution)

Value:

65.3

Sampling time:

28 d

Details on results:

The test item reached a maximum mean biodegradation value of 65.31 % (% of ThCO2) for two bottles within 28 days which exceeded the criteria of 60 % biodegradation. As the test item is an UVCB substance, the 10-day window doesn't apply.

Results with reference substance:

The reference substance attained 62.91 % biodegradation in 14 days and 92.45 % after 28 days.

Validity of the test

The differences in replicate values of the removal of the test substance at the end of the test were less than 20 % (i.e. -1.94 %).

The percentage degradation of the procedure control substance (sodium acetate) attained 62.91 % (% of ThCO2) biodegradationon 14 days (greater than 60 % degradation).

The total CO2 evolution in the control blanks at the end of the test was 1.98 mg/L which is less than the validity criteria of 40 mg/L.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item reached a maximum mean biodegradation value of 65.31 % after 28 days, therefore, the test item is readily biodegradable.

Executive summary:

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in a test design according to OECD 301 B and Regulation (EC) No. 440/2008 Method C.4 -C. The test item was tested at a inital concentration of 15 mg/L. The evolved CO2 was trapped in 0.25 M Ba(OH)2. The refenrece item degraded to 92.45 % after 28 days. The pass level for ready biodegradability of 60 % removal was fulfilled. As the test item is an UVCB substance, the 10-day window criterion does not apply. The biodegradation percentage of the test item at the 28 day mark was 65.3 %. The test item is considered to be ready biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Please refer to section 13 for "Read-Across justification".

Reason / purpose for cross-reference:

read-across source

Key result

Parameter:

% degradation (O2 consumption)

Value:

63

Sampling time:

28 d

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

November 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study well documented

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Activated sludge micro-organisms from the secondary treatment stage of the Severn Trent Water plc sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage.

Duration of test (contact time):

28 d

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Remarks:

3 mg/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

63

Sampling time:

28 d

Results with reference substance:

Sodium benzoate attained 75 % degradation after 28 days, confirming the suitability of the inoculum and culture conditions.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item attained 63 % degradation after 28 days. However, despite attaining in excess of 60 % degradation after 28 days, the test material did not achieve the “10-day window” criteria. The test substance can be considered as readily biodegradable, because the REACH substance is a multi constituent substance.

Executive summary:

The test item attained 63 % degradation after 28 days. However, despite attaining in excess of 60 % degradation after 28 days, the test material did not achieve the “10-day window” criteria and so, therefore, cannot be considered to be ready biodegradable und strict terms and conditions of OECD Guideline No. 301D. Regarding REACH the substance can be considered as readily biodegradable, because substance is a multi constituent substance.

 The toxicity control, containing both test substance and sodium benzoate attained 74 % degradation after 28 days, confirming that the test material was not toxic to the activated sludge micro-organisms used in the study. Sodium benzoate attained 75 % degradation after 28 days, confirming the suitability of the inoculum and culture conditions.

Description of key information

The test item reached a maximum mean biodegradation value of 65.31 % after 28 days in a OECD 301B study, therefore, the test item is readily biodegradable. A read-across to one of the components supports the obtained results.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of the test item was determined with a non-adapted activated sludge over a test period of 28 days in a test design according to OECD 301 B and Regulation (EC) No. 440/2008 Method C.4 -C. The test item was tested at a inital concentration of 15 mg/L. The evolved CO2 was trapped in 0.25 M Ba(OH)2. The refenrece item degraded to 92.45 % after 28 days. The pass level for ready biodegradability of 60 % removal was fulfilled. As the test item is an UVCB substance, the 10-day window criterion does not apply. The biodegradation percentage of the test item at the 28 day mark was 65.3 %. The test item is considered to be ready biodegradable.

The test substance is a mixture of C12 and C18 chain phosphoric acid esters. Additionally, a read-across approach to the C12 phosphoric acid ester was applied. A read across study is available assessing the biodegradability of Phosphoric acid, dodecyl ester, potassium salt (CAS 39322-78-6).

The source substance CAS 39322-78-6 attained 63 % degradation after 28 days. However, despite attaining in excess of 60 % degradation after 28 days, the test material did not achieve the “10-day window” criteria and so, therefore, cannot be considered to be ready biodegradable und strict terms and conditions of OECD Guideline No. 301D. Regarding REACH the substance can be considered as readily biodegradable, because substance is a multi-constituent substance. The 10-day window is not applicable for multi-constituent substances. The toxicity control, containing both test substance and sodium benzoate attained 74 % degradation after 28 days, confirming that the test material was not toxic to the activated sludge microorganisms used in the study. Sodium benzoate attained 75 % degradation after 28 days, confirming the suitability of the inoculum and culture conditions.

In conclusion, based on the available information, the test item is considered to be readily biodegradable.