pentasodium 3,7,11-tris(carboxylatomethyl)-15-(C12-18)-alkyl-3,7,11,15-tetraazaheptadecane-1,17-dioate

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:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

The test item was tested for biodegradability according to the OECD-Test Guideline 301 B "Ready Biodegradability: Modified Sturm Test" and to the 6th Amendment of the Council Directive 67/548/EEC.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

other: See below

Details on inoculum:

Prior to use activated sludge from the sewage plant (Frankfurt/M.-Niederad) was washed twice with mineral nutrient solution (test medium) as
described in the OECD Guideline 301 B to eliminate organic and toxic components from the sludge. After resuspension in mineral nutrient
medium the sludge was aerated by means of compressed humidified air for approximately four hours then allowed to settle for 30 to 60 minutes
and filtered. The filtrate was used as inoculum (1% of the final volume of the test solution).

Duration of test (contact time):

28 d

Initial conc.:

5 mg/L

Based on:

test mat.

Initial conc.:

10 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

The test chemical and polyvalent inoculum and mineral nutrient solution (sewage microorganisms from a sewage plant working without industrial wastes) were incubated together for a period of 28 days in the dark at 22 +/- 1 °C.
The biodegradation observed in the course of the study was determined as a percentage of the amount of CO2 that the test chemical could have
theoretically produced. This is based on the assumption that the organic carbon of the test chemical would have been quantitatively converted to
C02. For full composition see attached report.

Reference substance:

benzoic acid, sodium salt

Test performance:

Temperature was measured on working days and documented. Values were within the range of 21 ± 2 °C.
The C02 evolution of the blank slightly exceeded the value of 50 mg/3 L indicated in the guideline OECD 301 B of 1981 but it is fully within the range of 40 mg/L indicated by the latest version adopted in July 1992. The test is valid since sodium benzoate as reference was degraded to more than
60 % within 28 days (observed value: 87.7% within 9 days).

Parameter:

% degradation (CO2 evolution)

Value:

122.9

Sampling time:

28 d

Remarks on result:

other: 5 ppm

Parameter:

% degradation (CO2 evolution)

Value:

62.2

Sampling time:

28 d

Remarks on result:

other: 10ppm

Parameter:

% degradation (CO2 evolution)

Value:

32.3

Sampling time:

28 d

Remarks on result:

other: 20ppm

Results with reference substance:

sodium benzoate as reference was degraded to more than 60 % within 28 days (observed value: 84.2% within 8 days).

Biodegradation calculation

Determination of Biodegradation: Degradation was calculated as a percentage of the theoretical CO2 that should have been produced from the organic matter of the substance by complete oxidation. The CO2 being generated were calculated to the nearest 0.01 mg and biodegradation values were rounded to the nearest 0.1 percent.

The TKO, was calculated to be 0.559 mg CO,/mg test chemical determined as TOC of the test substance

Biodegredation therefore equals = mg Co2 produced x 100

mg of test chemical added x ThC02

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The substance is considered readily biodegradable.

Executive summary:

The substance is considered readily biodegradable.

Description of key information

Sodium cocoamphopolycarboxyglycinate was biodegraded by 35% at day 28 in the Closed Bottle test. This test substance should therefore not be classified as readily biodegradable. In the prolonged Closed Bottle test sodium cocoamphopolycarboxyglycinate was biodegraded 39% at day 60. The biodegradation curve levels off between 20 and 60% biodegradation suggesting partial degradation of the test substance. The lack of complete biodegradation in the Closed Bottle test does not mean that part of the test substance is recalcitrant in nature because the stringency of the test procedures could account for the recalcitrance in the Closed Bottle test.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable, not fulfilling specific criteria

Type of water:

freshwater

Additional information

There are two ready biodegradability test results available for Sodium cocoamphopolycarboxy glycinate. One OECD 301D enhanced test where is was concluded that the test substance should not be considered readily biodegradable based on 35% biodegradation on day 28. The prolongation of this study resulted in 39% biodegradation on day 60 suggesting partial degradation of the test substance. The result of this study will be used for risk assessment and classification because the results of the study from Danneberg were difficult to interpret .

In this study from Danneberg (1993) the ready biodegradability was evaluated in a Zahn Wellens test according to OECD TG 301B. 122.9% biodegradation was observed based on CO2 evolution at 5 ppm test substance. Based on the results of this study the substance may be evaluated as readily biodegradable. Lower percentages of biodegradation were observed at 10 and 20 ppm test substance.