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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2004-04-30 to 2004-05-28
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Closely followed OECD301 D guideline, GLP but on analog substance.
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test material information:
Composition 1
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge: Municipal sewage treatment plant, D-31137 Hildesheim- Laboratory culture: Not available - Storage conditions: Not available - Pretreatment: The activated sludge was filtered with a folded filter. The first 200 ml of the filtrate were not used. The second filtrate effluent from the domestic waste water was used to initiate inoculation.- Concentration of sludge: Not available- Initial cell/biomass concentration: 10(+4) to 10(+6) CFU/L- Water filtered: Not available- Type and size of filter used: Folded filter
Duration of test (contact time):
28 d
Initial conc.:
6 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS- Composition of medium: Mineral nutrient medium prepared according to the OECD Guideline 301 D- Solubilising agent: Not used- Test temperature: 21 +/- 1 degree C- pH: ranged 7.22 to 7.25- pH adjusted: No- CEC (meq/100 g): Not available- Aeration of dilution water: Aerated- Suspended solids concentration: Not available- Continuous darkness: YesTEST SYSTEM- Culturing apparatus: BOD bottles with glass stoppers (300 ml).- Number of culture flasks/concentration: Duplicate test, blanks and reference treatment- Method used to create aerobic conditions: One day before the test started the demineralized water for the test medium was aerated until oxygen saturation, and then left at room temperature for at least 20 h.- Measuring equipment: Oximeter, "WTW" Oxi 530- Test performed in closed vessels: Yes. Incubation vessels were closed without air bladders.SAMPLING- Sampling frequency: Day 0, 7, 14, 21, 28.- Sampling method: Duplicate incubation vessels taken.- Sample storage before analysis: Not availableCONTROL AND BLANK SYSTEM- Inoculum blank: 10 bottles containing only inoculum and nutrient medium- Toxicity control: 3.0 mg/L test item + 5.0 mg/L reference item + nutrient solution and inoculumSTATISTICAL METHODS: Concerning the OECD-guideline 301 D the index of the atoms of the item CcHhClclNnNanaOoPpSs was used for the calculation of the ThODNO3 and ThOD, respectively.
Reference substance:
acetic acid, sodium salt
Remarks:
CAS no: 127-09-3, 100.9% Pure, Concentration: 10 mg/L
Test performance:
Not available
Parameter:
% degradation (O2 consumption)
Value:
3
Sampling time:
7 d
Parameter:
% degradation (O2 consumption)
Value:
12
Sampling time:
14 d
Parameter:
% degradation (O2 consumption)
Value:
18
Sampling time:
21 d
Parameter:
% degradation (O2 consumption)
Value:
17
Sampling time:
28 d
Details on results:
Test substance was not readily biodegradable, in 10 day window and after 28 days. See Table below.
Results with reference substance:
The reference material, sodium acetate, reached 10% biodegradation within 2 days and >60% within 7 days. It met the validity criteria established in the guideline for a reference material.

Biodegradation of the Test Substance in the Ready Test (study # AFW94571)

Day

Biodegradation %

Test item (6 mg/L)

Reference Material (10 mg/L)

Toxicity Control (3.0 + 5.0 mg/L)

7

3

79

41

14

12

85

46

21

18

79

49

28

17

86

54

Biodegradation based on oxygen consumption (OECD 301D test).

Validity criteria fulfilled:
yes
Remarks:
All criteria for guideline OECD 301 D were fullfilled.
Interpretation of results:
other: Not readily biodegradable.
Conclusions:
The test substance, 2-methyl-p-phenylenediaminesulfate, is not readily biodegradable. Biodegradation through Oxygen consumption after 28 days was determined to be 17%.
Executive summary:

An OECD 301 D Ready Test was conducted on 2 -methyl-p-phenylenediaminesulfate (CAS # 615 -50 -9). The test concentration was 6 mg/L, and the inoculum concentration was 10(+4)-10(+6) CFU/L. The test treatment, controls, reference, and blank were conducted in duplicate. Biodegradation was monitored by oxygen consumption.

The biodegradation of the test substance reached 17% on the 28th day. Hence the test material was not readily biodegradable.

The reference material, sodium acetate, reached >60% after day 6 and met 10 day window. It met the validity criteria established in the guideline for a reference material.

Description of key information

An OECD 301 D Ready Test was conducted on a structured related substance: 2 -methyl-p-phenylenediaminesulfate (CAS # 615 -50 -9). The test concentration was 6 mg/L, and the inoculum concentration was 10(+4)-10(+6) CFU/L. The test treatment, controls, reference, and blank were conducted in duplicate. Biodegradation was monitored by oxygen consumption. The biodegradation of the test substance reached 17% on the 28th day. Hence the test material was not readily biodegradable. The reference material, sodium acetate, reached >60% after day 6 and met 10 day window. It met the validity criteria established in the guideline for a reference material.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, not fulfilling specific criteria

Additional information