C.I. Reactive Yellow 161

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:

key study

Study period:

25 Oct - 22 Nov 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Version / remarks:

1981 (Modified AFNOR Test)
Ready biodegradability

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

Version / remarks:

BOD5

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.6 (Degradation: Chemical Oxygen Demand)

Version / remarks:

COD

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: polyvalent mixture of bacteria (collected on 25 Oct 1983) from sewage treatment plant (ARA Rhein, Basel), river Birs (CH) and river Wiese (CH)
- Pretreatment: sterilisation
- Concentration of bacteria: 6.2 x 10^5 /mL (determined by plating)

Duration of test (contact time):

28 d

Initial conc.:

40 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: according to OECD 301A
- Additional substrate: none
- Test temperature: 23°C
- Continuous darkness: no - indirect daylight

TEST SYSTEM
- Culturing apparatus: flasks
- Number of culture flasks/concentration: 3

CONTROL AND BLANK SYSTEM
- Inoculum blank: 1
- Abiotic sterile control: 1
- Toxicity control: 1

STATISTICAL METHODS: calculation of DOC removal

Reference substance:

other: glucose

Preliminary study:

N/A

Key result

Parameter:

% degradation (DOC removal)

Value:

2

Sampling time:

28 d

Parameter:

BOD5

Value:

0 mg O2/g test mat.

Parameter:

COD

Value:

1 008 mg O2/g test mat.

Results with reference substance:

92% degradation within 7 days (functional control)
47% degradation within 28 d (toxicity control)

The BOD5 and COD measurements were run in parallel to OECD 301A with the same test material.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance reached a mean biodegradation of 2% within 28 d based on DOC removal (OECD 301A). The substance is not readily biodegradable. The biodegradation activity in the toxicity control was >40% from day 3. Therefore, the substance is not considered inhibitory to activated sludge microorganims. The additional determination of the BOD5 (0 mg O2/g) and the COD (1008 mg O2/g) do not indicate any potential for biodegradation.

Description of key information

The substance reached a mean biodegradation of 2% within 28 d based on DOC removal (OECD 301A). The substance is not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater