Sodium 3,3'-(9,10-dioxoanthracene-1,4-diyldiimino)bis(2,4,6-trimethylbenzenesulphonate)

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: screening test, other

Remarks:

inherentl biodegradation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June 10, 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

other: Safepharm Standard Method Number FT/ETAD02/90

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Severn Trent Plc sewage treatment plant at Belpe
- Pretreatment: the sample was maintained at 21 °C with continuous aeration and washed by settlement and resuspension in test medium prior to use.
- Concentration of sludge: equivalent to 1.0 g dry weight/l.

Duration of test (contact time):

ca. 28 d

Initial conc.:

ca. 100 mg/L

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST SOLUTION
2.5 g of test material was dispersed in deionised water and the volume adjusted to 1 liter to give a 2000 mg/l active ingredient stock dispersion. 100 ml of this was added to the vessel to give a test concentration of 100 mg a.i/l.

TEST CONDITIONS
- Vessel: 3 l glass beker
- Test temperature: 22 ± 1 °C
- pH: 7-8
- pH adjusted: yes, with NaOH of H2SO4 as necessary
- Continuous darkness: yes
- Other: losses by evaporation were made good by the addition of deionised water immediately prior to sampling.

SAMPLING
Aeration of the test vessels was stopped and the contents of the vessels allowed to Bettle for 20 minutes. Samples (appoximately 20 ml) were withdrawn from the supernatent and centrifuged at 3900 rpm for 15 minutes to remove any further suspended solids. Samples were analysed immediately. Samples were taken at 0 and 3 hours and an Days 7, 14, 21, 27 and 28 for dissolved organic carbon and spectrophotometric analysis.

Reference substance:

diethylene glycol

Parameter:

% degradation (DOC removal)

Value:

> 4 - < 16

Sampling time:

28 d

Results with reference substance:

Digol attained 100 % degradation within 14 days.

Percentage of biodegradation for Didigol and test item calculated from DOC levels:

Day	DOC value mg/l (mean of 3 Assays)
	Test substance	Didigol
3 h	4	2
7	14	98
14	14	100
21	16	100
27	11	99
28	4	99

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

Biodegradation based on DOC removal within 28 days is between 4 and 16 %

Executive summary:

Methods:

The inherent biodegradability of test substance was determined in a 28 days Zahn-Wellens -test according to the OECD Guideline for Testing of Chemicals, No. 302B and according to Safepharm Standard Method Number FT/ETAD02/90.

Results:

Bioelimination of test substance measured as DOC removal after 28 days is between 4 and 16 %.

Description of key information

Not readily biodegradable

Additional information

The inherent biodegradability of test substance was determined in a 28 days Zahn-Wellens -test according to the OECD Guideline for Testing of Chemicals, No. 302B and according to Safepharm Standard Method Number FT/ETAD02/90.

The bioelimination of test substance measured as DOC removal after 28 days is between 4 and 16 %, so it is possible to conclude that the test substance is not Inherently biodegradable.

In a supporting study the substance has been tested to evaluate the BOD5/COD ratio. The test has been conducted in 1974 according to the German guideline DEV H4 and DEV H5.

Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) are the most commonly used parameters for the characterization of the biodegradability capacity.

COD results are typically higher than BOD5 values, and their ratio vary depending on the characteristics of the substrate. This ratio has been commonly used as an indicator for biodegradation capacity, the "Biodegradability index" (B.I.).

As indicated in ECHA Guidance requirement R.7B, the BOD5 test is a traditional biodegradation test that is now replaced by the ready biodegradability tests. Therefore, this test should not be performed today for assessment of the ready biodegradability of substances.

Older test data may, however, be used when no other degradability data are available.

For the assessment it is only available a summary on BOD5 and COD.

COD was measured according to the German guideline DEV H4. The COD measured was 1180 mg/g O2.

BOD5 was measured according to the German guideline DEV h5. The BOD5 measured was 39 mg/g O2, at concentration of 100 mg/L.

As reported in the ECHA Guidance R7.b, a substance is considered as readily biodegradable if BOD5/COD > = 0.5. The ratio BOD5/COD for the test item is 0.03, therefore the substance is considered as not readily biodegradable

This result is in line with the one obtained in the key study above described.