Reaction products of Hydrogen amino-4-hydroxynaphthalene-2-sulfonate, Potassium substituted-5-{[2-(sulfonatooxy)ethyl]sulfonyl}benzenesulfonate and Sodium substituted-({4-[(2-chloroethyl)sulfonyl]butanoyl}amino)benzenesulfonate

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:

2018

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

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Test item: FAT 40875/A TE
Physical appearance: Dark red powder
Content as per CoA: 86.4% all organic components
Batch No: BOP 05-17 (BS-ROE 1550 NIM 25+26+27)
Manufactured date: December 20, 2017
pH: 4.3 (aq. Soln. (2% (w/w) at room temperature))
Recommended storage condition: Refrigeration (+2 to +8 °C) and protection from light.

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

The inoculum was secondary effluent, collected from a treatment plant receiving predominantly domestic sewage. This effluent was used as test system as it is recommended in the guideline. A fresh sample of secondary effluent was collected from the treatment plant and was kept aerobic during transport. This effluent was allowed to settle for one hour, decanted and the decanted effluent was used in the test.

Source of the Inoculum: Sewage Treatment Plant Eurofins Advinus Limited Bengaluru - 560 058 India

Determination of Bacterial Population in the Inoculum:
The bacterial population in the inoculum was determined as colony forming units (CFU/mL) by diluting the inoculum to an appropriate dilution and then plating on nutrient agar plates.

Preconditioning of the Inoculum: The decanted effluent was preconditioned by aerating for 5 days at 22 to 24°C.

Duration of test (contact time):

28 d

Initial conc.:

46 mg/L

Based on:

ThCO2

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Test temperature: 21 to 24°C
- pH: The pH of the test solutions at the end of the test was 7.85, 7.84, 7.81, 7.81, 7.79 and 7.81 in Flask 1, 2, 3, 4, 5 and 6 respectively
- pH adjusted: no
- Aeration of dilution water: Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air.
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Conical flask
- Number of culture flasks/concentration: Two flask for "Test suspension - test item and inoculum" and "Inoculum blank - only inoculum" each.
One flask for "Procedure control - reference item and inoculum" and " Toxicity control - test item, reference item and inoculum" each.
- Measuring equipment: Tritration (Burette, pipettes and other laboratory apparatus)

CONTROL AND BLANK SYSTEM
- Inoculum blank: Flasks numbered 3 and 4

STATISTICAL METHODS: None

Reference substance:

benzoic acid, sodium salt

Preliminary study:

Test Item Solubility: The test item formed a suspension in mineral medium at 460 mg/L.
Bacterial Population in the Inoculum: The bacterial population in the inoculum was 6.0 x 10^7 CFU/L.

Parameter:

% degradation (CO2 evolution)

Value:

47.84

Sampling time:

28 d

Details on results:

The percent degradation of test item was 48.82 % and 46.85 % in the Flask No. 1 and 2, respectively at the end of the test. The mean percent degradation of test item was 47.84% at the end of test.

Results with reference substance:

The percent degradation of reference item was 70.91% and the toxicity control was 52.64% at the end of the test.

VALIDITY OF THE TEST

For the test to be valid, the following performance criteria were applied: At the end of the test, the degradation of the test item at the plateau was 48.82% in Flask 1 and 46.85% in Flask 2, respectively. The percent difference in test item flask replicates was 4.12% as against the guideline requirement of less than 20% difference.

The degradation of reference item was 70.91% on Day 13 as against the guideline requirement of at least 70% degradation of reference item by Day 14 of treatment.

 

The inorganic carbon (IC) content of the mineral medium at the beginning of the test was zero. The total CO2 evolution in the inoculum blank throughout the test was 66.96 mg/L, as against the guideline requirement that the total CO₂ evolution should not normally exceed 40 mg/Lmedium and values greater than 70 mg CO₂/L requires critical examination.

 

There was 52.62% degradation [based on ThCO2] in the toxicity control flask on Day 13 as against the guideline requirement that, in a toxicity test, containing both the test item and a reference item, if less than 25% ThCO2 occurs within 14 days, the test substance can be assumed to be inhibitory. This shows the test item is not inhibitory to the test system.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

FAT 40875/A TE is not readily biodegradable as 47.84% mean degradation was achieved at the end of test.

Executive summary:

The ready biodegradability of FAT 40875/A TE was tested using the CO2 Evolution test conducted according to OECD test guideline 302B in a GLP certified laboratory.

 

The test item was added to two test vessels at the concentration of 46 mg/L (equivalent to 15.2 mg of Total Organic Carbon/L). Two control treatments containing only the inoculum, one reference item treatment and one toxicity control treatment containing the test item and the reference item were also tested. All the treatments were added with equal volume of inoculum which was collected from the secondary effluent treatment plant receiving predominantly domestic sewage.

 

Treatment mixtures were aerated for 29 days with carbon dioxide (CO2) free air. The CO2 released was trapped in a series of bottles containing barium hydroxide, which were connected to the outlet of each test vessel. The residual barium hydroxide was measured on Days 3, 6, 8, 10, 13, 16, 20, 24, 27 and 29 after the initiation of the test.

 

The mean percent degradation of test item was 47.84% at the end of test while, the percent degradation of reference item was 96.01 % and the toxicity control was 72.48% at the end of the test. It was observed that the mean degradation of test item, FAT 40875/A TE was 47.84% which is less than 60% pass level in 10-day window period within the 28-d period of the test.

The test fulfilled all the validity criteria.

Based on the results, it was concluded that the test item, FAT 40875/A TE is not readily biodegradable as 47.84% mean degradation was achieved at the end of test.

Description of key information

FAT 40875/A TE is not readily biodegradable as 47.84% mean degradation was achieved at the end of test.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of FAT 40875/A TE was tested using the CO2 Evolution test conducted according to OECD test guideline 302B in a GLP certified laboratory.

The mean percent degradation of test item was 47.84% at the end of test while, the percent degradation of reference item was 96.01 % and the toxicity control was 72.48% at the end of the test. It was observed that the mean degradation of test item, FAT 40875/A TE was 47.84% which is less than 60% pass level in 10-day window period within the 28-d period of the test.

Based on the results, it was concluded that the test item, FAT 40875/A TE is not readily biodegradable as 47.84% mean degradation was achieved at the end of test.