Alkali salt of (sulfonato oxyethane sulfonyl) arylamino triazinylamino sulfonato (sulfonato arylazo) aryl sulfonate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From April 18, 2006 to June 14, 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to EU Method C.4-D, in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report):Reaktiv Rot F99-0078

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Type: Mixed population of aquatic microorganisms (activated sludge)
Origin: Aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper Area Water Authority, STP Odenthal)
Date of collection: 2006-04-18
Pretreatment: Activated sludge was washed twice with mineral medium; sludge was separated by centrifugation
Concentration of inoculum: 30 mg ss/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

(The consumption of oxygen was determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant gas volume in the respirometer flask.)

Details on study design:

PRETREATMENT OF THE TEST SUBSTANCE
- 25 mg test substance was weighed out on aluminium foil. This substance inclusive of the aluminium foil was added to the test vessels to give a test substance concentration of 100 mg/L.

EXPOSURE CONDITIONS
- Test volume: 250 mL
- Test apparatus: Oxi Top System (WTW)
- Mixing: One magnetic stirrer per test vessel
- Incubation time: 28 d
- Incubation temperature: 22±2°C

TREATMENT
- Control (3 replicates)
- Test substance (3 replicates)
- Reference substance (3 replicates)
- Toxicity Control (2 replicates)

CHEMICAL ANALYSIS
- Nitrate-N/Nitrite-N method: Determination of nitrite nitrogen and nitrate nitrogen and the sum of both by flow analysis (CFA and FIA) and spectrometric detection
- Standard: EN ISO 13395
- Test apparatus: Continuous Flow Analyser SKALAR SAN Plus System

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

(purity: 99%)

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Remarks on result:

other: Oxygen consumption was determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant gas volume in the respirometer flask. The BOD values of test substance were corrected for oxygen consumed by nitrification.

Details on results:

pH of the test vessels: 7.3-7.4

Degradation of test substance:
0% degradation after 4 d
0% degradation after 6 d
0% degradation after 8 d
0% degradation after 12 d
0% degradation after 14 d
0% degradation after 18 d
0% degradation after 20 d
0% degradation after 22 d
0% degradation after 26 d
0% degradation after 28 d

BOD5 / COD results

Results with reference substance:

Degradation of reference substance:
64% degradation after 4 d
78% degradation after 6 d
82% degradation after 8 d
87% degradation after 12 d
88% degradation after 14 d
90% degradation after 18 d
91% degradation after 20 d
92% degradation after 22 d
92% degradation after 26 d
94% degradation after 28 d

Any other information on results incl. tables

- The used concentrations of the test substance did not show toxic effects to bacteria.

- Oxygen uptake by nitrification was determined. The oxygen consumed by nitrification was 7 mg/L. This oxygen consumption by nitrification was subtracted from the respective 28 days measurements of the test substance.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: not readily biodegradable

Conclusions:

Under the study conditions, the test substance was considered to be ‘not readily biodegradable’.

Executive summary:

A study was conducted to assess the ready biodegradability of the test substance according to EU Method C.4-D (which is in most parts equivalent to OECD Guideline 301 F), in compliance with GLP.

Activated sludge was inoculated with 100 mg/L of the test substance (in triplicate) in a closed flask at a constant temperature (22±2°C) for 28 d. Degradation was assessed by the determination of Biochemical Oxygen Demand (BOD) on Days 4, 6, 8, 12, 14, 18, 20, 22, 26 and 28. A toxicity test, a control solution and a reference substance (benzoic acid, sodium salt) were used for validation purposes. The test substance degraded 0% by Day 28. No toxicity of the test substance was observed in the toxicity control. The reference compound showed 88% degradation at Day 14.

Hence, under the study conditions, the test substance was considered to be ‘not readily biodegradable’.