3-(benzothiazol-2-yl)-7-(diethylamino)-2-oxo-2H-1-benzopyran-4-carbonitrile

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Remarks:

mixed population of aquatic microorganisms

Details on inoculum:

Test organisms
Type : mixed population of aquatic microorganisms (activated sludge)
Origin : aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Date of collection : 2017-03-06
Concentration of inoculum : 30 mg/L suspended solidsPre-treatment of the inoculum

− Before use, the inoculum was stored for two days at room temperature under continuous stirring with aeration.
− The sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant.
− An aliquot of the wet sludge was dried in order to determine the wet weight / dry weight ratio of the sludge and to prepare a stock suspension (activated sludge) of 3 g dw/L.
− The calculated amount of sludge, needed to achieve 300 mL of this stock suspension, was dissolved in mineral medium and then filled up to a defined end volume.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Details on study design:

Exposure conditions
Test volume : 250 mL
Test apparatus : OxiTopControl System (WTW)
Mixing : 1 magnetic stirrer per test vessel
Incubation time : 28 days
Incubation temperature : 22 ± 1 °C

Reference substance:

benzoic acid, sodium salt

Remarks:

Acros Organics, Batch No. A0357641, purity 99.9%

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Results with reference substance:

The reference compound sodium benzoate showed 86 % degradation after 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

After 28 days Macrolex Fluoreszenzrot G shows 0% biodegradation. Thus, the substance is considered as not readily biodegradable.

Executive summary:

The biodegradation of Macrolex Fluoreszenzrot G was investiagted according to OECD Guideline 301 F and EU method C.A-D in a manometric respirometry test. To this end, a suspension of Macrolex Fluoreszenzrot G in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by continuous automated BOD determinations. As a results after 28 days 0% degradation was obeserved. Conclusively, Macrolex Fluoreszenzrot G is considered to be not readily biodegradable (Currenta 2017).

Description of key information

After 28 days Macrolex Fluoreszenzrot G shows 0% biodegradation. Thus, the substance is considered as not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed