Reaction mass of (2R*,4R*,4aR*,9bS*)-2,4-dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxine and (2R*,4R*,4aS*,9bR*)-2,4-dimethyl-4,4a,5,9b-tetrahydroindeno[1,2-d][1,3]dioxine

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Feb - 16 Mar 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Niedersächsisches Umweltministerium, Hannover, Germany

Oxygen conditions:

aerobic

Inoculum or test system:

other: Inoculum of the aqueous phase of non adapted activated sludge

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, Hildesheim, Germany
- Laboratory culture: no
- Pretreatment: Activated sludge was filtered with folded filter. The first 200 mL of the filtrate were not used. The second filtrate effluent from the domestic waste water is used to initiate inoculation.
- Initial cell/biomass concentration: 10E+4 - 10E+6 Colony Forming Units (CFU)/L

Duration of test (contact time):

28 d

Initial conc.:

2.5 mg/L

Based on:

test mat.

Initial conc.:

7.5 mg/L

Based on:

ThOD/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: according to guideline
- Test temperature: 19 - 21 °C
- pH: 7.3 - 7.64 (test item), 7.17 - 7.64 (toxicity control), 6.93 - 7.57 (reference substance), 7.20 - 7.55 (inoculum control)
- pH adjusted: no
- Aeration of dilution water: yes, 1 day before test start
- Continuous darkness: no reported

TEST SYSTEM
- Culturing apparatus: BOD bottles with glass stoppers
- Number of culture flasks/concentration: 2 replicates (10 bottles)
- Measuring equipment: Oximeter, "WTW" oxi 530
- Test performed in closed vessels: yes

SAMPLING
- Sampling frequency: Sampled on day 0, 7, 14, 21 and 28.
- Sampling method: Oxygen contration of duplicates was measured

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 replicates (10 bottles)
- Abiotic sterile control: no
- Toxicity control: yes, 2 replicates (10 bottles)
- Other: reference substance: yes, 2 replicates (10 bottles)

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

0% degradation after 28 d, 60% pass level and 10 day window were not met.

Results with reference substance:

77% after 28 d, 60% pass level was reached.

Table 1: % degradation of the reference substance, test substance and in the toxicity control.

Study day	Reference substance, mean of 2 replicates [%]	Test substance, mean of 2 replicates [%]	Toxicity control, mean of 2 replicates [%]
0	-	-	-
7	71	0	33
14	69	0	31
21	77	0	36
28	76	0	38

The toxicity control attained 31% degradation after 14 d indicating that the test substance is not inhibitory to the inoculum (degradation > 25% based on ThOD).

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

This study indicates that the substance is not readily biodegradable (0% after 28 d (O2 consumption), OECD 301D).