Thuj-4(10)-ene

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:

2017

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Thuj-4(10)-ene

EC Number:

222-212-4

EC Name:

Thuj-4(10)-ene

Cas Number:

3387-41-5

Molecular formula:

C10H16

IUPAC Name:

4-methylidene-1-(propan-2-yl)bicyclo[3.1.0]hexane

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Duration of test (contact time):

ca. 28 d

Results and discussion

Preliminary study:

The test vessels were filled with medium, then test item and positive control were added to the appropriate vessels and the pH in the test vessels was measured as 7.3, pH in abiotic control was adjusted to 7.2. The vessels were incubated at 22.0 ± 2.0 °C. After pH-adjustment, the inoculum was added, the vessels were connected to the OxiTop® measuring heads and they were started via the OxiTop® Controllers.

Test performance:

The oxygen which was consumed by the content of the vessels was measured automati-cally by the test apparatus.
After 28 days, the test was ended.
Because the test item and positive control do not contain nitrogen, presence of nitrate and nitrite was not checked.

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 36

Sampling time:

28 d

Details on results:

The degree of biodegradation reached 36 % after 28 days.
The 10-day-window began on day 7 (this is stated as lag phase), at its end (day 17), 26 % were reached, staying below the pass level of 60 % given in the OECD guideline.
The degradation phase is defined as interval between the end of the lag phase to the time when 90% of the maximum level of degradation has been reached. End of the degradation phase was on day 24.
Therefore, regardless of the 10-day-window, the test item Thuj-4(10)-ene is not readily biodegradable following OECD 301F/EU C.4-D.

Applicant's summary and conclusion

Interpretation of results:

not readily biodegradable

Conclusions:

The test item Thuj-4(10)-ene was tested using a concentration of 31 mg test item/L (equiv-alent to a theoretical oxygen demand of 100.96 mg O2/L). Activated sludge was used as inoculum. The test was left running for 28 days.

All validity criteria were met. The positive control reached the pass level of 60 % on day 4 (criterion:<=14).

The following data could be determined for the test item Thuj-4(10)-ene:

10-day-window: day 7 – 17
degradation at the end of 10-day-window 26 %
degradation at the end of the test 36 %

Therefore, regardless of the 10-day-window, Thuj-4(10)-ene is classified as not readily biodegradable following OECD 301F/EU C.4-D.