Thuya plicata, ext.

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:

december 2017 to january 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Thuya occidentalis, ext.

EC Number:

290-370-1

EC Name:

Thuya occidentalis, ext.

Cas Number:

90131-58-1

Molecular formula:

not relevant for a UVCB substance

IUPAC Name:

Water steam distillation of leaves and twigs of Thuya occidentalis (family cupressaceae)

Test material form:

liquid

Specific details on test material used for the study:

batch number 4802

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

water treatment plant "STEP de Lille" 33290 Blanquefort (France) - The inoculum was a fresh sample of activated sludge and was collected from the aeration tank of a sewage treatment plant receiving predominantly domestic sewage.

Duration of test (contact time):

28 d

Details on study design:

The medium was prepared from concentrated stock solutions in ultrapure water as decribed in the guideline.

Reference substance

Reference substance:

other: sodium benzoate

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

average

Value:

58.44

Sampling time:

28 d

Details on results:

The test item “HUILE ESSENTIELLE DE THUYA OCCIDENTALIS / THUYA OCCIDENTALIS OIL” contains no nitrogen according to the elementary analysis (see Appendix 6: Study plan, Annex 1-2), the evaluation of biodegradation has to be based in the following expressed as ThODNH4.
The degradation for the 10-day window beginning was reached on Day 5, at the end of the 10-day window on Day 15 the mean degradation was 45.87%, therefore the D-day window failed.
The degradation rate of the test item “HUILE ESSENTIELLE DE THUYA OCCIDENTALIS /THUYA OCCIDENTALIS OIL” reached 58.44% (54.40 to 63.05), following the ThODNH4, after 28 days of incubation.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test item “HUILE ESSENTIELLE DE THUYA OCCIDENTALIS /THUYA OCCIDENTALIS OIL” reached 58.44% (54.40 to 63.05), following the ThODNH4, after 28 days of incubation.
According to the OECD guideline 301F, the test item is not considered to be readily biodegradable.