2-methylcyclohexanone

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

Study period:

December 14 2017 - January 18 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Remarks:

The preparation of a sample of the aerobic sludge was a mixture of treatment plant of urban (about 66%) and industrial (about 34%) liquid sewage located in Monza Italy.

Duration of test (contact time):

ca. 10 - ca. 28 d

Initial conc.:

33.39 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

The study was conducted in the Eurofins Biolab S.r.l. Test Facility, Vimodrone (Ml) - Italy, Via Bruno Buozzi, 2.

EXPERIMENTATION: Aerobic Biodegradability of organic compounds in aqueous medium

START: December 14th, 2017

END: January 18th, 2018

RESEARCHER: D. Facchetti

- OECD 310 - 2014. Ready Biodegradability - C02 in sealed vessels (Headspace Test)

- EN ISO 10634:1995 - Guidance for the preparation and treatment of poorly water soluble organic compounds for the subsequent evaluation of their biodegradability in an aqueous medium.

Reference substance:

other: 1-octanol

Key result

Parameter:

% degradation (TOC removal)

Value:

78

Sampling time:

7 d

Details on results:

EXPRESSION OF RESULTS

The calculation of biodegradation is done at each sampling time for the reference substance, test sample and blank.
Total biodegradation has been calculated using the equation:
D=(TIP-TIC)/TOC*100
Where:
D = total biodegradation calculated with reference to values of blank, expressed in percentage. TIC, = concentration of inorganic carbon, in mg, produced by biodegradation of the test item.
TIC = concentration of inorganic carbon, in mg, produced by biodegradation in blank.
TOC = concentration of organic carbon of the test item, in mg, added at the beginning.
The result of biodegradability is expressed as the percentage ratio between the value of inorganic carbon measured and the value of organic carbon added at the beginning. The value of inorganic carbon is the highest value recorded during 28 days of experimental period
INTERPRETATION OF RESULTS

The test is considered valid when:
- the percentage of average degradation of the reference substance is more than 60% after 14 days of incubation.
-the mean amount of TIC present in the blank at the end of the test is < 3 mg C/L.
A substance is considered biodegradable when its level of biodegradability is at least 60%, within a period of 28 days.
A substance is considered readily biodegradable when its level of biodegradability is at least 60%, within 10d window during the test.
If, at day 28, the biodegradation in the bottle contained both the test sample and the reference substance referred to biodegradation in the bottle with reference substance result < 25%, it may be assumed that the test substance don't inhibited the activity of the inoculum.
If in the bottle to check abiotic biodegradation a significant increase (>10%) in the amount of TIC is observed, abiotic degradation processes may have occurred.
RESULTS

Quality criteria of the test are satisfied (see table below and Attachment N. 2). Temperature has remained in the range required by the guideline (20 ± 1 °C).
The mean amount of TIC present in the blank controls at the end of the test is <3 mg C/L.
The vessels show < 20% difference and no outliers have been observed. The trend of the inorganic carbon and related biodegradation percentages in the bottle contained both the test sample and the reference substance confirm the absence of inhibitory effect of the test sample on inoculum (<25%).

Results with reference substance:

Check Point (Days) and % OF BIODEGRADATION Reference substance
0 and 0,
1 and 4,
7 and 105,
14 and 113,
21 and 89,
28 and 98

Check Point (Days)	% OF BIODEGRADATION Reference substance	% OF BIODEGRADATION Test substance	% OF BIODEGRADATION Reference substance + Test substance
0	0	0	0
1	4	1	1
7	105	78	-
14	113	78	-
21	89	68	-
28	98	90	86

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

On the basis of results obtained, interpreted in accordance to OECD 310: 2014, the test item 2-methylcyclohexanone is considered readily biodegradable in aerobic conditions

Description of key information

On the basis of results obtained, interpreted in accordance to OECD 310: 2014, the test item 2-methylcyclohexanone is considered readily biodegradable in aerobic conditions

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater