2-ethoxy-2,6,6-trimethyl-9-methylenebicyclo[3.3.1]nonane

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Commercial name : BOISIRIS
Chemical nature : 2-ethoxy-9-methylene-2,6,6-trimethylbicyclo[3.3.1]nonane
Empirical formula : C15H26O
Molecular weight : 222.3 g/mol
CAS Number : 68845-00-1
Aspect : colourless to pale yellow liquid
Lot No. : 263382

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aïre) was used.

The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.

Duration of test (contact time):

31 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Remarks:

The reference substance is used to test the activity of the inoculum used in a series of parallel studies. The reference substance concentration is 100 mg/l and the inoculum concentration is 100 mg/l (dry weight).

Test performance:

Oxygen uptakes, as recorded by the BI-1000, are corrected:

- by deducting the basic oxygen uptake of sludge (average of flasks 1/5 and 1/6)

- proportionally to account for the differences between actual and nominal concentrations of test substances.

Averages of identical flasks were used to obtain the different results and curves that can be found in Appendixes 1, 2, 3 and 4.

Degradation of sodium benzoate is 68 % after 7 days and 94 % after 14 days, widely in excess of the validity criterium: the activity of the inoculum is thus verified and the test is considered as valid.

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

31 d

Details on results:

BOISIRIS undergoes no biodegradation after 31 days in the test conditions.

Thus, BOISIRIS should be regarded as not inherently biodegradable according to this test.

However, inhibition of the inoculum was observed. This is clearly seen in the biodegradation time plot, where negative levels of biodegradation are observed on most days and in particular during the first 7 days (see illustration section). Thus, the influence of toxicity on the result of this test cannot be ruled out.

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The Inherent Biodegradability of BOISIRIS was determined by the Manometric Respirometry Test according to the OECD Guidelines for Testing of Chemicals, Method No. 302 C.

BOISIRIS undergoes no biodegradation after 31 days in the test conditions.

Thus, BOISIRIS should be regarded as not inherently biodegradable according to this test.

At the test concentration, Boisiris did inhibit the intrinsic respiration of the inoculum. This is clearly seen in the biodegradation time plot, where negative levels of biodegradation are observed on most days and in particular during the first 7 days. Thus, the influence of toxicity on the result from this test cannot be ruled out for this substance.

Reference 2

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)

Qualifier:

according to guideline

Guideline:

other: Revised Introduction to the OECD Guidelines for Testing of Chemicals, Section 3, Part 1, 2006

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

other: ECHA Guidance for the implementation of REACH, Guidance on information requirements and chemical safety assessment, Chapter R.7b: Endpoint specific guidance, November 2014 (version 2.0)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Commercial name : Boisiris
Givaudan Code No. : 2786903
Chemical nature : 2-Ethoxy-9-methylene-2,6,6-trimethylbicyclo(3.3.1)-nonane
Empirical formula : C15H26O
Molecular weight : 222.37 g/mol
CAS No. : 68845-00-1
Aspect : Colourless to pale yellow liquid
Lot No. : VE00383856
Expiration date : August 06, 2017

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (Bois-de-Bay, Satigny, Switzerland) was used.

The sludge is collected in the morning, washed three times in the mineral medium (by centrifuging at 1000 g for 10 minutes, discarding the supernatant and resuspending in mineral medium) and kept aerobic until being used on the same day.

Duration of test (contact time):

42 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Test performance:

Oxygen uptakes, as read on the Oxitop controller, are corrected to account for the small differences between actual and nominal concentrations of test and reference substances.

Degradation of sodium benzoate exceeded 40% after 7 days and 65% after 14 days: the activity of the inoculum was thus verified (validity criterion).

The repeatability validity criterion (not more than 20% difference between replicates) is fulfilled. Therefore, the test is considered valid.

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

42 d

Details on results:

Boisiris undergoes 1% biodegradation after 28 days (4% after 42 days) in the test conditions.

At the test concentration Boisiris did inhibit the intrinsic respiration of the inoculum by 22.8% on day 1 of the test. Slight toxicity towards the inoculum at test concentration can therefore not be excluded.

Boisiris should be regarded as not readily biodegradable according to this test.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The Ready Biodegradability of Boisiris was determined by the Manometric Respirometry Test.

Boisiris undergoes 1% biodegradation after 28 days (4% after 42 days) in the test conditions.

At the test concentration Boisiris did inhibit the intrinsic respiration of the inoculum by 22.8% on day 1 of the test. Slight toxicity towards the inoculum at test concentration can therefore not be excluded.

Boisiris should be regarded as not readily biodegradable according to this test.

Description of key information

The substance is neither readily or inherently biodegradable according to the screening data available. The levels of biodegradation observed are <= 4%. Thus the conclusion is that under these test conditions no biodegradation (based on oxygen consumption) was observed.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The ready biodegradability of Boisiris has been investigated in an OECD 301F screening test. The level of biodegradation based on BOD (biological oxygen demand) was 1% after 28 days (4% after 42 days). Thus Boisiris is regarded as not readily biodegradable (or inherently biodegradable) according to this test. At the test concentration of 30 mg/L, Boisiris did inhibit the intrinsic respiration of the inoculum by 22.8% on day 1 of the test. Thus toxicity towards the inoculum at the test concentration can not be excluded.

The inherent biodegradability was assessed according to OECD Guideline 302C. The test item concentration in this study was also 30mg/L. The main difference between this inherent test and the aforementioned ready test is the higher concentration of inoculum employed (100 mg/L versus 30 mg/L). Boisiris underwent no biodegradation after 31 days and thus should be regarded as not inherently biodegradable according to this test. However, inhibition of the inoculum was again observed. This is clearly seen in the biodegradation time plots, where negative levels of biodegradation are observed on most days and in particular during the first 7 days.

The registrant considers that the influence of toxicity on the results of these two screening tests cannot be ruled out for this substance. Furthermore, the 30mg/L test concentration employed in the two studies is significantly higher than the water solubility of Boisiris, which is only 4mg/L. Thus, bioavailability is another potential issue for the screening data available.