5-methylheptan-3-one oxime

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:

key study

Study period:

28 May 1998 to 29 June 1998

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))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Lot No: 282716
Purity: 96.8% (GC, sum of the two isomers).

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, Aire) 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

Reference substance:

benzoic acid, sodium salt

Remarks:

(Fluka, Buchs, Switzerland, Art. No. 71300), purity: min. 99.0 %.

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

31 d

Remarks on result:

other:

Remarks:

test concentration of 30 mg/L

RESULTS

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

- by deducting the basic oxygen uptake of sludge (average of flasks 1/3 and 1/4)

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

 

Degradation of sodium benzoate is 65 % after 7 days and 86 % 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.

 

The Theoretical Oxygen Demand was calculated assuming that the nitrogen atom is degraded to ammonia. Assuming that it becomes nitrate would lead to a different ThOD but, since no degradation occurs, the ThOD value is meaningless.

 

 

COMMENTS AND CONCLUSIONS

STEMONE undergoes no significant biodegradation after 31 days in the test conditions.

In a previous study (96-E114), a toxicity test was performed which showed that at a higher concentration (100 mg/l), STEMONE was not toxic to activated sludge microorganisms.

The absence of biodegradation is not due to toxicity to the inoculum. Thus, STEMONE should be regarded as not inherently biodegradable according to this test.

 

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

STEMONE undergoes no significant biodegradation after 31 days in the test conditions.
STEMONE should be regarded as not inherently biodegradable according to this test.

Executive summary:

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

STEMONE undergoes no significant biodegradation after 31 days in the test conditions.

In a previous study (96-E114), a toxicity test was performed which showed that at a higher concentration (100 mg/l), STEMONE was not toxic to activated sludge microorganisms. The absence of biodegradation is not due to toxicity to the inoculum.

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

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11 October 1996 to 13 November 1996

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)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Lot No: 263992
Purity: 96.3% (GC, sum of 2 isomers).

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

Fresh activated sludge from a biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aire) 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):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

aniline

Remarks:

(Merck, Darmstadt, Germany, Art. No. 1261) Purity: min. 99.5 %

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

RESULTS

 Oxygen uptakes, as read on the SAPROMAT meters, are corrected:

-         By deducting the basic oxygen uptake of sludge (flasks 2/5 and 2/6)

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

 

In flasks containing aniline alone, pH remained roughly at the same level: this suggests that the final form of nitrogen is partly one of the acid forms NO2or NO3 –and partly the alkaline ion NH4 +.The Theoretical Oxygen Demand (ThOD) corresponding to NO3 -was used for the calculation of the biodegradation rates of aniline. Using the ThOD corresponding to NH4+would lead to higher degradation rates. In both case, degradation of Aniline exceeds40% after 7 days and 65 % after 14 days: the activity of the inoculum is thus verified and the test is considered as valid.

 

COMMENTS AND CONCLUSIONS

STEMONE undergoes almost no (1%) biodegradation after 28 days in the test conditions.

Thus, STEMONE should be regarded as not readily biodegradable according to this test.

The curves obtained with Aniline alone and with STEMONE+Aniline show no significant toxic effect of STEMONE on the micro-organisms at the test concentration.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

STEMONE undergoes almost no (1%) biodegradation after 28 days in the test conditions.
Thus, STEMONE should be regarded as not readily biodegradable according to this test.

Executive summary:

The method used is basically the one described under No. 301 F in the OECD Guidelines for Testing of Chemicals. A measured volume of inoculated mineral medium, containing a known concentration of test substance (100 mg/l) as the nominal sole source of organic carbon, is stirred in a closed flask at a constant temperature (± 1°C) for up to 28 days. The consumption of oxygen is determined by measuring the quantity of oxygen (produced electrolytically) required to maintain constant the gas volume in the respirometer flask. Evolved carbon dioxide is absorbed in soda lime pellets. The amount of oxygen taken up by the microbial population during biodegradation of the test chemical (corrected for uptake by blank inoculum, run in parallel) is expressed as a percentage of ThOD (Theoretical Oxygen Demand, calculated from the elemental composition, assuming that carbon is oxidized to carbon dioxide and hydrogen to water) .

STEMONE undergoes almost no (1%) biodegradation after 28 days in the test conditions.

Thus, STEMONE should be regarded as not readily biodegradable according to this test.

The curves obtained with Aniline alone and with STEMONE+Aniline show no significant toxic effect of STEMONE on the microorganisms at the test concentration.

Reference 3

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

27 October 2010 to 11 January 2011

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Lot No.: VE00105458
Purity: 97.85%

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

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):

70 d

Initial conc.:

30 mg/L

Parameter followed for biodegradation estimation:

O2 consumption

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

70 d

Remarks on result:

other:

Remarks:

test concentration of 30 mg/L

RESULTS

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.

Calculated % biodegradation curves and detailed in the table below:

O₂uptake (mg O₂/L, adjusted to nominal concentrations):

	Days:		5	7	14	21	28	56	70
O2 uptake of sludge (inoculum blank)	1	B1	18.8	21.5	28.3	32.3	36.3	49.8	55.2
	2	B2	17.5	20.2	26.9	35.0	41.7	61.9	72.7
	mean	B	18.2	20.9	27.6	33.7	39.0	55.9	64.0
O2 uptake of Test Subst. + sludge	21	C1	18.8	21.5	29.5	35.0	37.7	53.8	61.9
	22	C2	17.5	20.2	28.3	33.7	36.3	52.5	59.2
O2 uptake of Test Substance		C1-B	0.7	0.6	2.0	1.4	-1.3	-2.1	-2.1
		C2-B	-0.6	-0.7	0.7	0.1	-2.7	-3.3	-4.8
% biodegradation of test substance		D1	1	1	3	2	-2	-3	-3
		D2	-1	-1	1	0	-4	-5	-6
	mean	D	0	0	2	1	-3	-4	-5

Calculations:

B1, B2, C1, C2, A1, A2, E1: experimental O₂uptake values

B = (B1 + B2)I2

D1 = 100 * (C1- B) /ThOD * [S]

D2 = 100 * (C2- B) /ThOD * [S]

D = (D1 + D2)/2

[S] : Initial test substance concentration (mg/L)

 

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 for the flasks containing test substance. Therefore, the test is considered valid.

 

COMMENTS AND CONCLUSIONS

The Ready Biodegradability of Stemone was determined by the Monometric Respirometry Test.

Stemone undergoes no biodegradation after 28 days (no biodegradation after 56 days, no biodegradation after 70 days) in the test conditions.

Stemone did not significantly inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

Thus, Stemone 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 Stemone was determined by the Monometric Respirometry Test.
Stemone undergoes no biodegradation after 28 days (no biodegradation after 56 days, no biodegradation after 70 days) in the test conditions.
Stemone did not significantly inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.
Thus, Stemone should be regarded as not readily biodegradable according to this test.

Executive summary:

The Ready Biodegradability of Stemone was determined by the Monometric Respirometry Test.

Stemone undergoes no biodegradation after 28 days (no biodegradation after 56 days, no biodegradation after 70 days) in the test conditions.

Stemone did not significantly inhibit the intrinsic respiration of the inoculum at the test concentration and was therefore considered to be non-toxic to the inoculum at the test concentration.

Thus, Stemone should be regarded as not readily biodegradable according to this test.

Description of key information

The Ready Biodegradability of Stemone has been determined in two ready biodegradability tests (Rudio 1996 and Kreutzer 2010). Both are GLP studies, performed according to the Manometric Respirometry OECD 301F Test. The level of degradation achieved after 28 days was 1% in the 1996 Rudio study. In the second Kreutzer study Stemone undergoes no biodegradation after 28 days (no biodegradation after 56 days, no biodegradation after 70 days) in the test conditions. Stemone did not significantly inhibit the intrinsic respiration of the inoculum at the test concentrations of 100 mg/l (Rudio 1996) and 30 mg/l (Kreutzer 2010) and was therefore considered to be non-toxic to the inoculum at these test concentrations. Thus, Stemone should be regarded as not readily biodegradable.

Additionally, in 1998 an Inherent Biodegradability test was performed according to the Manometric Respirometry OECD 302C Test. This showed that Stemone undergoes no significant biodegradation after 31 days in the test conditions. Thus Stemone should be regarded as not inherently biodegradable according to this test.

Based on the above three tests, the conclusion for the chemical safety assessment is that no biodegradation was observed.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

An inhibition control was included in the Rudio 1996 ready biodegradability test. At the concentration used in the test (100 mg/l), Stemone was not inhibitory to the micro-organisms. This concentration can be considered as a NOEC for the toxicity to STP microorganisms.