2,6,10-trimethylundec-9-enal

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:

21 January 1997 - 19 February 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant study conducted according to OECD Guidelines, with no or minor deviations.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Lot/batch No.of test material: N°256231
- Appearance: colorless liquid

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

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 was 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 under aerobic conditions until use 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

Details on study design:

TEST CONDITIONS
- Composition of medium: Prepared by mixing 50 mL of solution A and 2000 mL deionised water, adding 5 mL of each of the solutions B, C and D and making up to 5 litres with deionised water.
Activated sludge:
- Dry weight of suspended solids: 5.638 g/L
- Suspended solids concentration: To obtain a concentration of 30 mg/L (dry weight) in a 250 mL flask, 1.33 mL of sludge was needed (inoculum).

STOCK SOLUTIONS
The following stock solutions were prepared:

Solution A:
KH2PO4 8.5 g
K2HPO4 21.75 g
Na2HPO4.2H2O 33.4 g
NH4Cl 0.5 g
dissolved in water and made up to 1 litre.

Solution B:
CaCl2 27.5 g
dissolved in water and made up to 1 litre.

Solution C:
MgSO4.7H2O 22.5 g
dissolved in water and made up to 1 litre.

Solution D:
FeCl3.6H2O 0.25 g
HCl Conc. one drop
dissolved in water and made up to 1 litre.

TEST SYSTEM:
Preparation fo the Flasks:
Test substance samples (25 mg, corresponding to 100 mg/L in a 250-mL flask) were weighed in small aluminium boats and added directly to the test flasks of the respirometer, whereas reference substance samples (sodium benzoate) were added as 1.0 mL of a 25 mg/mL solution in mineral medium. All flasks were partly filled with mineral medium. Samples of test or reference substance, or both, were added. Then, a volume of suspended sludge corresponding to 7.5 mg dry weight was added and the content adjusted to 250 mL with mineral medium. The pH of each flask was measured and, if necessary, adjusted to 7.4 ± 0.2 with phosphoric acid or potassium hydroxide. About 2 g of soda lime was placed in an attachment of the stopper, the flasks were closed and placed in the water bath of the respirometer. After temperature and pressure equilibration, the oxygen meters of the instrument were set to zero (time zero of the experiment).
Every day the oxygen consumption of each flask was recorded and correct temperature and stirring checked. At the end of the test period, the pH of each flask was measured again.

TOXICITY OF TEST CHEMICAL:
As suggested in the OECD301F method, the toxicity of the test chemical was checked by comparing the respiration of flasks filled with:
mineral medium + test chemical (100 mg/l) + reference substance (100 mg/l) + inoculum
mineral medium + reference substance (100 mg/l) + inoculum

Reference substance:

other: Sodium Benzoate

Test performance:

Oxygen uptakes, as read on the respirometers, are corrected by deducting the basic oxygen uptake of sludge (flasks 2/3 and 2/4), proportionally to account for the differences between actual and nominal concentrations of test and reference substances.

Key result

Parameter:

% degradation (O2 consumption)

Value:

84

Sampling time:

28 d

Details on results:

Biodegradation starts on day 2 and reaches 71% at the end of 10-day window (Days 2 to 12)

The curves obtained with the reference substance alone and with ADOXAL + reference substance show no toxic effect of ADOXAL on the micro-organisms at the test concentration.

Results with reference substance:

Degradation of sodium benzoate exceeded 40 % after 7 days and 65 % after 14 days; the activity of the inoculum was thus verified and the test can be considered valid.

Table 2: Biodegradability of Test Substance in Terms of Biological Oxygen Demand (BOD, mg O2/L, adjusted to nominal concentrations)

		Days:	2	7	12	14	21	28
BOD Sludge	1^stflask	B1	8.0	16.0	20.0	23.0	27.0	32.0
	2^ndflask	B2	8.0	16.0	19.0	21.0	25.0	30.0
	Mean	B	8.0	16.0	19.5	22.0	26.0	31.0
BOD Test Substance	1^stflask	C1	42.7	170.0	234.7	251.4	272.3	286.9
	2^ndflask	C2	41.7	164.5	233.2	249.8	277.9	288.3
	1^stflask corr.	C1-B	34.7	154.0	215.2	229.4	246.3	255.9
	2^ndflask corr.	C2-B	33.7	148.5	213.7	227.8	251.9	257.3
% degradation	1^stflask	D1	11	51	71	75	81	84
	2^ndflask	D2	11	49	70	75	83	85
	Mean	D	11	50	71	75	82	84

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Under the conditions of the study the test substance underwent 84 % biodegradation after 28 days. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12). Thus, the test substance should be regarded as readily biodegradable according to this test.

At the concentration used in the test (100 mg/L), Adoxal is not inhibitory to the micro-organisms.

Executive summary:

The ready biodegradability of Adoxal was determined by the Manometric Respiratory Test according to OECD Guidelines No 301F. Under the conditions of the study the test substance underwent 84 % biodegradation after 28 days. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12). Thus, the test substance should be regarded as readily biodegradable according to this test.

Description of key information

The ready biodegradability of Adoxal was determined by the Manometric Respiratory Test according to OECD Guidelines No 301F. Under the conditions of the study the test substance underwent 84 % biodegradation after 28 days. Biodegradation started on day 2 and reached 71 % at the end of the 10-day window (days 2 to 12). Thus, the test substance should be regarded as readily biodegradable according to this test.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

At the concentration used in the test (30 mg/l), Adoxal is not inhibitory to the micro-organisms. This concentration can be considered as a NOEC for the toxicity to STP microorganisms.