Benzyl cinnamate

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:

06.10 - 04.11.1999

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: biological waste water treatment plant treating predominantly domestic sewage (City of Geneva, Aïre)
- Preparation of inoculum for exposure: sludge is collected in the morning, washed 3 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.
- Determination of the dry weight of suspended solids: the dry weight of suspended solids is determined by taking two 50 mL samples of the homogenised sludge, evaporating water on a steam bath, drying in an oven at 105-110°C for two hours and weighing the residue.

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: mineral medium is 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 liters with deionised water. The pH is measured and if necessary adjusted to 7.4 +/- 0.2 with phosphoric acid or potassium hydroxide.
* Solution A: 8.5g KH2PO4, 21.75g K2HPO4, 33.4g Na2HPO4.2H2O and 0.5g NH4Cl dissolved in water and made up to 1 litre.
* Solution B: 27.5g CaCl2 dissolved in water and made up to 1 litre.
* Solution C: 22.5g MgSO4.7H2O dissolved in water and made up to 1 litre.
* Solution D: 0.25g FeCl3.6H2O and one drop of HCl conc. dissolved in water and made up to 1 litre.
- Test temperature: 22°C
- pH:7.4
- pH adjusted: no
- Suspended solids concentration: dry sludge suspended solids: 2.576g/L. To obtain a concentration of 30mg/L in a 250mL flask, 2.91 mL of sludge is needed.
- Test duration: 28 days

TEST SYSTEM
- Number of culture flasks/concentration: 4
- Measuring equipment: Respirometer SAPROMAT D 12, made by J.M. VOITH GmbH, D-7920 Heidenheim, Germany

CONTROL AND BLANK SYSTEM
- Toxicity control: yes: 100 mg/L test chemical + 100 mg/L reference substance sodium benzoate.

Reference substance:

benzoic acid, sodium salt

Remarks:

purity min 99.0%

Key result

Parameter:

% degradation (O2 consumption)

Value:

94

Sampling time:

28 d

Parameter:

% degradation (O2 consumption)

Value:

83

Sampling time:

10 d

Results with reference substance:

Degradation of reference substance > 40% after 7 days and 65% after 14 days: the activity of the sludge is verified and the test is considered as valid.

Biological Oxygen Demand (BOD, mg O₂/L, adjusted to nominal concentrations):

	Days	1	7	11	14	21	28
BOD sludge	1st flask	6.0	17.0	19.0	20.0	24.0	26.0
	2nd flask	7.0	17.0	19.0	19.0	23.0	24.0
	mean	6.5	17.0	19.0	19.5	23.5	25.0
BOD test substance	1st flask	45.1	195.7	225.1	236.8	250.6	257.4
	2nd flask	45.4	195.4	227.0	238.8	250.7	256.7
	1st flask corr.	38.6	178.7	206.1	217.3	227.1	232.4
	2nd flask corr.	38.9	178.4	208.0	219.3	227.2	231.7
% degr.	1st flask	16	72	83	88	92	94
	2nd flask	16	72	84	88	92	93
	mean	16	72	83	88	92	94

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance is considered as readily biodegradable

Executive summary:

In the current study the ready biodegradability of the test substance was determined by the Manometric Respirometry according to OECD 301 F guideline without significant deviation.

The measured volume of inoculated mineral medium, containing a known concentration of test substance (100 mg/L) is stirred in a closed flask at a constant temperature (22°C) for up to 28 days. The Biological Oxygen Demand (BOD) is monitored by determining oxygen consumption with a SAPROMAT D12 respirometer.

The test substance undergoes 94% biodegradation after 28 days in the test conditions. Biodegradation starts on day 1 and reaches 83% at the end of the 10- day window.

The test substance is considered to be readily biodegradable according to this test.

Description of key information

ready biodegradable (94% after 28 days; OECD 301 F)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two studies are available that assess the biodegradation of the test substance in water.

In the first study the ready biodegradability of the test substance was determined by the Manometric Respirometry according to OECD 301 F guideline. In this study the test substance underwent 94% biodegradation after 28 days in the test conditions and reaches 83% at the end of the 10- day window. The test substance was not inhibitory to micro-organisms at the used concentration of 100 mg/L.

In the second study the biodegradability was assessed with a Closed Bottle Test according to EU Method C.4-E and GLP.

Test substance is not inhibitory at tested concentration of 2.8 mg/L.

The biodegradability of the test item reached 50% within 28 days. Therefore, the test item is to be considered as not readily biodegradable under the conditions of this test.

Taking together the results and comparing them to the criteria set out in the CLP regulation EC No 1272/2008 in Annex 1 section 4.1.2.9 the test item is considered to be ready biodegradable as it meets the criteria in at least one ready biodegradation test.