3-methyl-2-butenyl salicylate

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:

Dec. 2010 - Feb. 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)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of activated sludge: from a wastewater treatment plant (ARA Ergolz II, Füllinsdorf, Switzerland) treating predominantly domestic wastewater
- Pretreatment: washed twice with tap water by centrifugation and the supernatant liquid phase was decanted. A homogenized aliquot of the final sludge suspension was weighed, thereafter dried and the ratio of wet to dry weight was calculated.
- Concentration of sludge: 4 g (±10%) dry material per liter

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Initial conc.:

> 220 - < 222 other: mg O2/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: test water (according to guidelines)
- Solubilising agent: no
- Test temperature: 22 °C
- pH: 7.4 - 7.7
- pH adjusted: yes, for test water (7.8 to 7.4)
- Suspended solids concentration: final concentration of 30 mg dry material per liter
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 500 mL reaction vessels
- Number of culture flasks/concentration: 2
- Measuring equipment: The CO2 is adsorbed by soda lime, which results in a decrease of the total pressure in the airtight test flasks. The pressure drop is detected and converted into an electrical signal by means of an electrode type manometer.

SAMPLING
- Sampling frequency: at least on each working day

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Procedure control: sodium benzoate
- Toxicity control: sodium benzoate and test item

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (CO2 evolution)

Value:

86

Sampling time:

28 d

Details on results:

After 7 days a degradation of 56 % was determined, after 14 days a degradation of 77 %, after 21 days a degradation of 84 % and after 28 days a degradation of 86 %. The 10 day window was passed. The degradation of the toxicity control was 78 % after 28 days. No toxicity of the test substance was observed in the toxicity control.

Results with reference substance:

In parallel preparations with the reference substance, sodium benzoate showed a degradation of 65 % was achieved within 14 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

Within the test period of 28 days, a degradation of 86 % was determined for the test item.

Executive summary:

The biodegradation of the test item was determined in a manometric respirometry test according to EU method C.4 D and OECD 301 F. The test substance is suspended in test medium, inoculated with activated sludge of a domestic WWTP and incubated for 28 days under aerobic conditions in the dark at 22 °C. During this period, the biodegradation of the test substance is determined on the basis of the generation of CO2. Within the test period of 28 days, a degradation of 86 % was determined. The degradation of the toxicity control was 78 % after 28 days. No toxicity of the test substance was observed in the toxicity control.

Description of key information

In a manometric respirometry test the biodegradation of the test item was determined to be 86 % after 28 days, therefore it was considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The biodegradation of the test item was determined in a manometric respirometry test according to EU method C.4 D and OECD 301 F. The test substance is suspended in test medium, inoculated with activated sludge of a domestic WWTP and incubated for 28 days under aerobic conditions in the dark at 22 °C. During this period, the biodegradation of the test substance is determined on the basis of the generation of CO2. Within the test period of 28 days, a degradation of 86 % was determined. The degradation of the toxicity control was 78 % after 28 days. No toxicity of the test substance was observed in the toxicity control.