Pent-3-enenitrile

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:

supporting study

Study period:

03 SEPTEMBER 2008 to 13 JANUARY 2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study test the ready biodegradability of the test substance according to standard guidelines (OECD 310). Since the test substance is suspected to be volatile this precaution is welcome. The report is fully detailed and despite it is not GLP, results presented are highly reliable. Therefore this data can be considered of high reliability with the only restriction it is not GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 310 (Ready Biodegradability - CO2 in Sealed Vessels (Headspace Test)

Deviations:

no

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Activated sludge was collected from the aeration tank of a full-scale wastewater treatment plant which treats predominantly domestic sewage (ETE Jundiai-SP/Brazil).
- Laboratory culture: no
- Method of cultivation:no
- Storage conditions:no data
- Storage length: none
- Preparation of inoculum for exposure: The activated sludge was treated by allowing to settle three times for 30 minutes. For each settling the supernatant was rejected and the solids were redispersed in the mineral medium. In order to lower carbon organic content and to reduce the blank CO2 evolution, the activated sludge was aerated overnight. The concentration of the treated activated sludge was adjusted to 1000 mg/L dry solids. In order to achieve a final concentration of 4 mg/L activated sludge dry solids, the treated activated sludge was diluted with the mineral medium.
- Pretreatment: no
- Concentration of sludge: 4 mg/L
- Initial cell/biomass concentration: no data
- Water filtered: no data
- Type and size of filter used, if any: none

Duration of test (contact time):

28 d

Initial conc.:

19.91 other: mgC/L

Based on:

ThIC

Parameter followed for biodegradation estimation:

inorg. C analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: KH2PO4 (85 mg/L), K2HPO4 (217.5 mg/L), Na2HPO4, 2H20 (334 mg/L), NH4Cl (5 mg/L), CaCl2, 2H2O (36.4 mg/L), MgSO4, 7H20 (22.5 mg/L), FeCl3, 6H2O (0.25 mg/L)
- Additional substrate: none
- Solubilising agent (type and concentration if used): none
- Test temperature: 22 +- 2°C
- pH: 7.62
- pH adjusted: no
- CEC (meq/100 g): no data
- Aeration of dilution water: no data
- Suspended solids concentration: 4 mg/L
- Continuous darkness: incubation in the dark


TEST SYSTEM
- Number of culture flasks/concentration: 15 bottles for blank control, test and reference treatments. 4 bottles for inhibition controls.
- Method used to create aerobic conditions: shaking in a rotary apparatus at 160-10 rpm
- Test performed in closed vessels due to significant volatility of test substance: 120mL-bottles sealed with butyl rubber stoppers and aluminium crimp seals.

SAMPLING
- Sampling frequency: on day 2, 5, 7, 14, 21, and 28
- Sampling method: see "analytical method"
- Sterility check if applicable: no abiotic control
- Sample storage before analysis: no data

CONTROL AND BLANK SYSTEM
- Inoculum blank: 80 mL of inoculated medium
- Abiotic sterile control: none
- Inhibition control: 80 mL of inoculated medium containing test substance (19.91 mg/L TOC) and reference substance (20 mg/L TOC)
- Other: reference bottles (80 mL of inoculated medium containing the reference substance at 20 mg/L TOC)

STATISTICAL METHODS:
no statistics were performed

Reference substance:

benzoic acid, sodium salt

Preliminary study:

none

Test performance:

met all validity criteria

Parameter:

% degradation (inorg. C analysis)

Value:

48.81

Sampling time:

5 d

Parameter:

% degradation (inorg. C analysis)

Value:

68.12

Sampling time:

7 d

Parameter:

% degradation (inorg. C analysis)

Value:

69.31

Sampling time:

14 d

Parameter:

% degradation (inorg. C analysis)

Value:

81.3

Sampling time:

21 d

Key result

Parameter:

% degradation (inorg. C analysis)

Value:

83.94

Sampling time:

28 d

Details on results:

On day 2, 1.07% of degradation was measured.
The ihibition control showed the test substance was not toxic to the inoculum with 90.62 % of biodegradation after 28 days.

Results with reference substance:

Sodium benzoate was degraded at 74.93% after 2 days and 97.06% after 28 days of test. Furthermore, this reference substance passed the OECD "10-day window" criterion.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test substance degraded at 83.94% after 28 days based on inorganic carbon analysis. The 10-day window started on day 5, and the pass level of 60 % degradation was attained during these 10 days. Thus the test substance is considered as readily biodegradable.

Executive summary:

This study tests the ready biodegradability of the test substance according to standard guidelines (OECD 310). The report is fully detailed and despite it is not GLP, results presented are highly reliable.

Biodegradation of the test substance was measured by inorganic carbon analysis on day 2, 5, 7, 14, 21, and 28 in duplicate but on day 28 where five replicates (bottles) were measured. The inoculum used was sampled from a WWTP receiving domestic sewage and was aged carefully prior to testing. Suspended matter concentration in the inoculum was adjusted to 4 mg/L. Blank, test, reference, and toxicity bottles were filled in with mineral medium plus inoculum, test substance, sodium benzoate or both respectively. Each 120 mL-bottles were filled up to 80 mL and sealed with butyl rubber cap and aluminum crimp seals. Concentration of the test substance was 19.91 mg/L TOC.

The 10d-window started before day 5 (48.81%) and 69.31% degradation was calculated on day 14. The test was terminated on day 28 drawing 83.94% of degradation of the test substance. All validity criteria were met.

Therefore the test substance is considered to be readily biodegradable meeting the 10d-window.

Description of key information

Based on reliable data, the test substance is readily biodegradable and meets the 10-day window.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable