2-ethoxyethyl ethyl carbonic acid ester

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:

27 January 2015 to 12 March 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Japanese notification, Yakushokuhatsu 0331 No. 7, Heisei 23.03.29 Seikoku No. 5, Kanpokihatsu No. 110331009 - Biodegradability Test of Chemical Substances by Microorganisms

Version / remarks:

31 March 2011 (latest revision 02 April 2012)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

anaerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from Chemicals Evaluation and Reseatch Institute, Japan
- Mixed liquor suspended solids: 3200 mg/L (BOD measurement and recovery test)

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: Basal medium
Composition of liquids A, B, C and D (Japanese industry Standards (JIS) K0102-2008, 21)
Liquid A: 21.75 g K2HPO4, 8.5 g KH2PO4, 44.6 f Na2HPO4.12H2O, 1.7 g NH4Cl dissolved in 1 L ultra pure water.
Liquid B: 22.5 g MgSO4.7H2O dissolved in 1 L ultra pure water.
Liquid C: 27.5 g CaCl2 dissolved in 1 L ultra pure water.
Liquid D: 0.10 g FeCl3.6H2O dissolved in 400 mL ultra pure water.
Basal medium prepared as an aqueous solution containing 0.3 % each of liquids A, B, C and D with pH adjusted to 7.0 ± 0.04 with 0.33 mol/L H3PO4 or 1 mol/L NaOH
- Test temperature: 25 ± 1 °C
- Aeration of dilution water: the contents of the test flasks were continuously stirred with a magnetic stirrer


TEST SYSTEM
- Culturing apparatus: Glass culture bottle
- Number of culture flasks/concentration:
Abiotic control: 1
Test suspension: 3
Activity control: 1
Control blank: 1
- Test performed in open system: test performed in closed system
- Details of CO2 absorbent: Soda lime

BOD measurement
The BOD was measured continuously for 28 days
- Apparatus: closed system oxygen consumption measuring apparatus (OM-3100A), Ohkura Electric Co.
- Data processing program: BODPrint (ver. 2.0)
In the apparatus, the temperature, stirring, recording meter and air-tightness of the closed system were checked daily (except holidays) during the measurement period. Observation was made on the colour of the contents of the test bottles, dissolution state of the test material and growth of the activated sludge.

CONTROL AND BLANK SYSTEM
- Inoculum blank: basal medium (300 mL) + activated sludge (2.8 mL)
- Abiotic sterile control: water (300 mL) + test material (30.0 mg)
- Toxicity control: basal medium (300 mL) + aniline (30.0 mg) + activated sludge (2.8 mL)
- Test suspension: basal medium (300 mL) + test material (30.0 mg) + activated sludge (2.8 mL)

EVALUATION OF TEST RESULTS
Degradability based on BOD:

Degradability (%) = [(BODs - BODb) / ThOD] x 100
where
BODs = oxygen consumption (mg) in the [sludge + test material] or the [sludge + aniline]
BODb = oxygen consumption (mg) in the [inoculum blank]
ThOD = theoretical oxygen demand (mg) of the test material or aniline

Degradability based on DOC:

Degradability (%) = [1 - (DOCs - DOCb) / DOCc] x 100
where
DOCs = DOC (mg) in the [sludge + test material]
DOCb = DOC (mg) in the [inoculum blank]
DOCc = DOC (mg) in the [water + test material]

Degradability based on the residual amount of test material

Degradability (%) = (1 - Cs / Cc) x 100
where
Cs = amount (mg) in the [sludge + test material]
Cc = amount (mg) in the [water + test material]

Disappearance rate (%) = [(Initial amount - Residual amount) / Initial amount] x 100

Reference substance:

aniline

Key result

Parameter:

% degradation (DOC removal)

Remarks:

(average)

Value:

96

Sampling time:

28 d

Key result

Parameter:

% degradation (O2 consumption)

Remarks:

(average)

Value:

89

Sampling time:

28 d

Key result

Parameter:

% degradation (test mat. analysis)

Value:

> 99

Sampling time:

28 d

Details on results:

- Observation on the contents after the end of BOD measurement
After the end of BOD measurement, observations were made on the colour of the contents and growth of the activated sludge in the test bottles using the [inoculum blank] as a comparative reference, and dissolution state of the test material.
The content on the [water + test material] was colourless, the [sludge + test material] and [sludge + aniline] bottles were white. Growth of the sludge was observed in the [sludge + test material] and the [sludge + aniline]. In the [water + test material] system, the test material was dissolved, and [sludge + test material] system decomposed the test material.

- pH measurement
At the end of BOD measurement, the pH values were 7.7 for the [water + test material] and 7.2, 7.2 and 7.1 for the three [sludge + test material] bottles, respectively.

- Degradability based on BOD
The BOD in the [water + test material] after 28 days was 0.0 mg, and the BOD in the [sludge + test material] bottles after 28 days (as corrected with the value in the [inoculum blank]) were 43.6, 46.7 and 41.4 mg, respectively. (Theoretical value = 50.3 mg)
The degradability based on the BOD after 28 days was calculated to be 92 %, 93 % and 82 % for the [sludge + test material] bottles, respectively.
The degradability based on the BOD after 7 and 14 days was calculated to be 88 % and 94 %, respectively, for the [sludge + aniline].

- Degradability based on the DOC
The DOC in the [water + test material] after 28 days was 0.6 mg, and the DOC in the [sludge + test material] bottles after 28 days (as corrected with the value in the [inoculum blank]) were all 0.6 mg. (Theoretical value = 15.5 mg).
The degradability based on the DOC after 28 days was calculated to be all 96% for the [sludge + test material] bottles.

- Degradability based on the residual test material amount
The residual amounts of test material in the [water + test material] after 28 days was 25.7 mg, and the residual amounts of the test material in the [sludge + test material] bottles were all < 0.3 mg. (Initial amount = 30.0 mg).
As the residual amount of the test material in the [water + test material] was less than 90 % of the initial amount, the disappearance rate was calculated instead of degradability.
The disappearance rates of the residual amount of the test material were calculated to be 14 % for the [water + test material] and all >99 % for the [sludge + test material] bottles.

In GC analysis of transformation product, no peak from transformation product was observed.

- Validity of the test
All of the validity criteria given on the guideline were fulfilled and hence the test was judged valid.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test material was readily biodegradable under the conditions of the study.

Executive summary:

The ready biodegradability of the test material was assessed in accordance with the standardised guideline Japanese notification, Yakushokuhatsu 0331 No. 7, Heisei 23.03.29 Seikoku No. 5, Kanpokihatsu No. 110331009, under GLP conditions.

During the study the test material was exposed to activated sludge in a closed system oxygen consumption measuring apparatus. The biochemical oxygen demand was measured over a 28 -day period. After this period, the amount of dissolved organic carbon (DOC) and the residual amount of test material were measured. The biodegradability of the test material was evaluated from these results.

According to the degradability to the degradability results on the BOD (av. 89 %), the DOC (av. 96 %) and the residual amount of test material (all > 99 %) after 28 days, it is concluded that the test material is readily biodegradable under the conditions of the test. In GC analysis of transformation product, no peak from transformation product was observed.

It was therefore concluded that the test material was readily biodegradable under the conditions of the study.

Description of key information

The test material was readily biodegradable under the conditions of the study.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of the test material was assessed in accordance with the standardised guideline Japanese notification, Yakushokuhatsu 0331 No. 7, Heisei 23.03.29 Seikoku No. 5, Kanpokihatsu No. 110331009, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

During the study the test material was exposed to activated sludge in a closed system oxygen consumption measuring apparatus. The biochemical oxygen demand was measured over a 28 -day period. After this period, the amount of dissolved organic carbon (DOC) and the residual amount of test material were measured. The biodegradability of the test material was evaluated from these results.

According to the degradability to the degradability results on the BOD (av. 89%), the DOC (av. 96%) and the residual amount of test material (all > 99%) after 28 days, it is concluded that the test material is readily biodegradable under the conditions of the test. In GC analysis of transformation product, no peak from transformation product was observed.

It was therefore concluded that the test material was readily biodegradable under the conditions of the study.