Indene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 October 2007 - 21 November 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Version / remarks:

17 July 1992

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Indene

EC Number:

202-393-6

EC Name:

Indene

Cas Number:

95-13-6

Molecular formula:

C9H8

IUPAC Name:

indene

Test material form:

not specified

Details on test material:

- Details on test material are confidential

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge: sludge was collected from 10 different locations in Japan (4 sewage treatment plants, 3 rivers, 1 lake and 2 bays) in September 2007.
- Method of collection from sewage plant: return sludge was collected. Method of collection from rivers, lake and sea: surface water and surface soil which was in contact with the atmosphere were collected.
- Method of cultivation: After ceasing aeration for approx. 30 minutes, supernatant of the sludge mixture corresponding to about 1/3 of the whole colume was removed. Dechlorinated water was added to the mixture so that the concentration of the synthetic sewage was 0.1% in the volume of dechlorinated water added. This procedure was repeated once every day at a temperature of 25±2°C
- Preparation of inoculum for exposure: the filtrate (5 L) of the supernatant of the activated sludge cultivated for 3 months was mixed with the mixed filtrate (5 L) of the supernatant of a sludge collected newly at each location. The mixed filtrate (10 L) was aerated with prefiltered open air after the pH value was adjusted to 7.0 +/- 1.0.
- Concentration of sludge: 3970 mg suspended solids/L

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

test mat. analysis

Remarks:

(HPLC)

Details on study design:

TEST CONDITIONS
- Composition of medium: according to OECD 301C
- Additional substrate: no
- Test temperature: 25±1°C
- pH: not measured due to volatility of the test item
- pH adjusted: no, only the pH of the initial inoculum was adjusted
- Aeration of dilution water: no
- Suspended solids concentration: 30 mg/L
- Continuous darkness: yes
- Other: each test solution was stirred with a magnetic stirrer

TEST SYSTEM
- Culturing apparatus: closed system oxygen consumption measuring apparatus
- Number of culture flasks/concentration: 3 bottles for the test item + sludge, 1 bottle for the other vessels (see below)
- Measuring equipment: automatic data sampler
- Test performed in closed vessels due to significant volatility of test substance: yes

SAMPLING
- Sampling frequency and method: BOD was measured automatically with a data sampler, HPLC was used at the end of the test to analyse the amount of test item left in the system.
- Other: appearance of the test solution was observed once a day

CONTROL AND BLANK SYSTEM
- Blank control: yes, mineral medium only (1 bottle)
- Abiotic control: yes, test item in water (1 bottle)
- Toxicity control: no
- Other: reference control (1 bottle, reference item in medium)

Reference substance

Reference substance:

aniline

Remarks:

(100 mg/L)

Results and discussion

% Degradation

% Degradation 1

Key result

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Remarks on result:

other: regarded as 0% because the calculated average value was calculated to be negative

% Degradation 2

Parameter:

% degradation (test mat. analysis)

Value:

1

Sampling time:

28 d

Details on results:

- Degradation percentages in individual bottles were -6, -6 and -4% (based on BOD) and 0, 1 and 1% (based on HPLC).

BOD5 / COD results

Results with reference substance:

Aniline was degraded for 75% after 14 days.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

See 'overall remarks'

Interpretation of results:

not readily biodegradable

Conclusions:

Based on a biodegradation study (MITI test), performed according to OECD guideline 301 C and GLP principles, no biodegradation of Indene was observed after a 28 day test duration.

Executive summary:

In a MITI test, performed according to OECD guideline 301 C and GLP principles, Indene was assessed for its biodegradation over a period of 28 days. Sludge was collected from ten different sites and inoculated for a period of 3 months. This inoculum was used to prepare the mineral medium for the study. The test item was tested in mineral medium containing sludge at a concentration of 100 mg/L in triplicate next to one replicate of test item in water, the reference item (aniline) in mineral medium and one control blank containing only mineral medium. During the test the amount of consumed oxygen was measured and at the end of the test period the amount of remaining test item was analysed by using HPLC. Based on the BOD the average % degradation was calculated to be 0% for the 3 replicates. Based on HPLC analysis, the average % degradation was calculated to be 1% for the 3 replicates. The acceptability criteria were met and the study was considered to be valid. Based on the results, Indene is considered to be not readily biodegradable.