Linseed oil, polymerized

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 March 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

Linseed oil, polymerized

EC Number:

614-114-9

Cas Number:

67746-08-1

Molecular formula:

Not applicable for UVCB

IUPAC Name:

Linseed oil, polymerized

Details on test material:

- Name of test material (as cited in study report): Standolized linseed oil
- Substance type: Hazy yellow/brown viscous liquid
- Physical state: liquid
- Analytical purity: treated as 100% pure
- Lot/batch No.: 09.317.013
- Expiration date of the lot/batch: 21 December 2010
- Stability under test conditions: stable
- Storage condition of test material: At room temperature in the dark
- Other: -

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

Since Standolized linseed oil was hardly soluble in water test concentrations were prepared separately in Milli-RO water (tap water purified by reverse osmosis; Millipore Corp., Bedford, Mass., USA). Two 1 litre test bottles were filled with 250 ml of test substance mixtures with initial loading rates of 200 mg/l. These mixtures were stirred in closed bottles for 24 hours.
Subsequently, 16 ml synthetic sewage feed, 200 ml sludge and Milli-RO water up to 500 ml were added resulting in a loading rate of 100 mg/l . Optimal contact between the test substance and test organisms was ensured applying continuous aeration and stirring during the 3-hour exposure period.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

The sludge was coarsely sieved, washed and diluted with ISO-medium. A small amount of the sludge was weighed and dried overnight at ca. 105°C to determine the amount of suspended solids (4.2 g/l of sludge, as used for the test). The pH was 8.0 on the day of testing. The batch of sludge was used one day after collection; therefore 50 ml of synthetic sewage feed was added per litre of activated sludge at the end of the collection day. The sludge was kept aerated at test temperature until use.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Post exposure observation period:

Oxygen consumption was measured and recorded for approximately 10 minutes afther the 3-hour exposure period.

Test conditions

Test temperature:

between 19.9 and 20.1°C.

pH:

8.3 - 8.4

Dissolved oxygen:

Oxygen consumption:
Controls: 62 - 64 mg O2/l/h
Standolized linseed oil: 63 mg O2/l/h
The oxygen concentration at the start of measurents was at least 4.2 mg O2/l.

Nominal and measured concentrations:

Loading rate of 100 mg/l

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): open
- Material, size, headspace, fill volume:All glass, approximately 300 ml oxygen bottles and 1 litre test bottles.
- Aeration: During exposure with clean, oil-free air.
- No. of vessels per concentration (replicates):2
- No. of vessels per control (replicates):2
- Biomass loading rate: 1.7 g/l suspenden solid in final test mixture.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap-water purified by reverse osmosis (Milli-RO)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
The respiration rate from each vessel, in mg O2/l/hr, was calculated from the linear part of the respiration curve, which was generally between 2.5 and 6.5 mg O2/l.

TEST CONCENTRATIONS
-limit test at a loading of 100 mg/l.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

No inhibition of respiration rate of the sludge was recorded at a loading rate of 100 mg Standolized linseed oil per litre. The duplicate measurement confirmed the result of the first measurement. Therefore, no further testing was needed.

Results with reference substance (positive control):

The EC50 of 3,5-dichlorophenol was in the accepted range of 5-30 mg/l (9.8 mg/l)

Reported statistics and error estimates:

For the reference substance the percentage inhibition was plotted against the logarithm of the concentrations and the EC50 was determined using linear regression analysis.
For Standolized linseed oil no EC50 could be calculated because the test substance proved to be non-toxic (EC50 > 100 mg/l).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this present test, Standolized linseed oil was not toxic to waste water (activated sludge) bacteria at a loading rate of 100 mg/l. The 3-hour EC50 of Standolized linseed oil exceeded a loading rate of 100 mg/l.