Rape oil, oxidized

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

July 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Not GLP, according to standard test method, but not in agreement with OECD 209.

Qualifier:

according to guideline

Guideline:

other: ROBRA test

Deviations:

no

Principles of method if other than guideline:

Pseudomonas putida cultures are exposed to the test substance for a period of 30 min to 3 hours. The oxygen consumption (in terms of mg/L/hour) is then measured and compared to that of the control. The percentage inhibition of the oxygen consumption is measured and EC values are estimated.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

- Concentrations: 20000, 30000, 40000, 50000, 60000, 80000 and 100000 mg/L
- Sampling method: not relevant, during this test the oxygen consumption is measured using e.g. an oxygen electrode
- Sample storage conditions before analysis: not relevant

Vehicle:

yes

Details on test solutions:

The test solutions were prepared using an emulsifying agent: Laurylmyristylalcoholethoxylate 7 E.O.

Test organisms (species):

Pseudomonas putida

Details on inoculum:

no data

Test type:

static

Water media type:

not specified

Limit test:

no

Remarks on exposure duration:

no data, the guideline prescribes a period of 30 min to 3 hours

Post exposure observation period:

not relevant

Hardness:

not relevant

Test temperature:

no data

pH:

no data

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

Nominal concentrations were 20000, 30000, 40000, 50000, 60000, 80000 and 100000 mg/L. The concentrations were not verified by chemical analysis.

Details on test conditions:

TEST SYSTEM
- Test vessel: no data
- Type (delete if not applicable): no data
- Material, size, headspace, fill volume: no data
- Aeration: no data
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- No. of organisms per vessel: no data
- No. of vessels per concentration (replicates): one
- No. of vessels per control (replicates): one (if performed; not reported which type of control was used)
- No. of vessels per vehicle control (replicates): one (if performed; not reported which type of control was used)
- Biomass loading rate: no data

TEST MEDIUM / WATER PARAMETERS: no data

OTHER TEST CONDITIONS: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : oxygen consumption was measured, the inhibition of oxygen consumption was calculated and the EC10 was determined

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.25-1.5
- Justification for using less concentrations than requested by guideline: not relevant
- Range finding study: no data

Reference substance (positive control):

no

Dose descriptor:

EC0

Effect conc.:

30 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Dose descriptor:

EC10

Effect conc.:

37 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Dose descriptor:

EC50

Effect conc.:

54 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: EC50 not reported; estimated by the author of this summary from the reported graph of % inhibition versus test concentration

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no data
- Effect concentrations exceeding solubility of substance in test medium: yes, because the solubility of the test material in water is <1 mg/L. However, an emulsifying agent was used and the guideline prescribes that the test solutions are aerated during the test, which enhances mixing.

The information on test results was confined to the following: at 20000, 30000, 40000, 50000, 60000, 80000 and 100000 mg/L, respectively, the percentage inhibition was 0%, 0%, 18%, 62%, 70% and 72%.

Validity criteria fulfilled:

not specified

Conclusions:

Single species test with Pseudomonas putida: EC10 based on oxygen consumption 37000 mg/L.

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04-mar-2010 to 19-mar-2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

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

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

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)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The batch of Blown rapeseed oil tested was a yellow to brown viscous liquid and 100% pure.
Since Blown rapeseed oil was hardly soluble in water test concentrations were prepared separately in Milli-RO water. 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 dark glass closed bottles for 25 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 time.

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 (4.0 g/l of sludge, as used for the test). The pH was 7.9 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.

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 after the 3 hours exposure period.

Test temperature:

Between 18.9 and 19.9°C.

pH:

Controls: 7.7
Blown rapeseed oil: 7.5 - 7.6

Dissolved oxygen:

Oxygen consumption:
Control series: 67-68 mg O2/l/h
Blown rapeseed oil series: 65-72 mg O2/l/h
Control series, the oxygen concentration at the start of the measurments was at least 6.8 mg/l
Blown rapeseed oil series: the oxygen concentration at the start of the measurments was 3.9 and 7.2 mg/l , for the duplicate measurements.

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 (measuring) and
1 litre test bottles(exposure)
- Aeration:During exposure with clean, oil-free air
- No. of vessels per concentration (replicates):2
- No. of vessels per control (replicates):2/ series
- Biomass loading rate: 1.6 g/l suspended solids 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
- Test concentrations: limit study at 100 mg/l

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Milli-RO water (tap water purified by reverse osmosis; Millipore Corp., Bedford, Mass., USA).

OTHER TEST CONDITIONS
- Adjustment of pH: no

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Key result

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

100 other: mg/l (loading rate)

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: mg/l (loading rate)

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

No significant inhibition of respiration rate of the sludge was recorded at a loading rate of 100 mg Blown rapeseed oil per litre. The duplicate measurement confirmed the result of the first measurement. Therefore, no further testing was needed. Hence, the EC50 of Blown rapeseed oil exceeded a loading rate of 100 mg/l.

Results with reference substance (positive control):

Results with reference substance valid: yes.
The inhibitory effect of 3,5-dichlorophenol on aerobic waste water (activated sludge) bacteria increased with increased with increasing concentration , ranging from a 43 % inhibition at 5,0 mg/l to 87% at 30 mg/l.
Relevant effects levels: The EC50 of 3,5-dichlorophenol was: 6.0 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 Blown rapeseed oil no EC50 could be calculated because the test substance proved to be non-toxic (EC50 > 100 mg/l).

Validity criteria fulfilled:

yes

Conclusions:

Blown rapeseed oil was not toxic to waste water (activated sludge) bacteria at a loading rate of 100 mg/l. The 3-hour EC50 of Blown rapeseed oil exceeded a loading rate of 100 mg/l.

Description of key information

In the respiration inhibition test (OECD 209), a NOEC of 100 mg/L was found.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

100 mg/L