Oligomerisation products of ethylene oxide with reaction products of rape oil and ethanolamine

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 20 September 2007 to 27 September 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

An amount of reference material (160 mg) was dissoled in water with the aid of ultrasonication for approximately 20 minutes and the volume adjusted to 1litre to give a 160 mg/L stock solution. Aliquots (10 and 100 ml) of the 160 mg/L stock solution were removed and dispersed with activated sewage sludge and water to give the final concentrations of 3.2 and 32 mg/L. the volumetric flask containing the reference material was inverted several time to ensure homogeneity of the solution.

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: Loughborough, Leicestershire, UK

Test type:

not specified

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Hardness:

140 mg/L as CaCO3

Test temperature:

21ºC

pH:

Maximum 8.7

Dissolved oxygen:

initial O2 Reading: 8.7 mg O2/L
O2 Consumption Rates: 0.53 mg O2/L/min

Details on test conditions:

TEST SYSTEM
An amount of test material (2000 mg) was dispersed in water with the aid of ultrasonication for approximately 15 minutes and the volume adjusted to 1 litre to give a 2000 mg/L stock dispersion. An aliquot (250 mL) of this stock dispersion was dispersed with synthetic sewage (16 ml), activated sewage sludge (200ml) and water, to a final volume of 500 ml, to give the required concentration 1000 mg/l. The volume flask contained the stock dispersion was inverted several times to ensure homogeneity of the stock dispersion.

This method of preparation was performed for the three separate replicate test vessels.

Synthetic Sewage:
Peptone: 16 g
Meat extract: 11 g
Urea: 3 g
NaCl: 0.7 g
CaCl2.2H20: 0.4 g
MgSO4.7H2O: 0.2 g
K2HPO4: 2.8 g

dissolved in 1L of water with the aid of ultrasonication

Reference substance (positive control):

yes

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Duration:

30 min

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Duration:

30 min

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Remarks on result:

other: 7.0-11 mg/L

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Results with reference substance (positive control):

EC 50 (3 hours)= 8.9 mg/L

	ECx (30 minutes) (mg/L)	95% Confidence Limits (mg/L)	ECx (30 minutes) (mg/L)	95% Confidence Limits (mg/L)
EC20	>1000	-	>1000	-
EC50	>1000	-	>1000	-
EC80	>1000	-	>1000	-
NOEC	1000	-	1000	-

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test material on the respiration sewage sludge micro-organisms gave a 3-Hour EC50 of greater than 1000 mg/L. The NOEC after 3 hours exposure was 1000 mg/L

Executive summary:

A study was performed to assess the effect of the test material on the respiration of activated sewage sludge. The method followed that described in the OECD 209.

Following a preliminary range-finding test, activated sewage sludge was exposed to an aqueous dispersion of the test material at a concentration of 1000 mg/L (three replicates flasks) for a period of 3 hours at a temperature of approximately 21ºC with the addition of a synthetic sewage as a respiratory substance.

The rate of respiration was determined after 30 minutes and 3 hours contact time and compared to data for the control and a reference material, 3,5 -dichlorophenol.

The effect of the test material on the respiration of activated sewage sludge gave a 3 -Hours EC50 of greater than 1000 mg/L. NOEC after 3 hours exposure was 1000 mg/L.

It was considered unnecessary and unrealistic to test at concentration in excess of 1000 mg/L.

The reference material gave a 3 -Hour EC50 value of 8.9 mg/L, 95% confidence limits 7.0 -11 mg/L.

Description of key information

A study was performed to assess the effect of the test material on the respiration of activated sewage sludge. The method followed that described in the OECD 209.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The effect of the test material on the respiration of activated sewage sludge gave a 3 -Hours EC50 of greater than 1000 mg/L. NOEC after 3 hours exposure was 1000 mg/L.

It was considered unnecessary and unrealistic to test at concentration in excess of 1000 mg/L.