Glycerides, C8-18 and C18-unsatd., reaction products with ethylene oxide and glycerol

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:

key study

Study period:

Started on 27th April 1993 and completed on 27th April 1993

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:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
- Eluate:
- Differential loading:
- Controls:
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc):

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: The aeration stage of the Severn Trent Water Plc sewage treatment plant at Belper, Derbyshire, treating predominantly domestic sewage.
- Preparation of inoculum for exposure: The sample was maintained at 21ºC with continuous aeration and used on the day of collection. The pH was equal to 6.7 and the suspended solids equal to 3.7 g/l prior to use.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Hardness:

Approximately 50 mg/L as CaCO3

Test temperature:

21 ºC

Nominal and measured concentrations:

Nominal concentration: 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 ml conical flasks
- Aeration: Compressed air via narrow bore glass tubes.
- No. of vessels per concentration (replicates): Three replicates
- No. of vessels per control (replicates): Two replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Laboratory tap water, dechlorinated by sodium thiosulphate and aged by recirculation through a gravel filter.

OTHER TEST CONDITIONS
- Photoperiod: Normal laboratory lighting

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : As each vessel reached 30 minutes contact time the contents were poured into the measuring vessel and the rate of respiration measured. The procedure was repeated after a 3-hour contact period.

Reference substance (positive control):

yes

Remarks:

(3,5-dichlorophenol at 3.2, 10 and 32 mg/L)

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Details on results:

Variation in respiration rates of controls 1 and 2: ±2%

Results with reference substance (positive control):

- Results with reference substance valid
- Relevant effect levels:
EC50 (30 minutes) = 16 mg/L
EC50 (3 hours) = 9 mg/L

Table 1: Oxygen consumption rates and percentage inhibition for 3 hour contact time

 

Concentration (mg/L)	O2 consumption rates (mg O2/L/min)	% inhibition
Control R1	0.67	-
Control R2	0.65	-
Test substance 1000 mg/L R1	0.63	5
Test substance 1000 mg/L R2	0.61	8
Test substance 1000 mg/L R3	0.61	8
Reference substance 3.2 mg/L	0.57	14
Reference substance 10 mg/L	0.28	58
Reference substance 32 mg/L	0.11	83

 

Validity criteria fulfilled:

yes

Remarks:

(the two control respiration rates are within 15% of each other; the results for the referene substance are in the accepted range).

Conclusions:

The EC50 (3-h) was greater than 1000 mg/L.

Executive summary:

This study describes the methods used and results obtained during a study to assess the inhibitory effect of the test substance on the respiration of activated sewage sludge. The method followed the OECD Guideline 209 and EU method C.11. At time "0" 16 ml of synthetic sewage was made up to 300 ml with water in a 500 ml conical flask. 200 ml inoculum were added and the mixture aerated at approximately 0.5-1 litre per rninute. Thereafter, at 15 minute intervals the procedure was repeated wit h appropriate amounts of the test or reference material being added. As each vessel reached 30 minutes contact time the contents were poured into the measuring vessel and the rate of respiration rneasured. The procedure was repeated after a 3-hour contact period. The EC50 (3-h) for the test material was greater than 1000 mg/L.

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

From 16th April 1996 to 17th July 1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Standard national method. GLP study

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Source: German collection of micro-organisms (D-38124 Braunschweigh, FRG)
- Laboratory culture:
- Method of cultivation:
- Preparation of inoculum for exposure:
- Pretreatment:
- Initial biomass concentration:

Test type:

static

Total exposure duration:

16 h

Test temperature:

21 ± 1 ºC

Nominal and measured concentrations:

Nominal concentrations:
Experiment 1: 0.04, 0.08, 0.16, 0.31, 0.63, 1.25, 2.5, 5.0 and 8.0 g/L
Experiment 2: 4.2, 8.4, 16.9, 33.8, 67.5, 135.0, 270.0, 540.0 and 864.0 g/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 ml Erlenmeyer
- No. of vessels per concentration (replicates): Three replicates

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Cell density: The absorption of the bacterial suspension was determined at 436 nm.

Reference substance (positive control):

no

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

50.6 g/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Conclusions:

An inhibition of 50 % (EC 50) was reached at a concentration of 50.6 g/L. In conclusion it can be stated that the test article did not inhibit bacterial proliferation under the conditions described and within the limits of the test system used up to a concentration of 10 g/L. This concentration is recommended as the upper limit when testing potentially water hazardous materials. At higher concentrations a dose dependent inhibition of bacterial proliferation occurred.

Executive summary:

This study was performed to assess the potential of the test article to inhibit the reproduction of Pseudomonas putida. Two experiments were performed since no inhibition of bacterial growth was detected in the concentration range of the first experiment.

Each concentration was tested in triplicate and the controls fivefold. The test article was tested at the following concentrations:

Experiment 1: 0.04, 0.08, 0.16, 0.31, 0.63, 1.25, 2.5, 5.0 and 8.0 g/L

Experiment 2: 4.2, 8.4, 16.9, 33.8, 67.5, 135.0, 270.0, 540.0 and 864.0 g/L

Growth reduction of the bacteria was observed at concentrations above 10 g/L.

An inhibition of 50 % (EC 50) was reached at a concentration of 50.6 g/L.

An inhibition of 10 % (EC 10) was reached at a concentration of 17.0 g/L.

In conclusion it can be stated that the test article did not inhibit bacterial proliferation under the conditions described and within the limits of the test system used up to a concentration of 10 g/L. This concentration is recommended as the upper limit when testing potentially water hazardous materials. At higher concentrations a dose dependent inhibition of bacterial proliferation occurred.

Description of key information

Key study: Experimental results: OECD guideline 209 and EU method C.11. GLP study.
The EC50 (3-h) was greater than 1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

Key study: Experimental results: OECD guideline 209 and EU method C.11. GLP study.

The EC50 (3-h) was greater than 1000 mg/L.