Reaction mass of glycerol, glycerol 1-formate, glycerol 2-formate, glycerol 1,2-diformate, glycerol 1,3-diformate and glycerol triformate

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

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 (Carbon and Ammonium Oxidation))

Version / remarks:

2010

GLP compliance:

yes

Specific details on test material used for the study:

Purity: 100%

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: test concentrations were prepared by direct addition and stock dilution

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Cambridge Sewage Treatment Works, Cowley Road, Cambridge
- Initial biomass concentration: 3.75 g/L (dry weight) on day of collection; 1.5 g/L (dry weight) for testing

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.9 - 22.3 °C

Nominal and measured concentrations:

3.33, 33.33, 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL conical flasks
- Aeration: continually aerated for 3 hours
- No. of vessels per concentration (replicates): 1 for 2.22 and 33.33 mg/L and 3 for 1000 mg/L
- No. of vessels per control (replicates): 2
- No. of vessels per abiotic control (replicates): 3
- Sludge concentration (weight of dry solids per volume): 1.50 g/L
EFFECT PARAMETERS MEASURED: Dissolved oxygen for 10 minutes following 3 hour exposure

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- The mean blank respiration rate for this study was 23.08 mg oxygen/g dry weight activated sludge/hour.
- The coefficient of variation for oxygen uptake in the control replicates for this study was 19.15%.

Results with reference substance (positive control):

In this study the EC50 of the 3,5-dichlorophenol was 2.84 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The 3 hour EC50 value of the test substance was determined to be > 1000 mg/L.

Executive summary:

The activated sludge respiration inhibition of the test substance was assessed according to OECD 209 under GLP conditions.

The test substance did not cause any significant effects on activated sludge respiration inhibition at the concentrations tested, up to and including 1000 mg/L. The results of the abiotic control flask (test without addition of inocula) indicated that there would be no reduction in oxygen concentration in any of the test vessels up to, and including, 1000 mg/L of the test substance, attributable to processes in the test system other than those due to the activity of the activated sludge. The 3 hour EC50 value of the test substance was determined to be >1000 mg/L.

Description of key information

The activated sludge respiration inhibition of the test substance was assessed according to OECD 209 under GLP conditions.

The test substance did not cause any significant effects on activated sludge respiration inhibition at the concentrations tested, up to and including 1000 mg/L. The results of the abiotic control flask (test without addition of inocula) indicated that there would be no reduction in oxygen concentration in any of the test vessels up to, and including, 1000 mg/L of the test substance, attributable to processes in the test system other than those due to the activity of the activated sludge. The 3 hour EC50 value of the test substance was determined to be >1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L