Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 04 April 1997 (Preliminary test).
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in accordance with EC, OECD, and US EPA test guidelines, and in compliance with GLP.
Qualifier:
according to
Guideline:
other: EEC Directive 87/302, Biodegradation - Activated sludge respiration test.
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test item was added directly to test vessles containing carbon filtered tap water. The mixtures were treated with ultra-sound for 10 minutes, and shaken for 10 minutes before the addition of synthetic sewage and the microbial inoculum.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Laboratory culture: Maintained under aerobic conditions until required.
- Preparation of inoculum for exposure: Aliquots (25 mL) of the activated sludge were filtered through dried and preweighed filter papers which were dried again at 110°C for at least one hour, allowed to cool in a dessicator and reweighed. The mixed liquor suspended solids (MLSS) content of the activated sludge was then calculated. Synthetic sewage (50 mL/L) was added and the mixture aerated overnight. On the day of the test, the MLSS content was determined and adjusted to 4 g/L by the addition of dechlorinated tap water. The pH of the activated sludge was measured after its MLSS content had been adjusted to 4 g/L.
- Initial biomass concentration: 4 g/L.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
3 h
Hardness:
200 - 250 mg CaCO3/L
Test temperature:
Preliminary test: 18.4 - 19.7°C.
Main test: 19.0 - 20.6°C.
pH:
Preliminary test: 7.8 - 8.3
Main test: 7.8 - 8.3
Nominal and measured concentrations:
Preliminary test: 1, 10, and 100 mg/L nominal
Main test: 100 mg/L (in triplicate) nominal.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: One-litre glass beaker, 500 mL fill volume
- Aeration: Aerated throughout the exposure period using a pasteur pipette connected to a laboratory supply of oil-free compressed air.

- No. of vessels per concentration (replicates): One during preliminary test, three in main test
- No. of vessels per control (replicates): Two
- Biomass loading rate: 4 g/L

OTHER TEST CONDITIONS
- Adjustment of pH: pH was measured, but not reference to adjustment was made.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Biochemical oxygen demand.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not applicable - main test used a single (limit) concentration only.
- Range finding study
- Test concentrations: 1, 10, and 100 mg/L nominal
- Results used to determine the conditions for the definitive study:Yes
Reference substance (positive control):
yes
Remarks:
3,5-DCP
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
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- Relevant effect levels: Tested at 3.0, 10, and 32.0 mg/L; 3-hour 50% effect concentrations were found to be 14.5 mg/L in the preliminary test and 19.0 mg/L in the main test.
- Other:
Validity criteria fulfilled:
yes
Conclusions:
DEGDB had no significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the tests. The EC20 and EC50 of the test material could not therefore be calculated but these must be greater than 100 mg/L the highest tested level.
Executive summary:

An activated sludge respiration inhibition test was conducted to determine the effect on sewage micro-organisms of the test material DEGDB. The study was conducted in accordance with EC, OECD, and US EPA test guidelines, and in compliance with GLP.

DEGDB had no significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the tests. The EC20 and EC50 of the test material could not therefore be calculated but these must be greater than 100 mg/L, the highest tested level.

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
4 April 1997 - 10 April 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in accordance with EC, OECD, and US EPA test guidelines, and in compliance with GLP.
Qualifier:
according to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.6800 (Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble Chemicals)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test item was added directly to test vessels containing carbon filtered tap water. The mixtures were treated with ultra-sound for 10 minutes, and shaken for 10 minutes before the addition of synthetic sewage and the microbial inoculum.
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Laboratory culture: Maintained under aerobic conditions until required.
- Preparation of inoculum for exposure: Aliquots (25 mL) of the activated sludge were filtered through dried and preweighed filter papers which were dried again at 110°C for at least one hour, allowed to cool in a desiccator and reweighed. The mixed liquor suspended solids (MLSS) content of the activated sludge was then calculated. Synthetic sewage (50 mL/L) was added and the mixture aerated overnight. On the day of the test, the MLSS content was determined and adjusted to 4 g/L by the addition of dechlorinated tap water. The pH of the activated sludge was measured after its MLSS content had been adjusted to 4 g/L.
- Initial biomass concentration: 4 g/L.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Hardness:
200-250 mg/L CaCO3
Test temperature:
18.4 to 20°C preliminary test
19.0 to 20.9°C main test
pH:
7.7 to 8.3 preliminary test
7.8 to 8.3 main test
Nominal and measured concentrations:
Preliminary test: 1, 10, and 100 mg/L nominal
Main test: 100 mg/L (in triplicate) nominal.
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: One-litre glass beaker, 500 mL fill volume
- Aeration: Aerated throughout the exposure period using a pasteur pipette connected to a laboratory supply of oil-free compressed air.
- No. of vessels per concentration (replicates): One during preliminary test, three in main test
- No. of vessels per control (replicates): Two
- Biomass loading rate: 4 g/L

OTHER TEST CONDITIONS
- Adjustment of pH: pH was measured, but not reference to adjustment was made.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Biochemical oxygen demand.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Not applicable - main test used a single (limit) concentration only.
- Range finding study
- Test concentrations: 1, 10, and 100 mg/L nominal
- Results used to determine the conditions for the definitive study: Yes
Reference substance (positive control):
yes
Remarks:
3,5 Dichlorophenol
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- Relevant effect levels: Tested at 3.0, 10, and 32.0 mg/L; 3-hour 50% effect concentrations were found to be 14.5 mg/L in the preliminary test and 19.0 mg/L in the main test.
Validity criteria fulfilled:
yes
Conclusions:
DPGDB had no inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the test.
The EC20, EC50 and EC80 of the test material could not therefore be calculated but these must be greater than a nominal concentration of 100 mg/L, the highest tested level.
Executive summary:

An activated sludge respiration inhibition test was conducted to determine the effect on sewage micro-organisms of the test material DPGDB. The study was conducted in accordance with EC, OECD, and US EPA test guidelines, and in compliance with GLP.

DPGDB had no inhibitory effect on the respiration rate of activated sludge at any ofthe concentrations employed in the test.

The EC20 and EC50 of the test material could not therefore be calculated but these must be greater than 100 mg/L, the highest tested level.

Description of key information

DEGDB:

Toxicity to microorganisms:

- Key study, reliabiltiy 1, OECD 209, activated sludge of a predominantly domestic sewage - EC50 (3 h) > 100 mg/L and NOEC (3 h) >= 100 mg/L

- Supporting study, reliability 2, ISO 10712 Determination of the inhibitory effect of water constituents on bacteria Pseudomonas cell multiplication inhibition test, Pseudomonas putida - EC10 and EC50 > 10 mg/L, NOEC >= 10 mg/L

DPGDB:

Toxicity to microorganisms:

- Key study, reliabiltiy 1, OECD 209, activated sludge of a predominantly domestic sewage - EC50 (3 h) > 100 mg/L and NOEC (3 h) >= 100 mg/L

- Supporting study, reliability 1, ISO 10712 Determination of the inhibitory effect of water constituents on bacteria Pseudomonas cell multiplication inhibition test, Pseudomonas putida - EC10 and EC50 > 10 mg/L, NOEC >= 10 mg/L

Key value for chemical safety assessment

EC50 for microorganisms:
100 mg/L
EC10 or NOEC for microorganisms:
100 mg/L

Additional information

This substance is a reaction mass of dipropylene glycol dibenzoate (DPGDB) and diethylene glycol dibenzoate (DEGDB). No testing has been performed on the reaction mass itself but data are available for DPGDB and DEGDB indivudually. All the studies were performed according to international test guidelines and in compliance with GLP. They are presented below, by component.

For each component an ASRIT study was performed to determine the effect on sewage micro-organisms. A second study on each component was also conducted to assess the effect on the growth of the bacteria Pseudomonas putida. These latter studies followed the method described in the German Water Hazard Classification Scheme, Bewertung Wassergefahrdender Stoffe LTWS Nr 10 and ISO 10712.

These data demonstrate that DPDGB and DEGDB have similar environmental profiles with all EC/EL/LC/LL50 values in the range of >1.0 mg/L and <20 mg/L.

The most sensitive endpoint result obtained for these components has been used as the key value to evaluate hazard and is highlighted below. Where no data exist an overall statement that applies to the reaction mass has been made. No further testing is proposed.

The key value is:

Toxicity to microorganisms EC50 = > 100 mg/L

 

These values are from DEGDB and DPGDB, toxicity to microorganisms performed on both of the components.

 

DEGDB

Toxicity to microorganisms

In the ASRIT (HLS 1998, VCL245/970386) DEGDB had no significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the tests. The NOEC was >=100 mg/L, the highest tested level.

In the study on the bacteria Pseudomonas putida (Safepharm 1998, 1104/002), which supports the results from the ASRIT, EC10 and EC50 values of greater than 10 mg/L were obtained. The NOEC was >= 10 mg/L.

DPGDB

Toxicity to microorganisms

In the ASRIT (HLS 1998, VCL235/970385) DPGDB had no significant inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the tests. The NOEC was >=100 mg/L, the highest tested level.

In the study on the bacteria Pseudomonas putida (Safepharm 1998, 1104/001), which supports the results from the ASRIT, EC10 and EC50 values of greater than 10 mg/L were obtained. The NOEC was >= 10 mg/L.