Reaction mass of 2-[2-(benzoyloxy)ethoxy]ethyl benzoate, 1-[2-(benzoyloxy)propoxy]propan-2-yl benzoate, and 2-[2-[2-(benzoyloxy)ethoxy]ethoxy]ethyl benzoate

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:

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

Guideline:

other: EEC Directive 87/302, Biodegradation - Activated sludge respiration test.

Deviations:

no

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

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.

Reference 2

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

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

Qualifier:

according to guideline

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.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 July 1997 - 22 July 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

Guideline:

other: EEC Directive 87/302, Biodegradation - Activated sludge respiration test.

Deviations:

no

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

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The results of a preliminary solubility test at 1, 10 and 100 mg/L showed that TEGDB was insufficiently soluble in water to allow the preparation of an aqueous stock solution so appropriate weights of the test material were deposited onto the inner walls of the test vessels from solutions in acetone. The acetone was evaporated in a stream of nitrogen before the addition of inoculated medium.

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

Post exposure observation period:

Following the exposure period, a well mixed sample of each mixture was transferred to a biochemical oxygen demand BOD bottle capacity 270 mL and its rate of oxygen consumption over a period of approximately ten minutes was measured using a Yellow Springs Instruments (YSI) dissolved oxygen meter with temperature probe and self stirring bottle probe connected to a chart recorder. The pH and temperature of the samples were measured at the start and end of the test.

Hardness:

200 -250 mg/L as CaCO3

Test temperature:

Preliminary test: 18.5 - 19.6°C
Main test: 19.8 - 20.2°C

pH:

Preliminary test: 7.3 - 8.0
Main test: 7.5 - 8.0

Nominal and measured concentrations:

Preliminary study: 1, 10 and 100 mg/L nominal
Main study: 100mg/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 no 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 9. 6 mg/L in the preliminary test and 8.3 mg/L in the main test

Validity criteria fulfilled:

yes

Conclusions:

TEGDB had no inhibitory effect on the respiration rate of activated sludge at any of the concentrations employed in the tests. The EC20, 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 TEGDB. The study was conducted in accordance with EC, OECD and US EPA test guidelines, and in compliance with GLP.

TEGDB had no inhibitory effect on the respiration rate of activated sludge at any of the 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.

Reference 4

Endpoint:

toxicity to microorganisms, other

Remarks:

Pseudomonas cell multiplication inhibition test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 August 1997 - 12 August 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study conducted to named International Test Guideline (but not to EU or OECD Test Guidelines), but details of the specific lot of test substance tested are not stated.

Qualifier:

according to guideline

Guideline:

other: German Water Hazard Classification Scheme (Bewertung Wassergefahrdender Stoffe LTWS - Nr 10)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: ISO 10712 "Determination of the inhibitory effect of water constituents on bacteria Pseudomonas cell multiplication inhibition test".

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

- Sampling method: After incubation

Vehicle:

yes

Details on test solutions:

CHECK
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: For the definitive test, 1.0 g of test substance was dispersed in acetone and the volume adjusted to 10 mL to give a 1.0 g/10 mL stock solution. An aliquot, 10 µL of this stock solution was dispersed in 100 mL of test culture medium to give the test concentration of 10 mg/L.
- Controls: Yes, water and vehicle controls

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture:
- Method of cultivation: Freeze dried cultures of Pseudomonas putida (strain NCIMB 8248) were obtained from the National Collections of Industrial and Marine Bacteria, Aberdeen, Scotland. Cultures and were maintained in the laboratory by routine sub-culturing onto fresh agar slopes approximately once per week.
- Preparation of inoculum for exposure: Approximately 22½ hours prior to commencing the test an aqueous suspension of Pseudomonas putida was produced by adding pre-culture medium to a stock culture of the bacterium and gently shaking in order to wash the bacterial cells off the solid medium. The resultant suspension was dispersed into a sterile flask plugged with sterile non-absorbent cotton wool and incubated at 25°C.
- Pretreatment: After the initial incubation period of approximately 22 hours the bacterial suspension was diluted using pre-culture medium to give a turbidity of approximately 100 Formazine Turbidity Units (FTU). An aliquot 50 mL of the 100 FTU bacterial suspension was added to 450 mL of pre-culture medium and incubated at 25°C. After incubation at 25°C for approximately 5 hours the bacterial suspension had a turbidity of approximately 50 FTU.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

16 h

Post exposure observation period:

After incubation the absorbance of each test and control culture was determined at 436 nm using a spectrophotometer.
Preliminary work conducted showed that the test material did not absorb light at the wavelength used to monitor bacterial growth, 436 nm.

Hardness:

Not reported

Test temperature:

25°C

pH:

Not reported

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

10 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: open (sterile cotton wool)
- Material, size, headspace, fill volume: Glass conical flask , 250 mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 10
- No. of vessels per vehicle control (replicates): 10

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10 mg/L
- Results used to determine the conditions for the definitive study: Yes

Reference substance (positive control):

no

Duration:

16 h

Dose descriptor:

EC10

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Duration:

16 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Key result

Duration:

16 h

Dose descriptor:

NOEC

Effect conc.:

>= 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Results with reference substance (positive control):

N/A

Reported statistics and error estimates:

A Students t test was carried out on the absorbance values after 16 hours exposure for the solvent control and 10 mg/I test concentration to determine any statistically significant differences between the test and solvent control groups.

There were no statistically significant differences between the solvent control and 10 mg/L test group and therefore the "No-Observed Effect Concentration" (NOEC) is given as >= 10 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The effect of TEGDB on the growth of Pseudomonas putida has been investigated and gave EC10 and EC50 values of greater than 10 mg/L. The "no-observed effect level" (NOEC) was >= 10 mg/L.

Executive summary:

A study was performed to assess the effect of TEGDB on the growth of the bacteria Pseudomonas putida. The method followed that described in the German Water Hazard Classification Scheme Bewertung Wassergefahrdender Stoffe LTWS Nr 10 and ISO 10712, and was conducted to GLP.

Exposure of Pseudomonas putida to TEGDB gave EC10 and EC50 values of greater than 10 mg/L . The "no-observed effect level" (NOEC) was >= 10 mg/L.

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

TEGDB

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

- Key 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

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), diethylene glycol dibenzoate (DEGDB) and triethylene glycol dibenzoate (TEGDB). No testing has been performed on the reaction mass itself but data are available for DPGDB, DEGDB and TEGDB individually. 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. TEGDB is less toxic with EC/EL/LL50 values in excess of 16 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 used in the chemical safety assessment is:

Toxicity to micro-organisms = > 100 mg/L

 

These values are from DEGDB, activated sludge respiration inhibition tests (ASRIT) performed on any 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.

TEGDB

Toxicity to microorganisms

In the ASRIT (HLS 1998, VCL286/973419) TEGDB 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, 1104/003), 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.