Hydroquinone

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Microcystis aeruginosa

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

8 d

Test temperature:

27°C

Details on test conditions:

TEST SYSTEM
- Test vessel: 10 mL tubes
- Type (delete if not applicable): culture tubes were stoppered with cotton-lined metal caps
- Material, size, headspace, fill volume: glass/10 mL/0/10 mL
- Aeration: not reported
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 12

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: bistilled water supplemented with nutrient solution (sterile conditions)
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continuous lighting
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : cell multiplication inhibition

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: not reported

Duration:

8 d

Dose descriptor:

other: TT (toxicity threshold)=EC3

Effect conc.:

1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration. A 8 d TT (EC3)=1 mg/L nominal was found.

Validity criteria fulfilled:

not applicable

Conclusions:

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration. A 8 d TT (EC3)=1 mg/L nominal was found.

Executive summary:

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration. The cultures of M. aeruginosa were exposed to hydroquinone for 8 d under static conditions. The concentration of the algal suspension was determined turbidimetrically. A 8 d TT (EC3)=1 mg/L nominal was found.

This study is regarded as reliable with restrictions.

Results Synopsis
Test organism: Microcystis aeruginosa

Test Type: static
8 d TT (EC3): 1 mg/L (nominal)

Endpoint(s) Effected: cell multiplication

Reference 2

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. The concentration of the bacterial suspension was measured turbidimetrically.

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: yes
- Method of cultivation: Stock cultures were kept on nutrient in agar slant tubes. New stock cultures were prepared every week. The stock cultures were inoculated at 25°C for 24 h. Preliminary cultures were prepared from stock cultures and the cell material was washed of with sterile saline.
- Preparation of inoculum for exposure: The extinction of the bacterial suspension was adjusted with saline to the extinction value of a Formazin standard suspension TE/F/436 nm=10
- Pretreatment: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Test temperature:

25°C

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flasks
- Type (delete if not applicable): test vessels were sealed with cotton-lined plastic caps
- Material, size, headspace, fill volume: glass/300 mL/200 mL/100 mL
- Aeration: not reported
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Sterile double-distilled water supplemented with nutrient medium
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Adjustment of pH: not reported
- Photoperiod: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): cell multiplication inhibition

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Duration:

16 h

Dose descriptor:

other: TT (toxicity threshold)=EC3

Effect conc.:

58 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. The concentration of the bacterial suspension was measured turbidimetrically. A 16 h TT (EC3)=58 mg/L nominal was obtained.

Validity criteria fulfilled:

not applicable

Conclusions:

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. A 16 h TT (EC3)=58 mg/L nominal was obtained.

Executive summary:

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. The cultures were inoculated at 25°C for 16 h under static conditions. The concentration of the bacterial suspension was measured turbidimetrically. A 16 h TT (EC3)=58 mg/L nominal was obtained.

This study is regarded as reliable with restrictions.

Results Synopsis
Test organism: Pseudomonas putida

Test Type: static
16 h TT (EC3): 58 mg/L (nominal)

Endpoint(s) Effected: cell multiplication

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

The respiration inhibition of activated sludge was investigated using a scanning respirometer. A luminescence-based scanning respirometer, using a ruthenium (II) complex as the oxygen-sensing element, was employed to monitor the toxicity of phenolic chemicals to activated sludge. The ruthenium (II) complex was irradiated with an excitation light source and the resulting light emission was then sensed and transmitted by an optical fiber connected to a photomultipler tube. The light intensities sensed at a specific wavelength could be related to the dissolved oxygen concentrations in the samples.

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution (500 or 5000 mg/L; not specified for hydroquinone) was prepared by dissolving the test chemical in distilled-deionized water.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): no vehicle used
- Evidence of undissolved material (e.g. precipitate, surface film, etc):not reported

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Laboratory culture: no
- Preparation of inoculum for exposure: Activated sludge was collected at a wwtp treating predominantly domestic sewage. On return to the laboratory, the sludge was allowed to settle and the waste liquor was discarded. The concentrated sludge was stored at 4°C and aerated occassionally. In each run of experiment, 1 mL of concentrated sludge was mixed with 100 mL deionized water and 2 mL of sodium acetate, which was used as exogenous substance to ensure that the microorganisms were respiring, growing and dividing rapidly when exposed to the potential inhibitor. The resulting sample solution was then aerated for about 2 h at 20°C before conducting the toxicity tests. The concentration of suspended solids in the sample solution was ca. 300 mg/L.
- Pretreatment: no
- Initial biomass concentration: ca. 300 mg/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

2 h

Test temperature:

20 +/- 1°C

pH:

7.0 +/- 0.1

Nominal and measured concentrations:

not reported

Details on test conditions:

TEST SYSTEM
- Test vessel: vial
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: not reported
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionized water and 10% w/w sodium acetate

OTHER TEST CONDITIONS
- Adjustment of pH: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : respiration inhibition

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not reported

Duration:

2 h

Dose descriptor:

IC50

Effect conc.:

71 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

The respiration inhibition of activated sludge was investigated using a scanning respirometer. A luminescence-based scanning respirometer, using a ruthenium (II) complex as the oxygen-sensing element, was employed to monitor the toxicity of phenolic chemicals to activated sludge. The ruthenium (II) complex was irradiated with an excitation light source and the resulting light emission was then sensed and transmitted by an optical fiber connected to a photomultipler tube. The light intensities sensed at a specific wavelength could be related to the dissolved oxygen concentrations in the samples. The 2 h IC50 was determined to be 71 mg/L (nominal).

Validity criteria fulfilled:

not applicable

Conclusions:

The respiration inhibition of activated sludge was investigated using a scanning respirometer. The 2 h IC50 was determined to be 71 mg/L (nominal).

Executive summary:

The respiration inhibition of activated sludge was investigated using a scanning respirometer. A luminescence-based scanning respirometer, using a ruthenium (II) complex as the oxygen-sensing element, was employed to monitor the toxicity of phenolic chemicals to activated sludge. The ruthenium (II) complex was irradiated with an excitation light source and the resulting light emission was then sensed and transmitted by an optical fiber connected to a photomultipler tube. The light intensities sensed at a specific wavelength could be related to the dissolved oxygen concentrations in the samples. The 2 h IC50 was determined to be 71 mg/L (nominal).

This study is regarded as reliable with restrictions.

Results Synopsis
Test organism/age: activated sludge treating predominantly domestic sewage

Test Type: static
2 h IC50: 71 mg/L (nominal)

Endpoint(s) Effected: respiration inhibition

Description of key information

The respiration inhibition of activated sludge was investigated using a scanning respirometer. The 2 h IC50 was determined to be 71 mg/L (nominal). The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. A 16 h TT (EC3)=58 mg/L nominal was obtained.

Key value for chemical safety assessment

EC50 for microorganisms:

71 mg/L

EC10 or NOEC for microorganisms:

58 mg/L

Additional information

The respiration inhibition of activated sludge was investigated using a scanning respirometer. A luminescence-based scanning respirometer, using a ruthenium (II) complex as the oxygen-sensing element, was employed to monitor the toxicity of phenolic chemicals to activated sludge. The ruthenium (II) complex was irradiated with an excitation light source and the resulting light emission was then sensed and transmitted by an optical fiber connected to a photomultipler tube. The light intensities sensed at a specific wavelength could be related to the dissolved oxygen concentrations in the samples. The 2 h IC50 was determined to be 71 mg/L (nominal).

The toxicity of hydroquinone to Pseudomonas putida was determined by measuring the cell multiplication inhibition. The cultures were inoculated at 25°C for 16 h under static conditions. The concentration of the bacterial suspension was measured turbidimetrically. A 16 h TT (EC3)=58 mg/L nominal was obtained.

The toxicity of hydroquinone to Microcystis aeruginosa was investigated by determining the cell multiplication inhibition threshold concentration. The cultures of M. aeruginosa were exposed to hydroquinone for 8 d under static conditions. The concentration of the algal suspension was determined turbidimetrically. A 8 d TT (EC3)=1 mg/L nominal was found.