Hydroquinone

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

study conducted comparable to national standard methods without analytical monitoring using daphnia culture issued from a wild population.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted comparable to the German DIN 38412, Part II

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution was prepared by dissolving the test compound in tap water. The test concentrations were obtained by dilution with tap 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):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea (Daphnia magna)
- Source: wild caught
- Age at study initiation (mean and range, SD): <=24 h
- Method of breeding: The daphnids (wild caught) were sieved (2 mm mesh width) and the parental animals transferred to tap water. The 30 largest animals were isolated and transferred individually into Erlenmeyer flasks and fed with algae. The clone producing the most juveniles were used for further culturing.
- Feeding during test: not reported

ACCLIMATION
- Acclimation period: not necessary
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Chlorella vulgaris
- Feeding frequency: daily
- Health during acclimation (any mortality observed): not reported


QUARANTINE (wild caught)
- Duration: not reported
- Health/mortality: not reported

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Hardness:

16° d.H.

Test temperature:

20-22°C

pH:

not reported

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

not reported

Details on test conditions:

TEST SYSTEM
- Test vessel: 50 ml beaker
- Type (delete if not applicable): test vessels were lossely capped with filter paper
- Material, size, headspace, fill volume: glass/50 mL/30 mL/20 mL
- Aeration: the dilution water used in the tests was oxygen saturated
- Type of flow-through (e.g. peristaltic or proportional diluter): test conducted under static conditions
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water (chlorine free, oxygen saturated) with the following characteristics: hardness: 16° d.H., pH 7.6-7.7
- Culture medium different from test medium: no
- Intervals of water quality measurement: not reported

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

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mobility

TEST CONCENTRATIONS
- Spacing factor for test concentrations: in depandance of the observations dilutions steps of 1:2, 1:1.3 or 1:1.1 were performed
- Range finding study: not reported

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

LC0

Effect conc.:

0.04 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

0.09 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LC100

Effect conc.:

0.31 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Reported statistics and error estimates:

The LC50 value was determined graphically.

Validity criteria fulfilled:

not applicable

Conclusions:

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted comparable to the German DIN 38412, Part II. The 24 h LC50 was determined to be 0.09 mg/L nominal.

Executive summary:

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted comparable to the German DIN 38412, Part II. Daphnids were exposed to hydrquinone for 24 h under static conditions. The 24 h LC50 was determined to be 0.09 mg/L nominal. This study is regarded as reliable with restrictions.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

guideline study without analytical monitoring of test substance concentration

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

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 (1-2 g/L) was prepared by dissolving the test material in demineralized Super Q water or bi-distilled water.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): no vehicle used

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea (Daphnia magna)
- Source: Ciba-Geigy/Monthey (Switzerland)
- Age at study initiation (mean and range, SD): not reported
- Method of breeding: According to the breeding protocol developed at the Ecole Polytechnique Federale de Lausanne: The daphnids were fed with Chlorella pyrenoidosa and held in the basic culture medium described by ISO norm 6341 (total hardness: 250 mg/L as CaCO3; pH 7.8). It was supplemented with SeO2 and Vitamin B12. Artifical light was provided 16 h/d and the temperature remained at 20 +/- 1°C.
- Feeding during test: no

ACCLIMATION: not necessary (daphnids were held at same conditions as in the test)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

250 mg/L as CaCO3

Test temperature:

20 +/- 1°C

pH:

culture medium: 7.8
test medium: not reported

Dissolved oxygen:

no data

Salinity:

no data

Nominal and measured concentrations:

no data

Details on test conditions:

TEST SYSTEM: according to guideline

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guideline
- Culture medium different from test medium: no
- Intervals of water quality measurement: not reported

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light/8 h dark
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility

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

Reference substance (positive control):

not specified

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% c.i.: 0.12-0.15 mg/L (results based on two tests)

Reported statistics and error estimates:

Probit Analysis according to Finney (1971) or moving average method according to Stephan (1977)

Validity criteria fulfilled:

yes

Remarks:

(no deviations from guideline reported)

Conclusions:

The acute toxicity of hydroquinone was investigated in a study conducted according to ISO 6341. The 48 h EC50 was found to be 0.13 mg/L nominal (mean of two tests).

Executive summary:

The acute toxicity of hydroquinone was investigated in a study conducted according to ISO 6341 15 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea)) under static conditions. The 48 h EC50 was found to be 0.13 mg/L nominal (mean of two tests).

This study is regarded as reliable with restrictions.

Reference 3

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Principles of method if other than guideline:

The test was conducted according to the notice of the Director General of the Pharmaceutical and Food Safety Bureau, Ministry of Helth, Labour and Welfare, Director General of the Manufacturing Industries Bureau, Ministry of Economy, Trade and Industry, and Director General of the Environmental Policy Bureau, Ministry of the Environment, 'Methods for Testing New Chemical Substances' (Pharmaceutical and Food Safety Bureau, MHLW No. 1121002 dated November 21, 2003, Manufacturing Industries Bureau, METI No. 2 dated November 13, 2003, and Environmental Policy Bureau, MOE No. 031121002.

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.07, 0.11, 0.16, 0.24, 0.35 mg/L nominal
- Sampling method: the test solution was collected via a micropipette and immediately fixed with phosphate solution
- Sample storage conditions before analysis: stored at 4°C in the refrigerator

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution (400 mg/L) was prepared. Then a concentrated solution of 100 times the test solution was prepared. A specified volume of this solution was added to the test medium.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): no vehicle used

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: waterflea (Daphnia magna)
- Source: formerly: National Institue for Environmental Studies, Environmental Agency; Currently: Independent Administrative Institution National Institute for Environmental Studies
- Age at study initiation (mean and range, SD): <=24 h
- Method of breeding: Parent daphnids were breed in Elendt M4 medium. The entire solution was replaced twice a week. 20 animals were held in 800 mL medium at 20 +/- 1°C with a photoperiod of 16 h light/8 h dark and a light intensity of 800-1200 lux. The daphnids were fed with Pseudokirchneriella subcapitata (0.1-0.2 mg C/d/parent daphnia) every day except for Saturdays and Sundays.
- Feeding during test: no

ACCLIMATION: not necessary
- Acclimation conditions (same as test or not): yes

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

240 mg/L as CaCO3

Test temperature:

20 +/- 1°C

pH:

new solution (0 h): 8.1-8.2
new solution (24 h): 7.8-8.0
old solution (24 h): 7.9-8.0
old solution (48 h): 7.9

Dissolved oxygen:

new solution (0 h): 8.4-8.6 mg/L (95.7-98.3% of its air saturation value)
new solution (24 h): 8.3-8.4 mg/L (94.7-95.5% of its air saturation value)
old solution (24 h): 8.6-8.7 mg/L (97.3-99.1% of its air saturation value)
old solution (48 h): 8.6-8.7 mg/L (98.1-99.3% of its air saturation value)

Salinity:

not relevant - freshwater test

Nominal and measured concentrations:

nominal: 0 (control), 0.070, 0.11, 0.16, 0.24, and 0.35 mg/L
measured initial: 0.052, 0 .095, 0.160, 230 and 340 mg/L hydroquinone.
after 24 hours the measured concentrations were between 17.3 and 27% of the initial concentrations
mean measured: 0 (control), 0.029, 0.043, 0.074, 0.11, and 0.18 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass beaker
- Type (delete if not applicable): closed (a glass lid was placed on the top of the test vessel)
- Material, size, headspace, fill volume: glass/100 mL/0/100 mL
- Aeration: no aeration during the exposure period
- Type of flow-through (e.g. peristaltic or proportional diluter): testing conducted under semi-static conditions
- Renewal rate of test solution (frequency/flow rate): the test solution was replaced after 24 h
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4 medium was used for the tests
- Culture medium different from test medium: no
- Intervals of water quality measurement: Temperature, pH and dissolved oxygen were measured at time 0 and after 24 (new and old solution) and 48 h (new and old solution)

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light/8 h dark
- Light intensity: 800-1200 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : immobilization after 24 and 48 h

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5
- Range finding study
- Test concentrations: 0.07, 0.11, 0.16, 0.24, and 0.35 mg/L nominal
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.134 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.095 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

0.148 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% c.i. 0.130-0.165 mg/L

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

0.095 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.061 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% c.i.; 0.054-0.069 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.029 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

0.071 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% c.i. 0.061-0.093 mg/L

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

0.11 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

0.029 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

48 h EC50=0.62 mg/L (using Elendt M4 medium)

Reported statistics and error estimates:

The natation inhibitory rate and the half natation inhibitory concentration were calculated using the probit method. 'ECOTox-Statics ' was used for the calculation of EC50. The re-calculation based on measured initial concentrations was done using the probit method and the calculation programm ToxRat V. 2.10.

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted equivalent to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) and under GLP. The 48 h NOEC, EC50, and EC100 were determined to be 0.029, 0.061, and 0.11 mg/L based on mean measured concentrations. Provided that the formed degradation products are also of high ecotoxicity the evaluation of the test based on the concentration of the parent compound alone may overestimate its toxicity. Provided further that the total amount of toxic equivalents is stable during the exposure period the initial concentration is regarded as relevant concentration. Therefore, the daphnia test was re-evaluated based on the measured initial concentration. The testing/validity criteria laid down in the OECD guideline 202 are fulfilled (e.g. dissolved oxygen in test vessels and control: >=3 mg/L; age of daphnids <=24 h; pH: not adjusted; pH in the range between 6 and 9 during the test; temperature: 20 -20.6°C etc.).

Thus, a 48 h EC50=0.134 mg/L (recalculated measured initial concentration) has to be taken into account for the risk assessment.

Validity criteria fulfilled:

yes

Conclusions:

In a GLP-study conducted equivalent to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test), a 48 h EC50=0.134 mg/L (recalculated measured initial concentration) was determined.

Executive summary:

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted equivalent to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) under semi-static conditions and under GLP. The endpoint examined was immobilization.

The daphnids (20 animals/concentration) were exposed to nominal concentrations of 0.070, 0.11, 0.16, 0.24, and 0.35 mg/L hydroquinone. The test substance concentrations were measured by HPLC/UV. The measured initial concentrations were 0.052, 0 .095, 0.160, 230 and 340 mg/L hydroquinone. After 24 hours the measured concentrations were between 17.3 and 27% of the initial concentrations resulting in mean measured concentrations of 0.029, 0.043, 0.074, 0.11 and 0.18 mg/L for the 48 hour exposure period.

The 48 h NOEC, EC50, and EC100 were determined to be 0.029, 0.061, and 0.11 mg/L based on mean measured (geometric means) concentrations.

However, hydroquinone is known to be fast degraded to several toxic degradation products depending on the environmental conditions like oxygen, pH and light (e.g. p-benzoquinone). The degradation products were not analyses in this study. Provided that the formed degradation products are of high ecotoxicity, the evaluation of the test based on the concentration of the parent compound alone may overestimate its toxicity. Provided further that the total amount of toxic equivalents is stable during the exposure period the initial concentration is regarded as relevant concentration. Therefore, the daphnia test was re-evaluated based on the measured initial hydroquinone concentration. The testing/validity criteria laid down in the OECD guideline 202 are fulfilled. This study is regarded as reliable without restriction.

Thus, a 48 h EC50=0.134 mg/L (recalculated based on measured initial concentrations) has to be taken into account for the assessment

Description of key information

The acute toxicity of hydroquinone to Daphnia magna was investigated in a study conducted equivalent or similar to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) under semi-static conditions and under GLP. A 48 h EC50=0.134 mg/L based on measured initial concentration was determined.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

0.134 mg/L

Additional information

Four studies dealing with the acute toxicity of hydroquinone to Daphnia are available; three studies with an exposure period of 48 hours and one study with 24 hours. The EC50 nvalues of the 48 hour tests ranged from 0.13 to 0.29 mg/L based on nominal or measured initial concentrations.

Only in one study the acute toxicity of hydroquinone to Daphnia magna was investigated equivalent to OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) under semi-static conditions and under GLP. The daphnids (20 animals/concentration) were exposed to measured concentration of 0 (control), 0.029, 0.043, 0.074, 0.11, and 0.18 mg/L for 48 h. The test substance concentrations were measured by HPLC/UV. The endpoint examined was immobilization. The 48 h NOEC, EC50, and EC100 were determined to be 0.029, 0.061, and 0.11 mg/L based on mean measured concentrations. As it has not been possible to discriminate between the effect of hydroquinone and its oxidation products the initial concentration is regarded as relevant concentration.

Therefore, the daphnia test is re-evaluated based on the measured initial concentration. Thus, a 48 h EC50=0.134 mg/L (recalculated measured initial concentration) has to be taken into account for assessment. The testing/validity criteria laid down in the OECD guideline 202 are fulfilled. These findings are supported by a study conducted according to ISO 6341 15 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea)) and in a study conducted according to DIN 38412, Part II 'Daphnia short-time test' (comparable to OECD Guideline 202 'Daphnia sp. Acute Immobilisation Test'). The 48 h EC50 values were found to be 0.13 mg/L nominal (ISO 6341 15; mean of two tests) and 0.29 mg/L nominal (DIN 38412, Part II). The very high acute toxicity of hydroquinone to Daphnia magna (24 h LC50=0.09 mg/L nominal) found in a study conducted comparable to the German DIN 38412, Part II in 1977 could not be confirmed in the aforementioned guideline studies.