Thymol

Sediment toxicity

Administrative data

Endpoint:

sediment toxicity: short-term

Type of information:

experimental study

Adequacy of study:

other information

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study acceptable for assessment

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA-600/3-75-009

Version / remarks:

April 1975

Deviations:

not specified

Principles of method if other than guideline:

U.S. Environmental Protection Agency. 1975. Methods for Acute Toxicity Tests with Fish, macroinvertebrates and Amphibians.
Ecology Series. EPA-600/3-75-009. Duluth. MN.
The method evaluates the potential of substance to cause acute aquatic effects in seven juvenile aquatic species simultaneously.

GLP compliance:

no

Remarks:

Study took place before GLP became official standard

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The maximum concentration used in these bioassays was 100 mg/L. Chemicals known to be readily soluble at 100 mg/L were added directly to the diluent water in each aquarium in the appropriate amounts to give nominal concentrations of 100, 10, 1 and 0.1 mg/L. Test chemical concentrations were not analysed.

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: Fathead minnow
Simultaneously seven species from five phyla were exposed at multi-species test, a duplicate single species test was performed with thymol.
- Age at study initiation (mean and range, SD): juveniles
- Weight at study initiation (mean and range, SD): 0.2 - 0.5g

ACCLIMATION
- Acclimation period: yes
- Acclimation conditions (same as test or not): same
- Type and amount of food during acclimation: not specified
- Feeding frequency during acclimation: not specified
- Health during acclimation (any mortality observed): not specified
- Food was withheld for 24h before start of the test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

130 mg/L

Test temperature:

20 +/- 1°C

pH:

6.5 - 8.5 (7.4)

Dissolved oxygen:

dissolved oxygen was determined, but no values specified

Salinity:

not applicable

Conductivity:

260 µmhos/cm

Nominal and measured concentrations:

Nominal: 0.1, 1.0, 10 and 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: seamless glass, 30.5 cm cuboidal, Pyrex chromatography jars
- Material, size, headspace, fill volume: 20 L
- Aeration: if the dissolved oxygen concentration fell belo 40% of the starting level, the test was repeated with a 0.05 L/min glass-sparger aeration
- No. of organisms per vessel: 10
- No. of animals per concentration (replicates): 10 - duplicate trial for single species test
- Biomass loading rate: < 0.5 g wet weight per liter of test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: activated carbon-filtered, dechlorinated and tempered industrial service water from Lake Ontario
- Total organic carbon: 1.8 mg/L
- Particulate matter: 180 mg/L
- Metals: < 1.25 mg/L, besides Ca 39 mg/L, Mg 6.9 mg/L, Potassium 6.7 mg/L, Na 10 mg/L:
- Chlorine: 26 mg/L
- Alkalinity: 93 mg/L
- Ca/mg ratio: 39/6.6 mg/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: routinely monitored

OTHER TEST CONDITIONS
- Adjustment of pH: yes, to 7 with 10% NaOH or 10% H2SO4 if out of extreme range
- Photoperiod: 16h light
- Light intensity: 50ft-c of cool-white fluorescence light
Temperature, dissolved oxygen and pH values were determined at the beginning of the test and daily. If required the values were adjusted. Values were not reported.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Biological observations were made daily (survival, conditions, behavior). A test organism was considered dead if it appeared motionless and exhibited no response to gentle prodding.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

The LC50 values were estimated by an interpolation method using a Computer program written for aquatic toxicity studies

Reported statistics and error estimates:

not reported

Validity criteria fulfilled:

not specified

Conclusions:

In this multispecies test a 96 h - LC50 of 3.2 mg/L was obtained with the test item. This result is also confirmed in a single species test and is thus regarded as valid.

Executive summary:

The acute toxicity of thymol to juvenile fish (Pimephales promelas) was determined together with seven species according to the Methods of US-EPA, 1975. Simultaneously seven species from five phyla were exposed to the test item concentrations of nominal 0.1, 1.0, 10 and 100 mg/L in the multi-species test. A duplicate single species test was also performed with thymol.

In this multispecies test and in the single species test an LC50 (96h) of 3.2 mg/L was obtained.

Cross-reference 2

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1986

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

other: EPA-600/3-75-009

Version / remarks:

April 1975

Deviations:

not specified

Principles of method if other than guideline:

U.S. Environmental Protection Agency. 1975. Methods for Acute Toxicity Tests with Fish, macroinverte-brates and Amphibians.
Ecology Series. EPA-600/3-75-009. Duluth. MN.
The method evaluates the potential of substance to cause acute aquatic effects in seven juvenile aquatic species simultaneously.

GLP compliance:

no

Remarks:

Study took place before GLP became official standard

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The maximum concentration used in these bioassays was 100 mg/L. Chemicals known to be readily soluble at 100 mg/L were added directly to the diluent water in each aquarium in the appropriate amounts to give nominal concentrations of 100, 10, 1 and 0.1 mg/L. Test chemical concentrations were not analysed.

Test organisms (species):

Daphnia magna

Details on test organisms:

Simultaneously seven species from five phyla were exposed.

Four other aquatic invertebrates were also examined in the study:
Duesia tigrina (Flatworm), Helisoma trivolvis: (Snail), Asellus intermedius: (Pillbug), Gammarus fasciatus: (Sideswimmer)

For thymol a single-species test was also performed.

TEST ORGANISM
- Common name: water flea
Simultaneously seven species from five phyla were exposed at multi-species test, a duplicate single species test was performed with thymol.
- Age at study initiation (mean and range, SD): first and second larval instar

ACCLIMATION
- Acclimation period: yes
- Acclimation conditions (same as test or not): same
- Type and amount of food during acclimation: not specified
- Feeding frequency during acclimation: not specified
- Health during acclimation (any mortality observed): not specified
- Food was withheld for 24h before start of the test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

130 mg/L

Test temperature:

20 +/-1°C

pH:

6.5 - 8.5 (7.4)

Dissolved oxygen:

dissolved oxygen was determined, but no values specified

Salinity:

not applicable

Conductivity:

260 µmhos/cm

Nominal and measured concentrations:

Nominal concentration: 0.1, 1.0, 10 and 100 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: seamless glass, 30.5 cm cuboidal, Pyrex chromatography jars
- Material, size, headspace, fill volume: 20 L
- Aeration:
if the dissolved oxygen concentration fell belo 40% of the starting level, the test was repeated with a 0.05 L/min glass-sparger aeration
- No. of organisms per vessel: 10, Ten juvenile organisms of each species were exposed to each treatment
- No. of animals per concentration (replicates): 10 - duplicate trial for single species test
- Biomass loading rate: < 0.5 g wet weight per liter of test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: activated carbon-filtered, dechlorinated and tempered industrial service water from Lake Ontario
- Total organic carbon: 1.8 mg/L
- Particulate matter: 180 mg/L
- Metals: < 1.25 mg/L, besides Ca 39 mg/L, Mg 6.9 mg/L, Potassium 6.7 mg/L, Na 10 mg/L:
- Chlorine: 26 mg/L
- Alkalinity: 93 mg/L
- Ca/mg ratio: 39/6.6 mg/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: routinely monitored

OTHER TEST CONDITIONS
- Adjustment of pH: yes, to 7 with 10% NaOH or 10% H2SO4 if out of extreme range
- Photoperiod: 16h light
- Light intensity: 50ft-c of cool-white fluorescence light

Temperature, dissolved oxygen and pH values were determined at the beginning of the test and daily. If required the values were adjusted. Values were not reported.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Biological observations were made daily (survival, conditions, behavior). A test organism was considered dead if it appeared motionless and exhibited no response to gentle prodding. If more than one-half of the population of a species exposed in any treatment was determined to be dead, additional aquaria containing lower concentrations of test solution were set up. All seven species were exposed to each dose level. At any time during the test when all 10 organisms of a species were considered dead, these biological Parameters were determined and recorded

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The LC50 values were estimated by an interpolation method using a Computer program written for aquatic toxicity studies.

Reported statistics and error estimates:

not reported

A multispecies test was performed together with seven species tests, one for each type of aquatic animal.

Results for four other aquatic species :

96 -h LC50 values:
Duesia tigrina (Flatworm): LC50 =  5.9 mg/L
Helisoma trivolvis (Snail): LC50 = 32   mg/L
Gammarus fasciatus (Sideswimmer): LC50 =  3.2 mg/L
Asellus intermedius (Pillbug): LC50 = 17   mg/L

Validity criteria fulfilled:

not specified

Conclusions:

In this multispecies test a 96 h - LC50 of 3.2 mg/L was obtained with the test item. This result is also confirmed in a single species test and is thus regarded as valid.

Executive summary:

The acute toxicity of thymol to invertebrates (Dapnia magna) was determined together with seven species according to the Methods of US-EPA from 1975. Simultaneously seven species from five phyla were exposed to the test item concentrations of nominal 0.1, 1.0, 10 and 100 mg/L in the multi-species test. A duplicate single species test was also performed with thymol.

In this multispecies test, a 96 h LC50 of 3.2 mg/L of thymol to Daphnia magna was obtained.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1986

Report date:

1986

Materials and methods

Test guideline

Guideline:

other: EPA-600/3-75-009

Principles of method if other than guideline:

U.S. Environmental Protection Agency. 1975. Methods for Acute Toxicity Tests with Fish, macroinverte-brates and Amphibians.
Ecology Series. EPA-600/3-75-009. Duluth. MN.
The method evaluates the potential of substance to cause acute aquatic effects in seven juvenile aquatic species simultaneously.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Thymol

EC Number:

201-944-8

EC Name:

Thymol

Cas Number:

89-83-8

Molecular formula:

C10H14O

IUPAC Name:

5-methyl-2-(propan-2-yl)phenol

Sampling and analysis

Details on sampling:

The maximum concentration used in these bioassays was 100 mg/L. Chemicals known to be readily soluble at 100 mg/L were added directly to the
diluent water in each aquarium in the appropriate amounts to give nominal concentrations of 100, 10, 1 and 0.1 mg/L. Test chemical concentrations
were not analysed.

Test organisms

Test organisms (species):

Lumbriculus variegatus

Details on test organisms:

The method simultaneously exposes seven species from five phyla. All test organisms were acclimated to the control diluent water in the breeding/rearing tanks. Food was withheld for the 24 h preceding start of the test. Juveniles of each species, as uniform in size as possible, were collected from
the colonies. Ten juvenile organisms of each species were routinely exposed to the test chemical in each treatment. Stratified randomisation was
accomplished by proportioning out no more than 20% of any one species into an aquarium at any one time. Biological loading was kept below
0.5 gram wet weight per liter of test solution. The average wet weight for a randomly chosen set of minnows was determined at the start of the test.
The other six species were not weighed. The minnows and snails were placed in the test vessels. The remaining five species were segregated in
welded stainless steel, 55-mesh wirecloth baskets (5.5 cm in diameter * 7.5 cm in depth).
Each basket was suspended from a 1-rpm motor-driven mechanism that raised and lowered the baskets in the water column. A stainless steel band, slotted every 0.5 cm, facilitated the positioning of the baskets so that the submerged volumes changed from one-third to two-thirds during each
cycle. The baskets were spaced around the test vessel rim so that they did not interfere with each other. One-half of the volume of the submerged
basket was exchanged with the main tank volume every minute.

Study design

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

not specified

Exposure duration

Duration:

96 h

Exposure phase:

total exposure duration

Test conditions

Test temperature:

20 +/- 1°C

pH:

6.5 - 8.5

Dissolved oxygen:

dissolved oxygen was determined, but no values specified

Nominal and measured concentrations:

Nominal concentration: 0.1, 1.0, 10 and 100 mg/l

Results and discussion

Effect concentrations

Duration:

96

Dose descriptor:

LC50

Effect conc.:

3.2 other: mg/l

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The LC50 values were estimated by an interpolation method using a Computer program written for aquatic toxicity studies
Dead organisms were removed when observed. A test organism was considered dead if it appeared motionless and exhibited no response
to gentle prodding. If more than one-half of the population of a species exposed in any treatment was determined to be dead, additional aquaria
containing lower concentrations of test solution were set up. All seven species were exposed to each dose level. At any time during the test when all 10 organisms of a species were considered dead, these biological Parameters were determined and recorded.

Applicant's summary and conclusion

Executive summary:

Sediment toxicity of thymol to segmented worm (Lumbriculus variegatus) were performed together with seven single-species according to the Methods of US-EPA from 1975. In this multispecies test, a 96 h LC50 of 3.2 mg/L were obtained (Ewell, 1986).