1H-Imidazole-1-ethanol, 4,5-dihydro-, 2-nortall-oil alkyl derivs.

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental Starting Date: 21-May-2007 Experimental Completion Date: 10-Jul-2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

Principles of method if other than guideline:

EXAMPLE:
In view of the difficulties associated with the evaluation of aquatic toxicity of poorly water soluble test materials, a modification of the standard method for the preparation of aqueous media was performed. An approach endorsed by several important regulatory authorities in the EU and elsewhere (ECETOC 1996, OECD 2000 and Singer et al 2000), is to expose organisms to a Water Accommodated Fraction (WAF) of the test material in cases where the test material is a complex mixture and is poorly soluble in water and in the permitted auxiliary solvents and surfactants. Using this approach, aqueous media are prepared by mixing the test material with water for a prolonged period. Pre-study work showed that a preparation period of 24 hours was sufficient to ensure equilibration between the test material and water phase. At the completion of mixing, the test material phase is separated by siphon and the test organisms exposed to the aqueous phase or WAF (which may contain dissolved test material and/or leachates from the test material). Exposures are expressed in terms of the original concentration of test material in water at the start of the mixing period (loading rate) irrespective of the actual concentration of test material in the WAF.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: The following nominal concentrations were used in the study, 0.046, 0.10, 0.22, 0.46 and 1.0 mg/L.

- Sampling method:
The test item (24.55 mg) was dissolved in methanol and made up to the mark in a 50 mL
volumetric flask to prepare a stock solution of 491000 μg/L. Defined volumes of this stock
solution were diluted with methanol / water (v/v; 2/8) to obtain standard solutions of the test item
in the range of 9.82 to 123 μg/L. These solutions were used to calibrate the LC/MS-system.

- Sample storage conditions before analysis:
All samples were taken from the approximate center of the aquaria without mixing of the test media, and were deep-frozen (at about -20 °C) immediately after sampling. Based on preexperiments for investigation of the storage stability (without GLP) the test item is sufficiently stable in the test water under the storage conditions. The samples were stored deep-frozen and protected from light until analysis was performed.

Vehicle:

no

Details on test solutions:

The test media were prepared as follows: A concentrated stock solution of nominal 20 mg/L was freshly prepared at the start of the test and before each test medium renewal by completely dissolving 40 mg (range: 39.6–40.2 mg) of the test item in 2 liters of test water using ultrasonic treatment for 10 minutes and stirring for 10 minutes at room temperature. Adequate volumes of this intensively stirred stock solution were added to the test water in the aquaria and were intensively mixed to prepare the test media with the test concentrations as stated above.

The test media were freshly prepared just before introduction of the fish (= start of the test) and before each test medium renewal. The actual concentrations of the test item in the test media were analytically determined

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow Trout

- Strain: Not stated

- Source: The test fish were obtained from P. Hohler, trout breeding station Zeiningen, CH-4314 Zeiningen, Switzerland.

- Age at study initiation (mean and range, SD): Juvenile.

- Length at study initiation (length definition, mean, range and SD): The mean body length of the fish was 5.0 ± 0.17 cm (Mean ± SD)

- Weight at study initiation (mean and range, SD): The mean body wet weight was 1.2 ± 0.14 g (Mean ± SD).

- Method of breeding: Not stated

- Feeding during test
The fish were not fed during the test.

ACCLIMATION
- Acclimation period: Fish were acclimatised to test conditions from 17 September 2008 to 29 September 2008.

- Acclimation conditions (same as test or not): Same as test conditions.

- Type and amount of food: The fish were fed with a commercial fish diet (HOKOVIT 502, 1.2 mm, supplied by H.U. Hofmann AG, CH-4922 Bützberg, Switzerland).

- Feeding frequency: Not stated

- Health during acclimation (any mortality observed): Zero mortality in the 7 days prior to the start of the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

Any mortalities and sub-lethal effects of exposure were recorded at 3, 6, 24, 48, 72 and 96 hours after the start of exposure. The criteria of death were taken to be the absence of both respiratory movement and response to physical stimulation.

Hardness:

The total hardness of the test water was 188 as CaCO3

Test temperature:

Water temperature: 13–14 °C during the test period

pH:

The pH values in the test media and the control ranged from 8.1 to 8.6

Dissolved oxygen:

The oxygen concentration was always measured to be 8.2 or higher and thus higher than 60% oxygen saturation.

Salinity:

No Data - fresh water study

Nominal and measured concentrations:

The following nominal concentrations of 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives were tested: 0.046, 0.10, 0.22, 0.46 and 1.0 mg/L. Additionally, a control was tested in parallel (test water without test item).

Measured: In the analyzed test medium samples from the start of the test medium renewal periods the measured test item concentrations ranged between 72 and 91% of the nominal values

Details on test conditions:

TEST SYSTEM

Experimental Conditions
A semi-static test with daily test medium renewal was performed to keep the test item concentrations in the test media as constant as possible during the test period of 96 hours. During this semi-static test, the surviving test fish were placed each day into a clean aquarium with
freshly prepared test medium of the corresponding test concentration. One glass aquarium with 15 liters test medium was used for each test concentration and the control. The test vessels were labeled with the study number and all necessary additional
information to ensure unmistakable identification. At the start of the test 7 fish were introduced into each aquarium in a random order. The loading
rate was 0.55 g fish wet weight per liter test medium. The test media and the control were slightly aerated during the test period.

Light conditions: A 16-hour light to 8-hour dark photoperiod, with a 30-minute transition period (light intensity during the light period was approximately within the range of 50 to 500 Lux).

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
Laboratory tap water was dechlorinated by passage through an activated carbon filter (Purite Series 500) and partly softened (Elga Nimbus 1248D Duplex Water Softener) giving water with a total hardness of approximately 188 mg/l as CaCO3.

OTHER TEST CONDITIONS
The test vessels were then sealed and maintained at approximately 14ºC in a temperature controlled room with a photoperiod of 16 hours light and 8 hours darkness with 20 minute dawn and dusk transition periods for a period of 96 hours.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any mortalities and sub-lethal effects of exposure were recorded at 3, 6, 24, 48, 72 and 96 hours after the start of exposure. The criteria of death were taken to be the absence of both respiratory movement and response to physical stimulation.

TEST CONCENTRATIONS
The test concentrations were based on the results of a range-finding test (without GLP).
Definitive study:
The following nominal concentrations of 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives were tested: 0.046, 0.10, 0.22, 0.46 and 1.0 mg/L. Additionally, a control was tested in parallel (test water without test item).

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

IC50

Effect conc.:

0.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% confidence limits of 0.22 - 0.73 mg/l loading rate

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.37 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: CL not stated

Details on results:

The reported biological results are related to the total mean measured test item concentrations:
Nominal test item
concentration Total mean measured test item concentration
0.046 mg/L not analyzed
0.10 mg/L not analyzed
0.22 mg/L 0.17 mg/L (75% of nominal)
0.46 mg/L 0.37 mg/L (80% of nominal)
1.0 mg/L 0.77 mg/L (77% of nominal)

In the control and at the test concentrations up to and including 0.17 mg/L all fish survived until the end of the test and no visible abnormalities were observed at the test fish. At the next higher test concentration of 0.37 mg/L, all test fish showed one or several visible abnormalities. At the end of the test, five of the seven test fish died at this test concentration. At the highest test concentration of 0.77 mg/L, all fish were dead already after 24 hours of test duration.

Thus, the 96-hour NOEC of 1H-Imidazole-1-ethanol, 4,5-dihydro, 2- nortall-oil, alky derivatives to rainbow trout were determined to be 0.17 mg/L. The 96-hour LOEC (lowest concentration tested with observable toxic effects) was 0.37 mg/L.

The 96-hour LC50 of 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives was calculated to be 0.40 mg/L, with a 95% confidence interval of 0.22 – 0.73 mg/L. The 96-hour LC100 was 0.77 mg/L.

No remarkable observations were made concerning the appearance of the test media. All test media were clear solutions throughout the entire test duration

Reported statistics and error estimates:

See Attachment 1 - Data Evaluation and Quantification

Sublethal observations / clinical signs:

In the analyzed test medium samples from the start of the test medium renewal periods the measured test item concentrations ranged between 72 and 91% of the nominal values. During the test medium renewal period of 24 hours a slight decrease of the test item concentration in the test media was determined. At the end of the test medium renewal periods, the measured concentrations were in the range of 68 to 79% of nominal.

The mean measured test item concentrations during the renewal periods of 24 hours were calculated as the geometric means between the measurements at the start and the end of the renewal periods. From these mean concentrations, the total mean measured test concentrations during the test period of 96 hours were calculated as arithmetic means.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of the test item 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives to rainbow trout (Oncorhynchus mykiss) was determined in a 96-hour semi-static test with a daily test medium renewal according to the EU Commission Directive 92/69/EEC, Part C.1 (1992), and the OECD Guideline for Testing of Chemicals No. 203, (1992). The substance achieved a NOEC of 0.17 mg/L and a 96 hour LOEC of 0.37 mg/L, the highest concentration used in the study was 1.0 mg/L which means the substance will be classified as acute category 1 to the environment.

Executive summary:

The acute toxicity of the test item 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives to rainbow trout (Oncorhynchus mykiss) was determined in a 96-hour semi-static test with a daily test medium renewal according to the EU Commission Directive 92/69/EEC, Part C.1 (1992), and the OECD Guideline for Testing of Chemicals No. 203, (1992).

The nominal test item concentrations tested were 0.046, 0.10, 0.22, 0.46 and 1.0 mg/L, and in parallel a control.

In the analyzed test medium samples from the start of the test medium renewal periods the measured test item concentrations ranged between 72 and 91% of the nominal values. During the test medium renewal period of 24 hours a slight decrease of the test item concentration in the test media was determined. At the end of the test medium renewal periods, the measured concentrations were in the range of 68 to 79% of nominal.

The mean measured test item concentrations during the renewal periods of 24 hours were calculated as the geometric means between the measurements at the start and the end of the renewal periods. From these mean concentrations, the total mean measured test concentrations during the test period of 96 hours were calculated as arithmetic means.

The results are as follows:

96 -hour LC50: 0.4 mg/L

96-hour NOEC: 0.17 mg/L

96-hour LOEC: 0.37 mg/L

Description of key information

The mean measured test item concentrations during the renewal periods of 24 hours were calculated as the geometric means between the measurements at the start and the end of the renewal periods. From these mean concentrations, the total mean measured test concentrations during the test period of 96 hours were calculated as arithmetic means.
The results are as follows:
96 -hour LC50: 0.4 mg/L
96-hour NOEC: 0.17 mg/L
96-hour LOEC: 0.37 mg/L

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.4 mg/L

Additional information

The acute toxicity of the test item 1H-Imidazole-1-ethanol, 4,5-dihydro, 2-nortall-oil, alky derivatives to rainbow trout (Oncorhynchus mykiss) was determined in a 96-hour semi-static test with a daily test medium renewal according to the EU Commission Directive 92/69/EEC, Part C.1 (1992), and the OECD Guideline for Testing of Chemicals No. 203, (1992).

The nominal test item concentrations tested were 0.046, 0.10, 0.22, 0.46 and 1.0 mg/L, and in parallel a control.

In the analyzed test medium samples from the start of the test medium renewal periods the measured test item concentrations ranged between 72 and 91% of the nominal values. During the test medium renewal period of 24 hours a slight decrease of the test item concentration in the test media was determined. At the end of the test medium renewal periods, the measured concentrations were in the range of 68 to 79% of nominal.

The mean measured test item concentrations during the renewal periods of 24 hours were calculated as the geometric means between the measurements at the start and the end of the renewal periods. From these mean concentrations, the total mean measured test concentrations during the test period of 96 hours were calculated as arithmetic means.

The results are as follows:

96 -hour LC50: 0.4 mg/L

96-hour NOEC: 0.17 mg/L

96-hour LOEC: 0.37 mg/L