2-(1,1-dimethylethyl)-6-[[3-(1,1-dimethylethyl)-2-hydroxy-5-methylphenyl]methyl]-4-methylphenyl acrylate

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:

27 Feb - 3 Mar 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

Adopted 17 July 1992

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 100 mg/L
- Sampling method: Each sample was collected from the approximate midpoint of the test vessel. Archive samples were also collected from the exposure solutions at each sampling interval and stored frozen for possible future analysis and were discarded if not analyzed.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A water-accommodated fraction (WAF) was prepared at exposure initiation and daily thereafter from a 100 mg/L stock solution by adding, for example, 1.8976 g of the test item to an exposure aquarium and bringing it to volume with 19 L of laboratory well water. After addition of the test substance, the solution was observed to be clear with a layer of visible undissolved test substance on the surface. The solution was stirred slowly for approximately two days at the test temperature (14 ± 1 °C) using a magnetic stir plate and Teflon®-covered stir bar. After mixing, the solution was observed to be clear and colorless with undissolved test substance on the surface. The stock solution was filtered through a 0.45 μm nitrocellulose filter. Following filtration and mixing with a glass rod for approx. one minute, the resulting solution was observed to be clear and colorless with no visible undissolved test substance. This 100% of a 100 mg/L WAF was used as the treatment level solution for this exposure.
- Eluate: no
- Differential loading: no
- Controls: yes, test medium control

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: rainbow trout
- Source: obtained from Troutlodge, Inc., Sumner, Washington, USA
- Length at study initiation: mean total length of 49 mm (range 40 - 58 mm)
- Weight at study initiation: 1.0 g (range 0.53 - 1.9 g)
- Holding conditions: Fish were held in approximately 300 L of laboratory well water in a fiberglass tank under a photoperiod of 16 hours light and 8 hours darkness. The well water which flowed into this holding tank was characterized as having total hardness and total alkalinity ranges as calcium carbonate (CaCO3) of 62 to 78 mg/L and 24 to 27 mg/L, respectively, and a conductivity range of 470 to 510 μS/cm. Other parameters monitored in the holding tank were a pH of 7.4 and a dissolved oxygen concentration range of 81 to 98% of saturation. The fish were fed a dry commercial fish food, Trout Chow, daily during culture.

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions (same as test or not): same as test
- Type and amount of food during acclimation: The fish were fed a dry commercial fish food, Trout Chow, daily during culture. Fish were not fed during the 24-hour period prior to exposure initiation or during the exposure period.
- Health during acclimation (any mortality observed): No mortality was observed 48 h prior to testing.

FEEDING DURING TEST
- None

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

62 - 76 mg/L

Test temperature:

13.3 - 17.8 °C

pH:

6.5 - 6.8

Dissolved oxygen:

6.7 - 10.0 mg/L (> 60% air saturation)

Conductivity:

470 - 510 μS/cm

Nominal and measured concentrations:

nominal: control, 100 mg/L (WAF)
measured: < LOQ, 0.12 µg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Each aquarium was constructed of glass and silicone adhesive and measured 39 × 20 × 25 cm.
- Renewal rate of test solution (frequency/flow rate): every 24 h
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.6 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: laboratory well water
- Total organic carbon: 0.66 - 0.79 mg/L
- Culture medium different from test medium: same as test
- Intervals of water quality measurement: Water quality parameters were measured regularly.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light / 8 h darkness
- Light intensity: 400 - 520 lux

EFFECT PARAMETERS MEASURED
- Mortality and sub-lethal effects were recorded after 6, 24, 48, 72 and 96 h.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable
- Range finding study
- Test concentrations: control and 100 mg/L Water Accommodated Fraction
- Results used to determine the conditions for the definitive study: Following 96 h of exposure, no mortality or sublethal effects were observed in the treatment level tested or the control.

Reference substance (positive control):

not required

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 0 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 0 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: No sub-lethal effects were observed.
- Mortality of control: 0%
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Test solutiosn were clear and colorless.

Reported statistics and error estimates:

No statistical analysis was necessary since no effects on fish were observed.

Sublethal observations / clinical signs:

Table 1: Measured concentrations

Nominal concentration	Measured [µg/L]				Geometric mean [µg/L]
	0 h	24 h aged	72 h new	96 h aged
Control	< LOQ	< LOQ	< LOQ	< LOQ	n.a.
100 mg/L	0.13	0.066	0.25	0.10	0.12

Table 2: Validity criteria for OECD 203.

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality in the control(s) should not exceed 10% (or one fish if less than ten are used) at the end of the test	0%	yes
The dissolved oxygen concentration must have been at least 60 per cent of the air saturation value throughout the test	> 60%	yes

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Description of key information

LC50 (96 h) > 100 mg/L (nominal, Oncorhynchus mykiss, OECD 203)
LC50 (96 h) > 0.00012 mg/L (measured geometric mean, Oncorhynchus mykiss, OECD 203)

Additional information

One experimental study is available investigating the toxicity of 2-(1,1-dimethylethyl)-6-[[3-(1,1-dimethylethyl)-2-hydroxy-5-methylphenyl]methyl]-4-methylphenyl acrylate (CAS 61167-58-6) to the freshwater species Oncorhynchus mykiss. The study was performed according to OECD 203 (GLP) as a limit test with a filtered test solution of 100 mg/L under semi-static conditions. An appropriate amount of the test item was added to test medium followed by a two day stirring period. After mixing, the solution was observed to be clear and colorless with undissolved test substance on the surface. Thus, the stock solution was filtered through a 0.45 μm nitrocellulose filter. After this additional filtration step the test solution was clear and colorless with no floating particles. The actual test concentration in the exposure vessels was determined by LC-MS/MS analysis after 0, 24, 72 and 96 h in order to calculate the geometric mean exposure concentrations. After 96 h no mortality was recorded. The LC50 (96 h) was reported as > 100 mg/L (nominal) and > 0.00012 mg/L (geometric mean measured concentration). All validity criteria of the study are met.