2,4-Hexadienoic acid, 3-(trimethoxysilyl)propyl ester, (2E,4E)-

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:

20th to 24th August 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

temperature range of the test solution; method validation

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Nominal: control, 6.3, 13, 25, 50 and 100 mg/l.
- Sampling method: Prior to the start of the definitive exposure one water sample was removed from Replicate A of the 6.3, 25 and 100 mg/L treatment levels and the control and analysed for test substance concentration. Results of this pretest analysis were used to judge whether sufficient quantities of test substance were being delivered to the test vessels and whether the appropriate test concentrations were being maintained in order to initiate the definitive exposure.
During the in-life phase of the definitive study, one water sample from each treatment level and the control was collected, processed, then analysed for the test substance at 0 hour (exposure initiation), 48 hours and 96 hours (exposure termination). Samples were collected from the approximate midpoint of the test vessel by pipet.
Three quality control (QC) samples each were prepared at each sampling interval and remained with the appropriate set of exposure solution samples throughout the analytical process. These QC samples were prepared in dilution water at nominal concentrations similar to the exposure concentration range. Results of the analyses of the QC samples were used to judge the precision and quality control maintained during the analysis of exposure solution samples.

- Sample storage conditions before analysis: Not reported

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Prior to exposure initiation, a 50-mL Glenco~ gas-tight syringe in conjunction with a Harvard Apparatus Syringe Pump was calibrated to deliver 0.0680 mL/cycle of the test substance, with a density of 1.200 g/cm3 (neat test substance) into the diluter system's chemical mixing chamber which also received 0.790 L of dilution water per cycle. The mixing chamber was positioned over a water-driven magnetic stirrer and was partially submerged within an ultrasonic water bath which continuously mixed the contents of the mixing chamber. The solution contained in the mixing chamber constituted the highest nominal treatment level (100 mg/l) and was subsequently proportionately diluted (50%) to produce the remaining nominal test concentrations 50, 25, 13 and 6.3 mg/l.
- Controls: Dilution water with no test substance.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): None in definitive test.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): An oily sheen was observed on the surface of the solution in the mixing chamber. No undissolved test substance (e.g., precipitate or oily sheen) was observed in the exposure solutions, and all exposure solutions were observed to be clear and colourless.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Strain: SMV Lot No. 12AI21
- Source: TroutLodge, Inc., Sumner, Washington
- Age at study initiation (mean and range, SD): Juvenile
- Length at study initiation (length definition, mean, range and SD): 39 mm (range 35 to 42 mm); N = 30
- Weight at study initiation (mean and range, SD): 0.69 g (range 0.50 to 0.87 g); N = 30
- Method of breeding: Not reported
- Feeding during test
- Food type: No feeding during test
- Amount: n/a
- Frequency: n/a

ACCLIMATION
- Acclimation period: 12 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: commercial fish food diet, (Trout chow), ad libitum, until 48 hours prior to testing.
- Feeding frequency: Daily
- Health during acclimation (any mortality observed): no mortality

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

64-68 mg/l

Test temperature:

13-16 °C

pH:

6.9-7.2

Dissolved oxygen:

8.1 - 11 mg/l

Nominal and measured concentrations:

Nominal: control, 6.3, 13, 25, 50 and 100 mg/l
Mean measured: control, 3.7, 6.5, 16, 34 and 63 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass aquarium
- Type (delete if not applicable): open / closed: not reported but presumed open
- Material, size, headspace, fill volume: Glass, 30 x 15 x 20 centimeters (L x W x H), headspace not reported, fill volume: 6.8 l
- Aeration: Not reported
- Type of flow-through (e.g. peristaltic or proportional diluter): intermittent-flow proportional diluter
- Renewal rate of test solution (frequency/flow rate): 10 solution volume replacements per day: 90% test solution replacement rate of approximately 6 hours.
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 1
- No. of vessels
per control (replicates): 1
- No. of vessels per vehicle control (replicates): n/a
- Biomass loading rate: 0.10 grams of biomass per litre of solution per day

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: 100 metre deep bedrock well supplemented with town of Wareham well water, well water into an epoxy-coated concrete reservoir where it was aerated.
- Total organic carbon: 0.1 mg/l
- Alkalinity: range as calcium carbonate (CaCO3) 19-21 mg/l
- Conductivity: conductivity range of 330 to 410 microsiemens per centimetre (µs/cm)
- Culture medium different from test medium: no
- Intervals of water quality measurement: Dissolved oxygen concentration, temperature and pH measured daily.

OTHER TEST CONDITIONS
- Adjustment of pH: None reported
- Photoperiod: 16-hour light, 8-hour dark
- Light intensity: light intensity range of 23 to 31 footcandles (250 to 330 lux) using fluorescent bulbs

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, adverse effects including lethargy and loss of equilibrium, physical characteristics of test solution (e.g. presence of precipitate, film on the solution's surface) observed at 0, 24, 48, 72 and 96 hours.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: approximately 1.9
- Justification for using less concentrations than requested by guideline: n/a
- Range finding study
- Test concentrations: 0.63, 1.3,2.5,5.0 and 10 mg/l
- Results used to determine the conditions for the definitive study: No mortality observed after 96 hours.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

23 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CL 18-30 mg/l

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

6.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: See table 1
- Observations on body length and weight: None
- Other biological observations: See table 1
- Mortality of control: No
- Other adverse effects control: No
- Abnormal responses:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

LC50 value was estimated by binomial probability.

Sublethal observations / clinical signs:

The 96-hour LC₅₀ value for rainbow trout (Oncorhynchus mykiss) was estimated by binomial probability to be 23 mg/L, with 95% confidence intervals of 18 to 30 mg/L. The No-Observed-Effect Concentration (NOEC) was determined to be 6.5 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

A 96 hour LC50 value of 23 mg/l and a NOEC value of 6.5 mg/l have been determined for the effects of the test substance on mortality on rainbow trout, based on mean measured concentrations.

Executive summary:

Short-term toxicity of the test substance to Rainbow Trout (Oncorhynchus mykiss) was determined under Flow-Through Conditions, Following OECD Guideline Number 203. 96 hour LC₅₀ value of 23 mg/l was determined.

Description of key information

Short-term toxicity to fish: 96-h LC50 23 mg/l, NOEC 6.5 mg/l (mean measured concentration) (OECD 203) 

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

23 mg/L

Additional information

A 96 hour LC₅₀ value of 23 mg/l and a NOEC value of 6.5 mg/l (arithmetic mean measured concentrations) have been determined for the effects of 3-(trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate on mortality of Oncorhynchus mykiss.

In view of the flow-through exposure regime and neutral pH, it is likely that the test organisms were exposed predominantly to the parent test substance. Due to the flow rate producing 90% test solution renewal every 6 hours, it is likely that the fish were exposed to 60 -70% parent substance.

Because assessment is based on the hydrolysis product, a molecular weight correction can be applied:

(MW of silanol = 232.31 / MW of parent = 274.37) * 23 = 19 mg/l as the hydrolysis product 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate.