2-ethylhexyl 12-ethyl-5,5-dioctyl-9-oxo-10-oxa-4,6-dithia-5-stannahexadecanoate

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

November 17th 2003 to September 3rd, 2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Justification for Read Across is given in Section 13 of IUCLID.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Reference 2

Reference Type:

other: report amendment

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexyl 10-ethyl-4,4-dioctyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

EC Number:

239-622-4

EC Name:

2-ethylhexyl 10-ethyl-4,4-dioctyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

Cas Number:

15571-58-1

Molecular formula:

C36H72O4S2Sn

IUPAC Name:

2-ethylhexyl 10-ethyl-4,4-dioctyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecan-1-oate

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- During the final test, duplicate samples for analysis were taken from the control and the WAF prepared at a loading rate of 100 mg/l. Additionally, singular reserve samples of 25 ml were taken from the control and the WAF prepared at 100 mg/l for possible analysis. These samples were also treated with acetic acid. If not already used, these samples were stored at room temperature for possible analysis for a maximum of three months after delivery of the draft report, pending on the decision of the sponsor for additional analysis.
- Sampling frequency: at t=0 and t=72 h from freshly prepared solutions and at t=24 h and t=96 h from 24-hour old solutions.
- Storage: samples were stored at room temperature for a maximum of 4 days until transportation.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTIONS: the standard test procedures required generation of test solutions that contain completely dissolved test substance concentrations or stable and homogeneous mixtures or dispersions. The testing of concentrations that disturbed the test system were prevented (e.g. film of the test substance on the water surface). The substance was not soluble in test medium at the concentrations tested. Preparation of test solutions started with a dispersion of the stock solution in test medium at a nominal loading of 100 mg/l. The dispersion was stirred for approximately 24 hours applying an ultra thurrax, after which it was left to stabilise for one hour. The water fraction was then separated from the undissolved fraction of test substance and transferred to a separation funnel by means of siphoning. The Water Accommodated Fraction (WAF) collected from the separatory funnel was used for testing. The lower test concentrations were prepared by subsequent dilution of the WAF in test medium. All test vessels were pre-conditioned for 30 minutes with approximately 1 litre of the corresponding test solutions prior to the start of the test. Test solutions were daily renewed according to the above procedure.

Test organisms

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST SYSTEM
- Species: Zebra-fish (Brachydanio rerio, Teleostei, Cyprinidae).
- Source: Atlanta, Hellevoetsluis, the Netherlands.
- Mean length: 3.3 ± 0.2 cm.
- Mean weight: 0.85 ± 0.21 g.
- Other: healthy fish supplied with a health certificate.

ACCLIMATION
- Acclimation period: at least 12 days after delivery.
- Acclimation conditions: in ISO-medium [ISO International standard 734]. Measurements of pH, nitrate and nitrite concentration and ammonia concentration were perfommed once a week; temperature measurements every day.
- Feeding frequency during acclimation: daily with Trouvit.
- Health during acclimation: in the batch of fish used for the test, mortality during the seven days prior to the start of the test was less than 5 %.

Study design

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Hardness:

250 mg CaCO3

Test temperature:

21.0 - 22.5 °C.

pH:

7.3 - 7.8.

Dissolved oxygen:

oxygen > 60 % of air saturation value

Salinity:

no

Nominal and measured concentrations:

Nominal test concentrations: a WAF prepared at a loading rate of 100 mg/l and dilutions containing 0.1, 1.0 and 10 % of the WAF.

Details on test conditions:

TEST SYSTEM
- Test vessel: control and WAF: 20 litres, all-glass. WAF dilutions: 10 litres, all-glass.
- Aeration: the test media was not aerated during the test.
- Number of fish: control and WAF: 7 fish per test group. WAF dilutions: 3 fish per test group.
- Loading: control and WAF: 0.43 g fish/litre, i.e.7 fish per 14 litres of test medium. WAF dilutions: 0.28 g fish/litre, i.e. 3 fish per 9 litres of test medium.
- Photoperiod: 16 hours photoperiod daily.

TEST MEDIUM / WATER PARAMETERS
- Test medium: ISO-medium [ISO International Standard 7346] was made by diluting 1 ml of each solution with 1 I Milli-Q water: calcium chloride (293.8 g CaCl2.2H20/l), magnesium sulphate (123.3 g MgS04.7H20/l), sodium carbonate hydrogen (64.8 g NaHCO3 l) and potassium chloride (5.8 g KCl/l). This solution was bubbled with air during one hour. aerated until the dissolved oxygen concentration had reached saturation and the pH had stabilised. After aeration the hardness was 250 mg CaC03 per litre and the pH was between 7.7 and 7.9.
- Interval of water quality parameters measurement: temperature, pH and dissolved oxygen were measured daily in all vessels, beginning at the start of the test (day 0).

OTHER TEST CONDITIONS
- Feeding: no feeding from 48 hours prior to the test and during the total test period.
- Introduction of fish: within two hours after preparation of the test media.
- Euthanasia: at the end of the test, the surviving fish were rapidly killed by exposing them to ca. 1.2 % ethylene glycol monophenylether in water.

BLANK CONTROL: test medium without test substance or other additives (0 mg/l).

EFFECT MEASUREMENTS: mortality and other effects: at 3¼, 24, 48, 72 and 96 hours following the start of exposure. Dead fish were removed when observed. Fish length and weight: ten fish of the batch used for the test were weighed and measured prior to the start of the test.

Reference substance (positive control):

yes

Remarks:

Pentachlorophenol (PCP)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 3

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 4

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Results are based on geom. mean of measured concentrations.
- No mortality or visible clinical effects were observed in any of the solutions during the 96-hour test period.
- The substance was not soluble in the test medium at the concentrations tested. The 100 % WAF and its 10 % dilution were cloudy throughout the test period; however, no test substance film or precipitate were observed. Analyses showed poor repeatability of test solution preparation. This was not unexpected considering the low water solubility of the test substance (<0.1 mg/l) and difficulties encountered with the separation of the undissolved and dissolved fractions.

Results with reference substance (positive control):

At 24 hrs: LC50 = 0.29 mg/l with LC0 = 0.22 mg/l and LC80 mortality at 0.32 mg/l.
At 96 hrs: LC50 = 0.24 mg/l (95 % C.L.= 0.21-0.30 mg/l). This effect was already reached within 48 hours of exposure.
The range of the 96h-LC50 for zebra-fish is generally between 0.18 mg/l and 0.30 mg/l (with a 95 % confidence interval between 0.28 and 0.39 mg/l) based on historical data of reference tests performed by the laboratory. The response observed in zebra-fish originating from the present batch falls within this range.

Reported statistics and error estimates:

- No LC50 could be calculated because the test substance proved to be non-toxic (LC50>maximum soluble concentration).
- The No Observed Effect Concentrations (NOEC calues) are the highest concentrations tested showing no effect throughout the exposure time. The NOEC values are qualified affording to the duration of exposure and are estimated by comparing effects with regard to survival of the exposed animals with those of the control animals.

Any other information on results incl. tables

Sublethal observations / clinical signs:

Measured concentrations: the measured tin concentrations decreased slightly during the 24 -hour renewal periods. Analyses further showed poor repeatability of test solution preparation. This was not unexpected considering the extremely low solubility of the test substance in the test medium in combination with the difficulties encountered with the separation of the undissolved from the dissolved fraction, which is a common feature when testing WAFs.

Average exposure concentration:

% of a WAF at 100 mg/l: 100 %

Sn (mg/l): 3.91

Test substance (mg/l)*: 24.8

*Correction based on molecular weights (factor: 751.8/118.7*Sn measured)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

No mortality or other visible effects in zebra-fish (Brachydanio rerio) at or below a Water Accommodated Fraction (WAF) prepared at a loading rate of 100 mg/I.
NOEC (96 h) = 24.8 mg/l (measured, geom. mean); above the substance water solubility limit.
LC50 (96 h)> 24.8mg/l (measured, geom. mean)

Executive summary:

The toxicity of the substance to fish was evaluated in a limit test according to the OECD guideline 203 and EU Method C.1. Seven zebra fish per test group were exposed to a blank-control and a WAF prepared at a loading rate of 100 mg/l in the limit test, while three zebra-fish per test group were exposed to dilutions containing 0.1, 1.0 and 10 % of the WAF in the additional range-finding test. The zebra fish were exposed to the substance under semi-static conditions with daily renewal for 96 hours. Mortality and other effects: at 3¼, 24, 48, 72 and 96 hours following the start of exposure. Dead fish were removed when observed. Ten fish of the batch were used for the measurement of length and weight prior to the start of the test.

Samples for analytical confirmation of actual exposure concentrations were taken from freshly prepared solutions of the blank-control and the undiluted WAF at t=0 h and t=72 h and from the 24 -hour old solutions at t=24 h and t=96 h. Analysis showed that the measured tin concentrations decreased slightly during the 24 -hour renewal periods. Analyses further showed poor repeatability of test solution preparation. This was not unexpected considering the extremely low solubility of the test substance in the test medium in combination with the difficulties encountered with the separation of the undissolved from the dissolved fraction, which is a common feature when testing WAFs.

The test substance induced no visible effects in zebra-fish at or below a Water Accomodated Fraction (WAF) prepared at a loading rate of 100 mg/l. Based on average measured concentrations: NOEC (96 h) = 24.8 mg/l and LC50 (96 h)> 24.8 mg/l (measured, geom. mean)

Therefore it is possible to conclude that no toxic or harmful effects are expected to occur up to the solubility limit of the substance.