Bis(dodecylthio)dioctylstannane

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

17 November 2003 to 03 September 2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Guideline study conducted under GLP and according to OECD No. 203 and EU No. C.1. 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. Exposure concentrations were measured on the basis of total Sn and were converted to and reported as the parent substance, DOT(2-EHMA), using the conversion factor [751.8/118.71] consisting of the Mol weights of DOT(2-EHMA) and Sn, respectively. This method of analysis includes more water soluble tin compounds and hydrolysis products. All of the measured Sn (including contributions from more water-soluble tin compounds or impurities) was fully attributed to the parent substance. Total Sn concentrations were not stable during the exposure period.

Reason / purpose for cross-reference:

other: read-across target

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

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.

Frequency: at t=0 h and t=72 h from freshly prepared solutions and at t=24 h and t=96 h from 24-hour old solutions.
Volume: 25 ml from the approximate centre of the test vessels.
Treatment: 50 ml acetic acid (Merck, 100%) was added to each sample directly after sampling. Note that analytical end results were corrected for this dilution.
Storage: Samples were stored at room temperature for a maximum of 4 days until transportation to TNO Nutrition and Food Research.

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.

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 batch of DOT(EHMA) tested was a white to light yellow liquid enriched with 87.5% DOT(EHMA). DOT(EHMA) 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 (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
Characteristics: Healthy fish supplied with a health certificate.
Total fish used: 23

Quarantine/Acclimatisation: At least 12 days after delivery.
Medium: ISO-medium [ISO International standard 734]
Measurements: pH, nitrate and nitrite concentration and ammonia concentration: once a week.; temperature: every day.
Feeding: Daily with Trouvit.
Validity of batch: 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%.

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Remarks on exposure duration:

study included both a limit and range-finding test at 96 hr exposure

Post exposure observation period:

none.

Hardness:

250 mg CaCO3

Test temperature:

Measured daily in all vessels, beginning at the start of the test (day 0). All test conditions remained within the ranges prescribed by the protocol (temperature 21-25 °C, constant within ± 1 °C). Measured temperatures were 21.0 - 22.5 °C.

pH:

Measured daily in all vessels, beginning at the start of the test (day 0). All test conditions remained within the ranges prescribed by the protocol (pH: 6.0 - 8.5, constant within 1 unit). Measured pH was between 7.3 and 7.8.

Dissolved oxygen:

Measured daily in all vessels, beginning at the start of the test (day 0). All test conditions remained within the ranges prescribed by the protocol (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.

Blank-control: Test medium without test substance or other additives (0 mg/l).

- Determination of average exposure concentrations
The average exposure concentrations for the periods between refreshment were calculated as (Ct=0 * Ct=24)^(1/2), being the geometric means of the mean concentrations of DOT(EHMA) measured in the duplicate samples taken at the start (Ct=0) and the end of the 24-hour refreshment periods (Ct=24). This was applied for the periods 0-24 hours and the period 72-96 hours of exposure. The (rounded) mean of the average exposure concentrations determined during these two refreshment periods was taken as the average exposure concentration for the total 96-hour test period.

Details on test conditions:

TEST SYSTEM
- Test vessel: Control and WAF: 20 litres, all-glass. WAF dilutions: 10 litres, all-glass. The test media was not aerated during the test.
- Type of flow-through (e.g. peristaltic or proportional diluter): Not stated
- Renewal rate of test solution (frequency/flow rate): Not stated
- 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.
- 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.

TEST MEDIUM / WATER PARAMETERS
ISO-medium [ISO International Standard 7346], aerated until the dissolved oxygen concentration had reached saturation and the pH had stabilised. After aeration the hardness was 250 mg CaCO3 per litre and the pH was between 7.7 and 7.9.

OTHER TEST CONDITIONS
- Adjustment of pH: Not stated
- Photoperiod: 16 hours photoperiod daily
- Light intensity: Not stated

Reference substance (positive control):

yes

Remarks:

Pentachlorophenol (PCP)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Details on results:

No mortality or visible clinical effects were observed in any of the solutions during the 96-hour test period.

Results with reference substance (positive control):

The 24h LC50 was 0.29 mg/l with 0 % mortality at 0.22 mg/l and 80 % mortality at 0.32 mg/l. The 96h LC50 was 0.24 mg/l with a 95% confidence interval between 0.21 and 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 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 NOTOX. The response observed in zebra-fish originating from the present batch falls within this range.

Reported statistics and error estimates:

- Treatment of the results.
- LC-values.
No LC50 could be calculated because the test material proved to be non-toxic (LC50>maximum soluble concentration).

- NOEC values.
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.

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 material 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

DOT (EHMA) (mg/l)*: 24.8

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

Validity criteria fulfilled:

yes

Remarks:

Validity criteria were met to the extent possible; as noted above, the test compound was not soluble in the test medium (water); therefore, measured concentrations were variable, and results were based on geom. mean of these measured concentrations.

Conclusions:

Under the conditions of the present test DOT(EHMA) induced no visible effects in zebra-fish (Brachydanio rerio) at or below a Water Accommodated Fraction (WAF) prepared at a loading rate of 100 mg/I. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOT(EHMA) per litre (3.91 mg tin per litre) which is above the water solubility limit of DOT(EHMA).

Executive summary:

The study procedures described in this report were based on the EEC directive 92/69, Part C. L "Acute toxicity for fish"; and the OECD guideline No. 203: "Fish Acute Toxicity Test", Adopted 17 July, 1992.

The batch of DOT(EHMA) tested was a white to light yellow liquid enriched with 87.5% DOT(EHMA). DOT(EHMA) was not soluble in test medium at the concentrations tested.

Preparation started with a supersaturated dispersion at 100 mg/l, which was stirred for approximately 24 hours applying an ultra thurrax. The dispersion was then left to stabilise for one hour. Subsequently, the Water Accommodated Fraction (WAF)

was separated from the undissolved fraction of test material by means of siphoning. The lower test concentrations were prepared by subsequent dilution of the WAF in test medium. All test solutions were renewed daily and all test vessels were pre-conditioned for 30 minutes with the respective solution.

A limit test was combined with a range-finding test in a semi-static system with daily renewal. Seven zebra-fish per test group were exposed to a blank-control and a WAF prepared at a DOT(EHMA) 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. 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 material 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 study met the acceptability criteria prescribed by the protocol and the guidelines and was considered valid.

DOT(EHMA) induced no visible effectsin zebra-fish (Brachydanio rerio) at or below a Water Accomodated Fraction (WAF) prepared at a loading rate of 100 mg/l. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOT(EHMA) per litre (3.91 mg tin per litre).

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

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

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

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted on read-across material

Justification for type of information:

Read-across to DOTE (Dioctyltin bis(2-ethylhexyl thioglycolate)) (CAS 15571-58-1), see attached justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

> 24.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

other: DOT (EHMA)

Basis for effect:

mortality (fish)

Description of key information

Read-across to structurally similar substance

Under the conditions of the study DOTE (CAS NO 15571-58-1) induced no visible effects in zebra-fish (Brachydanio rerio) at or below a Water Accommodated Fraction (WAF) prepared at a loading rate of 100 mg/L. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOTE per litre (3.91 mg tin per litre) which is above the water solubility limit of DOTE.

Additional information

Read-Across to structurally similar substance DOTE

The test material DOTE (CAS No 15571 -58-1), was evaluated for 48-hour acute toxicity on Daphniain accordance with OECD Guideline No. 202, “Daphina sp., Acute Immobilisation Test”.

The toxicity of the read across substance to fish was evaluated according to EEC directive 92/69, Part C. L "Acute toxicity for fish"; and the OECD guideline No. 203: "Fish Acute Toxicity Test", Adopted 17 July, 1992. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).

The batch of DOTE tested was a white to light yellow liquid enriched with 87.5% DOTE. DOTE was not soluble in test medium at the concentrations tested.

Preparation started with a supersaturated dispersion at 100 mg/L, which was stirred for approximately 24 hours applying an ultra thurrax. The dispersion was then left to stabilise for one hour. Subsequently, the Water Accommodated Fraction (WAF) was separated from the undissolved fraction of test substance by means of siphoning. The lower test concentrations were prepared by subsequent dilution of the WAF in test medium. All test solutions were renewed daily and all test vessels were pre-conditioned for 30 minutes with the respective solution.

A limit test was combined with a range-finding test in a semi-static system with daily renewal. Seven zebra-fish per test group were exposed to a blank-control and a WAF prepared at a DOTE 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. 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 study met the acceptability criteria prescribed by the protocol and the guidelines and was considered valid.

DOTE induced no visible effectsin zebra-fish (Brachydanio rerio) at or below a Water Accomodated Fraction (WAF) prepared at a loading rate of 100 mg/L. Based on average measured concentrations the NOEC corresponded to 24.8 mg DOTE per litre (3.91 mg tin per litre).

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