Dibutyltin oxide

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:

August 1998

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Principles of method if other than guideline:

The test was carried out according to method no. TX ME 549.3 of the Experimental Toxicology, Schering AG.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

Oxgen concentrations, pH-value, and temperature were measured daily.
- Sampling method: To determine the contend and stability of the saturated solution of di-n-butyltin oxide samples for TOC analysis were taken directly after filtration of the suspension and at the end of exposure. Additionally, samples of the dilution (tap) water (control) were also taken at the same time points and analysed.

Vehicle:

yes

Details on test solutions:

In order to prepare a nominal concentration of 100 mg/l, 1.0020 g of the test substance di-n-butyltin oxide were dissolved in 4 l of tap water in a 10 l flask, which was then filled up to 10 l. This solution was stirred with a magnetic stir bar for approximately 67 hours. After this stirring period, the suspension was passed through a glass-fibre filter with the help of vaccuum and thereafter filled into the aquarium (saturated solution). The filtrate was almost clear, however, major residues of the test substance stuck to the funnel and the filter paper. The measured pH-value of this solution was 8.7. Pure tap water (dilution water) was used for the preparation of the saturated solution and the control group. The water of the control group was stirred and filtered in the same way as for the test solution.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebra fish
- Strain: Hamilton-Buchanan
- Source: Charles River Aquatics, Netherlands - distributor Charles River in Sulzgeld, Germany
- Length at study initiation (length definition, mean, range and SD): Deviating from TXM 549.3 but in accordance with OECD no. 203 fish size was 2 cm+_ 1 cm (the length of 5 rnadomly selected fish was measured)

ACCLIMATION
- Acclimation period: 20 days
- Acclimation conditions (same as test or not): Same as test

- Feeding frequency: Daily
- Health during acclimation (any mortality observed): No mortality

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Post exposure observation period:

No further information required.

Hardness:

262.89 mg/l as CaCO3
4:1 ratio of Ca:Mg

Test temperature:

Control group: 20.9-21.8 degrees Celsius
Test group: 20.8-21.8 degrees Celsius

pH:

Control group: 8.3-8.6
Test group: 8.7

Dissolved oxygen:

Control group: 88-98% of air saturation (7.8-8.6 mg/L)
Test group: 89-98% of air saturation (8-8.6 mg/L)

Salinity:

No information available.

Nominal and measured concentrations:

Nominal concentration: 100 mg/l
Measured concentration: 3.1 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: glass aquaria

- No. of organisms per vessel:5
- No. of vessels per concentration (replicates):2
- No. of vessels per control (replicates):2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:normal tap water, not polluted with harmful concentrations of chlorine, heavy metals and organochlorine pesticides based on quarterly measurements.

- Ca/mg ratio:4:1
- Conductivity:731 uS/cm

- Intervals of water quality measurement:pH was measured immediately after test solution preparation and during the whole test period. Oxygen and temperature were measured during the whole test period.

- Light intensity: light/dark rhythm was adjusted to 16 hours/8 hours

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

3.1 mg/L

Basis for effect:

mortality (fish)

Remarks:

3 fish showed abnormal behavior, one fish died

Details on results:

- Behavioural abnormalities: tail fins were contracted, fish were subdued, and abdomen was bent

- Mortality of control: no mortality

Results with reference substance (positive control):

Not applicable.

Sublethal observations / clinical signs:

Test Solutions	3 hours	6 hours	24 hours	48 hours	72 hours	96 hours
Control	0	0	0	0	0	0
Saturated Solution	0	0	0	0	1	1

Validity criteria fulfilled:

not specified

Conclusions:

No mortality was observed in the control whereas one fish was found dead after 72 hours of exposure in the saturated solution of di-n-butyltin oxide (10% mortality). The mortality and abnormal behavior of other fish observed at different time points of exposure were probably substance related. Results of the study showed that di-n-butyltin oxide is of low acute toxicity in a definitive study with dilutions of the saturated solution.

Executive summary:

Ten Zebra fish were used for a test solution of di-n-butyltin oxide. No mortality was observed in the control. One fish was found dead after 72 hours of exposure in the saturated solution of di-n-butyltin oxide. During exposure, the fish showed signs of abnormal behaviour nearly at all time points. 10% mortality was observed, therefore di-n-butyltin oxide is of low acute toxicity to fish up to 3.10 mg/l (maximum of solubility, determined on the basis of TOC analysis).

Description of key information

The following information is available for the short-term acute toxicity to fish endpoint:

 

Steger-Hartmann T. & Wendt B. (1998) Acute toxicity of di-n-butyltin oxide (ZK 26385) to the Zebra fish Danio rerio. Testing laboratory: Schering AG, Experimentelle Toxikologie.  Report no.: IC19. Owner company: Schering AG Report date: 1998-12-11. LOEC determined as 3.10 mg/l.

 

Nagase H. et al. (1991) Structure-activity relationships for organotin compounds on the red killifish Oryzias latipes. Applied Organometallic Chemistry 5: 91-97. The short term LC50 is 0.839 mg/L.

 

The Steger-Hartmann and Wendt study has been rated as 2 under the Klimisch scoring system and so is considered sufficient to address this endpoint. The Nagase et al study is a QSAR study but is insufficient to address the endpoint and has been rated as 4 under the Klimisch scoring system.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 3.1 mg/L

Additional information

Steger-Hartmann T and Wendt B (1998), the key study, was performed in compliance with GLP and according to the guideline OECD 203. As such, the study was assigned a reliability score of 2 and considered adequate for assessment. Ten Zebra fish were used in each test solution of di-n-butyltin oxide. No mortality was observed in the control. One fish was found dead after 72 hours of exposure in the saturated solution of di-n-butyltin oxide. During exposure, the fish showed signs of abnormal behaviour nearly at all time points. 10% mortality was observed, therefore di-n-butyltin oxide is of low acute toxicity to fish up to 3.10 mg/l (maximum of solubility, determined on the basis of TOC analysis).

 

Nagase H et al (1991) was provided as supporting information. The study was performed to the guideline OECD 203 in order to examine parameters for a QSAR of 29 organotins, however, areas of the methodology were lacking in detail and therefore it was not possible to accurately assign a reliability score. The LC50 for di-n-butyltin oxide was 0.839 mg/L, determined with red killifish Oryzias latipes. This paper studied the QSAR of 29 organotin compounds. They concluded that the physicochemical and topological parameters used as independent variables were not good descriptors for estimating the LC50 value.