Butyltris[(2-ethyl-1-oxohexyl)oxy]stannane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 May 2001 to 01 June 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

1984

Deviations:

yes

Remarks:

The test material was only analytically verified at test beginning due to the sponsor's wish.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

Deviations:

yes

Remarks:

The test material was only analytically verified at test beginning due to the sponsor's wish.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- DOC was measured in all concentration levels and control at test start (0 h, fresh media).

Vehicle:

no

Details on test solutions:

- A 1000 mg/L stock solution was prepared with dilution water one day prior to application
- Dispersion treatment: 30 minutes ultrasonic at room temperature, followed by 24 hours on a magnetic stirrer and then filtration with 45 μm filters (single use).
- Dilutions: 1:16, 1:8, 1:4, 1:2 and 1:1 to give 62.5, 125, 250, 500 and 1000 mg/L concentrations.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Strain/clone: Daphnia magna STRAUS (Clone 5)
- Source: lnstitut für Wasser-, Boden- und Lufthygiene des Bundesgesundheitsamtes, Corrensplatz, D-14195 Berlin. Bred in house.
- Age: 2 to 24 hour old daphnids were used for the preliminary and definitive test. They had been obtained by removing the mother animals twice within 22 hours.
- Feeding during test: no

ACCLIMATION AND CULTURE CONDITIONS
- Acclimation period: 2 h in dilution water
- Daphnia magna were cultured in 2-3 L glass vessels with approximatively 1.8 L culture medium, by 21°C (temperatures of 20 - 25°C were tolerated), in an incubator, 16 hours of illumination, illumination strength max. 20 μmol·m·^2-s^-1.
- Culture medium: Elendt M4, according to Elendt (1990), modified to a total hardness of 160 to 180 mg CaCO3/L.
- Type and amount of food: 5 x weekly ad libitum with a mix of Scenedesmus subspicatus and Chlorella vulgaris, with an algae cell density of > 10^6 cells/mL.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20 ± 2 °C

pH:

4.33 - 7.96

Dissolved oxygen:

8.03 - 8.18 mg/L

Nominal and measured concentrations:

Nominal: 62.5,125, 250, 500 andd 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glass beakers (5 cm ID x 8 cm H) 50 mL
- Material, size, headspace, fill volume: 20 mL
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: According to EEC 92/69 L383A C.2
- Intervals of water quality measurement: Prior to test start pH-values, dissolved oxygen concentration, conductivity, total hardness and temperature of the dilution water were measured. At the beginning of the test water parameters (pH value, oxygen concentration) were measured in one additional replicate per concentration and control groups. After 48 hours the water parameters in the old media were measured in all replicates per concentration and control. The temperature was recorded throughout the test with a hygrothermograph.

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: 16/8 h light/dark cycle
- Light intensity: Diffuse light, illumination range max. 20 μmol.m^-2. s^-1

EFFECT PARAMETERS MEASURED:
- The immobilisation of the daphnia was observed after 24 and 48 hours of exposure.

RANGE-FINDING STUDY
- A preliminary range finding test was conducted under static conditions with concentration levels of the test material ranging from 1 - 100 mg/L, set up in a geometrical series with a factor of 10. For the stock solution 100 mg/L were weighed out.
- Based on the results of the preliminary test a definitive test was performed with 5 dilution levels of a saturated stock solution of the test material ranging from 1:1 to 1: 16 with a dilution factor of 2 to enable the determination of 0 and 100% immobilisation after 24 and 48 hours.

VALIDITY CRITERIA
- The test is unacceptable if more than 10 percent of the control organisms are immobilised during the 48 h test period.
- The control daphnids should not be trapped on the surface of the water.
- The EC50 after 24 h of the reference material should be in the range from 1.0 - 2.5 mg/L.
- The dissolved oxygen concentration at the end should be > 5.21 mg/L (60% of the air saturation value at the temperature used).
- The deviation of the pH-value from the initial value should not be more than 1 unit in the control group.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

252 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CI: 235.7 - 269.3 mg/L

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC10

Effect conc.:

198.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Solubility of the Test Material
- The test material dilutions were clearly dissolved after filtration of the stock solution in all tested dilutions levels throughout exposure.

Range Finding Test Results
- The percentage immobility was determined in all test material and control groups after 24 and 48 hours of exposure under static conditions.
- After 48 h of exposure 100% immobilisation was not seen in the tested concentration range. No biologically significant effect (≤ 10%) after 48 h of exposure was seen at the nominal concentration of 10 mg/L.

Results of the Definitive Test
- The concentration-effect-relationships are graphically illustrated in a probability network, the 24 and 48 h EC10 and EC50 values were calculated by probit analysis and the 95% confidence interval for the EC50-value was calculated.

Water Parameters
- As the pH values of the three highest test concentrations at test start were lower than 6.0, a pH related effect is possible in the concentrations 250 to 1000 mg/L.
- During the test the temperature was in the range of 20 ± 2°C.

Validity Criteria
The validity criteria were fulfilled:
- In the control group no Daphnia were immobilised or trapped on the surface of the water.
- The EC50-value after 24 h of the reference material was in the range of 1.0 to 2.5 mg/L.
- The dissolved O2 concentration was > 5.21 mg/L (60% of the air saturation value at the temperature used).
- The pH-value did not vary by more than 1 unit in the control group.

Results with reference substance (positive control):

The percentage immobility for the reference item was determined after 24 h. The EC100-value was determined directly from the test results. The EC10 and EC50 with 95% confidence interval (Cl) was determined in a probability network by interpolation according to standard procedures.
EC-values after 24 h of the reference item in [mg/L]: EC10 = 1.1, EC50 = 1.5 (Cl 1.4 - 1.6) and EC100 = 3.2.
The EC50 -value of the reference item potassium dichromate after 24 h is within the prescribed concentration range of 1.0 - 2.5 mg/L of validity criteria according to AQS: DIN Guideline 38412 L 30.

Reported statistics and error estimates:

EC100-values were deduced directly from the dose-response relationship after 24 and 48 h. There was no mathematical calculation.
The concentration effect relationship is shown graphically in a probability network.
EC10 and EC50-values were calculated via probit analysis. Probits according to WEBER (1986).
Calculation of the confidence intervals was carried out using standard procedures according to BREITIG & TOMPLING (1982).
Calculations were performed using software SigmaPlot rel. 2000 (2000), SPSS CORPORATION

Table 1: Percentage of Daphnids Incapable of Swimming after 24 and 48 h of Exposure (n = 20)

Nominal Concentration (mg/L)	Immobilisation [%]
	24 Hour Replicates					48 Hour Replicates
	1	2	3	4	Mean	1	2	3	4	Mean
1000	100	100	100	100	100	100	100	100	100	100
500	100	100	100	100	100	100	100	100	100	100
250	40	40	20	40	35	80	40	20	40	45
125	0	0	0	0	0	0	0	0	0	0
62.5	0	0	0	0	0	0	0	0	0	0
Control	0	0	0	0	0	0	0	0	0	0

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study, the 48 hour EC50 value was 252.0 mg/L with 95% confidence interval of 235.7 - 269.3 mg/L.

Executive summary:

The acute toxicity of the test material to aquatic invertebrates was investigated in accordance with the standardised guidelines OECD 202 and EU Method C.2., under GLP conditions.

The toxicity was tested in an acute immobilisation test with Daphnia magna (STRAUS). The study was conducted under static conditions over a duration of 48 hours. During the study 20 test organisms were exposed to each test material dilution and control. The test material dilutions were clearly dissolved after filtration of the saturated solution in all tested dilution levels throughout exposure. The real test material concentrations could not be calculated based on DOC-analysis as content, purity and composition of the test material were not specified by the sponsor. The nominal concentrations were as follows: 62.5, 125, 250, 500 and 1000 mg/L. The 24 and 48 h EC10 and EC50 values were calculated by probit analysis in the tested concentration range.

In the highest test concentrations in the range 250 to 1000 mg/L at test start the pH of the solution was lower than 6 and so there may have been a pH-related effect at these concentrations.

A reference test is carried out once per month with potassium dichromate as reference item and the reference toxicity determined. The EC50-value of the reference item at 1.5 mg/L after 24 h was within the prescribed concentration range of 1.0 to 2.5 mg/L according to AQS, DIN Guideline 38412 L 30.

Water quality parameters of pH-value and dissolved oxygen concentration measured at 0 and 48 h were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

Under the conditions of this study, the 48 hour EC50 value was 252.0 mg/L with 95 % confidence interval of 235.7 - 269.3 mg/L. The 48 h EC10 and EC100 were 198.4 and 500 mg/L, respectively.

Description of key information

Under the conditions of this study, the 48 hour EC50 value was 252.0 mg/L with 95 % confidence interval of 235.7 - 269.3 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

252 mg/L

Additional information

The acute toxicity of the test material to aquatic invertebrates was investigated in accordance with the standardised guidelines OECD 202 and EU Method C.2, under GLP conditions.

The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

The study was conducted under static conditions over a duration of 48 hours with Daphnia magna (STRAUS). During the study 20 test organisms were exposed to each test material dilution and control. The test material dilutions were clearly dissolved after filtration of the saturated solution in all tested dilution levels throughout exposure. The real test material concentrations could not be calculated based on DOC-analysis as content, purity and composition of the test material were not specified by the sponsor. The nominal concentrations were as follows: 62.5, 125, 250, 500 and 1000 mg/L. The 24 and 48 h EC10 and EC50 values were calculated by probit analysis in the tested concentration range.

In the highest test concentrations in the range 250 to 1000 mg/L at test start the pH of the solution was lower than 6 and so there may have been a pH-related effect at these concentrations.

A reference test is carried out once per month with potassium dichromate as reference item and the reference toxicity determined. The EC50-value of the reference item at 1.5 mg/L after 24 h was within the prescribed concentration range of 1.0 to 2.5 mg/L according to AQS, DIN Guideline 38412 L 30.

Water quality parameters of pH-value and dissolved oxygen concentration measured at 0 and 48 h were determined to be within the acceptable limits. The validity criteria of the test guideline were fulfilled.

Under the conditions of this study, the 48 hour EC50 value was 252.0 mg/L with 95 % confidence interval of 235.7 - 269.3 mg/L. The 48 h EC10 and EC100 were 198.4 and 500 mg/L, respectively.