Bis[(2-ethyl-1-oxohexyl)oxy]dioctylstannane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1st October 2002 to 12 December 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

other: read-across target

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Sampling method: In duplicate, one sample of the newly prepared (clean) control medium and the newly prepared (clean) exposure medium were taken at t = 0 h. Thereafter, in duplicate, one sample of the control medium (24 h, spent; 24 h, clean; 48 h spent) and two samples of the exposure medium (24 h; spent, 24 h clean, 48 h, spent) were taken. 100 mL samples were collected in 125 mL Nalgene bottles. One set of samples was transferred to the analytical laboratories immediately after sampling. All other samples were stored in a freezer.
- Sample storage conditions before analysis: <-18 °C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A saturated test solutions was prepared as a WSF. One day prior, the test solutions were prepared by adding 300 mg test substance to 3 litres of DSWL-E (loading rate 100 mg/L). The contents of the flask were stirred for 16 hours followed by 6 hours standing. The aqueous phase was tapped off, the first 100 mL discarded and the aqueous phase aerated for 2 hours.
- Controls: DSWL-E was used as a control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: Cultured in the testing laboratory
- Feeding during test: The daphnids were not fed during the test
- Method of breeding: Every week cultures were started with ca. 150 daphnids of the same age (approximately 1 day) in 4 litres of dilution water. The medium was replaced completely at least once a week at which time, all young were removed. Cultures were discarded every 4 weeks

ACCLIMATION
- Acclimation period/conditions: The Daphnia were bred under the same conditions as the test.
- Type and amount of food: approximately 4 x 10^9 cells (Chlorella) and ca. 0.13 g of yeast per 4 L.
- Feeding frequency: Daily

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

209 mg/L as CaCO3

Test temperature:

20 ± 1 °C

pH:

8.1 - 8.2

Dissolved oxygen:

8.5 - 9.4 mg/L

Nominal and measured concentrations:

A WSF (Water soluble fraction) was prepared for the performance of this test. 0.15 mg/L (initial concentration) as determined by ICP-AES.

Details on test conditions:

TEST SYSTEM
- Test vessel: 150 mL all glass beakers
- Aeration: The beakers were not aerated
- Renewal rate of test solution: The test solutions were replaced at t = 24
- 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: The groundwater was obtained from a locality near Linschoted (the Netherlands).
- Total organic carbon: 1.55 mg/L
Composition:
6.05 mg/L CO2
164 mg/L Hydrocarbon dioxide
< 2 mg/L Carbonate
<1 mg/L Sulphate
<1 mg/8.03 mg/L Silicate
0.004 mg/L Manganese
0.069 mg/L Fluoride
1.22 mmol/L Na^+
0.20 mmol/L K^+
1.38 mmol/L Ca2^2+
0.71 mmol/L Mg^2+
2.81 mmol/L Cl^-
0.65 mmol/L SO4^2-
1.39 mmol/L HCO3^-
46.25 µmol/L B
1.82 µmol/L Mn
7.22 µmol/L Li
0.59 µmol/L Rb
0.57 µmol/L Sr
0.16 µmol/L Br
0.26 µmol/L Mo
0.10 µmol/L Cu
0.10 µmol/L Zn
0.04 µmol/L Co
0.02 µmol/L I
0.01 µmol/L Se
0.05 µmol/L V
0.36 µmol /L Fe
0.67 µmol/L Na2EDTA
- Conductivity: 26.7 Ms.m^-1
- Culture medium different from test medium: Culture medium was the same used in the test

OTHER TEST CONDITIONS
- Photoperiod: 16 h light and 8 h dark with a 30 minutes dusk transition period

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The mobile and immobile animals were counted after 24 hours and at the end of the test (animals not able to swim within 15 seconds after gentle agitation of the containers). Observations of the condition (swimming behaviour, colour and any other visually observable morphological or behavioural criterion) of the mobile animals was performed at the same time and compared with the control vessels.

TEST CONCENTRATIONS
- Range finding study: A range finding study demonstrated that no adverse effects were expected within the aqueous solubility of the test substance. The test was therefore carried out using a limit test with a WSF (water soluble fraction).

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: EC50 of the test material is greater than the limit of solubility of the test substance. Aqueous solubility of the test material is between 0.09 and 0.54 mg/L

Details on results:

- Behavioural abnormalities: One daphnid in the WSF was found to be swimming with irregular movements at the end of the test.
- Mortality of control: No daphnids were found to be immobile in the control

Table 1: Results of the chemical analysis

Dose	Measured concentrations
	t = 0 h (clean) mg/L	t = 24 h (spent)		t = 24 h (clean) mg/L	t = 48 h (spent)
		mg/L	% of initial		mg/L	% of initial
0	<0.04	<0.04		<0.04	<0.04
WSF	0.15	0.1	67	0.54	0.27	50
WSF		0.09	60	0.51	0.2	39

 

Table 2: Number of mobile daphnids and their condition

Time (h)	Concentration as volume % of a saturated solution
	0				WSF
0	5a	5a	5a	5a	5a	5a	5a	5a
24	5a	5a	5a	5a	5b	5b	5b	5b
48	5a	5a	5a	5a	4b 1j	5b	5b	5b
a = Condition of all test animals, visually assessed, normal (=good) b = Condition of all test animals visually assessed, equal to that of the control animals j = The daphnia swam with irregular movements WFS = Water soluble fraction

 

Table 3: Summary of results

Parameter	Effect	Dose	Concentration
24 h EC50	Mobility	WSF	> Aqueous solubility
48 h EC50	Mobility	WSF	> Aqueous solubility
48 h EC100	Mobility	WSF	> Aqueous solubility
48 h NOEC	Mobility	WSF	> Aqueous solubility
48 h NOEC	Condition	WSF	> Aqueous solubility

 

Table 4: pH and oxygen concentrations of test solutions

Time	Concentration as volume percentage of a saturated solution^1
	0								100
	A		B		C		D		A		B		C		D
	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)	pH	O2 (mg/L)
0 h (Newly prepared solutions)	8.1	9.3	8.1	9.4	8.1	9.4	8.1	9.3	8.2	8.6	8.2	8.6	8.2	8.5	8.2	8.5
24 h (Newly prepared solutions)	8.2	9.3	8.2	9.3	8.2	9.3	8.2	9.3	8.2	8.9	8.2	8.8	8.2	8.8	8.2	8.8
24 h (Spent solutions)	8.2	9.4	8.2	9.3	8.2	9.3	8.2	9.3	8.2	9.1	8.2	9.1	8.2	9.1	8.2	9.1
48 h (Spent solutions)	8.2	9.3	8.2	9.3	8.2	9.2	8.2	9.3	8.2	9.2	8.1	9.2	8.1	9.2	8.1	9.3
^1Water Soluble Fraction, prepared by stirring 100 mg test substance per litre of media

Validity criteria fulfilled:

no

Remarks:

All criteria were met except a stable concentration of the test substance in the media. This was attributed to the preparation method.

Conclusions:

Under the conditions of the test, the 48 h EC50 of the test substance with Daphnia magna was greater than the water solubility of the test substance.

Executive summary:

The acute toxicity of the test substance to the fresh-water crustacean Daphnia magna was determined in a semi-static test conducted in accordance with OECD 202 and EU Method C.2 and in line with GLP.

Due to the insolubility of the test substance, the study was performed with a water soluble fraction as a limit test.

Under the conditions of the test, the 48 h EC50 of the test substance was found to be greater than the water solubility of the test substance.

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

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 structurally similar substance dioctyltin oxide (Public name: DOTO, CAS: 870-08-6, EC: 212-791-1), see attached justification.

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 0.21 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: EC50 of the test material is greater than the limit of solubility of the test substance. Aqueous solubility of the test material is between 0.09 and 0.54 mg/L

Description of key information

Read-across to structurally similar substance: DOTO (Dioctyltin oxide), CAS 870-08-6

Under the conditions of the test, the 48 h EC50 of the test substance was found to be greater than the water solubility of the test substance.

Additional information

Read-across to structurally similar substance DOTO (Dioctyltin oxide), CAS 870-08-6

The acute toxicity of the test substance to the fresh-water crustacean Daphnia magna was determined in a semi-static test conducted in accordance with OECD 202 and EU method C.2 and in line with GLP. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

Due to the insolubility of the test substance, the study was performed with a water soluble fraction as a limit test.

Under the conditions of the test, the 48 h EC50 of the test substance was found to be greater than the water solubility of the test substance.

Supporting information was available in the form of Rufli (1988). The study was performed to the OECD guideline 202. However the observations performed during the study did not extend past the 24 hour period, with no explanation as to why the 48 hour observation was not performed. The study lacked details in the reporting in some areas and some deficiencies were present in the performance of the test, such as the test concentrations were not maintained throughout the entire test period. As such the study was assigned a reliability score of 2 in line with the principles of assigning data quality as outlined in Klimisch (1997). As the results of the study confirmed the lack of toxicity observed in the more reliable key study, the study was considered reliable with restrictions and suitable as supporting information to the key study.

Under the conditions of the test, the EC50 of the test substance in Daphnia magna was determined to be greater than the water solubility of the test substance.