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

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study. No analytical confirmation of exposure concentrations.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

not applicable

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A single 1,000 mg/L WAF was prepared for the test. The WAF was formulated by combining 1.0 g of test substance and 1 liter of dilution water in a plastic mixing vessel equipped with a magnetic stirrer. The mixture was stirred for approximately 24 hours (vortex was approximately 25% od media depth) and allowed to settle for approximately 1 hour. Following the settling period the water phase containing the WAF was removed from the mixing vessel with a siphon using care to exclude any material on the surface, bottom, or sides of the mixing vessel. Test media was prepared at 0.10, 1.0, 10, 100, and 1,000 mg/L by combining the appropriate volume of the 1,000 mg/L WAFG and dilution water.
- Eluate: No data
- Differential loading: No data
- Controls: deionized dilution water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): NA
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 0.10, 1.0, 10, 100, 1,000 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): The 1,000 mg/L WAF was slightly cloudy throughout the test. No other insoluble material was noted during the test.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Common name: water flea
- Strain: daphnia magna
- Source: Procured from a commercial supplier Aquatic Research Organisms, Hampton, New Hampshire on June 1, 1994
- Age at study initiation (mean and range, SD): Daphnids were Juveniles less than 24 hours old
- Weight at study initiation (mean and range, SD): Average 0.44 mg
- Length at study initiation (length definition, mean, range and SD): No data
- Valve height at study initiation, for shell deposition study (mean and range, SD): NA
- Peripheral shell growth removed prior to test initiation: NA
- Method of breeding: The daphnids were produced by adult daphnids that were maintained under test conditions at TR. Wilbury facility for more than 7 days.
- Feeding during test
- Food type: Daphnids were not fed during the test.
- Amount: NA
- Frequency: NA


ACCLIMATION
- Acclimation period: Seven days. - Acclimation conditions (same as test or not):
- Type and amount of food: Daphnids were provided with the freshwater alga, Selenastrujm capricornutum, and a yeast/trout chow mixture daily throughout the acclimation period.
- Feeding frequency: Ad libum
- Health during acclimation (any mortality observed): During acclimation daphnids were not treated for disease and they were free of apparent sickness, injuries, and abnormalities at the beginning of the test (no mortality occurred during the 48 hours before the start of the test).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not applicable

Hardness:

160 mg/l as CaCO3

Test temperature:

19.9-20.9 deg. C

pH:

8.0-8.6

Dissolved oxygen:

8.4-9.1 mg/l

Salinity:

no data

Nominal and measured concentrations:

nominal: 0.10, 1.0, 10, 100, and 1000 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 300 ml beakers that contained 250 ml of test solution
- Type (delete if not applicable): open / closed- Vessels were loosely covered during the test.
- Material, size, headspace, fill volume: Fill volume 300 ml
- Aeration: None
- Type of flow-through (e.g. peristaltic or proportional diluter): Static
- Renewal rate of test solution (frequency/flow rate): None
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): Single
- No. of vessels per control (replicates): Single
- No. of vessels per vehicle control (replicates): NA
- Biomass loading rate: Approximately 0.018 g/L.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Water used for acclimation of test organisms and for all toxicity testing was deionized. Water was adjusted to a hardness of 160 mg/L as CaCO3 and stored in 500- gallon polyethylene tanks where it was aerated and continuously passed through a particle filter, ultraviolet sterilizer, and activated carbon.

- Total organic carbon: 1 mg/L
- Particulate matter: No data
- Metals: all non detect; iron 0.03 mg/L
- Pesticides: non detect
- Chlorine: non detect
- Alkalinity: no data
- Ca/mg ratio: no data
- Conductivity: 600 to 650 µmhois/cm
- Culture medium different from test medium: No
- Intervals of water quality measurement: 24 hour intervals

OTHER TEST CONDITIONS
- Adjustment of pH: no range was 8.0 to 8.6
- Photoperiod: 16 hour’s light/8 hours dark
- Light intensity: Ambient laboratory lighting


EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality and sublethal effects recorded initially and after 24 and 48 hours


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10%
- Justification for using fewer concentrations than requested by guideline: NA
- Range finding study
- Test concentrations: Control, 0.10, 1.0, 10, 100 and 1,000 mg/L by combining the appropriate volume of the 1,000 mg/L WAF and dilution water.
- Results used to determine the conditions for the definitive study: This test is a range finding test.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CL 10 to 100 mg/L

Details on results:

- Behavioural abnormalities: none
- Observations on body length and weight: No data
- Other biological observations: immobility
- Mortality of control: One hundred percent survival occurred in the control and no control sublethal effects were noted during the test.
- Other adverse effects control: None
- Abnormal responses: immobility
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The 1,000 mg/L WAF was slightly cloudy throughout the test. No other insoluble material was noted during the test.
- Effect concentrations exceeding solubility of substance in test medium: The 1,000 mg/L WAF was slightly cloudy throughout the test. No other insoluble material was noted during the test.

Results with reference substance (positive control):

not applicable

Reported statistics and error estimates:

Data were evaluated using the binomial/non-linear interpolation method (Stephan 1983). The NOEC was defined as the highest concentration tested that allowed at least 90% survival and did not cause sublethal effects.

Control (0 mg/l): 100% survival
0.10 mg/l: 100% survival
1.0 mg/l: 100% survival
10 mg/l: 100% survival
100 mg/l: 20% survival
1000 mg/l: 0% survival

Validity criteria fulfilled:

yes

Conclusions:

Exposure of the aquatic invertebrate, Daphnia magna, to the test substance resulted in a 48-h EC50 of 32mg/L and a NOEC of 10 mg/L based on immobility and survival.

Executive summary:

The acute toxicity of the WAF of the test substance to the daphnid, Daphnia magna, was investigated during a range-finding study. The test was performed under static conditions with the WAF of 0.10, 1.0, 10, 100 and 1000 mg/L mixtures of test substance and water.

The 48 hour median effective concentration (EC50) of the WAF to daphnids is 32 mg/L. The 48 hour no observed effect concentration (NOEC) is 10 mg/L.

Description of key information

EC50 (48-h) 32 mg/L for Daphnia magna (OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

32 mg/L

Additional information

The acute toxicity testing available for the test substance is a range-finding study conducted with the daphnid, Daphnia magna. The study was performed under GLP conditions and followed OECD testing guideline 202. A water accommodated fraction (WAF) of the test substance was prepared for testing. The NOEC was defined as the highest concentration tested that allows at least 90% survival and does not cause sublethal effects. The 48 -hr NOEC was 10 mg/L based on sublethal effects, i.e. immobilization. The 48-hr EC50 was 32 mg/L.