A mixture of: propan-2-one-O,O'-(methoxymethylsilandiyl)dioxime; propan-2-one-O-(dimethoxymethylsilyl)oxime; propan-2-one-O,O',O''-(methylsilantriyl)trioxime

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:

February 22-24, 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

According to EU Method C.2, with GLP.

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 0.0498 g test substance was dispersed in 500 mL reconstituted water. The test substance was added in drops to approximately 200 mL reconstituted water, stirred by using magnetic stir plates and bars. Then the required amount of reconstituted water was added. The preparation was stirred for approximately half an hour to obtain a preparation for testing in which the test substance is completely hydrolysed.
- Controls: Yes (water)

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: (Crustacea, Cladocera)
- Source: MicroBioTests Inc., Industriezone "Oe Prijkels", Venecoweg 19,9810 Nazareth, Belgium
- Age at study initiation (mean and range, SD): less than 24 hours old
- Method of breeding: Neonates of Daphnia magna were obtained by hatching ephippia. The ephippia were hatched in the laboratory in a petri dish containing reconstituted water in a temperature controlled room at approx. 20-22 °C under continuous illumination of approximately 6000 Lux. Approximately 2 hours before the start of the test the neonates were fed with a suspension of Spirulina powder (MicroBioTests Inc.), as also in traditional cultures the neonates have the opportunity to take up some feed particles. The neonates were collected for this test at approximately 87 hours after initiation of hatching.
- Feeding during test: No.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

250 mg CaCO3/L

Test temperature:

20 ºC throughout the test period

pH:

Test substance medium: 7.6-7.9
Control medium: 7.6-7.8

Dissolved oxygen:

Test substance medium: 9.6-9.8 oxygen mg/L
Control medium: 9.5 oxygen mg/L

Nominal and measured concentrations:

Nominal concentrations: 0 (control) and 100 mg/L.

Details on test conditions:

TEST SYSTEM
- Test vessel: Disposable mutiwell test plates with 30 test wells.
- Type (delete if not applicable): closed with a transparent lid.
- Material, size, headspace, fill volume: Each plate has four 10 ml wells each (replicates A, B, C, D) for the control and for 5 concentrations. Additionally, for each concentration the plates are provided with "rinsing wells" to prevent dilution of the test substance during the transfer of the daphnia from the hatching petri dish to the test wells .
- Aeration: No extra aeration, but slight circulation of air is still possible when the lid of the test plate is closed.
- No. of organisms per vessel: 5 neonates per well
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The stock solutions for preparation of the reconstituted water according to ISO 6341 were obtained by MicroBioTests Inc. (Batch No. ISOD22050503). The water was aerated and the pH, the dissolved oxygen concentration and the water hardness were checked before using.

OTHER TEST CONDITIONS
- Photoperiod: Artificial light from 4 a.m. to 8 p.m.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): 24 and 48 hours after start of exposure to the test substance the neonates were observed for their swimming behaviour. Animals not able to swim within approximately 15 s after gentle agitation of the test container are evaluated as immobilised. Additionally immobilised animals trapped at the surface were counted to evaluate a possible influence of the test substance to
the water surface tension.
Visual observations were made at the same time as the animal observation. Any change (like change in colour or precipitation ) was recorded.
Temperature was determined daily in the "rinsing wells". Dissolved oxygen concentration and pH of the test media were determined in the surplus of the test media at the start of the test and in the pooled test media of each concentration at the end of the test. Total hardness of the reconstituted water was checked once before start of hatching.

TEST CONCENTRATIONS
- Range finding study: In a preliminary test with 10 and 100 mg/ test substance equivalents / L no immobilisation was noted.
- Test concentrations: 100 mg/L

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

other: test substance equivalents (variety of degradation products)

Basis for effect:

mobility

Details on results:

No immobilisation was noted.
The test media were clear and colourless during the whole exposure time.

Immobilisation 48 hours after the start of exposure

Group	Concentration (mg/L)	Immobilised neonates/total number of neonates
		Number of replicate				Total number	Total %
		A	B	C	D
Control	0	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0
Test substance	100	0 / 5	0 / 5	0 / 5	0 / 5	0 / 20	0

Validity criteria fulfilled:

yes

Remarks:

(Constant conditions were maintained (temperature, pH); there was no immobilisation in the negative control group; the dissolved oxygen concentration was higher than 3 mg/I at each determination)

Conclusions:

The 48-hour EC50 value of the test substance Wasox-MMAC2 was > 100 mg/L (based on mobility).

Executive summary:

The acute toxicity of the test substance Wasox-MMAC2 to Daphnia magna was determined in a 48 hours static test (According to EU Method C.2). A total of 20 daphnias, divided into 4 replicates (5 daphnias each) were treated with a single dose of 100 mg/L (limit test). A negative control group, exposed to reconstituted water only, was included. Daphnia immobilization was inspected at 24h and 48 h after the start of the test, as well as immobilized animals trapped at the surface were counted to evaluate a possible influence of the test substance to the water surface tension. The pH and the dissolved oxygen concentration were tested at the start and at the end of the test. The temperature was controlled at the start, after 24 hours and at the end of the test. Test validity criteria were fulfilled. The 24 and 48 hours EC50 value of the test substance was > 100 mg/L. The No Observed Effect Concentration (NOEC) was ≥100 mg/L.

Description of key information

Key study: EU Method C.2 and GLP. The 48-hour EC50 value of the test substance Wasox-MMAC2 was > 100 mg/L (based on mobility).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Key study: The acute toxicity of the test substance Wasox-MMAC2 to Daphnia magna was determined in a 48 hours static test (according to EU Method C.2 and GLP). The 48 hours EC50 value of the test substance, based on mobility, was > 100 mg/L.