Trimethoxyvinylsilane

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 Mar 19 Apr 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Deviations:

no

GLP compliance:

yes

Remarks:

according to the Japanese GLP Standard

Analytical monitoring:

yes

Details on sampling:

- Sampling method: sampled directly by each vessel and pre-treatment was not performed
- Sample storage conditions before analysis: no storage before analysis
- Methanol was measured, since the test item was quickly hydrolysed

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: test item was measured and diluted in dilution water with stirring for 120 min

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: Incorporated Administrative Agency, National Institute for Environmental Studies, Tsukuba, Japan
- Age of parental stock (mean and range, SD): within 24 hours
- Feeding during test: yes
- Food type: Chlorella vulgaris
- Amount: 0.15 mgC/animal/day

ACCLIMATION
- Acclimation period: 2006-03-08 ~ 2006-03-29
- Acclimation conditions (same as test or not): similar to test (acclimation condition: water was changed three times a week, test condition: water was changed everyday)
- Type and amount of food:Chlorella vulgaris, 0.2 mgC/animal/day
- Health during acclimation (any mortality observed): < 5% during 2 weeks before exposure

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

240 - 250 (as CaCO3) mg/L, measured at day 0, 7, 14, 15 and 21 in the freshly prepared test solution and at day 1, 8, 15 and 21 in the old test solution before renewal.

Test temperature:

19.7 - 20.2 °C, measured at day 0, 7, 14, 15 and 21 in the freshly prepared test solution and at day 1, 8, 15 and 21 in the old test solution before renewal.

pH:

7.1 - 8.4, measured at day 0, 7, 14, 15 and 21 in the freshly prepared test solution and at day 1, 8, 15 and 21 in the old test solution before renewal.

Dissolved oxygen:

4.4 - 8.8 mg/L (> 3mg/L), measured at day 0, 7, 14, 15 and 21 in the freshly prepared test solution and at day 1, 8, 15 and 21 in the old test solution before renewal.

Nominal and measured concentrations:

Nominal concentration: 12, 21, 38, 67 and 120 mg/L
Time-weighted mean: 7.2, 14.6, 28.1, 52.4 and 99.8 mg/L
The measured concentration was calculated based on the concentration of methanol yielded on hydrolysis

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL beaker
- Type (delete if not applicable): closed with a teflon sheet
- Material, fill volume: glass, 80 mL
- Aeration: no
- Renewal rate of test solution (frequency/flow rate): once a day
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): 10
- No. of vessels per control (replicates): 10

TEST MEDIUM / WATER PARAMETERS
- Culture medium different from test medium: same medium

OTHER TEST CONDITIONS
- Adjustment of pH: no adjustment
- Photoperiod: 16 hours in the light, 8 hours in the dark
- Light intensity: < 800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
mortality and general condition (abnormal behaviour) of parental animals, cumulative number of juveniles and time to first brood production were observed everyday.

RANGE-FINDING STUDY
- Test concentrations: 120 mg/L (nominal concentration)
- Results used to determine the conditions for the definitive study: An acute toxicity test of daphnia magna was performed and EC50 for 48 hours was > 120 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate (analytical grade)

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

28.1 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

cumulative number of juveniles per adult

Remarks on result:

other: The measured concentration was calculated based on the concentration of methanol yielded on hydrolysis

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

52.4 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks:

cumulative number of juveniles per adult

Remarks on result:

other: The measured concentration was calculated based on the concentration of methanol yielded on hydrolysis

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

119 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: (95% CL 104 - 149 mg/l; extrapolated from effects at conc. 14.6-99.8 mg/l).

Details on results:

- Mortality of parent animals: see Table 2
- No. of offspring produced per day per female: see Table 3
- Time to first brood release or time to hatch: Control: 8 - 9 days, 7.2 mg/L: 8 - 9 days, 14.6 mg/L: 8 - 13 days, 28.1 mg/L: 8 - 9 days, 52.4 mg/L: 8 - 9 days, 99.8 mg/L: 9 - 15 days

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- Relevant effect levels: EC 50 was 0.75 ± 0.14 mg/L

Reported statistics and error estimates:

Logit test for EC50, Williams's multi-comparison test for NOEC and LOEC

Table 1. Calculated concentration of the test item using methanol concentration in test water

Nominal concentration (mg/L)		Measured concentration (mg/L)						TWM (*1) (% of nominal)
	Date	0 new	1 old	14 new	15 old	20 new	21 old
Control		<0.05	<0.05	<0.05	<0.05	<0.05	<0.05	-
12.0		10.1	10.5	9.75	7.21	10.3	0.32 (*2)	7.20 (60) (*3)
21.0		19.2	17.6	17.1	13.5	15.6	6.01	14.6 (70)
38.0		33.5	32.0	31.1	20.2	31.6	21.5	28.1 (74)
67.0		57.3	51.3	60.3	37.6	67.4	44.3	52.4 (78)
120		104	96.4	102	77.0	120	101	99.8 (83)

New: Freshly prepared test solution

Old: Old test solutions before renewal

*1: Time-weighted mean calculated concentration during 21 days

*2: This value is estimate because it is not within the range of the calibration curve.

*3: This value is given for reference because of containing the estimate value.

Table 2. Mortality of parental Daphnia

Nominal concentration (mg/L)	Mean measured concentration (mg/L)	Cumulative Number of Dead (Percent Mortality)
		Day 1	2	4	7	14	21
Control	-	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
12.0	7.20	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
21.0	14.6	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
38.0	28.1	0 (0)	1 (10)	1 (10)	1 (10)	1 (10)	1 (10)
67.0	52.4	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
120	99.8	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)	0 (0)
12.0	7.20	0 (0)	0 (0)	0 (0)	1 (10)	1 (10)	1 (10)

Table 3. Cumulative number of juveniles produced per adult alive for 21 days

Nominal Conc., mg/L	Calculated Cnc., mg/L	Mean Cumulative Numbers of Juveniles ± S.D.	Inhibition Rate (%)	Significant difference
Control	-	107.8 ± 13.8
12.0	7.20	123.7± 8.1	-14.7	-
21.0	14.6	124.5 ± 18.9	-15.5	-
38.0	28.1	108.0 ± 19.4	-0.2	-
67.0	52.4	95.7 ± 17.2	11.2	**
120	99.8	69.8 ± 16.5	35.5	**

-: indicates no significant difference

**: indicates a significant difference (a = 0.01) from the control.

Validity criteria fulfilled:

yes

Conclusions:

A 21 day NOEC value of 28.1mg/L has been determined for the effects of the test substance on reproduction of Daphnia magna. Due to the rapid rate of hydrolysis the concentration was calculated using the measured concentration of the non-silanol hydrolysis product, methanol.

Description of key information

21-day EC₅₀: 119 mg/L (extrapolated) and NOEC: 28.1 mg/L for effects of the test substance on reproduction of Daphnia magna. Under the conditions of the test it is likely that the test organisms were primarily exposed to the hydrolysis products of the substance. The NOEC is equivalent to 20 mg/L when expressed in terms of the silanol hydrolysis product, vinylsilanetriol (CAS 143-48-6).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

20 mg/L

Additional information

A 21-day EC₅₀ of 119 mg/L (extrapolated) and NOEC of 28.1 mg/L (calculated concentration of test substance using measured concentration of the non-silanol hydrolysis product methanol (CAS 67-56-1; EC No. 200-659-6) have been determined for the effects of the test substance on reproduction of Daphnia magna. Under the conditions of the test it is likely that the test organisms were primarily exposed to the hydrolysis products of the substance. The results may be expressed in terms of the silanol hydrolysis product by adjusting for the respective molecular weights: MW hydrolysis product/MW parent * E(L)C₅₀ or NOEC value, thus 106.15/148.24 * NOEC of 28.1 mg/L = 20 mg/L as vinylsilanetriol (CAS 143-48-6).