[3-(2,3-epoxypropoxy)propyl]trimethoxysilane

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:

guideline study with acceptable restrictions

Remarks:

Study is considered to be reliable with the following restrictions: · study was not conducted under GLP · exposure concentrations were not analytical verified · age of neonates not documented · sublethal effects not documented · dissolved oxygen not documented

Principles of method if other than guideline:

USEPA. 1975. Methods for Acute Toxicity Tests with Fish, Macroinvertebrates, and Amphibians. Ecological Research Services, EPA-660/3-75-009. 61

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION

- Method: Neat test material added directly to exposure vessels

Test organisms (species):

other: Simocephalus vetulus

Details on test organisms:

TEST ORGANISM

- Source: Simocephalus vetulus neonates (age not documented) were obtained from laboratory cultures maintained under the same conditions used for testing.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

Hard water

Test temperature:

23±1ºC

pH:

7.4-7.7

Dissolved oxygen:

Not reported

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal concentrations: 0, 100, 250, 300, 350, 400, 450, 500 mg/L

Details on test conditions:

TEST SYSTEM

- Test design:  static exposure, no solution renewal

- Dilution water:  reconstituted hard-water; glass-distilled water reconstituted with 192 mg/L NaHCO3, 120 mg/L CaSO4, 120 mg/L MgSO4, and 8 mg/L KCl (pH adjusted to 7.5 with NaOH).      

- Exposure vessel:  250-mL glass beakers containing 200 mL of dilution water; vessels aerated prior to but not after study initiation; vessels covered during exposure

- Replication:  duplicate controls and exposure concentrations, 10 organisms per exposure vessel; total of 160 organisms

- Observation periods:  0, 24, 48 h after study initiation

- Photo-period:  18-h light/6-h dark; 600 foot-candle

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

< 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

324 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 301-343

Details on results:

- Mortality of control: 0%

Reported statistics and error estimates:

LC50 values were determined by Probit analysis.

Table 1. Test results

Nominal concentration (mg/L)	Percentage mortality after 24 hours	Percentage mortality after 48 hours
0 (Control)	0	0
250	5	20
300	5	25
350	20	45
400	15	90
450	15	95
500	30	100

Validity criteria fulfilled:

yes

Conclusions:

A 48-hour LC50 value of 324 mg/L and NOEC of <250 mg/L have been determined for the effects of the test substance on mortality of Simocephalus vetulus (Family Daphnidae). It is likely that the test organisms were exposed primarily to the hydrolysis products of the substance.

Description of key information

Short-term toxicity to invertebrates: 48 hour LC₅₀ value of 324 mg/l (nominal) (OECD 202). The LC₅₀ is equivalent to 266 mg/l when expressed in terms of [3-(2,3-epoxypropoxy)propyl]silanetriol.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

266 mg/L

Additional information

A 48 hour LC₅₀ value of 324 mg/l (nominal concentration) has been determined for the effects of the test substance on mortality of Simocephalus vetulus (Family Daphnidae) (Dow Corning, 1978).

In view of the test media preparation method and exposure regime it is likely that the test organisms were exposed primarily to the hydrolysis products of the substance. The results may be expressed in terms of concentration of the hydrolysis product, [3-(2,3-epoxypropoxy)propyl]silanetriol, by applying a molecular weight correction: (MW of silanol = 194.26 / MW of parent = 236.34) * 324 = 266 mg/l.

These values have been selected in preference to those from two equally reliable tests on the basis of being lower.

The other reliable studies report the following values:

A 48 hour EC₅₀ value of 710 mg/l (nominal concentration) has been determined for the effects of the test substance on mobility of Daphnia magna (Springborn Smithers, 2002).

A 48 hour EC₅₀ value of 473 mg/l (nominal concentration) has been determined for the effects of the test substance on mobility of Daphnia magna (Huls, 1993).