Methyl-tris acetonoximo-silane

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

The source compound Wasox-MMAC2 (mixture of: propan-2-one-O,O'-(methoxymethylsilandiyl)dioxime; propan-2-one-O-(dimethoxymethylsilyl)oxime; propan-2-one-O,O',O''-(methylsilantriyl)trioxime, EC No. 460-110-3) is considered a suitable read across partner for the target substance MAC (CAS 2594-75-4). This read-across is based on the hypothesis that source and target substances have similar toxicological properties because:

- structural similarity of the target and the source substances (the presence or absence of additional functional groups or substituents that could influence the behaviour of a chemical),

- similarity in physico-chemical profile of the source and target substances (rapid decomposition in water under cleavage of the same substance (acetone oxime)).

Both substances are similar in terms of the substitution pattern at the silicon atom (i.e. acetoneoximo and methyl group(s)). Both substances exhibit consequently similar physico-chemical properties (rapid decomposition in water, decomposition upon heating to determine boiling point) and exhibit also similar properties in terms of hydrolysis, resulting in the release of the same decomposition product (here: acetone oxime).

Reason / purpose for cross-reference:

read-across source

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No immobilisation was noted in this test. Immobilisation of contral graup daphnia was 0 % at the end of the test (guideline: maximum of 10 %).
There were no contral daphnia trapped at the water surface. pH and temperature were sufficiently stable thraughout the test period. Dissolved oxygen concentration was always higher than 3 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid?: Yes, according to OECD guideline 202
- 24h EC50: 1.19 mg / L

Validity criteria fulfilled:

yes

Conclusions:

In an acute toxicity test according to the Directive 92/69/EEC Part C.2 Daphnia magna was exposed to 100 mg WASOX-MMAC2/L. No toxic effect on D. magna was observed.

Executive summary:

The 48-hr-acute toxicity of WASOX-MMAC2 to Daphnia magna was studied under static conditions in accordance with EU Method C.2 and under GLP. Daphnias were exposed to control, and test chemical at nominal concentration of 100 mg/L for 48-hr in a limit test. Mortality, immobilization and sublethal effects were observed daily. The 48- hour EC50 was above 100 mg/L as no effects could be observed.

 

Based on the results of this study, WASOX-MMAC2 would not be classified as toxic to Daphnia magna Straus in accordance with the CLP classification system. 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates. 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): less than 24 hours old

Test Type (Flowthrough, Static, Static Renewal): Static

 

EC50 > 100 mg/L                           

NOEC ≥ 100 mg a.i./L

                      

Endpoint(s) Effected: Mortality, immobilisation

Description of key information

To evaluate the toxicity of Methyl-tris acetonoximo-silane (MAC) to aquatic invertebrates read-across from WASOX-MMAC2 is available.

Under the conditions of the valid study reported by Frenzl (2005), the acute toxicity of WASOX-MMAC2 to the freshwater invertebrates Daphnia magna has been investigated according to EU Method C.2 and gave a 48-hr EC50 of greater than 100 mg/L. Correspondingly, the No Observed Effect Concentration was 100 mg/L. This study showed that there were no toxic effects at highest concentration tested. This information is used in a read-across approach in the assessment of the target substance Methyl-tris acetonoximo-silane (MAC).

Additional information

The information on WASOX-MMAC2 is used in a read-across approach in the assessment of Methyl-tris acetonoximo-silane (MAC).

For details on the read across justification refer to the read across statement in IUCLID section 13.