Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Please refer to the justification for grouping of substances provided in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 118 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 118 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Conclusions:
A 72-hour EC50 value of >118 mg/L and a NOEC of ≥118 mg/L have been determined for the effects of the source substance on growth rate of Pseudokirchnerella subcapitata (OECD 201, GLP). The source substance is the hydrolysis product of the target substance. Since the hydrolysis half life is < 1 h, the results derived for the source substance describe additionally the effects of the the target substance.

Description of key information

ErC50 (72 h) >118 mg/L (OECD 201, Pseudokirchneriella subcapitata); read across from hydrolysis product (dimethylsilanediol)
NOErC (72 h) ≥ 118 mg/L (OECD 201, Pseudokirchneriella subcapitata); read across from hydrolysis product (dimethylsilanediol)

Key value for chemical safety assessment

Additional information

Experimental data for dimethoxydimethylsilane (CAS 1112-39-6) are not available. However, since dimethoxydimethylsilane hydrolyses rapidly to dimethylsilanediol and methanol (DT50 < 0.6 h) the hydrolysis products rather than the parent substance should be considered for the assessment, read-across data for the hydrolysis product, dimethylsilanediol, are considered appropriate for the assessment.

The toxicity to aquatic algae was investigated according to OECD 201 (GLP). Pseudokirchneriella subcapitata was exposed to dimethylsilanediol at concentrations of 7.5, 15, 30, 60, and 120 mg/L (nominal) including a control (Dow Corning, 2009c). The actual exposure concentrations were measured by HPLC/RID analysis. Mean measured concentrations were 93 - 121% of nominal. Thus, the effect concentrations were based on the measured concentrations. The ErC50 (72 h) was estimated to be >118 mg/L, the highest concentration tested. The NOEC (72 h) for growth rate is ≥118 mg/L.