Reaction mass of Silicic acid, calcium salt and Silicic acid, magnesium salt

Short-term toxicity to aquatic invertebrates

Administrative data

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:

secondary literature

Data source

Reference

Reference Type:

review article or handbook

Title:

Unnamed

Year:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Silicon dioxide

EC Number:

231-545-4

EC Name:

Silicon dioxide

Cas Number:

7631-86-9

Molecular formula:

O2Si

IUPAC Name:

Silicon dioxide

Test material form:

solid

Specific details on test material used for the study:

hydrophilic SAS, tradename Ultrasil VN3, purity 98%

Test organisms

Test organisms (species):

Daphnia magna

Study design

Total exposure duration:

24 h

Results and discussion

Effect concentrations

Key result

Duration:

24 h

Dose descriptor:

EC0

Effect conc.:

ca. 1 000 - ca. 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

not determinable

Details on results:

With the water flea (Daphnia magna), SAS suspensions exceeding the limit of solubility were tested, without analysis during the 24 hours of exposure, and some immobilisation was observed. However, no significant immobilisation was observed when a solution filtered through microfibre glass filter was tested. The observed effects were likely caused by physical hampering of the Daphnia due to the presence of undissolved particles. In ecotoxicity assays, the tested concentrations should normally not exceed the limit of solubility of the substance and should not affect the test system (Method C2 - Annex V of Directive 67/548/CEE [EC, 1967]). Therefore the immobilisation of Daphnia, obtained with turbid suspensions, cannot be considered as a true toxic effect of SAS.

Applicant's summary and conclusion

Conclusions:

With the water flea (Daphnia magna), SAS suspensions exceeding the limit of solubility were tested, without analysis during the 24 hours of exposure, and some immobilisation was observed. However, no significant immobilisation was observed when a solution filtered through microfibre glass filter was tested. The observed effects were likely caused by physical hampering of the Daphnia due to the presence of undissolved particles. In ecotoxicity assays, the tested concentrations should normally not exceed the limit of solubility of the substance and should not affect the test system (Method C2 - Annex V of Directive 67/548/CEE [EC, 1967]). Therefore the immobilisation of Daphnia, obtained with turbid suspensions, cannot be considered as a true toxic effect of SAS.

Executive summary:

With the water flea (Daphnia magna), SAS suspensions exceeding the limit of solubility were tested, without analysis during the 24 hours of exposure, and some immobilisation was observed. However, no significant immobilisation was observed when a solution filtered through microfibre glass filter was tested. The observed effects were likely caused by physical hampering of the Daphnia due to the presence of undissolved particles.  In ecotoxicity assays, the tested concentrations should normally not exceed the limit of solubility of the substance and should not affect the test system (Method C2 - Annex V of Directive 67/548/CEE [EC, 1967]). Therefore the immobilisation of Daphnia, obtained with turbid suspensions, cannot be considered as a true toxic effect of SAS.