Registration Dossier

Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
26 Sep. 1991 - 27 Sep. 1991
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study with acceptable restrictions (24 h instead of 48 h)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
Test duration 24 h (acc. to the valid guideline of 04 April 1984) instead of 48 h (today) / In one test, the oxgen content was 4.4 mg/L at time 0, i.e. less than 60 % of saturation (not assumed to have affected the outcome).
GLP compliance:
yes

Test material

Constituent 1
Reference substance name:
Automatically generated during migration to IUCLID 6, no data available
IUPAC Name:
Automatically generated during migration to IUCLID 6, no data available
Details on test material:
Aerosil 200: approx. 99.8 % (SiO2): CAS-Name: Silica, amorphous,
fumed, cryst.-free; CAS-No.: 112945-52-5

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: stirring for 20 h at 20 °C, followed by gross filtration (perlon wool) and microfiltration (1.7 µm and/or 1.2 µm)
- Eluate: no, filtrate
Filtration: through perlon wool, then through glass-fibre filter
A filtrate through 1.7 microfilter (still milky/cloudy)
B. filtrate through 1.7 and 1.2 µm microfilter (visibly clear)
- Differential loading: no, limit test with 1000 mg/L
- Controls: Synthetic medium from groundwater

Note: In two pre-tests, suspensions with 1000 and 10,000 mg/L SiO2 were used.
(see following entry: 02_Degussa AG 92-0139-DGO_pre-test, short-term toxicity to aquatic invertebrates)

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: see above
- Strain: --
- Source: laboratory culture
- Age at study initiation (mean and range, SD): <24 h
- Method of breeding: standard conditions according to principles of NPR 6503 (Nederlandse practijkrichtlijn of 1980)
- Feeding during test: no

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
24 h
Post exposure observation period:
none

Test conditions

Hardness:
204 mg/L as CaCO3
Test temperature:
20 +-1°C
pH:
7.9 - 8.2
Dissolved oxygen:
4.4 - 8.3 mg/L
Salinity:
not applicable
Nominal and measured concentrations:
1000 mg/L SiO2 nominal
Details on test conditions:
TEST SYSTEM
- Test vessel: 150-ml beaker
- Type: open
- Material, size, headspace, fill volume: glass, 50 mL headspace, 100 mL test volume
- Aeration: none
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 8
- No. of vessels per pure control (replicates): 8 (synthetic medium)
- No. of vessels per filtration control (replicates): 8 (test in synthetic medium passed through perlon filter)
- Biomass loading rate: 5 animals/100 mL


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: groundwater with mineral salts supplemented (synthetic medium)
- Total organic carbon: 1.5 mg/L
- Alkalinity: no data
- Ca/mg ratio: 1.76
- Conductivity: no data


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark
- Light intensity: no data
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
24 h
Dose descriptor:
EL50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
1/40 animals were immobile (see Results table below)
Duration:
24 h
Dose descriptor:
EL0
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Remarks:
1/40 animals were immobile (see Results table below)
Details on results:
- Mortality/immobility of control: none [0/40 animals]
- Mortality/immobility of treated animals: 1/40
Overall, 1/40 animals treated with the WAFs was found immobile after 24 h of exposure (2.5 %) (Report, Table B5 and B6 [Third (main) test]:
This consisted of two parallel series using clear or slightly milky solutions of the water-soluble fractions (WSF):
0/15 immobile animals (0 %) (assumed to relate to test medium microfiltrated 1.7 µm #)
1/25 immobile animals (4 %) (in the clear solution, assumed to relate to test medium microfiltrated 1.7 µm and 1.2 µm #)

- Abnormal responses: Based on pre-tests with suspensions, it is suspected that the immobility observed,
particularly with the 10,000 mg/l suspensions, could be attributed to physical effects.
(see following entry 02_Degussa 92-0139-DGO_pre-test.)
-----------------------------------

# Note: The wording under 3.5 (p. 14) says that "....there was one immobile animal (out of 25) in the clear solution prepared by filtration of the 1000 mg/L solution". This statement would correlate with the test medium microfiltrated at 1.7 and 1.2 µm, according to Report 3.4.3 (p. 14). However, the allocation of the results to the filtration conditions is inconsistent due to contradictory indexing in the Tables B5 and B6 of the Report (p.24/25).
Results with reference substance (positive control):
not applicable
Reported statistics and error estimates:
not applicable

Any other information on results incl. tables

Number of mobile animals at given loadings of Aerosil 200

(from Report, Table B5):

Test 3

Loading [mg/L]

Time [h]

0

0*)

1000*)

1000**)

0

40

40

25

15

24

40

40

24

15

*)filtered through perlon wool, followed by microfiltration of 1.7- and 1.2-µm pore size

**)filtered through perlon wool, followed by microfiltration of 1.7-µm pore size

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Aerosil 200 is not acutely toxic at a loading of >=1 000 mg/l.