Silicic acid, aluminum magnesium sodium salt

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2.-6.7.2009

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Due to the design of the study and analytical difficulties the effect levels were first stated based on limit of quantification. Later they were restated based on the nominal concentration.

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Deviations:

yes

Remarks:

The temperature was higher than stated in the guideline; however as no mortality was observed this deviation was assessed to be uncritical.

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Rheinland-Pfalz

Specific details on test material used for the study:

- Name of test material (as cited in study report): Silicic acid, aluminium magnesium sodium salt
- Substance type: solid
- Physical state: white powder
- Analytical purity: > 99%
- Lot/batch No.: 901274002
- Expiration date of the lot/batch: 26.01.2011
- Production date: 27.01.2009
- Storage condition of test material: room temperature, dry, 20 +/- 0.5°C

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L
- Sampling method: Observations were made every 24 hours, measuring pH and O2-concentration of the test solution in each vessel and documenting mortalities or abnormal behaviour. The content of the test item in the test vessels was measured at the beginning and at the end of the study.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A saturated solution was prepared for the test. This was done by weighing the nominal load, adding the corresponding amount of silicate free water and shaking vigorously for 24 hours. The resulting solution was enriched with mineral nutriments and filtrated through 0.45 µm filters.
- Eluate: yes
- Controls: yes
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: Zebrafish
- Strain: Danio rerio HAMILTON-BUCHANAN
- Source: Dehner Garten Center, 67433 Neustadt
- Age at study initiation (mean and range, SD): sexually immature young fish
- Length at study initiation (length definition, mean, range and SD): length 2 +/- 1 cm
- Feeding during test
- Food type: warmwater fishfood and daphnia
- Amount: about 1-2% of body weight per day
- Frequency: three times a day


ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: see test conditions
- Feeding frequency: see test conditions
- Health during acclimation (any mortality observed): Mortality didn´t sur-pass 5 %.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Post exposure observation period:

no

Hardness:

250 mg CaCO3/L

Test temperature:

25.1 to 26.4°C

pH:

adjusted to 7.8 +/- 0.2, ranging from 7.7 to 7.9 in the control and in the treatment group

Dissolved oxygen:

The concentration of dissolved oxygen stayed above 8.2 mg/L or 99 % throughout the test (100 % at 101300 Pa equals 8.57 mg/L, following DIN 38408 part 22).
Ranges were 8.1-9.5 mg/L in the control, and 8.3-10.0 mg/L in the treatment group.

Salinity:

not relevant

Nominal and measured concentrations:

The measured SiO2 concentrations of treatment and control were in the same range. The content of test item was determined by calculation from content of SiO2 of the test item (73.73%) and SiO2-determination in the test solutions. Therefore the limit of quantification (LOQ) was used for the determination of the results.
LOQ (Si): 1 mg/L, LOQ (SMAS): 1.4 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: stainless steel aquaria
- Material, size, headspace, fill volume: stainless steel, maximal volume 10 L
- Aeration: yes, accomplished with glass tubes (covered with plastic tip), frequency of bubbles 1/s
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 1 fish/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Silicate free water enriched with mineral nutriments (following the rules of EN ISO 6341)
- Culture medium different from test medium: yes, chlorine-free tap water


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 12/12 hours using neon tubes


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, behaviour

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Remarks:

based on nominal concentration

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Remarks:

based on nominal concentration

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Remarks:

based on limit of quantification

Effect conc.:

> 1.4 mg/L

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Remarks:

based on limit of quantification

Effect conc.:

>= 1.4 mg/L

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: 0%
- Other adverse effects control: no

Sublethal observations / clinical signs:

No mortality and no abnormal behaviour of the surviving fish could be observed in the substance exposed test group.

Validity criteria fulfilled:

yes

Conclusions:

Test item Silicic acid Aluminium Magnesium Sodium salt showed no toxic effects to fish. The NOEC after 96 hours was greater or equal than and the LC50 greater than 100mg/l. These results are based on the amendments dated March 18th and 25th, 2020.

Executive summary:

The short-term toxicity of SMAS to fish was examined in a 96-hour experiment. The original results stated in the study report were based on the limit of quantification. These were restated in an amendment dated March 18th, 2020, which reports the effect levels based on the nominal concentration. A second amendment, dated March 25th, 2020, corrects the erroneously reported NOECs of the original study report and the first amendment.

Description of key information

A key study on the test item showed no toxic effects on fish, resp. mortal effects on fish: EC50 > 100 mg/L, resp. NOEC >= 100 mg/L (96h)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

100 mg/L