12-wolframosilicic acid

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

12-wolframosilicic acid

EC Number:

234-719-8

EC Name:

12-wolframosilicic acid

Cas Number:

12027-38-2

Molecular formula:

H.1/4O40SiW12

IUPAC Name:

tetrakis(hexaoxocyclotritungstoxane); silicic acid

Test material form:

solid

Specific details on test material used for the study:

Identification: Tungstosilicic-acid
Physical state/Appearance: White Crystalline Solid
Batch: MKBR8664V
Purity: 65.0% w/w
Expiry Date: 26 August 2016
Storage Conditions: Room temperature in the dark over silica gel

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Sampling for analysis at 0 and 48 hours.

Test solutions

Vehicle:

no

Details on test solutions:

A nominal amount of test item (2000 mg) was dissolved in test water and the volume adjusted to 2 liters to give the 1000 mg/L test concentration from which a series of dilutions was made to give further test concentrations of 56, 100, 180, 320 and 560 mg/L. Due to the acidic nature of the test item, the pH of the 1000 mg/L test concentration was adjusted using 1 Molar NaOH to 7.7 prior to preparation of the test series.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Source: in-house laboratory cultures.
- Age of test items k (mean and range, SD): <24 hours
- Feeding of stock: mixture of algal suspension (Desmodesmus subspicatus) and Tetramin flake food suspension.
- Frequency: daily.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

250 mg/L as CaCO3

Test temperature:

21 to 22 C

pH:

7.8 +/-22

Dissolved oxygen:

8.1 - 8.4mg O2/L

Nominal and measured concentrations:

Nominal: of 56, 100, 180, 320, 560, 1000 mg/L.
Measurements at time 0: 46, 87, 159, 299, 511, 948mg/L
Measurements at time 48hrs: 39, 68, 118, 210, 378, 966mg/L
Geometric means: 42, 77, 137, 251, 439, 957mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:150ml glass jars
- Type (delete if not applicable): covered
- Material, size, headspace, fill volume: 100ml fill
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter):
- Renewal rate of test solution (frequency/flow rate):
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates):4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M7 Medium - reconstitued water.

OTHER TEST CONDITIONS
- Adjustment of pH: Yes
- Photoperiod: 16/8 (light/dark)
- Light intensity: 1200Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility

VEHICLE CONTROL PERFORMED: not applicable

RANGE-FINDING STUDY
- Test concentrations: 0.10, 1.0, 10, 100 and 1000 mg/L -with and without pH adjustment.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

120 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

EC50(48hr) 0.54mg/L. The results from the positive control with potassium dichromate were within the normal range for this reference item.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

In a guideline study, daphnia magna were exposed to tungstosilicic acid for a period of 48hrs. An EC50 value of 120mg/L was established.