12-wolframosilicic acid

Short-term toxicity to fish

Administrative data

Endpoint:

short-term toxicity to fish

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:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Limit study approach based on lowest value from non-vertebrate tests.

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 at 0, 24, and 96hrs

Test solutions

Vehicle:

no

Details on test solutions:

An amount of test item (400 mg) was dissolved in test water and the volume adjusted to 2 liters to give a 200 mg/L stock solution. This stock solution was dispersed in a final volume of 20 liters of test water to give the required test concentration of 20 mg/L.

Test organisms

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Brow Well Fisheries Limited, Hebden, near Skipton, Yorkshire, UK.
- Length at study termination (length definition, mean, range and SD): 5.3 cm (sd = 0.3.
- Weight at study termination (mean and range, SD): 1.15 g (sd = 0.13.

ACCLIMATION
- Acclimation period: 10 days.
- Type and amount of food during acclimation: commercial trout pellets which were discontinued approximately 18 hours prior to the start of the definitive test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test conditions

Hardness:

140mg/L as CaCO3

Test temperature:

13C

Dissolved oxygen:

at least 10 mg O2/L.

Nominal and measured concentrations:

20mg/L nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: glass
- Type (delete if not applicable): covered
- Material, size, headspace, fill volume: 25-30 litre. Fill volume 20L.
- Aeration: yes
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- No. of vessels per vehicle control (replicates): 1
- Biomass loading rate: 0.4 g bodyweight/liter.

TEST MEDIUM / WATER PARAMETERS (typical parameters for supply)
- Source/preparation of dilution water: Tap water, dechlorinated and partially softened.
- Metals(ug/L): Sb 0.11-0.46; Cd 0.08-0.17, Al<0.19; As<0.37; Cd<0.17; Cr<0.7, Cu<0.052; Fe 221; Pb 1.0; Mn 18; Ni 5.2;
- Pesticides: below LOD except Flutriafol <0.048ug/L, metaldehyde <0.03
- Chlorine (free):0.01-0.61mg/L
- Conductivity: 214-486uS/cm
- pH 6.9 - 8.1

OTHER TEST CONDITIONS
- Adjustment of pH: yes
- Photoperiod: 16/8 hrs light/dark

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

TEST CONCENTRATIONS
- Single concentration based on EC50 from definitive tests on daphnia and algae (lowest figure).

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

5.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Effect concentrations 2

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

20 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Any other information on results incl. tables

Sublethal observations / clinical signs:

Analysis of the fresh test preparations at 0 and 72-Hours showed measured test concentrations of 5.0 and 5.2 mg/L. Analysis of the old test preparations at 24 and 96-Hours showed measured test concentrations of 5.1 and 5.4 mg/L. The measured concentrations were between 25% and 27% of the nominal concentrations, therefore the duplicate samples at 0 and 24-Hours were analyzed results from which confirmed the original results. Post test solubility samples were also prepared and analyzed at a nominal concentration of 20 mg/L in dechlorinated laboratory water which showed measured concentrations of 32 and 43% of the nominal concentration. Results of the chemical analysis show that there was a media effect which resulted in the low recovery of the test item. Given these results it was considered justifiable to base the results on the geometric mean measured test concentration to give a "worst case" analysis of the data

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

In a limit test, a nominal concentration of 20mg/L (determined as the EC50 in algae) of tungstosilicic acid at the start of the study had no adverse effects on rainbow trout during the 96 hours of the study. The measured analytical concentrations were found to decline substantially over the course of the study such that the geometric mean concentration was calculated at 5.8mg/L. Due to the differences in test media between this study and the Algal Growth Inhibition test performed on this test item (see chapter 6.1.3) the geometric mean measured test concentration of 5.8 mg/L obtained in dechlorinated tap water was considered to be equivalent to a concentration of 20 mg/L in algal culture medium. This study therefore showed that rainbow trout were not any more sensitive to the test item than algae