Reaction Mass of zirconium difluoride oxide and fluorozirconic 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

Study period:

2018-06-18 to 2018-07-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction Mass of zirconium difluoride oxide and fluorozirconic acid

EC Number:

947-897-3

Molecular formula:

(ZrOF2 )x(F6Zr.2H)y

IUPAC Name:

Reaction Mass of zirconium difluoride oxide and fluorozirconic acid

Test material form:

other: aqueous solution

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Identification: Reaction Mass of zirconium difluoride oxide and fluorozirconic acid
- Source and lot/batch No.of test material: 18-KTS-003
- Expiration date of the lot/batch: no data
- Weight % water: 73.8%
- Weight % Zr: 11.5%
- Weight % solids: 26.2%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature, protected from light

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Sampling method: Duplicate test water samples were collected from the batches of test solution prepared for each treatment and control group at the beginning of the test, and from two of the four replicate test chambers in each group 48 hours (± 1 hour) to measure concentrations of the test substance. Test concentrations were measured as zirconium (Zr) and fluoride (F) ion in samples. Results of the analyses were used to calculate mean measured test concentrations. Samples were collected from mid-depth and placed in plastic vials. One set of samples collected at each sampling interval was processed immediately for analysis. The duplicate set of samples was stored under refrigeration as back-up samples for possible analysis. A third set of samples (50 mL) was collected as above for the analysis of fluoride in the test solutions. Samples were analysed using an ISE probe for fluoride and ICP-MS for zirconium.

- Sample storage conditions before analysis: the samples were stored in a refrigirator.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Test solution concentrations were not adjusted for the active ingredient of the test substance during preparation, and all concentrations are based on the test substance as received.
A primary stock solution was prepared by mixing a calculated amount (0.2002 g) of test substance into a tared glass beaker. The contents of the beaker were rinsed with dilution water into a 2 L glass volumetric flask partially filled to volume. The solution was sonicated for approximately 15 minutes, then filled to volume, producing a 2 L stock solution at a nominal concentration of 100 mg/L, the highest concentration tested. The 100 mg/L solution was then stirred with a Teflon®-lined magnetic stir bar on a magnetic stir plate for approximately 15 minutes.
After mixing the stock solution appeared white and translucent, but with no visible precipitates. Aliquots of the primary stock solution were proportionally diluted with dilution water to a final volume of 1 L to prepare four additional test solutions at nominal concentrations of 6.3, 13, 25 and 50 mg/L. The solutions were stirred with a Teflon®-lined magnetic stir bar on a magnetic stir plate for approximately 15 minutes, and 250 mL of solution was placed in each of two replicate test chambers per treatment group. The negative control solution was dilution water only.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): At test initiation, 24 hours and test termination (48 hours), the negative control and 25 mg/L test solutions in the test chambers at these nominal concentrations appeared clear and colorless. The 50 and 100 mg/L test solutions were translucent and white (increasing with increasing concentration) throughout the test.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water-flea
- Source: in-house laboratory culture with a known history
- Age at study initiation (mean and range, SD): <24h (from parental daphnids of more than 2 weeks old)
- Feeding during test: no

ACCLIMATION
- Acclimation period: 21 days
- Acclimation conditions (same as test or not): yes. Water temperatures in the cultures ranged from 19.4 to 20.3ºC, the pH of the water ranged from 8.1 to 8.4, and the DO concentrations were >= 7.5 mg/L (>= 82% of saturation).
- Type and amount of food: mixture of yeast, cereal grass media and trout chow (YCT), supplemented with a vitamin stock solution and a suspension of the freshwater green alga, Raphidocelis subcapitata formally (Pseudokirchneriella subcapitata).
- Feeding frequency: during the 24-hour period prior to test initiation
- Health during acclimation (any mortality observed): adults showed no signs of disease or stress, no ephippia were produced during the holding period, and mortality in the culture stock was < 20% in the two-day period prior to test initiation.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

136 mg/L as CaCO3

Test temperature:

20.3-21.0°C

pH:

At t= 0h: 7.5-8.1
At t= 24h: 8.0-8.4
At t= 48h: 8.2-8.4

Dissolved oxygen:

At t= 0h: 8.7-9.1 mg/L
At t= 24h: 8.7-9.0 mg/L
At t= 48h: 8.6-8.7 mg/L
Dissolved oxygen concentrations remained ≥ 8.6 mg/L (≥ 95% of saturation) throughout the test.

Salinity:

not relevant

Conductivity:

average: 317 μS/cm

Nominal and measured concentrations:

Final test:
Nominal concentrations: 0, 6.3, 13, 25, 50 and 100 mg/L
Measured concentrations of test item in test sample (mg/L) at t=0h: Measured concentrations of test item in test sample(mg/L) at t=48h: Measured concentrations of test item in test samples ranged from approximately 88.7 to 102% of nominal

Nominal Fluoride concentrations: 0, 3.47, 7.15, 13.8, 27.5, 55 mg/L
Measured concentrations of fluoride (mg/L) at t=0h: Measured concentrations of fluoride (mg/L) at t=48h: Measured concentrations of fluoride in test samples ranged from 20-32% of nominal concentrations but remained stable during the test period.

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Material, size, headspace, fill volume: glass beaker, 250 mL, filled with 200 mL, covered with a plastic petri dish. The depth of the test water in a representative chamber was 6.7 cm
- Aeration: not during the test
- 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: freshwater obtained from a well approximately 40 meters deep located on the EAG Laboratories-Easton site. The well water was passed through a sand filter to remove particles greater than approximately 25 µm, and pumped into a 37,800-L storage tank where the water was aerated with spray nozzles. Prior to use in the test system, the water was filtered to 0.45 µm to remove fine particles, and was passed through an ultraviolet (UV) sterilizer
- Total organic carbon: <2 mg C/L
- Alkalinity: 166 – 178 mg/L CaCO3
- Conductivity: 317 – 333 µS/cm
- Hardness: 124 – 144 mg/L as CaCO3
- Culture medium different from test medium: yes
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours of light and 8 hours of darkness.
- Light intensity: 564 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Immobility was defined as those organisms which are not able to swim within 15 seconds after gentle agitation of the test container and was monitored after 24 and 48 hours of continuous treatment with the test substance.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations range-finding: 0.24, 0.81, 2.7, 9.0, 30
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

- Mortality of control: none
- Other adverse effects control: none
- Abnormal responses: none
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: The negative control through 25 mg/L test solutions in the test chambers appeared clear and colorless during the test, with no evidence of precipitation observed. The 50 and 100 mg/L test solutions appeared translucent and white (increasing with increasing concentration) during the test, with no evidence of precipitation observed.
- 48-h NOEC ≥ 100 mg/L

Results with reference substance (positive control):

not examined

Reported statistics and error estimates:

The absence of immobility in any of the treatment groups during the test precluded the statistical calculation of EC50 values at 24 and 48 hours. Therefore, the EC50 values were estimated to be greater than the highest concentration tested. The no-immobility concentration and the no-observed-effect concentration (NOEC) were determined by visual interpretation of the immobility and observation data. The highest test concentration causing no immobility at test end and the lowest test concentration causing 100% immobility at test end are also reported.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of Reaction Mass of Zirconium Difluoride Oxide and Fluorozirconic Acid to Daphnia magna was determined in a 48 hour static test according to the OECD guideline 202.
Based on nominal concentrations, the 48-h EC50 was determined to be > 100 mg/L. The highest nominal concentration causing no immobility at test end was 100 mg/L.
It can be concluded that the Reaction Mass of Zirconium Difluoride Oxide and Fluorozirconic Acid (nominal 100 mg/L) did not induce any immobilisation of Daphnia magna after 48 hours of exposure.
The results of the test can be considered reliable without restriction.