Strontium hydrogen phosphate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03-05 February 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was performed in accordance with the OECD 202 guideline and complied with the principles of GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

4.8 mL samples for possible analysis were taken from all test concentrations and the control at t=0 and t-48 hours and were stored in the freezer until analysis. In addition, the filter containing undissolved residue was retained for possible analysis.

Vehicle:

no

Details on test solutions:

Preparation of test solutions started with a loading rate of 100 mg/L applying a 2-day period of magnetic stirring followed by a filtration through a 0.45 µm membrane filter. The obtained Water Soluble Fraction (WSF) was used as the highest concentration. The lower test concentrations were prepared by subsequent dilutions of the highest concentration in test medium. The final test solutions were all clear and colourless.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Dapnia magna
- Source: In-house laboratory culture with a known history, at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions.
- Age at study initiation (mean and range, SD): young daphnids with an age of < 24 hours, from parental daphnids of more than two weeks old.
- Method of breeding: start of each batch with newborn daphnids, i.e. less than 3 days old, by placing about 250 of them into 5 litres of medium in an all-glass culture vessel. Renewal of the cultures: after 7 days of cultivation half of the medium twice a week.
- Feeding during test: no

ACCLIMATION
- Acclimation period: <24 hours
- Acclimation conditions (same as test or not): no, breeding medium is M7
- Type and amount of food: a suspension of fresh water algae
- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

180 mg/L expressed as CaCO3

Test temperature:

19-21 ºC

pH:

7.7-8.2

Dissolved oxygen:

9.1-9.7

Salinity:

Not applicable.

Nominal and measured concentrations:

Nominal: Solutions containing 1.0, 10 and 100% of a WSF prepared at a loading rate of 100 mg/l.
Measured concentrations were 1.5 and 1.3 mg Sr/L for the 10% WSF at the beginning and end of the test, respectively. For the 100% WSF, measured concentrations were 14 and 13 mg Sr/L at the beginning and end of the test, respectively.

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100 mL, all-glass
- Aeration: None
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 20 for the limit concentration, 10 for the remaining concentrations
- No. of vessels per control (replicates): 20
- Biomass loading rate: 5 per vessel containing 80 mL test solution

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium
- Culture medium different from test medium: Culture medium had extra trace elements, macro nutrients and vitamins added as specified in Medium M7.


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours per day
- Light intensity: not indicated

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility at 24 and 48 hours ; pH and dissolved oxygen at the beginning and at the end of the test. Temperature continuously.

TEST CONCENTRATIONS
- Test concentrations: combined limit/range-finding test: 1.0, 10 and 100% of a WSF prepared at a loading rate of 100 mg/l.

Reference substance (positive control):

yes

Remarks:

Potassiumdichromate

Duration:

48 h

Dose descriptor:

EC50

Basis for effect:

mobility

Remarks on result:

other: EC50 > maximum soluble concentration in test medium

Details on results:

No effects were observed in any of the groups tested besides 10% WSF. The observed immobility in the solutions containing 10% of the WSF was considered not to be dose related as the measured concentration in this group was ten times lower than in the highest concentration where no effects were observed (see table 1 below).

Results with reference substance (positive control):

The 48h-EC50 was 0.29 mg/L with a 95% confidence interval between 0.25 and 0.34 mg/l.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study with Daphnia magna, the 48h-EC50 exceeded the maximum solubility of SrHPO4 in the test medium.

Executive summary:

A 48 -h Acute Toxicity study in Daphnia magna was performed with SrHPO4 according to OECD 202 and in compliance with GLP principles. The test substance solution was prepared as a water soluble fraction of a loading rate of 100 mg/L. The lower test concentrations were prepared by subsequent dilutions of this WSF in test medium. The actual measured concentration was 1.5 and 14 mg Sr/l at the start of the test in the solution containing 10% and the undiluted WSF prepared at a loading rate of 100 mg/l, respectively. The concentrations remained stable during the exposure (86 -95% of initial). The concentration obtained in the undiluted WSF was considered the maximum soluble concentration in the test medium. The 48h-EC50 was considered to exceed the maximum solubility of the test substance in medium.

Description of key information

A 48 -h Acute Toxicity study in Daphnia magna was performed with SrHPO4 according to OECD 202 and in compliance with GLP principles. The test substance solution was prepared as a water soluble fraction of a loading rate of 100 mg/L. Preparation started with a loading rate of 100 mg/L applying a 2-day period of magnetic stirring followed by a filtration through a 0.45 µm membrane filter. The lower test concentrations were prepared by subsequent dilutions of this WSF in test medium. The actual measured concentration was 1.5 and 14 mg Sr/l at the start of the test in the solution containing 10% and the undiluted WSF prepared at a loading rate of 100 mg/l, respectively. The concentrations remained stable during the exposure. The concentration obtained in the undiluted WSF was considered the maximum soluble concentration in the test medium. No substance related effects were observed in any of the groups tested, up to the WSF prepared at 100 mg/L. The 48h-EC50 was considered to exceed the maximum solubility of the test substance in medium.

 

Additional information

Key value for CSA: 48h-EC50 is > the maximum solubility of the test substance in medium