Nitric acid, ammonium calcium salt

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

- Concentrations: control and 100 mg/l
- Sampling method: 10 ml from the approximate centre of the test vessels at t=0h and t=48h
- Sample storage conditions before analysis: stored in a freezer

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions strated with a concentration of 100 mg/l. No special treatment other than careful shaking was necessary to completely soluble in test medium at the concentrations tested.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain: magna
- Source: in-house laboratory culture with a known history
- Age at study initiation (mean and range, SD): < 24 h
- Method of breeding: 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
- Feeding during test: no feeding

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

none

Hardness:

180 mg/l expressed as CaCo3

Test temperature:

18.9 - 19.6 ºC

pH:

7.5 - 7.8 (not varying by more than 1 unit)

Dissolved oxygen:

8.8 - 9.1 mg/l

Nominal and measured concentrations:

Samples were taken for analytical measurement, but it was decided not to include analytical confirmation of actual exposure concentrations, see details on analytical method.

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml, all-glass
- Aeration: No aeration of the test solutions
- No. of organisms per vessel: 5 per vessel containing 80 ml of test solution
- No. of vessels per concentration (replicates): 4 replicates for the highest concentration; 2 replicates for the lower concentrations
- No. of vessels per control (replicates): 4 replicates for the control


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Adjusted ISO medium
- Culture medium different from test medium: yes, for culturing M7 medium is used


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 hours daily


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 10
- Range finding study: study was a combined limit/range finding test
- Test concentrations: 0.1, 1, 10, 100 mg/l

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mobility

Details on results:

No effects on mobility of daphnids were observed in any of the concentrations tested.

Results with reference substance (positive control):

- Results with reference substance valid: yes
- Immobility after 48h: 5% at 0.1 mg/l, 0% at 0.18 mg/l, 15% at 0.32 mg/l, 75% at 0.56 mg/l, 100% at 1.0 mg/l and 100% at 1.8 mg/l
- EC50/LC50: The 48-EC50 was 0.45 mg/l with a 95% confidence interval between 0.35 and 0.56 mg/l.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the present study CN-nitcal did not induce acute immobilisation of Daphnia magna at 100 mg/l after 48 hours of exposure (NOEC).
The 48-EC50 based on nominal concentrations exceeded 100 mg/l, the regulatory concentration.

Description of key information

A reliable study with nitric acid, ammonium calcium salt showed an 48-hr EC50 of >100 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

A study was performed according to OECD 202, EC C.2 guidelines with daphnia magna exposed to nitric acid, ammonium calcium salt, showing an 48 -hr EC50 of >100 mg/L. No effects on mobility of daphnids were observed in any of the concentrations tested.

Samples were taken for analytical measurement, but it was decided not to include analytical confirmation of actual exposure concentrations. Possible analyses could be based on Calcium, Ammonium and/or Nitrate. However, analysis of actual exposure concentrations was not performed as the test substance consisted of inorganic salts, which are partly present in the test medium (Calcium and Ammonium) or could only be analysed by a non-specific spectrophotometric analytical method (Nitrate). Results were based on nominal concentrations and as the test substance was well soluble and the inorganic salts present in the test substance are all known to be stable in aquatic media.