Magnesium nitrate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

range finding: October 5 to 9, 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on test solutions:

At test initiation, test solutions were prepared by diluting the appropriate amount of test substance into 15 L of dilution water in the test chamber. Nominal total product test concentrations of 6.25, 12.5, 25.0, 50.0, and 100 mg/L were prepared by diluting approximately 0.0938, 0.1875, 0.3750, 0.7500, and 1.5000 grams of the test substance, respectively. The test substance was stirred into solution with a glass rod. The dilution water control was prepared using only dilution water.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
Common name: Rainbow trout
- Strain: Oncorhynchus mykiss
- Source: obtained as fertilized eggs from Troutlodge, Inc., (Sumner, WA) and were reared for approximately five months prior to definitive test initiation.

ACCLIMATION
- Acclimation period: two-day acclimation period
- Acclimation conditions: Approximately 160 fish were removed from the holding tank and placed in acclimation. Acclimation water temperature ranged from 15.0 to 15.6°C.
- Feeding: fish were not fed during acclimation
- Health during acclimation (any mortality observed): no mortality was observed. No diseases were observed or treated during the holding period prior to test initiation.

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Hardness:

Total hardness 146 mg/L as CaCO3, total alkalinity 142 mg/L as CaCO3, and conductivity 310 µS/cm.

Test temperature:

14.6 to 15.4°C

pH:

7.56 to 8.12 in control and treatment solutions during the conduct of the definitive test

Dissolved oxygen:

Dissolved oxygen concentrations were equal to or greater than 9.22 mg/L (equal to or greater than 95% of saturation) at initiation of the definitive test. Dissolved oxygen concentrations ranged from 6.16 to 8.14 mg/L (64 to 84% of saturation) during the remainder of the definitive test.

Nominal and measured concentrations:

Nominal total product test concentrations of 6.25, 12.5, 25.0, 50.0, and 100 mg/L were prepared by diluting approximately 0.0938, 0.1875, 0.3750, 0.7500, and 1.5000 grams of the test substance, respectively.

Details on test conditions:

TEST SYSTEM
- Test vessel: 5-gallon glass jars containing 15 L of control or test solution and covered with clear plastic petri dish covers
- Material, size, headspace, fill volume: The glass jars had measurements of
approximately 47 cm (height) by 26 cm (inside-diameter) with 29 cm solution depth
- No. of organisms per vessel: each chamber contained its complement of five fish (or 10 fish
per treatment)
- No. of vessels per concentration (replicates):duplicate
- No. of vessels per control (replicates):duplicate
- No. of vessels per vehicle control (replicates): (one)
- Biomass loading rate: Instantaneous loading was calculated to be 0.35 g of fish tissue per liter of test solution.

OTHER TEST CONDITIONS
- Adjustment of pH:
- Photoperiod: Fluorescent lighting was maintained on a 16-hour daylight photoperiod with 30-minute simulated dawn and dusk periods.
- Light intensity: The light intensity was measured daily during the definitive test
and ranged from 512 to 526 lux. The light intensity was measured with a LI-COR Model LI-189 light meter equipped with a photometric sensor.

TEST CONCENTRATIONS
- Test concentrations: 0.0 (control), 0.1, 1.0, 10, and 100 mg/L (nominal)
- Results used to determine the conditions for the definitive study: Five fish were tested per treatment. No mortality or sublethal effects were observed in the control or any treatment level following 96-hours of exposure. Based upon the results of this test, nominal total product test concentrations of 6.25, 12.5, 25.0, 50.0, and 100 mg/L were selected for the definitive test.

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: Nominal concentration confirmed by chemical analysis (>80% recovery)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: Nominal concentration confirmed by chemical analysis (>80% recovery)

Details on results:

- Mortality of control: 0%

All toxicity values were determined based on the mean calculated concentrations. No lethal or sublethal effects were noted at the highest concentration tested. Potassium sodium nitrate concentrations were calculated from total nitrate measurements. Measured total ammonium concentrations at the highest concentration tested were < 0.012 and 0.58 mg/L at test initiation and completion, respectively. Measured un-ionized ammonium concentration at the highest concentration tested were < 0.00039 and 0.0062 mg/L, respectively. The measured concentrations of both total and un-ionized ammonia for all control and treatment solutions were included as water quality parameters.

Reported statistics and error estimates:

Statistical analysis of the concentration versus effect data (mortality) was not performed due to the absence of mortality during the definitive test. The slope of the 96-hour dose-response line (log concentration vs. probit) could not be calculated due to the absence of fish mortality.

Validity criteria fulfilled:

yes

Conclusions:

No mortality or sublethal effects.
Nominal 96h-LC50 > 100 mg/L (confirmed by chemical analysis)
NOEC = 100 mg/L

Executive summary:

The acute toxicity of Potassium sodium nitrate to rainbow trout was investigated in a test according to OECD203 and GLP.

Test concentrations were confirmed by chemical analysis (nitrate measurements).

The nominal 96h-LC50 > 100 mg/L and the NOEC is 100 mg/L.

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Fry stage fish were used, which are younger fishes than recommended in OECD 203, but this can be considered as a worst case situation.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

fry stage fish were used, which are younger fishes than recommended in OECD 203 - considered as worst case situation

Principles of method if other than guideline:

Fry stage fish were exposed to a series of concentrations of potassium nitrate using aged tap water kept at 25°C. Tests were conducted in 5 gallon aquaria holding 10 or 20 fish, 6-11 mm in length. Water temperature was kept between 25and 27 °C. Mortality and other observations were made at 24, 48, 72 and 96 hours. Oxygen concentration was controlled daily and found to be maintained at 8.30 mg/L during the experiment. Water hardness varied between 117 and 126 mg/L and the pH between 7.40 and 7.68.

GLP compliance:

no

Analytical monitoring:

yes

Details on test solutions:

A stock solution of 2M potassium nitrate was prepared. From this stock solution the aquaria were dosed in five equal and separate batches through a period of 2h to bring the experimental water to the desired final concentration. This was done to avoid a sudden increase in toxicant concentration.
The test concentrations are not given in the publication.

Test organisms (species):

Poecilia reticulata

Details on test organisms:

TEST ORGANISM
- Strain: Poecilia reticulata
- Age at study initiation (mean and range, SD): Fry stage
- Length: 7.8-8.5 mm
- Feeding during test
- Food type: dried commercial food (TetraMin or Biorell) or brine shrimp hatched from eggs obtained from Mateframe Corporation
- Amount: not mentioned
- Frequency: at least once daily, but usually twice daily

ACCLIMATION
- Acclimation period: 48h - same conditions as test period

Test type:

static

Water media type:

freshwater

Total exposure duration:

96 h

Hardness:

117-126 mg/l CaCO3

Test temperature:

25 - 27 °C

pH:

7.4 - 7.68

Dissolved oxygen:

8.3

Details on test conditions:

TEST SYSTEM
- Test vessel: 5 gallon aquaria
- Material, size, headspace, fill volume: held 141 of water
- Aeration: yes
- Type of flow-through (e.g. peristaltic or proportional diluter):
- No. of organisms per vessel: 10-20

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Columbus tap water

OTHER TEST CONDITIONS
- Adjustment of pH: buffered to bring the phosphate concentration to 10^-3M
- Photoperiod: continuously lighted with fluorescent and incandescent bulbs

EFFECT PARAMETERS MEASURED
- The number of dead fish was observed and recorded several times daily.

TEST CONCENTRATIONS
- Not reported

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

1 378 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

At a nitrate concentration of 200 mg/l N, 50% of the fish died in the first 70h. In the next 7 days no further deaths were observed.

Sublethal observations / clinical signs:

LC₅₀= 191 mg N/L (1378 mg KNO₃/L; 845 mg NO₃/L)

Additional studies with ammonia alone and mixtures of ammonia and potassium nitrate indicated that the toxicities were simply additive except at very low ammonia to nitrate ratios.

Validity criteria fulfilled:

not applicable

Conclusions:

LC50= 191 mg N/L (1378 mg KNO3/L; 845 mg NO3/L)

Executive summary:

In a static study with potassium nitrate performed equivalent to OECD 203, only with fry stage fish (younger fish, considered to be a worst case) were exposed to a series of concentrations of potassium nitrate and nitrate concentrations were measured. Based on the measured concentration of nitrate the LC50 of potassium nitrate was calculated to be 1378 mg/L.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

Experiments were performed in aquariums under static conditions. Study comprised of 5-7 concentrations arranged in arithmetical progression and a control group. Each concentration was tested at 8 or 12 fish. 48-hr LC50 values and 95% confidence interval wee determined. Test was performed twice.

GLP compliance:

not specified

Analytical monitoring:

yes

Details on sampling:

- Sampling method: solutions were replaced every 24h. Before and after change of solutions, oxygen contents, temperature and pH of these solutions were measured.

Vehicle:

yes

Details on test solutions:

- Concentrations: range 50 - 140 mg/L (5-7 concentrations tested in arithmetical progression and one control group)

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISM
- Common name: carp
- Age at study initiation (mean and range, SD): 0+
- Weight at study initiation (mean and range, SD): 33.6 +/- 15.5 g
- Feeding during test: no
- Number of fish: 8-12 fish at each concentration

ACCLIMATION
- Acclimation period: 10-14 days
- Acclimation conditions (same as test or not): not indicated
- Type and amount of food: no
- Health during acclimation (any mortality observed): not indicated

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

not indicated

Hardness:

3.20-3.34 mval

Test temperature:

12.0-15.2 C

pH:

7.2-8.4

Dissolved oxygen:

9.0-9.8 mg/L

Salinity:

14.0-11.0 mg/L Na

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 245 dm3 aquaria
- Aeration: steady
- Renewal rate of test solution (frequency): 24 h


TEST MEDIUM / WATER PARAMETERS
- Total organic carbon: not indicated
- Chlorine: 17.8 - 13.2 mg/L
- Fe: 0.16-0.27 mg/L
- SiO2: 8.8-8.2 mg/L
- SO4: 19.0-13.6 mg/L
- HCO3: 352-170 mg/L
- Mg: 18.0-9.3 mg/L
- Mn: 0.0 mg/L
- Ca: 78.0-52.5 mg/L
- K: 6.4-3.3 mg/L
- Conductivity: 362 - 340 uS/cm

Reference substance (positive control):

yes

Remarks:

negative control group

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

447 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: calculated based on total ammonia

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI 391-513 mg/L

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

> 95 - < 102 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

other: total ammonia

Basis for effect:

mortality (fish)

Remarks on result:

other: 95% CI 83-109 mg/L and 78-134 mg/L)

Validity criteria fulfilled:

yes

Conclusions:

48-h LC50 is 102 mg total ammonia/L equivalent to 480 mg ammonium nitrate/L (95% CI 367-630 mg/L) when 8 fish/concentration were exposed. 48-h LC50 is 95 mg total ammonia/L equivalent to 447 mg ammonium nitrate/L (95% CI 391-513 mg/L) when 12 fish/concentration were exposed.
Conclusion: 48-h LC50 for ammonium nitrate is 447 mg/L (95% CI 391-513 mg/L).

Description of key information

No reliable study with magnesium nitrate is available. Based on reliable studies with ammonium nitrate, potassium sodium nitrate and potassium nitrate, the 96h-LC50 is >100 mg/L for fish. The read-across rationale can be found in the document attached in the target record.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

100 mg/L

Additional information

No reliable study with magnesium nitrate is avialable. In a reliable OECD 203 study in Oncorhynchus mykiss with potassium sodium nitrate, the nominal 96h-LC50 was determined to be >100 mg/L (confirmed by chemical analysis). No lethal or sublethal effects were noted at the highest concentration tested. Potassium sodium nitrate concentrations were calculated from total nitrate measurements. This is confirmed in a study with potassium nitrate, in a static study performed equivalent to OECD 203, only with fry stage fish (younger fish, considered to be a worst case). They were exposed to a series of concentrations of potassium nitrate and nitrate concentrations were measured. Based on the measured concentration of nitrate the 96h-LC50 of potassium nitrate was calculated to be 1378 mg/L. In addition a study with ammonium nitrate in carp is available. The 48h-LC50 of ammonium nitrate was calculated to be 447 mg/L.