Sodium azide

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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

See details below.

Deviations:

no

GLP compliance:

no

Specific details on test material used for the study:

Chemicals should be readily and easily available in a purified form. Sodium azide is available in a purified or technical grade from five companies.

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

No information available.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Age at study initiation (mean and range, SD):
- Length at study initiation (length definition, mean, range and SD): 7.32 ± 0.68 (exp. 1), 7.87 ± 0.84 (exp. 2), and 8.57 ± 1.12 (exp. 3)
- Weight at study initiation (mean and range, SD): 4.76 ± 1.36 (exp. 1), 6.07 ± 1.96 (exp. 2), and 7.84 ± 3.41 (exp. 3)

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Remarks on exposure duration:

mortality checks at: 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4, 5, 6, 7, 13, 24, 48, 72, and 96 h

Hardness:

Hardness (Ca, Mg) = 76

Test temperature:

15 °C

pH:

7.7 ± 0.1 (exp. 1 & 2), 7.7 ± 0.2 (exp. 3)

Dissolved oxygen:

9.6 ± 0.3 (exp. 1), 9.5 ± 0.4 (exp. 2), and 9.3 ± 0.8 (exp. 3)

Conductivity:

165 ± 6 µmho/cm²

Nominal and measured concentrations:

5 concentrations used in the bioassay were in 75 % proportional ranges (i.e. 10 mg/L, 7.5 mg/L, 5.625 mg/L, 4.219 mg/L, 3.164 mg/L; or 10 single concentrations used in the bioassay were in 75 % proportional ranges (10 mg/L, 7.5 mg/L, 5.625 mg/L, 4.219 mg/L, 3.164 mg/L, 2.373 mg/L, 1.778 mg/L, 1.335 mg/L, 1.001 mg/L, 0.075 mg/L).

Details on test conditions:

TEST SYSTEM
- Material, size, headspace, fill volume: 20 L vessel
- Aeration: Continuous with airstone
- Type of flow-through (e.g. peristaltic or proportional diluter): proportional diluter, 95 % replacement time in 17 hours
- Renewal rate of test solution (frequency/flow rate): 60 mL/min
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- Biomass loading rate: 2.38 g/L (exp. 1), 3.04 (exp. 2), and 3.92 (exp. 3)

TEST MEDIUM / WATER PARAMETERS
- Source: Winnipeg city tap water
- Metals: Sodium: 1.7 ± 0.2 mg/L; Potassium: 1.4 ± 0.1 mg/L; Magnesium: 5.1 ± 0.1 mg/L
- Chlorine: 5.0 ± 0.7 mg/L
- Ca/Mg ratio: 22.1 ± 0.5 mg/L

Reference substance (positive control):

yes

Remarks:

Phenol

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

10.52 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 1

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2.75 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 1

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

7.09 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 2

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

2.84 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 2

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

9.6 mg/L

Nominal / measured:

estimated

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 3

Remarks:

calculated by the straight-line graphical interpolation method

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

3.28 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Remarks on result:

other: Experiment 3

Reported statistics and error estimates:

With the exception of the 24 hour value in experiment 3, an adequate number of data points were obtained in the bioassays to use the log-probit method of Finney to calculate the LC50 values. The 24 hour value in experiment 3 was calculated by the straight-line graphical interpolation method.

Validity criteria fulfilled:

yes

Conclusions:

LC50 values for the 3 experiments for 24h results were: 10.52, 7.09, and 9.60 mg/L. LC50 values for the 3 experiments for 96h results were: 2.75, 2.84, and 3.28 mg/L. LC50 results for all three experiments fulfilled criteria for Chronic Aquatic Cat. 2 to O. mykiss in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

Executive summary:

In three separate 96-h acute toxicity studies, rainbow trout (Oncorhynchus mykiss) were exposed to sodium azide at nominal concentrations of 0 (control), 10 , 7.5, 5.625, 4.219, 3.164, 2.373, 1.778, 1.335, 1.001, and 0.075 mg/L under flow-through conditions. The 96-h LC50 were 2.75, 2.84, and 3.28 mg/L.  Based on the results of this study, sodium azide would be classified as Chronic Aquatic Cat. 2 to O. mykiss in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).
This toxicity study is classified as acceptable and satisfies the guideline requirement for fish acute toxicity studies.

Results synopsis

Test organism size/age (mean wet weight or length): 4.76 g ± 1.36 (exp. 1), 6.07 g ± 1.96 (exp. 2), and 7.84 g ± 3.41 (exp. 3) and 7.32 cm ± 0.68 (exp. 1), 7.87 cm ± 0.84 (exp. 2), and 8.57 cm ± 1.12 (exp. 3)

Test type: Flow-through

LC50: 2.96 mg/L (mean of three experiments)

Endpoint(s) effected: Mortality

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

A well documented publication which meet basic scientific principles, basic data given - even if not in conformity with nowadays technical guidelines and without analytical dose verification - the results and methods reported allow a ranking and comparison of about 1888 chemicals, but have significant methodological deficiencies regarding assessment of the endpoint short-term toxicity to fish.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

no guideline followed

Principles of method if other than guideline:

In order to conduct a piscicide screening program 2552 identical assays have been performed comparing effects on 1888 chemicals upon four fish species, i.e. Northern Squawfish (Ptychocheilus oregonensis), wildlife Chinook Salmon (Oncorhynchus tschawytscha), fish farm Coho Salmon (Oncorhynchus kisutch), fish farm Steelhead Salmo gairdneri (new name: Oncorhynchus mykiss).
The origin of the chemicals is documented and published. Standard conditions applied to the treatment test animals (trapping, transport),
acclimatisation, exposure, test item concentration and endpoint determination (i.e. time until loss of equilibrium and mortality).
Surface waters from five different and referenced sources have been used. Basic characterisation (pH, alkalinity and hardness) are reported, but some data are lacking.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

n.a.

Vehicle:

yes

Details on test solutions:

Most chemicals tested have been dissolved in minimal amounts of water or acetone before they have been added to the assay vessels.
Since sodium azide is highly water soluble (about 410 mg/L) it is assumend the dissolution in water has been applied to this test item.

Test organisms (species):

Oncorhynchus kisutch

Details on test organisms:

TEST ORGANISM
- Common name: coho salmon
- Strain: n.a.
- Source: Eagle Creek National Fish Hatchery, Oregon
- Age at study initiation (mean and range, SD): Not reported, but may be estimated according to their lengh
- Length at study initiation (length definition, mean, range and SD): The fish were about 5 to 10 cm long
- Weight at study initiation (mean and range, SD): not reported, but estimated on the biomass load (5 g/L) the test vessel water amount (4 L) and the number of organisms per vessel (3) a mean weight of 7 g is assumed
- Method of breeding: n.a., wildlife animals
- Feeding during test: No


ACCLIMATION
- Acclimation period: 3 - 24 h, mostly at least overnight
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: fich were starved during acclimatisation
- Feeding frequency: no feeding
- Health during acclimation (any mortality observed): not reported


QUARANTINE (wild caught): The fish were stored at 12-14 °C in a large wooden vat supplied with spring water
- Duration: no information given
- Health/mortality: none

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

24 h

Post exposure observation period:

none

Hardness:

Given in Table 1.

Test temperature:

9.4 to 20.6 °C

pH:

7.2

Dissolved oxygen:

not reported

Salinity:

Given in Table 1.

Nominal and measured concentrations:

Three independent tests at nominal concentrations of 10 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: a series of insulated, round steel tubs (0.61 m in diameter x 0.3 m deep) were used for water baths.
These tubs were served by a common refrigerated reservoir trough which temperature-controlled water was recirculated.
Each tub held four aerated 9.5-liter plastic aquaria lined with a disposable polyethylene poultry bag (0.3 m x 0.2m x 0.0 m deep). The bag was closed at the top to prevent the fish from escaping.
- Aeration: Yes, by a single stone air braker
- Type of flow-through (e.g. peristaltic or proportional diluter): no flow-trough conditions for exposure (static)
- Renewal rate of test solution (frequency/flow rate): no renewal
- No. of organisms per vessel: 1 (altogether 3 but of three different species)
- No. of vessels per concentration (replicates): not reported, only one is assumed
- No. of vessels per control (replicates): no control group reported
- No. of vessels per vehicle control (replicates): no vehicle control
- Biomass loading rate: 5 g/l


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Rochart Creek
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data
- Alkalinity: no data
- Ca/Mg ratio: no data
- Conductivity: no data
- Culture medium different from test medium: yes
- Intervals of water quality measurement: measured once only


OTHER TEST CONDITIONS
- Adjustment of pH: no adjustmend
- Photoperiod: not reported
- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : time until loss of equilibrium (defined as lost when a fish was no longer able to remain right-side-up) and / or mortality (death was designated when a fish ceased visible movement); observation intervall 30 min


TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable, limit test at 10 ppm
- Justification for using less concentrations than requested by guideline: n.a.
- Range finding study
- Test concentrations: no range finding study was performed
- Results used to determine the conditions for the definitive study: n.a.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

LC100

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: LC100 value based on observations with two individually treated fish; 10 ppm converted to 10 mg/L

Details on results:

- Behavioural abnormalities: None
- Observations on body length and weight: None, but test period too short gathering effects
- Other biological observations: None
- Mortality of control: No control group in the test
- Other adverse effects control: No control group in the test
- Abnormal responses: None
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Not reported
- Effect concentrations exceeding solubility of substance in test medium: No

For further details on results see Table 2 below.

Results with reference substance (positive control):

not conducted

Reported statistics and error estimates:

Nothing to report, since limit study with no observed effects and no analytical control

Sublethal observations / clinical signs:

Table 2: The loss-of-equilibrium and death intervals in hours of coho salmon subjected to small doses of sodium azide.

Concentration	5 mg/L ^a)	10 mg/L ^a)	10 mg/L ^a)	10 mg/L ^a)
Loss-of-equilibrium time	n.t.^d).	-^b)	-	n.t.
Death time	n.t.	0-1	0-1	n.t.
Water ^c)	2	4	1	2
Temp [°F]	58	49	51	69
Temp [°C]	14.4	9.4	10.6	20.6

        ^a)        5 and 10 ppm converted to 5 and 10 mg/L, respectively

^b)       - : no effect observed after 24h

^c)        The numbers in the row “water” refer to the water sources listed in Table 1.

^d)       n.t.: not tested

Validity criteria fulfilled:

not applicable

Remarks:

not tested according to a guideline

Conclusions:

The results of this study show a LC100 (coho salmon, 24h) of 10 ppm (10 mg/L), as two of two fish died at this concentration within 1h.

Executive summary:

In a 24-h acute toxicity study, coho salmon (Oncorhynchus kisutch) were exposed to Sodium azide at nominal concentrations of 0 (control), 10 ppm under static conditions.  The 24-h LC₁₀₀ was 10 ppm. Based on the results of this study, Sodium azide would be classified as Chronic Aquatic Cat. 2 to O. kisutch in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation). 

 

 

This toxicity study is classified as supplementary.

 

Results Synopsis

 

Test organism size/age (mean wet weight or length): 5 to 10 cm

Test Type (Flowthrough, Static, Static Renewal): Static

 

LC₁₀₀:  10 ppm                                                 

Endpoint(s) Effected: mortality, loss of equilibrium

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Qualifier:

equivalent or similar to guideline

Guideline:

other: ASTM standard E729-80

Principles of method if other than guideline:

Acute aquatic toxicity test on bluegill.
Laboratory tests were conducted in 19-L glass or stainless steel vessels containing 15 L of soft reconstituted well water at 12°C, according to the methods outlined by the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975) and ASTM (1980).

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Lepomis macrochirus

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Key result

Duration:

96 h

Dose descriptor:

LC100

Effect conc.:

3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Validity criteria fulfilled:

not specified

Conclusions:

The LC100 (Lepomis macrochirus, 96h) is 3.0 mg/L.

Executive summary:

The short-term aquatic toxicity of 19 different chemicals was assessed in a laboratory experiment to bluegill (Lepomis macrochirus).

For sodium azide, the observed LC₁₀₀ (bluegill, 96h) was 3.0 mg/L. No further information on tested concentrations or resulting mortality were given.

 

Results Synopsis

Test organism age: unclear, wild caught fish
Test type: static
LC100 (96 h) = 3.0 mg/L

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

yes

Remarks:

: toxicant concentrations and oxygen saturation were not measured throughout the assay; only limited information on housing conditions given

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

yes

Test organisms (species):

Pimephales promelas

Details on test organisms:

TEST ORGANISM
- Common name: fathead minnow
- Strain: no data
- Source: no data
- Age at study initiation (mean and range, SD): 30 d
- Length at study initiation (length definition, mean, range and SD): 18.8 mm ± 1.743 mm
- Weight at study initiation (mean and range, SD): 0.098 g ± 0.0303 g
- Method of breeding: no data
- Feeding during test
- Food type: no data
- Amount: no data
- Frequency: no data

ACCLIMATION
- Acclimation period: no data
- Acclimation conditions (same as test or not): no data
- Type and amount of food: no data
- Feeding frequency: no data
- Health during acclimation (any mortality observed): no data

QUARANTINE (wild caught)
- Duration: no data
- Health/mortality: no data

Test type:

not specified

Water media type:

not specified

Limit test:

no

Total exposure duration:

96 h

Hardness:

45.0 ± 0.41 mg/L CaCO3

Test temperature:

24.2 ± 0.15 °C

pH:

7.5 ± 0.0

Dissolved oxygen:

6.7 ± 0.38 mg/L

Nominal and measured concentrations:

Nominal concentrations: 2.8, 4.31, 6.63, 10.2, 15.7 mg/L
An analytical method was not developed for this chemical; therefore, nominal concentrations were used.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

5.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: CL = 5.09-5.87

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

5.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks:

: Affected fish lost schooling behavior, were hypoactive and underreactive to external stimuli, had increased respiration and lost equilibrium prior to death.

Remarks on result:

other: CL = 5.09-5.87

Sublethal observations / clinical signs:

Mortalities:

Hour	Control	2.8 mg/L	4.31 mg/L	6.63 mg/L	10.2 mg/L	15.7 mg/L
Initial (0)	20	20	20	20	20	20
24	0	0	0	0	7	17
48	0	0	0	13	20	20
72	0	0	0	16	20	20
96	0	0	1	18	20	20

 

 

Effect

Hour	Control	2.8 mg/L	4.31 mg/L	6.63 mg/L	10.2 mg/L	15.7 mg/L
Initial (0)	20	20	20	20	20	20
24	0	0	0	4	16	18
48	0	0	0	13	20	20
72	0	0	0	16	20	20
96	0	0	1	18	20	20

 

Validity criteria fulfilled:

not specified

Conclusions:

The LC50 (96h, Pimephales promelas) for sodium azide is 5.46 mg/L.

Executive summary:

In a 96-h acute toxicity study, fathead minnow (Pimephales promelas) were exposed to sodium azide at nominal concentrations of 0 (control), 2.8, 4.31, 6.63, 10.2, 15.7 mg a.i./L under presumably static conditions. The 96-h LC₅₀was 5.46 mg/L.  Based on the results of this study, sodium azide would be classified as not acute toxic, but as chronic 2 to P. promelas in accordance with the classification system of the Regulation (EC) No 1272/2008.

 

This toxicity study is classified as acceptable and satisfies the guideline requirement for acute toxicity studies on fish.

 

Results Synopsis

 

Test organism size/age (mean wet weight or length): length: 18.8 mm ± 1.743 mm, weight: 0.098 g ± 0.0303 g

Test Type (Flowthrough, Static, Static Renewal): presumably static, but not specified

 

LC₅₀:  5.46 mg a.i./L                        

Endpoint(s) Effected: mortality, abnormal behaviour

Reference 5

Endpoint:

short-term toxicity to fish

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

no guideline followed

Principles of method if other than guideline:

no details provided.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

- Weight at study initiation (mean and range, SD): 1.4 g

Total exposure duration:

96 h

Test temperature:

13 °C

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.8 mg/L

Remarks on result:

other: ; rainbow trout

Conclusions:

The LC50 for rainbow trout (Oncorhynchus mykiss) after 96h exposure time was reported to be 0.8 mg/L.

Executive summary:

The LC₅₀ for rainbow trout (Oncorhynchus mykiss) after 96h exposure time was reported to be 0.8 mg/L.

Reference 6

Endpoint:

short-term toxicity to fish

Type of information:

other: handbook data

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

secondary literature

Qualifier:

no guideline followed

Principles of method if other than guideline:

no details provided.

GLP compliance:

no

Test organisms (species):

Lepomis sp.

Details on test organisms:

- Weight at study initiation (mean and range, SD): 0.6 g

Total exposure duration:

96 h

Test temperature:

18 °C

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.68 mg/L

Remarks on result:

other: ; bluegill

Conclusions:

The LC50 (bluegill) after 96h exposure was reported to be 0.68 mg/L.

Executive summary:

The LC₅₀ (bluegill) after 96h exposure was reported to be 0.68 mg/L.

Reference 7

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

A well documented publication which meet basic scientific principles, basic data given - even if not in conformity with nowadays technical guidelines and without analytical dose verification - the results and methods reported allow a ranking and comparison of about 1888 chemicals, but have significant methodological deficiencies regarding assessment of the endpoint short-term toxicity to fish.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

no guideline followed

Principles of method if other than guideline:

In order to conduct a piscicide screening program 2552 identical assays have been performed comparing effects on 1888 chemicals upon four fish species, i.e. Northern Squawfish (Ptychocheilus oregonensis), wildlife Chinook Salmon (Oncorhynchus tschawytscha), fish farm Coho Salmon (Oncorhynchus kisutch), fish farm Steelhead Salmo gairdneri (new name: Oncorhynchus mykiss).
The origin of the chemicals is documented and published. Standard conditions applied to the treatment test animals (trapping, transport), acclimatisation, exposure, test item concentration and endpoint determination (i.e. time until loss of equilibrium and mortality).
Surface waters from five different and referenced sources have been used. Basic characterisation (pH, alkalinity and hardness) are reported, but some data are lacking.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

n.a.

Vehicle:

yes

Details on test solutions:

Most chemicals tested have been dissolved in minimal amounts of water or acetone before they have been added to the assay vessels.
Since sodium azide is highly water soluble (about 410 mg/L) it is assumend the dissolution in water has been applied to this test item.

Test organisms (species):

Ptychocheilus oregonensis

Details on test organisms:

TEST ORGANISM
- Common name: northern squawfish
- Strain: n.a.
- Source: wild caught
- Age at study initiation (mean and range, SD): Not reported, but may be estimated according to their lengh
- Length at study initiation (length definition, mean, range and SD): The fish were about 5 to 10 cm long
- Weight at study initiation (mean and range, SD): not reported, but estimated on the biomass load (5 g/L), the test vessel water amount (4 L), and the number of organisms per vessel (3) a mean weight of 7 g is assumed
- Method of breeding: n.a., wildlife animals
- Feeding during test: No


ACCLIMATION
- Acclimation period: 3 - 24 h, mostly at least overnight
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: fish were starved during acclimatisation
- Feeding frequency: no feeding
- Health during acclimation (any mortality observed): not reported


QUARANTINE (wild caught): The fish were stored at 12-14 °C in a large wooden vat supplied with spring water
- Duration: no information given
- Health/mortality: none

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

24 h

Post exposure observation period:

none

Hardness:

Given in Table 1.

Test temperature:

9.4 to 20.6 °C

pH:

7.2

Dissolved oxygen:

not reported

Salinity:

Given in Table 1.

Nominal and measured concentrations:

Three independent tests at nominal concentrations of 10 ppm and one at a nominal concentration of 5 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: a series of insulated, round steel tubs (0.61 m in diameter x 0.3 m deep) were used for water baths.
These tubs were served by a common refrigerated reservoir trough which temperature-controlled water was recirculated.
Each tub held four aerated 9.5-liter plastic aquaria lined with a disposable polyethylene poultry bag (0.3 m x 0.2m x 0.0 m deep). The bag was closed at the top to prevent the fish from escaping.
- Aeration: Yes, by a single stone air braker
- Type of flow-through (e.g. peristaltic or proportional diluter): no flow-trough conditions for exposure (static)
- Renewal rate of test solution (frequency/flow rate): no renewal
- No. of organisms per vessel: 1 (altogether 3 but of three different species)
- No. of vessels per concentration (replicates): not reported, only one is assumed
- No. of vessels per control (replicates): no control group reported
- No. of vessels per vehicle control (replicates): no vehicle control
- Biomass loading rate: 5 g/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Rochart Creek
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data
- Alkalinity: no data
- Ca/Mg ratio: no data
- Conductivity: no data
- Culture medium different from test medium: yes
- Intervals of water quality measurement: measured once only


OTHER TEST CONDITIONS
- Adjustment of pH: no adjustment
- Photoperiod: not reported
- Light intensity: not reported


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : time until loss of equilibrium (defined as lost when a fish was no longer able to remain right-side-up) and / or mortality (death was designated when a fish ceased visible movement); observation intervall 30 min.


TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable, limit test at 10 ppm
- Justification for using less concentrations than requested by guideline: n.a.
- Range finding study
- Test concentrations: no range finding study was performed
- Results used to determine the conditions for the definitive study: n.a.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

5 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

behaviour

Remarks:

mo mortality occurred

Remarks on result:

other: 5 ppm converted to 5 mg/L

Key result

Duration:

24 h

Dose descriptor:

LC100

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: LC100 value based on observations with three individually treated fish; 10 ppm converted to 10 mg/L

Details on results:

- Behavioural abnormalities: None
- Observations on body length and weight: None, but test period too short gathering effects
- Other biological observations: None
- Mortality of control: No control group in the test
- Other adverse effects control: No control group in the test
- Abnormal responses: Loss of equilibrium
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Not reported
- Effect concentrations exceeding solubility of substance in test medium: No

For details on results see also Table 2 below.

Results with reference substance (positive control):

not conducted

Reported statistics and error estimates:

Nothing to report, since limit study with no observed effects and no analytical control

Sublethal observations / clinical signs:

Table 2: The loss-of-equilibrium and death intervals in hours of northern squawfish subjected to small doses of sodium azide.

Concentration	5 mg/L ^a)	10 mg/L	10 mg/L	10 mg/L
Loss-of-equilibrium time	- ^b)	0-1	-	-
Death time	-	1-4	0-1	12-25
Water ^c)	2	4	1	2
Temp [°F]	58	49	51	69
Temp [°C]	14.4	9.4	10.6	20.6

 

^a)        5 and 10 ppm converted to 5 and 10 mg/mL, respectively

^b)       - : no effect observed after 24h

^c)        The numbers in the row “water” refer to the water sources listed in Table 1.

Validity criteria fulfilled:

not applicable

Remarks:

not tested according to a guideline

Conclusions:

The results of this study show a NOEC (squawfish, 24 h) of 5 mg/L while 10 mg/L can be regarded as LC100 as three of three fish died at this concentration within 25h.

In order to conduct a piscicide screening program 2552 identical assays have been performed comparing effects on 1888 chemicals upon altogether four fish species.
Wildlife northern squawfish (Ptychocheilus oregonensis) and two fish farmed salmonids, i.e. the steelhead (Salmo gairdneri) and the coho salmon (Oncorhynchus kisutch) have been exposed for 24 h to 10 ppm (10 mg/L) test item Sodium azide after an acclimatisation period of several hours. Three 5-10 cm long fish of all three species were exposed together in 4 litre test vessels containing water from Rochard Creek or from St. Maries River. Additionally, squawfish were exposed to 5 and 10 ppm (mg/L) sodium azide in water from Mission Point Spring. The endpoints taken were the time until loss of equilibrium and mortality.
The results revealed no adverse effects on squawfish after 24h in water treated with 5 ppm sodium azide, which can be regarded as NOAEC. A LC100 value of 10 ppm was obtained as three individually treated squawfish died within 25 h.

Executive summary:

In a 24-h acute toxicity study, sqawfish (Ptychocheilus oregonensis) were exposed to sodium azide at nominal concentrations of 0 (control), 10 and 5 ppm under static conditions.  The 24-h LC₁₀₀ was 10 ppm. Based on the results of this study, sodium azide would be classified as Chronic Aquatic Cat. 2 to P. oregonensis in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation). 

 

This toxicity study is classified as supplementary.

 

Results Synopsis

 

Test organism size/age (mean wet weight or length): 5 to 10 cm

Test Type (Flowthrough, Static, Static Renewal): Static

 

LC₁₀₀:  10 ppm                        

NOEC:  5 ppm                            

Endpoint(s) Effected: mortality, loss of equilibrium

Reference 8

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

A well documented publication which meets basic scientific principles; basic data given - even if not in conformity with recent technical guidelines and without analytical dose verification; results and methods reported allow a ranking and comparison of about 1888 chemicals, but have significant methodological deficiencies regarding assessment of the endpoint short-term toxicity to fish.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

no guideline followed

Principles of method if other than guideline:

In order to conduct a piscicide screening program 2552 identical assays have been performed comparing effects on 1888 chemicals upon four fish species, i.e. Northern Squawfish (Ptychocheilus oregonensis), wildlife Chinook Salmon (Oncorhynchus tschawytscha), fish farm Coho Salmon (Oncorhynchus kisutch), fish farm Steelhead Salmo gairdneri (new name: Oncorhynchus mykiss).
The origin of the chemicals is documented and published. Standard conditions applied to the treatment test animals (trapping, transport), acclimatisation, exposure, test item concentration and endpoint determination (i.e. time until loss of equilibrium and mortality).
Surface waters from five different and referenced sources have been used. Basic characterisation (pH, alkalinity and hardness) are reported, but some data are lacking.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

n.a.

Vehicle:

yes

Details on test solutions:

Most chemicals tested have been dissolved in minimal amounts of water or acetone before they have been added to the assay vessels.
Since sodium azide is highly water soluble (about 410 mg/L) it is assumend the dissolution in water has been applied to this test item.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: steelhead
- Strain: n.a.
- Source: Eagle Creek National Fish Hatchery, Oregon
- Age at study initiation (mean and range, SD): Not reported, but may be estimated according to their length
- Length at study initiation (length definition, mean, range and SD): Ca. 5–10 cm
- Weight at study initiation (mean and range, SD): not reported, but estimated on the biomass load (5 g/L) the test vessel water amount (4 L) and the number of organisms per vessel (3) a mean weight of 7 g is assumed
- Method of breeding: n.a., wild animals
- Feeding during test: No

ACCLIMATION
- Acclimation period: 3–24 h, mostly at least overnight
- Acclimation conditions (same as test or not): same as test
- Type and amount of food: fish were starved during acclimatisation
- Feeding frequency: no feeding
- Health during acclimation (any mortality observed): not reported

QUARANTINE (wild caught): The fish were stored at 12–14 °C in a large wooden vat supplied with spring water
- Duration: no information given
- Health/mortality: none

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

24 h

Post exposure observation period:

none

Hardness:

Given in Table 1.

Test temperature:

9.4 to 20.6 °C

pH:

7.2

Dissolved oxygen:

not reported

Salinity:

Given in Table 1.

Nominal and measured concentrations:

Three independent tests at nominal concentrations of 10 ppm and one at a nominal concentration of 5 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: a series of insulated, round steel tubs (0.61 m in diameter, 0.3 m deep) were used for water baths.
These tubs were served by a common refrigerated reservoir trough which temperature-controlled water was recirculated.
Each tub held four aerated 9.5-liter plastic aquaria lined with a disposable polyethylene poultry bag (0.3 × 0.2 × 0.0 m deep). The bag was closed at the top to prevent the fish from escaping.
- Aeration: Yes, by a single stone air braker
- Type of flow-through (e.g. peristaltic or proportional diluter): no flow-trough conditions for exposure (static)
- Renewal rate of test solution (frequency/flow rate): no renewal
- No. of organisms per vessel: 1 (altogether 3 but of three different species)
- No. of vessels per concentration (replicates): not reported, only one is assumed
- No. of vessels per control (replicates): no control group reported
- No. of vessels per vehicle control (replicates): no vehicle control
- Biomass loading rate: 5 g/L

TEST MEDIUM/WATER PARAMETERS
- Source/preparation of dilution water: Rochart Creek
- Total organic carbon: no data
- Particulate matter: no data
- Metals: no data
- Pesticides: no data
- Chlorine: no data
- Alkalinity: no data
- Ca/Mg ratio: no data
- Conductivity: no data
- Culture medium different from test medium: yes
- Intervals of water quality measurement: measured once only

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: not reported
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : time until loss of equilibrium (defined as lost when a fish was no longer able to remain right-side-up) and/or mortality (death was designated when a fish ceased visible movement); observation intervall 30 min.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable, limit test at 10 ppm
- Justification for using less concentrations than requested by guideline: n.a.
- Range finding study: Not performed

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

LC100

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: LC100 value based on observations with two individually treated fish; 10 ppm converted to 10 mg/L

Details on results:

- Behavioural abnormalities: None
- Observations on body length and weight: None, but test period too short gathering effects
- Other biological observations: None
- Mortality of control: No control group in the test
- Other adverse effects control: No control group in the test
- Abnormal responses: Loss of equilibrium
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Not reported
- Effect concentrations exceeding solubility of substance in test medium: No
For further details on results see Table 2 below.

Results with reference substance (positive control):

not conducted

Reported statistics and error estimates:

Nothing to report, since limit study with no observed effects and no analytical control

Sublethal observations / clinical signs:

Table 2: The loss-of-equilibrium and death intervals in hours of steelhead trout subjected to small doses of sodium azide.

Concentration	5 mg/L ^a)	10 mg/L ^a)	10 mg/L ^a)	10 mg/L ^a)
Loss-of-equilibrium time	n.t.^d).	- ^b)	-	n.t.
Death time	n.t.	0–1	0–1	n.t.
Water ^c)	2	4	1	2
Temp [°F]	58	49	51	69
Temp [°C]	14.4	9.4	10.6	20.6

        ^a)        5 and 10 ppm converted to 5 and 10 mg/L, respectively

^b)       -: no effect observed after 24h

^c)        The numbers in the row “water” refer to the water sources listed in Table 1.

^d)       n.t.: not tested

Validity criteria fulfilled:

not applicable

Remarks:

not tested according to a guideline

Conclusions:

The results of this study show a LC100 (steelhead trout, 24 h) of 10 ppm (10 mg/L), since two out of two fish died at this concentration within 1 h.
In order to conduct a piscicide screening program 2552 identical assays have been performed comparing effects on 1888 chemicals upon altogether four fish species.
Wildlife northern squawfish (Ptychocheilus oregonensis) and two fish farmed salmonids, i.e. the steelhead (Salmo gairdneri) and the coho salmon (Oncorhynchus kisutch) have been exposed for 24 h to 10 ppm (10 mg/L) test item sodium azide after an acclimatisation period of several hours. Three 5 to 10 cm long fish of all three species were exposed together in 4 litre test vessels containing water from Rochard Creek or from St. Maries River. Additionally, squawfish were exposed to 5 and 10 ppm (mg/L) sodium azide in water from Mission Point Spring. The endpoints taken were the time until loss of equilibrium and mortality.
The results of this study show a LC100 (steelhead trout, 24h) of 10 ppm (10 mg/L), as two of two fish died at this concentration within 1 h.

Executive summary:

In a 24-h acute toxicity study, fish farm steelhead Salmo gairdneri (new name: Oncorhynchus mykiss) were exposed to sodium azide at nominal concentrations of 0 (control) and 10 ppm under static conditions. The 24-h LC100 was 10 ppm. Based on the results of this study, sodium azide would be classified as Chronic Aquatic Cat. 2 in accordance with Regulation (EC) No 1272/2008 (CLP Regulation).

This toxicity study is classified as supplementary.

Results synopsis

Test organism size/age (mean wet weight or length): 5 to 10 cm

Test type: Static

LC100: 10 ppm

Endpoint(s) effected: mortality, loss of equilibrium

Description of key information

The Klaverkamp et al. (1975) study, is a well-documented flow-through study based on the principles of an OECD 203 acute toxicity test for fish, which also included basic analytical monitoring. The study reported a 96 hour LC₅₀of 2.75 to 3.28 mg/L in rainbow trout (Oncorhynchus mykiss).

Geiger (1987), a well-documented static study based on the principals of an OECD 203 acute toxicity test for fish, determined a 96 hour LC₅₀and EC₅₀of 5.46 mg/L for fathead minnows (Pimephales promelas).

As additional weight of evidence material handbook data lacking methodological details is added to the dossier as well containing 96 h LC₅₀values for O. mykiss (0.8 mg/L) and Lepomis sp. (0.68 mg/L). Furthermore, a study from McPhee and Ruelle (1969) presents 24 h LC₁₀₀ values of 10 mg/L for wildlife northern squawfish (Ptychocheilus oregonensis) and two fish farmed salmonids, i.e. the steelhead (Salmo gairdneri) and the coho salmon (Oncorhynchus kisutch). The study from Bills (1988) revealed a LC₁₀₀value of 3 mg/L for Lepomis macrochirus. Though this study is rated as Klimisch 3 the LC₁₀₀value is in range with the handbook data on Lepomis sp., indicating that Lepomis sp. is the most sensitive genus with a 96 h LC₅₀of 0.68 mg/L.

In a weight of evidence approach, considering  the lowest  LC₅₀value of 0.68 mg/L for Lepomis sp., sodium azide would be classified as Chronic Aquatic Cat. 1 to Lepomis sp. in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

0.68 mg/L