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Short-term toxicity to aquatic invertebrates

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Endpoint:
short-term toxicity to aquatic invertebrates
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
Reason / purpose for cross-reference:
reference to same study
Remarks:
Johnson and Finley 1980
Principles of method if other than guideline:
Handling of test organisms and procedures for static toxicity tests followed those described by Lennon and Walker (1964) and Macek and McAllister (1970), and conform well with those recommended by Brauhn and Schoettger (1975) and the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975).
GLP compliance:
not specified
Specific details on test material used for the study:
- Chemical name: sodium azide
- Alternative names: Kazoe, Smite
- Sample description: sodium azide 98 %
Analytical monitoring:
no
Details on sampling:
Sampling method: Stock solutions were prepared immediately before each test.
Vehicle:
yes
Remarks:
Commercial grade acetone was used as the carrier solvent. Occasionally, ethanol or dimethylform amide was substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water.
Details on test solutions:
Test water (dilution water) was reconstituted from deionized water of at least 10E+6 ohms resistivity by the addition of appropriate reagent grade chemicals. When purity of test chemicals was known, all calculated concentrations were based on percent active ingredients.
Test organisms (species):
Gammarus fasciatus
Details on test organisms:
TEST ORGANISM
- Common name: Freshwater shrimp
First instar stage of life cycle
Original stocks of invertebrates were collected and cultured from wild populations with no known source of contamination; these populations were replenished regularly. The invertebrates were cultured in the laboratory by methods similar to those described by Sanders and Cope (1966).
Test type:
static
Water media type:
other: reconstituted from deionized water of at least 10 ohms resistivity
Limit test:
no
Total exposure duration:
48 h
Remarks on exposure duration:
Immobilization tests with invertebrates were conducted for 96 h.
Post exposure observation period:
no data
Hardness:
40 to 50 mg/L as CaCO3
Test temperature:
15 °C
pH:
water was buffered to maintain a pH of 7.2 to 7.5
Dissolved oxygen:
no data
Salinity:
freshwater
Conductivity:
at least 10^6 ohms
Nominal and measured concentrations:
At least six concentrations were used per toxicity test; however, specific concentrations were not provided.
Details on test conditions:
Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. The tests began upon initial exposure to the toxicant. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber was recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times.
Reference substance (positive control):
not specified
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
5 mg/L
Basis for effect:
mobility
Remarks on result:
other: 95 % CI = 3.7-6.8
Reported statistics and error estimates:
Toxicity data were analyzed by a statistical method described by Litchfield and Wilcoxon (1949) to determine the LC50 (theoretical estimate of the concentration lethal to 50 % of the test animals) and 95 % confidence intervals.
Validity criteria fulfilled:
not applicable
Conclusions:
The EC50 for Gammarus fasciatus after 48 h exposure to sodium azide was 5.0 mg/L (95 % CI = 3.7–6.8 mg/L).
Executive summary:

The 48–hr acute toxicity of Sodium azide to Gammarus fasciatus was studied under static conditions. Mortality and immobilization were observed.  The 48–hour LC50was 5.0 mg a.i./L. The sublethal effects included were immobility.

Based on the results of this study, Sodium azide would  be classified as Chronic Aquatic Cat. 2 to G. fasciatus in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

This study is classified as supplementary, because methodological data are not complete (data from handbook).

 

Results Synopsis

Test Organism Age (e.g. 1stinstar): 1stinstar

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

 

LC50/ EC50 : 5.0 mg a.i./L                             95% C.I.:  3.7 to 6.8 mg a.i./L

Endpoint(s) Effected:  mortality, immobilisation

Endpoint:
short-term toxicity to aquatic invertebrates
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
Principles of method if other than guideline:
no data
GLP compliance:
not specified
Analytical monitoring:
not specified
Details on sampling:
no data
Vehicle:
not specified
Details on test solutions:
no data
Test organisms (species):
Daphnia pulex
Details on test organisms:
TEST ORGANISM
- Common name: water flea
Test type:
not specified
Water media type:
not specified
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
no data
Hardness:
no data
Test temperature:
15 °C
pH:
no data
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
no data
Details on test conditions:
no data
Reference substance (positive control):
not specified
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
4.2 mg/L
Basis for effect:
mortality
Remarks on result:
other: CL: 2.8-6.2
Details on results:
no data
Results with reference substance (positive control):
no data
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
not specified
Conclusions:
The LC50 (Daphnia pulex) after 48h exposure to sodium azide was 4.2 mg/L.
Executive summary:

The 48 –hr-acute toxicity of sodium azide to Daphnia pulex was studied under presumably static conditions.  Mortality and immobilization were observed.  The 48 – hour LC50was 4.2 mg/L. The sublethal effects included were immobility.

Based on the results of this study, sodium azide would  be classified as Chronic Aquatic Cat. 2 to D. pulex in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

This study is classified as supplementary, because methodological data are not complete (data from handbook).

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): 1stinstar

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

 

LC50/ EC50 : 4.2 mg/L                     95% C.I.:  2.8 to 6.2 mg/L

Endpoint(s) Effected:  mortality, immobilisation

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
test procedure in accordance with national standard methods with acceptable restrictions
Remarks:
This experiment was part of a larger multi-year study by the State Water Resources Control Board of California. It included multiple species, test conditions, and chemicals. The entire body of work went through extensive peer review. The body of evidence from this multi-year study adds to the reliability of this single study.
Qualifier:
according to guideline
Guideline:
other: EPA/600/R-95-136: Short-term methods for estimating the chronic toxicity of effluents and receiving waters to west coast marine and estuarine organisms
Version / remarks:
In the present study, both length and weight were measured.
Principles of method if other than guideline:
This guideline describes a 7-day semi-static toxicity test using growth and survival juvenile mysids to determine the toxicity of substances in marine waters. The test endpoints are survival and growth.
GLP compliance:
no
Specific details on test material used for the study:
Sodium azide is a cytochrome oxidase inhibitor that was evaluated as a candidate reference toxicant. Sodium azide was presumed to be an appropriate reference toxicant because we anticipated that it might inhibit mysid growth at concentrations lower than those causing significant mortality, therefore providing reference toxicant test data useful for evaluating both endpoints. Three tests were conducted, two range finding tests and a definitive test with more closely spaced toxicant concentrations. Nominal sodium azide concentrations in the definitive test were 0 (control), 10, 18, 32, 56, 100, and 320 pg/L. Azide concentrations were not chemically verified, but the compound is readily soluble and extremely stable in seawater.
Analytical monitoring:
no
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
no data
Test organisms (species):
other aquatic crustacea: Holmesimysis costata
Details on test organisms:
TEST ORGANISM
- Common name: opossum shrimp
- Source: wild caught
- Age at study initiation (mean and range, SD): 3-4 d
- Weight at study initiation (mean and range, SD): no data
- Length at study initiation (length definition, mean, range and SD): no data
- Method of breeding: Gravid females were isolated in the laboratory and placed in a screened compartment within a larger aquarium. Juveniles were collected the following day (day 0) by removing the adults (in the screened compartment) and siphoning the juveniles into another container.
- Feeding during test
- Food type: Artemianauplii and finely ground Tetramin® flake food. Feeding rate was adjusted daily for mortality.


ACCLIMATION
- Acclimation period: 3-4 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: Artemianauplii and finely ground Tetramin® flake food
- Feeding frequency: no data
- Health during acclimation (any mortality observed): no data
Test type:
semi-static
Water media type:
saltwater
Limit test:
no
Total exposure duration:
7 d
Post exposure observation period:
no data
Hardness:
no data
Test temperature:
12 ± 2 °C
pH:
no data
Dissolved oxygen:
60-100 % saturation
Salinity:
33 ± 2 %
Nominal and measured concentrations:
0 (control), 10, 18, 32, 56, 100, and 320 µg/L
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): no data
- fill volume: 200 mL
- Aeration: yes
- Renewal rate of test solution (frequency/flow rate):water renewal at 48 and 96 h by replacing 75 % of the test solution volume.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 5
- No. of vessels per vehicle control (replicates): no data
- Biomass loading rate: no data


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


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16h light, 8h dark
- Light intensity: 100 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : survival and growth (length and mass)


TEST CONCENTRATIONS
- Spacing factor for test concentrations: ca. 1.75 (except for the highest concentration which is 3.2)
- Range finding study: yes
- Test concentrations: no data
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
100 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
7 d
Dose descriptor:
LC50
Effect conc.:
149 µg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
no data
Results with reference substance (positive control):
no data
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
not specified
Conclusions:
The short-term acute toxicity test with sodium azide on marine mysid crustaceae Holmesimysis costata revealed a NOEC of 100 µg/L and a LC50 of 149 µg/L. The aquatic toxicity of sodium azide was assessed using a short-term test on marine mysid crustaceae Holmesimysis costata, according to guideline EPA/600/R-95-136 of the U.S. EPA. Three tests were conducted, two range finding tests and a definitive test with more closely spaced toxicant concentrations. Nominal sodium azide concentrations in the definitive test were 0 (control), 10, 18, 32, 56, 100, and 320 µg/L. Test parameters were survival and growth (mass and length).
Mysids were particularly sensitive to sodium azide. However, sodium azide did not significantly inhibit mysid growth at concentrations below those causing significant mortality. Two preliminary tests with azide found 100% mortality in the low milligram per liter and mid to high microgram per liter range. A third test with concentrations more closely spaced in the 10 to 320 µg/L range resulted in an NOEC of 100 µg/L and an LC50 of 149 µg/L.
Executive summary:

The 7-d toxicity of Sodium azide to Holmesimysis costata (opossum shrimp) was studied under semi-static conditions. Daphnids were exposed to 0 (control), 10, 18, 32, 56, 100, and 320 µg/L for 7 days. Mortality was recorded daily. Growth (mass and length) of the surviving shrimps was measured at test termination. The 7-d LC50 was 149 µg/L. The 7-d NOEC based on mortality was 100 µg/L.

 

Based on the results of this study, Sodium azide would be classified as Chronic Aquatic Cat. 1 and Acute Aquatic Cat. 1 to H. costata in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation). 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): 3-4 d

Test Type (Flowthrough, Static, Static Renewal): semi-static

 

LC50:  149 µg/L                           

NOEL:  100 µg/L        

               

Endpoint(s) Effected:  mortality, growth

Endpoint:
short-term toxicity to aquatic invertebrates
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 wild-caught rusty crayfish.
Crayfish were collected from the wild and were held at least 2 weeks before they were tested. Nineteen chemicals were tested as potential control agents on the basis of their previous use in fisheries or their suspected toxicity to and selectivity for crayfish. 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). Ten crayfish were exposed to each concentration of a chemical, and deaths were recorded daily for 96h. Immobile crayfish were considered dead if they did not respond to probing with a glass rod.
GLP compliance:
no
Analytical monitoring:
no
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
no data
Test organisms (species):
other aquatic crustacea: Orconectes rusticus
Details on test organisms:
TEST ORGANISM
- Common name: rusty crayfish
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
no data
Hardness:
256 CaCO3 (mg/L)
Test temperature:
12 °C
pH:
ca 7.98
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
no data
Details on test conditions:
no data
Reference substance (positive control):
no
Duration:
96 h
Dose descriptor:
LC100
Effect conc.:
1 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
no data
Results with reference substance (positive control):
no data
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
not specified
Conclusions:
The LC100 (Orconectes rusticus, 96h) was 1.0 mg/L in fresh water.
Executive summary:

The 96–hr acute toxicity of Sodium azide to Orconectes rusticus (rusty crayfish) was studied under static conditions. Mortality was observed.  The 96 – hour LC100was 1.0 mg a.i./L.

Based on the results of this study, Sodium azide would be classified as Chronic Aquatic Cat. 1 and Acute Aquatic Cat. 1 to O. rusticus in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

This study is classified as supplementary, because the documentation is insufficient.

 

Results Synopsis

 

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

 

LC100: 1.0 mg a.i./L         

Endpoint(s) Effected:  mortality

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
Red crawfish (Procambarus clarkii) were exposed to sodium azide individually and observations on death were made after each 24h for 96h total exposure duration. Graduated concentrations were used until a maximum of 1 ppm separated the crawfish that lived and the ones that died. These concentrations were verified on at least 5 animals.
GLP compliance:
no
Specific details on test material used for the study:
Technical grade
Analytical monitoring:
no
Details on sampling:
no data
Vehicle:
no
Details on test solutions:
no data
Test organisms (species):
other aquatic crustacea: Procambarus clarkii (Girard)
Details on test organisms:
TEST ORGANISM
- Common name: red crawfish; other names: red swamp crayfish, Louisiana crawfish or Louisiana crayfish
- Strain: no data
- Source: commercial crawfish farm near St. Landry Parish near Cankton, LA
- Age at study initiation (mean and range, SD): no data
- Weight at study initiation (mean and range, SD): 4-10 g
- Length at study initiation (length definition, mean, range and SD): no data
- Method of breeding: no data
- Feeding during test
- Food type: commercial catfish pelletized feed, raw liver, fresh dead fish
- Amount: no data
- Frequency: no data


ACCLIMATION
- Acclimation period: at least 1 week
- Acclimation conditions (same as test or not): 30-gallon aquarium
- Type and amount of food: commercial catfish pelletized water, raw liver, fresh dead fish
- Feeding frequency: no data
- Health during acclimation (any mortality observed): not reported
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
none
Hardness:
no data
Test temperature:
25 °C
pH:
no data
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
1ppm, 0.8 ppm, 0.6 ppm, 0.4 ppm
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: open
- Material, size, headspace, fill volume: one-gallon, wide-mouth glass jars lined with a 6 x 3.5 x 15-inch polyethylene bag (replaced after each test)
- Aeration: containers were placed in wooden racks that held the jars at a 30-degree angle. This allowed the crawfish sufficient shallow water to crawl to the surface, thereby eliminating the necessity of aeration.
- Type of flow-through (e.g. peristaltic or proportional diluter): not applicable
- Renewal rate of test solution (frequency/flow rate): not applicable
- No. of organisms per vessel: 1
- No. of vessels per concentration (replicates): at least 5
- No. of vessels per control (replicates): 1 control per every 4 test vessels
- No. of vessels per vehicle control (replicates): not applicable
- Biomass loading rate: 4-10 g/L, calculated from the values reported (crawfish weight 4-10 g, test vessel size: 1L)


TEST MEDIUM / WATER PARAMETERS
- Sourceof dilution water: Water from Bayou De Siard, a 1215-acre lake adjacent to the laboratory
- 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
- Intervals of water quality measurement: no data


OTHER TEST CONDITIONS
- Adjustment of pH:no data
- Photoperiod:no data
- Light intensity:no data


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality, observation interval: every 24h


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline:
- Range finding study: conducted, but not reported
- Test concentrations: not reported
- Results used to determine the conditions for the definitive study:not reported
Reference substance (positive control):
no
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
>= 0.4 - < 0.6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other:
Remarks:
autotomy
Remarks on result:
other: derived from values for LC0 and LC100
Details on results:
Two formulations of sodium azide were tested. The granular formulation was slightly less toxic to crawfish than the technical formulation. When the mud was added to the containers of both formulations, the toxicities were the same. These toxicities closely agreed with that for the technical sodium azide without mud.
Crawfish that were exposed to sub-lethal concentrations of sodium azide exhibited some irritation. Most of the crawfish held in concentrations of sodium azide from 0.4 ppm to 1 ppm would exhibit autotomy.
Results with reference substance (positive control):
no reference substance used
Reported statistics and error estimates:
no statistic determination reported

Table 1: Results of crawfish bioassays presented in ppm (mg/L).

Observation time

Status

Sodium azide

Sodium azide + muda)

technical

granular

technical

granular

24h

Alive

0.6

0.8

0.8

0.8

Dead

1.0

1.0

1.0

1.0

48h

Alive

0.4

0.8

0.4

0.4

Dead

0.6

1.0

0.6

0.6

72h

Alive

0.4

0.8

0.4

0.4

Dead

0.6

1.0

0.6

0.6

96h

Alive

0.4

0.8

0.4

0.4

Dead

0.6

1.0

0.6

0.6

a)Added 50 grams of mud to container

Validity criteria fulfilled:
no
Conclusions:
The supposed LC50 (crawfish, 48h) is in the range of 0.4-0.6 mg/L.
Executive summary:

The 96–hr acute toxicity of Sodium azide to Procambarus clarkii (crawfish) was studied under static conditions. Crawfish were exposed to control and test chemical at nominal concentration of 0.4, 0.6, 0.8 and 1 ppm for 96 hr.  Mortality and sublethal effects were observed daily. The 96–hr LC100based on mortality was 0.6 ppm. The NOEC for mortality equals 0.4 ppm, though autotomy was recorded as sublethal effect at 0.4 ppm.

 

Based on the results of this study, Sodium azide would be classified as Chronic Aquatic Cat. 1 and Acute Aquatic Cat. 1 to P. clarkii in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation). 

This study is classified as supplementary and does not satisfy the guideline requirements for an acute toxicity study with freshwater invertebrates (missing statistics, study design on replicates is not distinct).

 

Results Synopsis

 

Test Organism Age (e.g. 1stinstar): weight: 4 to 10 g

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

 

LC50:  not determined

LC100: 0.6 ppm

NOEL:  0.4 ppm

Endpoint(s) Effected: mortality

Endpoint:
short-term toxicity to aquatic invertebrates
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
Principles of method if other than guideline:
no data
GLP compliance:
not specified
Analytical monitoring:
not specified
Details on sampling:
no data
Vehicle:
not specified
Details on test solutions:
no data
Test organisms (species):
Simocephalus serrulatus
Details on test organisms:
TEST ORGANISM
- Common name: water flea
Test type:
not specified
Water media type:
not specified
Limit test:
no
Total exposure duration:
48 h
Post exposure observation period:
no data
Hardness:
no data
Test temperature:
15 °C
pH:
no data
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
no data
Details on test conditions:
no data
Reference substance (positive control):
not specified
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
6.4 mg/L
Basis for effect:
mortality
Remarks on result:
other: CL: 4.6-8.9
Details on results:
no data
Results with reference substance (positive control):
no data
Reported statistics and error estimates:
no data
Validity criteria fulfilled:
not specified
Executive summary:

The 48–hr acute toxicity of Sodium azide to Simocephalus sp. was studied under presumably static conditions. Mortality and immobilization were observed. The 48–hour LC50/EC50 was 6.4 mg/L. The sublethal effects included were immobility.

Based on the results of this study, Sodium azide would  be classified as Chronic Aquatic Cat. 2 to Simocephalus sp. in accordance with the Regulation (EC) No 1272/2008 (CLP Regulation).

This study is classified as supplementary, because methodological data are not complete (data from handbook).

 

Results Synopsis

Test Organism Age (e.g. 1stinstar): 1stinstar

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

 

LC50/ EC50 : 6.4 mg/L                     95% C.I.:  4.6 to 8.9 mg/L

Endpoint(s) Effected:  mortality, immobilisation

Description of key information

The LC50 for freshwater aquatic invertebrates range between 0.4 and 6.4 mg/L after 48 h exposure. Species examined were Procambarus clarkii, Daphnia pulex, Simocephalus sp., and Orconectes rusticus. For the marine species Holmesimysis costata a LC50 of 0.15 mg/L was reported after 7 d exposure. The effect concentrations for the sea urchin Paracentrotus lividus were less sensitive. The 48 h LOEC was determined with 6.5 mg/L and the NOEC with 0.65 mg/L.

Five different LC50 values, one LC100 and one NOEC were assessed for this weight of evidence approach. Four of seven values were below 1.0 mg/L (the LC100reported from Bills (1988) was 1.0 mg/L, indicating that the corresponding LC50 must be below 1 mg/L). The LC50 values from Johnson (1980) range from 4.2 to 6.4 mg/L.

The range of the LC-values for freshwater invertebrates are between the classifications into Chronic Aquatic Cat. 1 (concerning results from Bills 1998, Hughes 1966, and Hunt 1996) or Cat. 2 (concerning results from Johnson 1980). As data from Johnson 1980 are handbook data, and the experimental conditions are not described in detail, the data from the mentioned peer reviewed publications are consulted for the classification. Hence Sodium azide would be classified as Chronic Aquatic Cat. 1 to aquatic invertebrates in accordance with the CLP classification system.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
400 µg/L

Marine water invertebrates

Marine water invertebrates
Effect concentration:
150 µg/L

Additional information