reaction mass of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-2H -isothiazol-3-one

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Rohm and Haas, Batch No. 24088

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature
- Stability under test conditions: Stable at room temperature
- Solubility and stability of the test substance in the solvent/vehicle: Soluble and stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dilution in water
- Final dilution of a dissolved solid, stock liquid or gel: 0.10, 0.18, 0.28, 0.41 and 0.70 mg/L

OTHER SPECIFICS: Purity of test material was 14.17%

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.10, 0.18, 0.28, 0.41 and 0.70 mg CMIT/MIT per liter
- Sampling method: Samples were collected from each test vessel at the initiation of the test and from 1 replicate of each concentration at the conclusion of the test. The samples were stored in 40 mL glass bottles and transferred immediately to the analytical laboratory.
- Sample storage conditions before analysis: Stored at 2-4 ºC for 96 hours or less prior to analysis

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Mixing
- Controls: Negative control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Water
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): Not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): No

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

TEST ORGANISM
- Common name: Rainbow trout
- Source: Aquatic Research Organisms division of Resource Analysts, Inc.
- Age at study initiation (mean and range, SD): Juvenile fish
- Length at study initiation (length definition, mean, range and SD): 30.5 mm
- Weight at study initiation (mean and range, SD): 0.52 g

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not): Yes
- Type and amount of food during acclimation: Commercial dry food, ad libitum
- Feeding frequency during acclimation: Daily
- Health during acclimation (any mortality observed): Not described

FEEDING DURING TEST
Not applicable

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Remarks on exposure duration:

n/a

Post exposure observation period:

n/a

Hardness:

40-44 mg/L (as CaCO3)

Test temperature:

11.5-12.8°C (0h), 11.6-12.1°C (48h) and11.8-12.7°C (96h)

pH:

8.0 (0h), 7.8-7.9 (48h) and 8.2 (96h)

Dissolved oxygen:

10.2-10.4 mg/L (0h), 10.4 mg/L (48h) and 10.4-10.6 mg/L (96h)

Salinity:

Not applicable

Conductivity:

Not described

Nominal and measured concentrations:

Nominal (mg CMIT / MIT per liter):0.10, 0.18, 0.28, 0.41 and 0.70
Measured concentrations (mg CMIT/MIT per liter): 0.13, 0.20, 0.31, 0.45 and 0.71

Details on test conditions:

TEST SYSTEM
- Test vessel: Flow-through
-Renewal of test solution: An intermittent flow proportional diluter supplied the test substance to the test vessels. During the test the diluter was activated 773 times, resulting in an average of 6.4 media exchanges per 24 hours in each test vessel.
- Volume of vessel: 19.6 L test aquaria
-Volume/animal: 1.96 L
-Number of vessels/ concentration: 2
-Number of animals/vessel: 10
-Test performed in closed vessels due to significant volatility of TS: No

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: EnviroSystems well water
- Alkalinity: 100-110 mg/L


OTHER TEST CONDITIONS
- Adjustment of pH: No. pH range was variation measured during the conduct of the study.
- Photoperiod: 16 h daylight, 8 h dark
- Light intensity: Cool white fluorescent lights with intensity of 10 µEs-1m-2

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.19 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.13 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: One fish exposed to 0.20 mg CMIT/MIT/L exhibited loss of equilibrium and was gasping at the surface after 72 hours. One fish exhibited loss of equilibrium and erratic swimming after 96 hours.
- Observations on body length and weight: No effects
- Other biological observations: No
- Mortality of control: 5% (1 of 20 fish)
- Other adverse effects control: No
- Abnormal responses: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

The binomial method was used to calculate the 24, 48, 72 and 96 hour median lethal concentrations (LC50s). All calculations were performed using computer methods (Stephan C.E., 1983, Computer program for the calculation of LC50 Values, US EPA, Duluth, Minnesota, USA, Personal communication) and mean measured concentrations of the active ingredient.

Sublethal observations / clinical signs:

Mortality data Test Substance Concentration (mean measured) [mg CMIT/MIT per liter] Mortality Number    24 h         48 h         72 h         96 h Percentage    24 h        48 h         72 h          96 h 0 (water control) 0/20 1/20 1/20 1/20 0 5 5 5 0.13 0/20 0/20 0/20 0/20 0 0 0 0 0.20 1/20 5/20 8/20 11/20 5 25 40 55 0.31 20/20 20/20 20/20 20/20 100 100 100 100 0.45 20/20 20/20 20/20 20/20 100 100 100 100 0.71 20/20 20/20 20/20 20/20 100 100 100 100 Temperature [°C] 12.2-12.9 11.6-12.1 11.5-12.0 11.8-12.7   pH 8.1-8.2 7.8-7.9 8.2 8.2   Oxygen [mg/L] 10.6-10.9 10.4 10.4-11.0 10.4-10.6

Validity criteria fulfilled:

yes

Conclusions:

The 96h LC50 of CMIT/MIT to rainbow trout was determined to be 0.19 mg/L.

Executive summary:

US EPA Guideline 72-1, Acute flow-through 96 h fish study with analytical confirmation of test solution concentrations. At the end of the test, the mortality in the controls does not exceed 10%: one fish in twenty was found immobile in the water controls. Constant conditions are maintained throughout the test. The dissolved oxygen concentration has been at least 60% of the ASV throughout the test. The results were based on mean measured concentrations: 96h NOEC = 0.13 mg a.s./l; 96h LC50= 0.19 mg a.s./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:

Test substance was not analytically determined in the testing solutions

Qualifier:

according to guideline

Guideline:

other: American Society for Testing and Materials Committee E-35 on Pesticides, 1980, Standard practice for conducting basic acute toxicity tests with fishes, macro-invertebrates and amphibians.

Deviations:

yes

Remarks:

The test substance was not analytically determined in the testing solutions.

GLP compliance:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Rohm and Haas, Batch No. TD80-50

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature
- Stability under test conditions: Stable at room temperature
- Solubility and stability of the test substance in the solvent/vehicle: Soluble and stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dilution in water
- Final dilution of a dissolved solid, stock liquid or gel: 0.18, 0.31, 0.50, 0.83, and 1.39 ppm

OTHER SPECIFICS: Purity of test material was 13.9%

Analytical monitoring:

no

Details on sampling:

n/a

Vehicle:

yes

Details on test solutions:

n/a

Test organisms (species):

Cyprinodon variegatus

Details on test organisms:

TEST ORGANISM
- Common name: Sheepshead minnow
- Source: Hatached and reared at Bionomics Marine Research Laboratory, Pensacola, Florida, USA.
- Age at study initiation (mean and range, SD): Juvenile fish
- Length at study initiation (length definition, mean, range and SD): 4-7 mm standard length.
- Weight at study initiation (mean and range, SD): 3-7 mg wet weight

FEEDING DURING TEST
Not applicable

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

n/a

Hardness:

Not described

Test temperature:

21 °C

pH:

7.4 – 8.0

Dissolved oxygen:

58 – 87 %

Salinity:

22 ppt

Conductivity:

Not described

Nominal and measured concentrations:

Nominal (CMIT / MIT ppm or mg/liter) active substance: 0.18, 0.31, 0.50, 0.83, and 1.39 ppm
The test substance was not analytically determined in the testing solutions.

Details on test conditions:

TEST SYSTEM
- Test vessel: Static system
- Material, size, headspace, fill volume: 3.8 L glass jars
- Aeration: Yes
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Sea water pumped from Big Lagoon, a Gulf of Mexico estuary
- Alkalinity: 190-195 mg/L
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Adjustment of pH: Not described
- Photoperiod: Not described
- Light intensity: Not described

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality at 24, 48, 72 and 96h

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

0.3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.18 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Details on results:

- Behavioural abnormalities: No effects
- Observations on body length and weight: No effects
- Other biological observations: No
- Mortality of control: 0%
- Other adverse effects control: No
- Abnormal responses: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: No

Reported statistics and error estimates:

The binomial test for estimating LC50 was applied (Stephan, C.E. (1977) ‘Methods for Calculating an LC50’, Aquatic Toxicology and Hazard Evaluation, ASTM STP 634, F.L. Mayer and J.L. Hamelink, Editors, pp. 65-84, American Society for Testing and Materials).

Validity criteria fulfilled:

yes

Conclusions:

Based on the results of this study, CMIT/MIT is very toxic to aquatic organisms, with a 96-h LC50 of 0.30 mg/L.

Executive summary:

This study was conducted in compliance with: American Society for Testing and Materials Committee E-35 on Pesticides, 1980, Standard practice for conducting basic acute toxicity tests with fishes, macroinverrtebrates and amphibians, acute 96-hour static marine fish study. At the end of the test, the mortality in the controls does not exceed 10%: any fish in twenty is found immobile in the water controls. Constant conditions are maintained throughout the test. The dissolved oxygen concentration has been at least 60% of the ASV throughout the test. As the test substance concentrations are not analyzed, theresults are based on nominal concentrations: 96h NOEC = 0.18 mg a.s./l; 96h LC50= 0.30 mg a.s./l.

Description of key information

The results of the key study indicated that exposure of the rainbow trout to CMIT/MIT resulted

in a 96-hour median lethal concentration (LC50) of 0.19 mg a.i./L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.19 mg/L

Marine water fish

Marine water fish

Effect concentration:

0.3 mg/L