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Ecotoxicological information

Short-term toxicity to fish

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Reference
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:
test procedure in accordance with national standard methods with acceptable restrictions
Qualifier:
according to
Guideline:
other: US EPA Committee on Methods for Toxicity
Version / remarks:
1975
GLP compliance:
no
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source: Eastman Kodak Co.
- Purity: 99%
Analytical monitoring:
yes
Details on sampling:
- Sampling method: All test exposure chambers were sampled at approximately mid-depth at 0 and 96 hours and one of each duplicate exposure chamber at 24, 48 and 72 h additionally.
Vehicle:
no
Test organisms (species):
Pimephales promelas
Details on test organisms:
TEST ORGANISM
- Common name: Fathead minnow
- Source: from Environmental Research Laboratory, Duluth culture
- Age at study initiation (mean and range, SD): 29 days old
- Length at study initiation (length definition, mean, range and SD): 17.4 (±1.53) mm
- Weight at study initiation (mean and range, SD): 0.095 (±0.025) g
- Feeding during test: no
Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
96 h
Hardness:
47 mg/L total hardness (CaCO3)
Test temperature:
24.4°C
pH:
7.34
Dissolved oxygen:
6.5 mg/L
Nominal and measured concentrations:
Nominal: 0, 133, 222, 369, 616 and 1026 mg/L
Measured: <0.7, 120-124, 183-185, 304-310, 532-533, 942-652 mg/L. 100.7% recovery
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: flow-through exposure system, 6.3 L tank volume
- Type of flow-through (e.g. peristaltic or proportional diluter): Continuously proportioning diluter
- Renewal rate of test solution (frequency/flow rate): 3.6 volumes/day
- No. of organisms per vessel: 25
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.377 g/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dechlorinated Laboratory water or Lake Superior water
- Chlorine: 1.2 - 4.1 mg/l- Alkalinity: 40.2 mg/L as CaCO3- Ca/mg ratio: ca. 4:1
- Conductivity: 78 - 138 µmhos/cm
- Intervals of water quality measurement: temperature: daily, dissolved oxygen: after 0, 24 and 96 hours, total hardness: at least once, total alkalinity: at least once, pH: at least once

OTHER TEST CONDITIONS
- Adjustment of pH: The pH of the stock solution was adjusted to that of lake water with HCl.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Observations of fish behaviour, mortality and signs of intoxication were recorded at 2-8, 24, 48, 72 and 96 hours.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: appr. 1.67
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
704 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Behavioural abnormalities: Affected fish lost equilibrium prior to death. Fish in the 616 mg/L tank did not school after 30 hours of exposure.
- Mortality of control: No mortality.
Reported statistics and error estimates:
LC50 and EC50 were estimated using the "trimmed Spearman-Karber" method. Calculations were made for 96 hours of exposure and also for intermediate exposure using mean exposure concentrations of test substance. Russo RC, Thurston RV (1977). Trimmed Sprearman-Karber method for estimating media lethal concentrations in toxicity bioassays, Environ Sci Technol 11: 714-719.

At 96 hours, 100% mortality was observed at the highest dose level. No mortality was seen at other doses or in the control group at 96 hours.

Validity criteria fulfilled:
not applicable
Conclusions:
The 96h LC50 of cyclohexanol to Pimephales promelas was determined to be 704 mg/L, based on measured concentrations.
Executive summary:

A short-term fish toxicity test was performed according to US EPA Committee on Methods for Toxicity (1975) using fathead minnow (Pimephales promelas). Five concentrations were employed: 133, 222, 369, 616 and 1026 mg/L under flow-through conditions. One vessel with 25 fish was exposed per concentration, for up to 96 hours. Observations of fish behaviour, mortality and signs of intoxication were recorded at 2 -8, 24, 48, 72 and 96 hours. At 96 hours, 100% mortality was observed at the highest dose level. No mortality was seen at other doses or in the control group at 96 hours. The LC50 was determined to be 704 mg/L at 96h, based on measured concentrations.

Description of key information

LC50 (96h) = 704 mg/L, fathead minnow, Brooke (1984)

LC50 (96h) = 1382 mg/L, zebrafish embryo, Groth (1993)

Key value for chemical safety assessment

LC50 for freshwater fish:
704 mg/L

Additional information

A short-term fish toxicity test (Brooke 1984) was performed according to US EPA Committee on Methods for Toxicity (1975) using fathead minnow (Pimephales promelas). Five concentrations were employed: 133, 222, 369, 616 and 1026 mg/L. One vessel with 25 fish was exposed per concentration, for up to 96 hours. Observations of fish behaviour, mortality and signs of intoxication were recorded at 2-8, 24, 48, 72 and 96 hours. At 96 hours, 100% mortality was observed at the highest dose level. No mortality was seen at other doses or in the control group at 96 hours. The LC50 was determined to be 704 mg/L at 96h, based on measured concentrations. This study is considered to be relevant, adequate, and reliable for the purposes of classification and risk assessment.

Fertilized zebrafish (Danio rerio) eggs (8-cell stage) were exposed to cyclohexanol at concentrations ranging from 1 -30 mmol/L (ca. 10 -3005 mg/L) for 96 hours (Groth 1993). 12 eggs were used per concentration or control, and up to seven concentration levels were tested. The eggs were observed microscopically for about 96 h until hatching. Developmental stages were determined and marked signs of adverse development, e.g. abnormalities, and deaths were recorded. The aim of the study was to evaluate the embryotoxic and teratogenic effect of the test substance. A 96h NOEL of 300 mg/L and a 96h LC50 of 1382 mg/L could be derived. Exposure to high concentrations of the substance over the duration of the experiment induced certain malformations in the developing fish embryos. This study reported comparable but less severe results than the previous study (Brooke 1994), and it is considered to be supporting information.