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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
Study period:
1997-04-04
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
no guideline followed
Principles of method if other than guideline:
A 96-hour static range-finding test was conducted at nominal concetrations 0.10, 1.0, 10 and 100 mg wm/L prior to performing the definitive test. Five fish were tested at each concentration. After 96 hours of exposure, mortality was zero percent in the control and at all test concentrations. Since no toxicity was observed at concentrations <= 100 mg wm/L, a decision was made to cnoduct a limited definitive test at only the maximum concentration, 100 mg/L, in triplicate.

The 96-hour test was initiated in February 1997 with the impartial addition of fathead minnow, by twos, to all test chambers until 10 fish were distributed to each chamber. The fish were added to the test chambers following the chemical addition and the monitoring of the initial water quality parameters. The test chambers were 1-gallon galss jars (14-cm diameter x 23.5-cm height) containing 3L of dilution water and providing a water depth of approximately 19 cm. All test chambers were covered throughout the exposure period to reduce evaporation. The test chambers were prositioned in a water bath under fluorescent lighting regulated to a photoperiod of 16 hours light and 8 hours darkness. The light intensity ranged between 3.0 and 3.5 microEinsteins per square meter per second.

Survival of fathead minnow was monitored daily and any dead fish observed were removed. Any abnormalities in the behavior or physical appearance of the fathead minnow were also noted. Fish were not fed during the test, nor were test solutions aerated.

The diurnal range of the water bath temperature was continuously monitored using a minimum/maximum thermometer and recorded daily. The pH, temperature, and dissolved oxygen were measured in each test chamber daily. Specific conductivity, total alkalinity, and total hardness of the dilution water were measured at test initiation and termination.
GLP compliance:
yes
Specific details on test material used for the study:
Lot: 96-1
Purity: 80%
Analytical monitoring:
no
Details on sampling:
No chemical measurements of test substance concentrations were conducted. Nominal concentrations were used for the range-finding and definitive tests.
Vehicle:
no
Details on test solutions:
For each triplicate chamber, neat compound (approximately 0.30 grams) was added to 3 liters of dilution water. Dilution water controls maintained concurrently with the test solutions.
Test organisms (species):
Pimephales promelas
Details on test organisms:
Juvenile fathead minnow, Pimephales promelas, used for testing were from Toxikon Environmental Sciences in-house culture. The fathead minnow were hatched on February 3, 1997 and maintained in filtered freshwater with a temperature range of 23.5 to 25.8 °C during the 14-day period prior to test initiation. Holding temperature was 25.4 °C when fish were removed for testing. Fathead minnow were fed brine shimp nauplii, frozen brine shrimp and/or flake food daily during the holding period. Fathead minnow appeared to be in good health at test initiation and mortality during the 7-day period prior to test initiation was 0%. No diseases were observed or treated during the 14-day period prior to test initiation. Fathead minnow were fed until 24 hours prior to test initiation, but were not fed after that time or during the test.

Fathead minnow used for the test ranged from 12 to 20 millimeters (mm) standard lenght and from 0.02 to 0.14 grams wet wieght as measured from the control fish at test termination. Loading was calculated to be 0.22 grams of fish tissue per liter of test solution.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
96 h
Hardness:
72 - 78 mg/L as CaCO3
Test temperature:
21.7 - 23.0 °C
pH:
7.7 (initiation)
6.6 - 6.8 (termination)
Dissolved oxygen:
6.8 - 8.6 mg/L (78 - 100% saturation)
Conductivity:
402 - 417 µmhos/cm
Nominal and measured concentrations:
Nominal: 100 mg/L
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Details on results:
There was no mortality observed at 100 mg/L.
Conclusions:
Mortality of fathead minnow exposed for 96 hours to the test substance was 0% at 100 mg wm/L and in the control. The 96-hour LC50 was > 100 mg/L and the NOEC was 100 mg wm/L based upon the lack of mortality and sublethal effects observed at this concentration.
Executive summary:

In this study, the acute toxicity of the substance to fathead minnow was investigated. A final test was performed based on the results of a preceding range-finding test. Ten fish per test group were exposed to an untreated control and to a single test treatment (100 mg/L). The total test period was 96 hours and under the test conditions, a 96h-LC50 of >100 mg/L was determined, based on nominal concentrations (no mortality observed).

Description of key information

In this study, the acute toxicity of the substance to fathead minnow was investigated. A final test was performed based on the results of a preceding range-finding test.Ten fish per test group were exposed to an untreated control and to a single test treatment (100 mg/L). The total test period was 96 hours and under the test conditions, a 96h-LC50 of >100 mg/L was determined, based on nominal concentrations (no mortality observed).

Key value for chemical safety assessment

LC50 for freshwater fish:
100 mg/L

Additional information