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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study conducted under GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
yes
Remarks:
minor variance in temperature that did not affect results of test
GLP compliance:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Butyronitrile
EC Number:
203-700-6
EC Name:
Butyronitrile
Cas Number:
109-74-0
Molecular formula:
C4H7N
IUPAC Name:
butanenitrile
Details on test material:
- Name of test material (as cited in study report): n-B utyronitrile
- Physical state: Clear, colorless liquid
- Analytical purity: 99.937%
- Lot/batch No.: T-11

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Aliquots (approximately 40-mL) of the exposure solutions were submitted for concentration determinations at times 0 and 48 hours. Exposure concentrations used throughout this report, and in all endpoint calculations, were based on the geometric means of the analyzed values of the test substance exposure solutions at time 0 and 48 hours, averaged over the replicates.

Test solutions

Vehicle:
no
Details on test solutions:
A stock solution of the test substance was prepared in a 200-mL volumetric flask containing laboratory dilution water. The exposure solutions were prepared at a nominal concentration of 120 mg/L by the addition of the appropriate amount of the test substance stock solution to glass vessels containing 20 L of dilution water for the concurrently run minnow test. After the addition of the test substance, the exposure solutions in each test vessel were stirred with a Teflon-coated stir rod. Glass lids were placed on top of the minnow test vessels and sealed with Parafilm. Aliquots (200 mL) of each exposure solution were withdrawn via standpipes positioned at approximately mid-depth of the minnow test vessels and served as exposure solutions for the daphnid test. After the addition of the organisms, the daphnid test vessels were covered with a watch glass and wrapped with parafilm. All test solutions and controls were prepared in replicates of two and submitted for analysis at times 0 and 48 hours.

Test organisms

Test organisms (species):
Daphnia magna
Details on test organisms:
Adult Daphnia magna were reared within 100-L culturing tanks located within the Testing Facility. The gravid daphnids used to produce the test animals for the study were obtained from rearing tanks which had been established for at least two weeks. Prior to the study, approximately 100 gravid daphnids were transferred by net into two glass bowls containing diluent water and food. After approximately 18 hours in these bowls, all adult daphnids were removed by using nets and pipettes.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h

Test conditions

Hardness:
~120 mg/L as CaCO3
Test temperature:
The protocol states the temperature of the test will be held within 20 ± 1 °C. The temperatures of the exposure solutions in all test vessels maintained 22°C throughout the test. This slight increase in temperature did not adversely affect the study.
pH:
8.2 to 8.4
Dissolved oxygen:
8.6 to 8.7 mg/L
Nominal and measured concentrations:
120 mg/L nominal
110 mg/L measured
Details on test conditions:
The acute aquatic effects limit test was performed in 300-mL Pyrex glass lipless beakers with two replicates each for the control and test substance. The test vessels were set in a certified hood and test organisms received approximately 8.5 hours of fluorescent lighting each day of the test. Neonate daphnids were collected by pipette and transferred directly into the exposure vessels. Stratified randomization was accomplished by allocating to each vessel no more than 50% of any one set of test organisms at a time. A total of 10 daphnids were placed into each of the replicate test and control vessels. Observations for signs of immobility and stress were made during this test at times 0, 24, and 48 hours. The temperature, dissolved oxygen concentration, and pH of each exposure solution were measured at times 0 and 48 hours.

Results and discussion

Effect concentrations
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
> 110 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
mobility

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

The acute toxicity of the test substance to Daphnia magna was determined in a 48-hour, static, aquatic effects limit test. The daphnids in the dilution water controls exhibited normal behavior and appearance throughout the test. The 24 and 48-hour EC50 values for Daphnia magna were determined to be> 110 mg/L for pooled replicates A and B. The highest tested concentration causing no significant immobility (~10%) within the period of the test was determined to be 110 mg/L.

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