Registration Dossier

Administrative data

Endpoint:
short-term toxicity to fish
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to OECD guideline 203, EU 92/69/EEC, C.1, U.S Toxic Substances Control Act Test Guidelines. 40 CFR 797.1400 and in accordance with Good Laboratory Pracice (GLP).
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 203 (Fish, Acute Toxicity Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.1 (Acute Toxicity for Fish)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OTS 797.1400 (Fish Acute Toxicity Test)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): n-propyl propionate
- Molecular formula: C6H12O2
- Physical state: liquid
- Analytical purity: 99.96%
- Lot/batch No.: QC1355V1C1

Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0 (water control), 2.33, 3.89, 6.48, 10.8, 18.0, and 30.0 mg n-propyl propionate/L

Test solutions

Vehicle:
no
Details on test solutions:
For the definitive test, two replicate aquaria were prepared in laboratory dilution water (LDW) at each of six nominal (target) exposure concentrations of 2.33, 3.89, 6.48, 10.8, 18.0, and 30.0 mg npropyl propionate/L, in addition to two aquaria each of control laboratory dilution water.
Aquaria were replenished on a regular intermittent cycle with test solutions delivered from a flow-through proportional diluter.

Test organisms

Test organisms (species):
Oncorhynchus mykiss (previous name: Salmo gairdneri)
Details on test organisms:
TEST ORGANISM
- Common name: Rainbow trout (Oncorhynchus mykiss)
- Strain: Walbaum
- Source: Osage Catfisheries Inc., Osage Beach, Missouri.
- Length at study initiation (length definition, mean, range and SD): 4.3 ± 0.2 cm
- Weight at study initiation (mean and range, SD): 0.683 ± 0.134 g
- Feeding during test: Yes
- Food type: standard diet (Aquatic Diet Number 1 Lot #218452, Harlan-Teklad, Madison, Wisconsin)
- Frequency: at least once daily

ACCLIMATION
- Acclimation period: atleast 7 days
- Acclimation conditions (same as test or not): yes
- Type and amount of food: standard diet (Aquatic Diet Number 1 Lot #218452, Harlan-Teklad, Madison, Wisconsin)
- Feeding frequency: at least once daily

Study design

Test type:
flow-through
Water media type:
not specified
Limit test:
no
Total exposure duration:
96 h
Post exposure observation period:
Not applicable

Test conditions

Hardness:
88–92 mg/L CaCO3
Test temperature:
12.8–13.9°C
pH:
7.2–7.4
Dissolved oxygen:
7.0–8.8 (7.8 ± 0.5), averaged 76% of saturation and remained greater than or equal to 68% over the 96-hour exposure period
Salinity:
No data
Nominal and measured concentrations:
Nominal concentrations: 0 (water control), 2.33, 3.89, 6.48, 10.8, 18.0, and 30.0 mg npropyl propionate/L.
Measured concentrations: less than the lowest level quantified of 0.244 mg/L for the water control and 1.73, 2.86, 5.73, 9.20, 15.5, and 26.7 mg/L for the treatment solutions.
Details on test conditions:
TEST SYSTEM
- Test vessel: Test aquaria were constructed of double-strength glass held together with clear silicone adhesive and measured approximately 30 x 15.5 x 12.5 cm.
- Type: Each vessel had a cover and a Nitex (Tetko, Elmsford, New York) screen-covered drain guard
- Material, size, headspace, fill volume: approximately 3.7-L
- Aeration: No
- Type of flow-through : proportional diluter
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
- Biomass loading rate: The resulting average instantaneous biological loading rate was 0.9-g fish/L of test solution and the average standard loading rate (based on total solution flow in a 24-hour period) was 0.06-g fish/L/day

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The laboratory dilution water (LDW) is Lake Huron water supplied to The Dow Chemical Company by the City of Midland Water Treatment Plant. The water is obtained from the upper Saginaw Bay of Lake Huron near Whitestone Point and is limed and flocculated with ferric chloride. The water is pumped to the laboratory prior to treatment for municipal use.
- Total organic carbon: <2000 microgram/L
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Photoperiod: 16-hour light/8-hour dark

TEST CONCENTRATIONS
- Range finding study: Yes
- Results used to determine the conditions for the definitive study: yes
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
10.8 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 9.53–12.3 mg/L
Duration:
96 h
Dose descriptor:
NOEC
Effect conc.:
2.86 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
Fish were observed and any mortality and sublethal effects recorded at 24, 48, 72, and 96 hours of exposure. All biological results are expressed in terms of mean measured concentrations of n-propyl propionate. Sublethal effects were observed down through the 5.73 mg/L dose level during the conduct of this 96-hour exposure study and included lethargy, partial and complete loss of equilibrium, exophthalmia, and immobility.
Mortality following 24 hours of exposure was observed in 100% (10/10) of the fish at the 26.7 mg/L dose level. Mortality was observed in 90% (9/10)and 100% (10/10) of the fish at the 15.5 mg/L dose level following 48 and 72 hours of exposure, respectively.
Following 96 hours of exposure, mortality was observed in 20% (2/10) of the fish at the 9.20 mg/L dose level. Therefore, fish mortality, as a result from 96-hours of exposure (test termination), totaled 100% (10/10), 100% (1/10), and 20% (2/10) for fish exposed at the 26.7 mg/L, 15.5 mg/L, and
9.20 mg/L dose levels, respectively.
No fish mortality was observed in any of the remaining treatment or control solutions during the conduct of this study.
The 24-hour LC50 value was 20.3 mg/L with a Spearman-Karber trim of 0.0%; no reliable 95% confidence interval could be determined.
The 48-hour LC50 value was 12.6 mg/L, with a 95% confidence interval of 11.4-13.9 mg/L; the Spearman-Karber trim was 0.0%.
The 72-hour LC50 value was 11.9 mg/L with a Spearman-Karber trim of 0.0%; no reliable 95% confidence interval could be determined.
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
Standard statistical methods were employed

Any other information on results incl. tables

Preliminary study-

A 72-hour probe study was conducted under flowthrough conditions. The study was conducted with one replicate of five fish per dose level exposed to nominal test concentrations of 0 (water control), 17.5, 29.2, 48.6, 81.0, 135, and 225 mg n-propyl propionate/L. The study was terminated on day 3 since the npropyl propionate vessel feeding the diluter emptied sometime between the evening of day 2 and day 3 of the study. However, sufficient information was obtained from this probe study and a repeat probe study not deemed necessary.

Following ~72-hours of exposure, mortality was observed in 100% of the fish at the 29.2, 48.6, 81.0, 135, and 225 mg/L dose levels. No mortalities or sublethal effects were observed in the 17.5 mg/L dose level or the water control during the conduct of the study.

The information derived from this study was used to set the range of concentrations for the definitive test.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the study, the 96-hour LC50 of n-propyl propionate for fish was 10.8 mg/L, with a 95% confidence interval of 9.53-12.3 mg/L; and the NOEC being 2.86 mg/L.
Executive summary:

The purpose of this study was to evaluate the acute toxicity of n-propyl propionate to the rainbow trout (Oncorhynchus mykiss) over a 96-hour flow-through exposure period. These data were used to calculate 24-, 48-, 72-, and 96-hour LC50 values and a 96-hour no-observed-effect concentration or NOEC.

The study was conducted with two groups of five fish exposed to nominal test concentrations of 0 (water control), 2.33, 3.89, 6.48, 10.8, 18.0, and 30.0 mg n-propyl propionate/L, over a 96-hour exposure period. Observations were made every 24 hours for mortality. These data were statistically evaluated, where applicable, using mean measured n-propyl propionate concentrations.

Based on mean measured concentrations, the 96-hour LC50 of n-propyl propionate for fish was 10.8 mg/L, with a 95% confidence interval of 9.53-12.3 mg/L; and the NOEC being 2.86 mg/L.